TY  - CONF
AU  - Jovanović, Vladimir P.
AU  - Tomović, Aleksandar
AU  - Dražić, Miloš
AU  - Djurišić, Ivana
AU  - Žikić, Radomir
PY  - 2023
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/2169
AB  - Here in this talk, we propose the simultaneous measurement of rectification and amplitude of tunneling current during electrical probing of a molecule in a nanogap for efficient single-molecule detection. Also, we suggest the application of nitrogen-terminated graphene or CNT nanogaps due to their inherent outstanding features. With DFT and Non-Equilibrium Green's Function formalism, we show that tunneling current through various molecules, including ssDNA, TATP, or small organics placed in those nanogaps, exhibits unique rectification behavior under square pulses of alternating bias. The rectification arises by on-off switching of electronic transport through the molecular HOMO or LUMO levels, sustained by partial charging of the probed molecule, generated by asymmetric hybridization of that level with Bloch states from one of the electrodes. An effect that mimics local gating, i. e. an interaction between the molecule and the nitrogen-induced dipole moment located at the N-C interface of the electrode ends, strongly influences the rectification. The simultaneous measurement of rectification and amplitude of tunneling current could be applied to gas-phase single-molecule detection, as shown in the example case of the TATP. The TATP (triacetone triperoxide) is a volatile, potent, and hard-to-detect explosive made from commonly available chemicals, a terrorist weapon of choice in the last two decades. The rectification could also be applied in the liquid phase, offering the possibility of high-throughput and precise DNA sequencing. We found that the environment (neighboring nucleotides, water molecules, and counterions) does not mask ssDNA rectification while ssDNA traverses the nanogap.
PB  - Institute of Physics Belgrade
C3  - The 21st Symposium on Condensed Matter Physics - SFKM 2023, Belgrade
T1  - Single-Molecule Probing By Rectification in a Nanogap
SP  - 74
UR  - https://hdl.handle.net/21.15107/rcub_rimsi_2169
ER  - 

@conference{
author = "Jovanović, Vladimir P. and Tomović, Aleksandar and Dražić, Miloš and Djurišić, Ivana and Žikić, Radomir",
year = "2023",
abstract = "Here in this talk, we propose the simultaneous measurement of rectification and amplitude of tunneling current during electrical probing of a molecule in a nanogap for efficient single-molecule detection. Also, we suggest the application of nitrogen-terminated graphene or CNT nanogaps due to their inherent outstanding features. With DFT and Non-Equilibrium Green's Function formalism, we show that tunneling current through various molecules, including ssDNA, TATP, or small organics placed in those nanogaps, exhibits unique rectification behavior under square pulses of alternating bias. The rectification arises by on-off switching of electronic transport through the molecular HOMO or LUMO levels, sustained by partial charging of the probed molecule, generated by asymmetric hybridization of that level with Bloch states from one of the electrodes. An effect that mimics local gating, i. e. an interaction between the molecule and the nitrogen-induced dipole moment located at the N-C interface of the electrode ends, strongly influences the rectification. The simultaneous measurement of rectification and amplitude of tunneling current could be applied to gas-phase single-molecule detection, as shown in the example case of the TATP. The TATP (triacetone triperoxide) is a volatile, potent, and hard-to-detect explosive made from commonly available chemicals, a terrorist weapon of choice in the last two decades. The rectification could also be applied in the liquid phase, offering the possibility of high-throughput and precise DNA sequencing. We found that the environment (neighboring nucleotides, water molecules, and counterions) does not mask ssDNA rectification while ssDNA traverses the nanogap.",
publisher = "Institute of Physics Belgrade",
journal = "The 21st Symposium on Condensed Matter Physics - SFKM 2023, Belgrade",
title = "Single-Molecule Probing By Rectification in a Nanogap",
pages = "74",
url = "https://hdl.handle.net/21.15107/rcub_rimsi_2169"
}

Jovanović, V. P., Tomović, A., Dražić, M., Djurišić, I.,& Žikić, R.. (2023). Single-Molecule Probing By Rectification in a Nanogap. in The 21st Symposium on Condensed Matter Physics - SFKM 2023, Belgrade
Institute of Physics Belgrade., 74.
https://hdl.handle.net/21.15107/rcub_rimsi_2169

Jovanović VP, Tomović A, Dražić M, Djurišić I, Žikić R. Single-Molecule Probing By Rectification in a Nanogap. in The 21st Symposium on Condensed Matter Physics - SFKM 2023, Belgrade. 2023;:74.
https://hdl.handle.net/21.15107/rcub_rimsi_2169 .

Jovanović, Vladimir P., Tomović, Aleksandar, Dražić, Miloš, Djurišić, Ivana, Žikić, Radomir, "Single-Molecule Probing By Rectification in a Nanogap" in The 21st Symposium on Condensed Matter Physics - SFKM 2023, Belgrade (2023):74,
https://hdl.handle.net/21.15107/rcub_rimsi_2169 .

TY  - THES
AU  - Djurišić, Ivana
PY  - 2022
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/1855
AB  - Sekvenciranje DNK sledeće generacije (pouzdano, brzo i jeftino i imamogućnost očitavanja sekvence lanaca dužine jednog hromozoma), značajno je zaprimene u zdravstvu, naročito u personalizovanoj medicini, biotehnologiji i bezbednosti,sa mogućim dubokim uticajem na društvo. Pristupi zasnovani na nanoporama pojavilisu se kao platforme za sekvenciranje DNK i proteina, gde varijacija jonske struje tokomelektroforetičke translokacije jednolančane DNK (jDNK) kroz nanoporu dekodirasekvencu nukleotida. Uprkos napretku, izazovi u rezoluciji i očitavanju dugačkih lanacazahtevaju nove pristupe. Zarad povećanja rezolucije, nanoelektrode se mogu postavitina obodima nanopore da bi se iskoristila transverzalna elektronska struja tuneliranjakroz nukleotide i unakrsno korelalisala sa jonskom radi pouzdanijeg očitavanja.U ovoj disertaciji [1,2,3] izučavane su elektronske i transportne osobinenukleotida u nanoprocepu između elektroda od ugljeničnih nanocevi terminisanihazotom u cilju njihove moguće primene u sekvenciranju jDNK koristeći teorijufunkcionala gustine i formalizam neravnotežne Grinove funkcije. Na osnovu numeričkiizračunate I-V karakteristike za različite nukleotide predloženo je da se rektifikacijastruje (odgovor na kvadratne pulseve naizmeničnog napona) nukleotida koristi kaodobar parametar za očitavanje sekvence DNK koji poseduje rezoluciju od jednognukleotida zbog svoje visoke selektivnosti i robustnosti orijentacije molekula u odnosuna elektrode. Rektifikacija nastaje zbog naponske zavisnosti asimetrije otpora nainterfejsima nukleotid-elektroda. Asimetrija indukuje naelektrisavanje molekula i to daenergija HOMO prati promenu elektrohemijskog potencijala jedne od elektroda,potpomognuto efektom električnog polja unutar procepa izazvanog dipolima nakrajevima elektroda.
AB  - Next-generation DNA sequencing (reliable, fast, and inexpensive, and capableof reading a single-chromosome-size chains) is great importance for applications inhealthcare, especially personalized medicine, biotechnology, and security, withpotentially profound societal impacts. Nanopore-based approaches have emerged asplatforms for DNA and protein sequencing, where ionic current variation during singlestrandedDNA (ssDNA) electrophoretic translocation through the nanopore decodes thenucleotide sequence. Despite progress, the challenges in resolving and reading longchains require new approaches. To increase the resolution, side-embeddednanoelectrodes could be placed on nanopore edges to exploit the transverse electronictunneling current through nucleotides and cross-correlate with the ionic current for amore reliable reading.In this dissertation, the electronic and transport properties of nucleotides placedin a nanogap between nitrogen-terminated carbon nanotube electrodes were studied fortheir possible application in ssDNA sequencing using density functional theory andnon-equilibrium Green's function formalism. Based on numerically calculated I-Vcharacteristics for different nucleotides, a current rectification (response to squarepulses of alternating voltage) of nucleotides is proposed as a good parameter for DNAsequence readout with a resolution of one nucleotide due to its high selectivity androbustness to electrode-molecule orientation. Rectification arises because of biasdependentresistance asymmetry at the nucleotide-electrode interfaces. The asymmetryinduces molecular charging and the HOMO energy pinning to the electrochemicalpotential of one of the electrodes, assisted by an in-gap electric-field effect caused bydipoles at the terminated electrode ends.
PB  - Универзитет у Београду, Физички факултет
T2  - Универзитет у Београду
T1  - Elektronski transport i rektifikacija transverzalne električne struje kroz DNK nukleotide u nanoprocepu
UR  - https://hdl.handle.net/21.15107/rcub_nardus_20802
ER  - 

@phdthesis{
author = "Djurišić, Ivana",
year = "2022",
abstract = "Sekvenciranje DNK sledeće generacije (pouzdano, brzo i jeftino i imamogućnost očitavanja sekvence lanaca dužine jednog hromozoma), značajno je zaprimene u zdravstvu, naročito u personalizovanoj medicini, biotehnologiji i bezbednosti,sa mogućim dubokim uticajem na društvo. Pristupi zasnovani na nanoporama pojavilisu se kao platforme za sekvenciranje DNK i proteina, gde varijacija jonske struje tokomelektroforetičke translokacije jednolančane DNK (jDNK) kroz nanoporu dekodirasekvencu nukleotida. Uprkos napretku, izazovi u rezoluciji i očitavanju dugačkih lanacazahtevaju nove pristupe. Zarad povećanja rezolucije, nanoelektrode se mogu postavitina obodima nanopore da bi se iskoristila transverzalna elektronska struja tuneliranjakroz nukleotide i unakrsno korelalisala sa jonskom radi pouzdanijeg očitavanja.U ovoj disertaciji [1,2,3] izučavane su elektronske i transportne osobinenukleotida u nanoprocepu između elektroda od ugljeničnih nanocevi terminisanihazotom u cilju njihove moguće primene u sekvenciranju jDNK koristeći teorijufunkcionala gustine i formalizam neravnotežne Grinove funkcije. Na osnovu numeričkiizračunate I-V karakteristike za različite nukleotide predloženo je da se rektifikacijastruje (odgovor na kvadratne pulseve naizmeničnog napona) nukleotida koristi kaodobar parametar za očitavanje sekvence DNK koji poseduje rezoluciju od jednognukleotida zbog svoje visoke selektivnosti i robustnosti orijentacije molekula u odnosuna elektrode. Rektifikacija nastaje zbog naponske zavisnosti asimetrije otpora nainterfejsima nukleotid-elektroda. Asimetrija indukuje naelektrisavanje molekula i to daenergija HOMO prati promenu elektrohemijskog potencijala jedne od elektroda,potpomognuto efektom električnog polja unutar procepa izazvanog dipolima nakrajevima elektroda., Next-generation DNA sequencing (reliable, fast, and inexpensive, and capableof reading a single-chromosome-size chains) is great importance for applications inhealthcare, especially personalized medicine, biotechnology, and security, withpotentially profound societal impacts. Nanopore-based approaches have emerged asplatforms for DNA and protein sequencing, where ionic current variation during singlestrandedDNA (ssDNA) electrophoretic translocation through the nanopore decodes thenucleotide sequence. Despite progress, the challenges in resolving and reading longchains require new approaches. To increase the resolution, side-embeddednanoelectrodes could be placed on nanopore edges to exploit the transverse electronictunneling current through nucleotides and cross-correlate with the ionic current for amore reliable reading.In this dissertation, the electronic and transport properties of nucleotides placedin a nanogap between nitrogen-terminated carbon nanotube electrodes were studied fortheir possible application in ssDNA sequencing using density functional theory andnon-equilibrium Green's function formalism. Based on numerically calculated I-Vcharacteristics for different nucleotides, a current rectification (response to squarepulses of alternating voltage) of nucleotides is proposed as a good parameter for DNAsequence readout with a resolution of one nucleotide due to its high selectivity androbustness to electrode-molecule orientation. Rectification arises because of biasdependentresistance asymmetry at the nucleotide-electrode interfaces. The asymmetryinduces molecular charging and the HOMO energy pinning to the electrochemicalpotential of one of the electrodes, assisted by an in-gap electric-field effect caused bydipoles at the terminated electrode ends.",
publisher = "Универзитет у Београду, Физички факултет",
journal = "Универзитет у Београду",
title = "Elektronski transport i rektifikacija transverzalne električne struje kroz DNK nukleotide u nanoprocepu",
url = "https://hdl.handle.net/21.15107/rcub_nardus_20802"
}

Djurišić, I.. (2022). Elektronski transport i rektifikacija transverzalne električne struje kroz DNK nukleotide u nanoprocepu. in Универзитет у Београду
Универзитет у Београду, Физички факултет..
https://hdl.handle.net/21.15107/rcub_nardus_20802

Djurišić I. Elektronski transport i rektifikacija transverzalne električne struje kroz DNK nukleotide u nanoprocepu. in Универзитет у Београду. 2022;.
https://hdl.handle.net/21.15107/rcub_nardus_20802 .

Djurišić, Ivana, "Elektronski transport i rektifikacija transverzalne električne struje kroz DNK nukleotide u nanoprocepu" in Универзитет у Београду (2022),
https://hdl.handle.net/21.15107/rcub_nardus_20802 .

TY  - JOUR
AU  - Djurišić, Ivana
AU  - Jovanović, Vladimir P.
AU  - Dražić, Miloš
AU  - Tomović, Aleksandar
AU  - Žikić, Radomir
PY  - 2021
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/1493
AB  - The electrical current properties of single-molecule sensing devices based on electronic (tunneling) transport strongly depend on molecule frontier orbital energy, spatial distribution, and position with respect to the electrodes. Here, we present an analysis of the bias dependence of molecule frontier orbital properties at an exemplar case of DNA nucleotides in the gap between H-terminated (3, 3) carbon nanotube (CNT) electrodes and its relation to transversal current rectification. The electronic transport properties of this simple single-molecule device, whose characteristic is the absence of covalent bonding between electrodes and a molecule between them, were obtained using density functional theory and non-equilibrium Green's functions. As in our previous studies, we could observe two distinct bias dependences of frontier orbital energies: the so-called strong and the weak pinning regimes. We established a procedure, from zero-bias and empty-gap characteristics, to estimate finite-bias electronic tunneling transport properties, i.e., whether the molecular junction would operate in the weak or strong pinning regime. We also discuss the use of the zero-bias approximation to calculate electric current properties at finite bias. The results from this work could have an impact on the design of new single-molecule applications that use tunneling current or rectification applicable in high-sensitivity sensors, protein, or DNA sequencing.
PB  - MDPI, Basel
T2  - Nanomaterials
T1  - Predicting Finite-Bias Tunneling Current Properties from Zero-Bias Features: The Frontier Orbital Bias Dependence at an Exemplar Case of DNA Nucleotides in a Nanogap
IS  - 11
VL  - 11
DO  - 10.3390/nano11113021
ER  - 

@article{
author = "Djurišić, Ivana and Jovanović, Vladimir P. and Dražić, Miloš and Tomović, Aleksandar and Žikić, Radomir",
year = "2021",
abstract = "The electrical current properties of single-molecule sensing devices based on electronic (tunneling) transport strongly depend on molecule frontier orbital energy, spatial distribution, and position with respect to the electrodes. Here, we present an analysis of the bias dependence of molecule frontier orbital properties at an exemplar case of DNA nucleotides in the gap between H-terminated (3, 3) carbon nanotube (CNT) electrodes and its relation to transversal current rectification. The electronic transport properties of this simple single-molecule device, whose characteristic is the absence of covalent bonding between electrodes and a molecule between them, were obtained using density functional theory and non-equilibrium Green's functions. As in our previous studies, we could observe two distinct bias dependences of frontier orbital energies: the so-called strong and the weak pinning regimes. We established a procedure, from zero-bias and empty-gap characteristics, to estimate finite-bias electronic tunneling transport properties, i.e., whether the molecular junction would operate in the weak or strong pinning regime. We also discuss the use of the zero-bias approximation to calculate electric current properties at finite bias. The results from this work could have an impact on the design of new single-molecule applications that use tunneling current or rectification applicable in high-sensitivity sensors, protein, or DNA sequencing.",
publisher = "MDPI, Basel",
journal = "Nanomaterials",
title = "Predicting Finite-Bias Tunneling Current Properties from Zero-Bias Features: The Frontier Orbital Bias Dependence at an Exemplar Case of DNA Nucleotides in a Nanogap",
number = "11",
volume = "11",
doi = "10.3390/nano11113021"
}

Djurišić, I., Jovanović, V. P., Dražić, M., Tomović, A.,& Žikić, R.. (2021). Predicting Finite-Bias Tunneling Current Properties from Zero-Bias Features: The Frontier Orbital Bias Dependence at an Exemplar Case of DNA Nucleotides in a Nanogap. in Nanomaterials
MDPI, Basel., 11(11).
https://doi.org/10.3390/nano11113021

Djurišić I, Jovanović VP, Dražić M, Tomović A, Žikić R. Predicting Finite-Bias Tunneling Current Properties from Zero-Bias Features: The Frontier Orbital Bias Dependence at an Exemplar Case of DNA Nucleotides in a Nanogap. in Nanomaterials. 2021;11(11).
doi:10.3390/nano11113021 .

Djurišić, Ivana, Jovanović, Vladimir P., Dražić, Miloš, Tomović, Aleksandar, Žikić, Radomir, "Predicting Finite-Bias Tunneling Current Properties from Zero-Bias Features: The Frontier Orbital Bias Dependence at an Exemplar Case of DNA Nucleotides in a Nanogap" in Nanomaterials, 11, no. 11 (2021),
https://doi.org/10.3390/nano11113021 . .

TY  - JOUR
AU  - Djurišić, Ivana
AU  - Dražić, Miloš
AU  - Tomović, Aleksandar
AU  - Jovanović, Vladimir P.
AU  - Žikić, Radomir
PY  - 2021
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/1412
AB  - The requirement for controllable frontier orbital energy shift in single-molecule devices based on electronic (tunneling) transport yielded several rules for device design that lean on molecular level pinning to the electrochemical potential of nano-electrodes. We previously found that the pinning (designated as the strong pinning) was the consequence of the bias-induced molecular charge accumulation related to the hybridization of the highest occupied molecular orbital (HOMO) with one of the electrodes. However, in the wide bias range, only "partial" pinning (designated as the weak pinning) happens. In this work, we address the bias-induced shift of molecular orbitals in a weak pinning regime, where no hybridization or covalent bonds with electrodes exist. We found using density functional theory coupled with non-equilibrium Green's functions that the energy shift of frontier molecular orbitals of benzene and nicotine, placed between H-terminated (3, 3) CNTs, in weak pinning regime, is driven only by the electrostatic potential energy of an empty gap. For nicotine, whose HOMO and LUMO (lowest unoccupied molecular orbital) are located on different sides of the gap center, we show that the HOMO-LUMO energy gap changes with bias. We developed a theoretical model of a dielectric in a gap to depict this behavior. Application-wise, we expect that the weak pinning effect would be observable in novel single-molecule sensors based on electronic transport and molecular rectifying as long as the system exhibits a non-resonant behavior, and could serve for molecular gap tuning in single-molecule readout such as DNA, RNA and protein sequencing, or harmful single-molecule detection in gas phase.
PB  - Springer, Dordrecht
T2  - Journal of Nanoparticle Research
T1  - Electrostatically driven energy shift of molecular orbitals of benzene and nicotine in carbon nanotube gaps
IS  - 1
VL  - 23
DO  - 10.1007/s11051-021-05139-y
ER  - 

@article{
author = "Djurišić, Ivana and Dražić, Miloš and Tomović, Aleksandar and Jovanović, Vladimir P. and Žikić, Radomir",
year = "2021",
abstract = "The requirement for controllable frontier orbital energy shift in single-molecule devices based on electronic (tunneling) transport yielded several rules for device design that lean on molecular level pinning to the electrochemical potential of nano-electrodes. We previously found that the pinning (designated as the strong pinning) was the consequence of the bias-induced molecular charge accumulation related to the hybridization of the highest occupied molecular orbital (HOMO) with one of the electrodes. However, in the wide bias range, only "partial" pinning (designated as the weak pinning) happens. In this work, we address the bias-induced shift of molecular orbitals in a weak pinning regime, where no hybridization or covalent bonds with electrodes exist. We found using density functional theory coupled with non-equilibrium Green's functions that the energy shift of frontier molecular orbitals of benzene and nicotine, placed between H-terminated (3, 3) CNTs, in weak pinning regime, is driven only by the electrostatic potential energy of an empty gap. For nicotine, whose HOMO and LUMO (lowest unoccupied molecular orbital) are located on different sides of the gap center, we show that the HOMO-LUMO energy gap changes with bias. We developed a theoretical model of a dielectric in a gap to depict this behavior. Application-wise, we expect that the weak pinning effect would be observable in novel single-molecule sensors based on electronic transport and molecular rectifying as long as the system exhibits a non-resonant behavior, and could serve for molecular gap tuning in single-molecule readout such as DNA, RNA and protein sequencing, or harmful single-molecule detection in gas phase.",
publisher = "Springer, Dordrecht",
journal = "Journal of Nanoparticle Research",
title = "Electrostatically driven energy shift of molecular orbitals of benzene and nicotine in carbon nanotube gaps",
number = "1",
volume = "23",
doi = "10.1007/s11051-021-05139-y"
}

Djurišić, I., Dražić, M., Tomović, A., Jovanović, V. P.,& Žikić, R.. (2021). Electrostatically driven energy shift of molecular orbitals of benzene and nicotine in carbon nanotube gaps. in Journal of Nanoparticle Research
Springer, Dordrecht., 23(1).
https://doi.org/10.1007/s11051-021-05139-y

Djurišić I, Dražić M, Tomović A, Jovanović VP, Žikić R. Electrostatically driven energy shift of molecular orbitals of benzene and nicotine in carbon nanotube gaps. in Journal of Nanoparticle Research. 2021;23(1).
doi:10.1007/s11051-021-05139-y .

Djurišić, Ivana, Dražić, Miloš, Tomović, Aleksandar, Jovanović, Vladimir P., Žikić, Radomir, "Electrostatically driven energy shift of molecular orbitals of benzene and nicotine in carbon nanotube gaps" in Journal of Nanoparticle Research, 23, no. 1 (2021),
https://doi.org/10.1007/s11051-021-05139-y . .

TY  - JOUR
AU  - Djurišić, Ivana
AU  - Dražić, Miloš
AU  - Tomović, Aleksandar
AU  - Spasenović, Marko
AU  - Šljivančanin, Zeljko
AU  - Jovanović, Vladimir P.
AU  - Žikić, Radomir
PY  - 2021
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/1405
AB  - Functionalization of electrodes is a wide-used strategy in various applications ranging from single-molecule sensing and protein sequencing, to ion trapping, to desalination. We demonstrate, employing non-equilibrium Green ' s function formalism combined with density functional theory, that single-species (N, H, S, Cl, F) termination of graphene nanogap electrodes results in a strong in-gap electrostatic field, induced by species-dependent dipoles formed at the electrode ends. Consequently, the field increases or decreases electronic transport through a molecule (benzene) placed in the nanogap by shifting molecular levels by almost 2 eV in respect to the electrode Fermi level via a field effect akin to the one used for field-effect transistors. We also observed the local gating in graphene nanopores terminated with different single-species atoms. Nitrogen-terminated nanogaps (NtNGs) and nanopores (NtNPs) show the strongest effect. The in-gap potential can be transformed from a plateau-like to a saddle-like shape by tailoring NtNG and NtNP size and termination type. In particular, the saddle-like potential is applicable in single-ion trapping and desalination devices.
PB  - Wiley-V C H Verlag Gmbh, Weinheim
T2  - Chemphyschem
T1  - Field Effect and Local Gating in Nitrogen-Terminated Nanopores (NtNP) and Nanogaps (NtNG) in Graphene
EP  - 341
IS  - 3
SP  - 336
VL  - 22
DO  - 10.1002/cphc.202000771
ER  - 

@article{
author = "Djurišić, Ivana and Dražić, Miloš and Tomović, Aleksandar and Spasenović, Marko and Šljivančanin, Zeljko and Jovanović, Vladimir P. and Žikić, Radomir",
year = "2021",
abstract = "Functionalization of electrodes is a wide-used strategy in various applications ranging from single-molecule sensing and protein sequencing, to ion trapping, to desalination. We demonstrate, employing non-equilibrium Green ' s function formalism combined with density functional theory, that single-species (N, H, S, Cl, F) termination of graphene nanogap electrodes results in a strong in-gap electrostatic field, induced by species-dependent dipoles formed at the electrode ends. Consequently, the field increases or decreases electronic transport through a molecule (benzene) placed in the nanogap by shifting molecular levels by almost 2 eV in respect to the electrode Fermi level via a field effect akin to the one used for field-effect transistors. We also observed the local gating in graphene nanopores terminated with different single-species atoms. Nitrogen-terminated nanogaps (NtNGs) and nanopores (NtNPs) show the strongest effect. The in-gap potential can be transformed from a plateau-like to a saddle-like shape by tailoring NtNG and NtNP size and termination type. In particular, the saddle-like potential is applicable in single-ion trapping and desalination devices.",
publisher = "Wiley-V C H Verlag Gmbh, Weinheim",
journal = "Chemphyschem",
title = "Field Effect and Local Gating in Nitrogen-Terminated Nanopores (NtNP) and Nanogaps (NtNG) in Graphene",
pages = "341-336",
number = "3",
volume = "22",
doi = "10.1002/cphc.202000771"
}

Djurišić, I., Dražić, M., Tomović, A., Spasenović, M., Šljivančanin, Z., Jovanović, V. P.,& Žikić, R.. (2021). Field Effect and Local Gating in Nitrogen-Terminated Nanopores (NtNP) and Nanogaps (NtNG) in Graphene. in Chemphyschem
Wiley-V C H Verlag Gmbh, Weinheim., 22(3), 336-341.
https://doi.org/10.1002/cphc.202000771

Djurišić I, Dražić M, Tomović A, Spasenović M, Šljivančanin Z, Jovanović VP, Žikić R. Field Effect and Local Gating in Nitrogen-Terminated Nanopores (NtNP) and Nanogaps (NtNG) in Graphene. in Chemphyschem. 2021;22(3):336-341.
doi:10.1002/cphc.202000771 .

Djurišić, Ivana, Dražić, Miloš, Tomović, Aleksandar, Spasenović, Marko, Šljivančanin, Zeljko, Jovanović, Vladimir P., Žikić, Radomir, "Field Effect and Local Gating in Nitrogen-Terminated Nanopores (NtNP) and Nanogaps (NtNG) in Graphene" in Chemphyschem, 22, no. 3 (2021):336-341,
https://doi.org/10.1002/cphc.202000771 . .

TY  - JOUR
AU  - Djurišić, Ivana
AU  - Dražić, Miloš
AU  - Tomović, Aleksandar
AU  - Spasenović, Marko
AU  - Sljivancanin, Zeljko
AU  - Jovanović, Vladimir P.
AU  - Žikić, Radomir
PY  - 2020
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/1346
AB  - Fast, reliable, and inexpensive DNA sequencing is an important pursuit in healthcare, especially in personalized medicine with possible deep societal impacts. Despite significant progress in various nanopore-based sequencing configurations, challenges that remain in resolution and chromosome-size-long readout call for new approaches. Here we found strong rectification in the transversal current during single-stranded DNA translocation through a nanopore with side-embedded N-terminated carbon nanotube electrodes. Employing density functional theory and nonequilibrium Green's function formalisms, we show that the rectifying ratio (response to square pulses of alternating bias) bears high nucleobase specificity. Rectification arises because of bias-dependent resistance asymmetry on the deoxyribonucleotide-electrode interfaces. The asymmetry induces molecular charging and highest occupied molecular orbital pinning to the electrochemical potential of one of the electrodes, assisted by an in-gap electric-field effect caused by dipoles at the terminated electrode ends. We propose the rectifying ratio, due to its order-of-magnitude-difference nucleobase selectivity and robustness to electrode-molecule orientation, as a promising readout quantifier for single-base resolution and chromosome-size-long single-read DNA sequencing. The proposed configurations are within experimental reach from the viewpoint of both nanofabrication and small current measurement.
PB  - Amer Chemical Soc, Washington
T2  - Acs Applied Nano Materials
T1  - DNA Sequencing with Single-Stranded DNA Rectification in a Nanogap Gated by N-Terminated Carbon Nanotube Electrodes
EP  - 3043
IS  - 3
SP  - 3034
VL  - 3
DO  - 10.1021/acsanm.0c00385
ER  - 

@article{
author = "Djurišić, Ivana and Dražić, Miloš and Tomović, Aleksandar and Spasenović, Marko and Sljivancanin, Zeljko and Jovanović, Vladimir P. and Žikić, Radomir",
year = "2020",
abstract = "Fast, reliable, and inexpensive DNA sequencing is an important pursuit in healthcare, especially in personalized medicine with possible deep societal impacts. Despite significant progress in various nanopore-based sequencing configurations, challenges that remain in resolution and chromosome-size-long readout call for new approaches. Here we found strong rectification in the transversal current during single-stranded DNA translocation through a nanopore with side-embedded N-terminated carbon nanotube electrodes. Employing density functional theory and nonequilibrium Green's function formalisms, we show that the rectifying ratio (response to square pulses of alternating bias) bears high nucleobase specificity. Rectification arises because of bias-dependent resistance asymmetry on the deoxyribonucleotide-electrode interfaces. The asymmetry induces molecular charging and highest occupied molecular orbital pinning to the electrochemical potential of one of the electrodes, assisted by an in-gap electric-field effect caused by dipoles at the terminated electrode ends. We propose the rectifying ratio, due to its order-of-magnitude-difference nucleobase selectivity and robustness to electrode-molecule orientation, as a promising readout quantifier for single-base resolution and chromosome-size-long single-read DNA sequencing. The proposed configurations are within experimental reach from the viewpoint of both nanofabrication and small current measurement.",
publisher = "Amer Chemical Soc, Washington",
journal = "Acs Applied Nano Materials",
title = "DNA Sequencing with Single-Stranded DNA Rectification in a Nanogap Gated by N-Terminated Carbon Nanotube Electrodes",
pages = "3043-3034",
number = "3",
volume = "3",
doi = "10.1021/acsanm.0c00385"
}

Djurišić, I., Dražić, M., Tomović, A., Spasenović, M., Sljivancanin, Z., Jovanović, V. P.,& Žikić, R.. (2020). DNA Sequencing with Single-Stranded DNA Rectification in a Nanogap Gated by N-Terminated Carbon Nanotube Electrodes. in Acs Applied Nano Materials
Amer Chemical Soc, Washington., 3(3), 3034-3043.
https://doi.org/10.1021/acsanm.0c00385

Djurišić I, Dražić M, Tomović A, Spasenović M, Sljivancanin Z, Jovanović VP, Žikić R. DNA Sequencing with Single-Stranded DNA Rectification in a Nanogap Gated by N-Terminated Carbon Nanotube Electrodes. in Acs Applied Nano Materials. 2020;3(3):3034-3043.
doi:10.1021/acsanm.0c00385 .

Djurišić, Ivana, Dražić, Miloš, Tomović, Aleksandar, Spasenović, Marko, Sljivancanin, Zeljko, Jovanović, Vladimir P., Žikić, Radomir, "DNA Sequencing with Single-Stranded DNA Rectification in a Nanogap Gated by N-Terminated Carbon Nanotube Electrodes" in Acs Applied Nano Materials, 3, no. 3 (2020):3034-3043,
https://doi.org/10.1021/acsanm.0c00385 . .

TY  - JOUR
AU  - Popov, Igor
AU  - Djurišić, Ivana
AU  - Belic, Milivoj R.
PY  - 2017
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/1061
AB  - Engineering of materials at the atomic level is one of the most important aims of nanotechnology. The unprecedented ability of scanning probe microscopy to address individual atoms opened up the possibilities for nanomanipulation and nanolitography of surfaces and later on of two-dimensional materials. While the state-of-the-art scanning probe lithographic methods include, primarily, adsorption, desorption and repositioning of adatoms and molecules on substrates or tailoring nanoribbons by etching of trenches, the precise modification of the intrinsic atomic structure of materials is yet to be advanced. Here we introduce a new concept, scanning probe microscopy with a rotating tip, for engineering of the atomic structure of membranes based on two-dimensional materials. In order to indicate the viability of the concept, we present our theoretical research, which includes atomistic modeling, molecular dynamics simulations, Fourier analysis and electronic transport calculations. While stretching can be employed for fabrication of atomic chains only, our comprehensive molecular dynamics simulations indicate that nanomanipulation by scanning probe microscopy with a rotating tip is capable of assembling a wide range of topological defects in two-dimensional materials in a rather controllable and reproducible manner. We analyze two possibilities. In the first case the probe tip is retracted from the membrane while in the second case the tip is released beneath the membrane allowing graphene to freely relax and self-heal the pore made by the tip. The former approach with the tip rotation can be achieved experimentally by rotation of the sample, which is equivalent to rotation of the tip, whereas irradiation of the membrane by nanoclusters can be utilized for the latter approach. The latter one has the potential to yield a yet richer diversity of topological defects on account of a lesser determinacy. If successfully realized experimentally the concept proposed here could be an important step toward controllable nanostructuring of two-dimensional materials.
PB  - IOP Publishing Ltd, Bristol
T2  - Nanotechnology
T1  - Designing topological defects in 2D materials using scanning probe microscopy and a self-healing mechanism: a density functional-based molecular dynamics study
IS  - 49
VL  - 28
DO  - 10.1088/1361-6528/aa9679
ER  - 

@article{
author = "Popov, Igor and Djurišić, Ivana and Belic, Milivoj R.",
year = "2017",
abstract = "Engineering of materials at the atomic level is one of the most important aims of nanotechnology. The unprecedented ability of scanning probe microscopy to address individual atoms opened up the possibilities for nanomanipulation and nanolitography of surfaces and later on of two-dimensional materials. While the state-of-the-art scanning probe lithographic methods include, primarily, adsorption, desorption and repositioning of adatoms and molecules on substrates or tailoring nanoribbons by etching of trenches, the precise modification of the intrinsic atomic structure of materials is yet to be advanced. Here we introduce a new concept, scanning probe microscopy with a rotating tip, for engineering of the atomic structure of membranes based on two-dimensional materials. In order to indicate the viability of the concept, we present our theoretical research, which includes atomistic modeling, molecular dynamics simulations, Fourier analysis and electronic transport calculations. While stretching can be employed for fabrication of atomic chains only, our comprehensive molecular dynamics simulations indicate that nanomanipulation by scanning probe microscopy with a rotating tip is capable of assembling a wide range of topological defects in two-dimensional materials in a rather controllable and reproducible manner. We analyze two possibilities. In the first case the probe tip is retracted from the membrane while in the second case the tip is released beneath the membrane allowing graphene to freely relax and self-heal the pore made by the tip. The former approach with the tip rotation can be achieved experimentally by rotation of the sample, which is equivalent to rotation of the tip, whereas irradiation of the membrane by nanoclusters can be utilized for the latter approach. The latter one has the potential to yield a yet richer diversity of topological defects on account of a lesser determinacy. If successfully realized experimentally the concept proposed here could be an important step toward controllable nanostructuring of two-dimensional materials.",
publisher = "IOP Publishing Ltd, Bristol",
journal = "Nanotechnology",
title = "Designing topological defects in 2D materials using scanning probe microscopy and a self-healing mechanism: a density functional-based molecular dynamics study",
number = "49",
volume = "28",
doi = "10.1088/1361-6528/aa9679"
}

Popov, I., Djurišić, I.,& Belic, M. R.. (2017). Designing topological defects in 2D materials using scanning probe microscopy and a self-healing mechanism: a density functional-based molecular dynamics study. in Nanotechnology
IOP Publishing Ltd, Bristol., 28(49).
https://doi.org/10.1088/1361-6528/aa9679

Popov I, Djurišić I, Belic MR. Designing topological defects in 2D materials using scanning probe microscopy and a self-healing mechanism: a density functional-based molecular dynamics study. in Nanotechnology. 2017;28(49).
doi:10.1088/1361-6528/aa9679 .

Popov, Igor, Djurišić, Ivana, Belic, Milivoj R., "Designing topological defects in 2D materials using scanning probe microscopy and a self-healing mechanism: a density functional-based molecular dynamics study" in Nanotechnology, 28, no. 49 (2017),
https://doi.org/10.1088/1361-6528/aa9679 . .

TY  - CHAP
AU  - Tomović, Aleksandar
AU  - Djurišić, Ivana
AU  - Žikić, Radomir
AU  - Pejić, Milan
AU  - Jovanović, Vladimir P.
PY  - 2017
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/1898
AB  - There is an ongoing interest in organic materials due to their application in various organic electronic devices. However stability of organic materials limits their potential use. They are prone to degradation both during the working life and storage. One of the main causes is extrinsic degradation, under the influence of oxygen and moisture. This problem can be solved by encapsulation of devices. However no encapsulation is perfect. This paper presents a study of interaction of thin films of well-known organic blue emitters, namely N,N′-bis(3-methylphenyl)-N,N′-bis(phenyl)benzidine (TPD) and 4,4′-bis(2,2-diphenylvinyl)-1,1′-biphenyl (DPVBi), with UV light in air. Films of both materials are stable in vacuum, but readily degrade in the presence of oxygen. Thus, the necessary condition for interaction (degradation) is the simultaneous presence of UV light and oxygen. Chemical analysis of irradiated films by mass and infrared spectroscopy revealed presence of oxidized species (impurities). These impurities are responsible for increased morphological stability of irradiated films and quenching of photoluminescence (PL). Only small amount of impurities, 0.4 % (0.2 %) for TPD (DPVBi), causes 50 % decrease of PL. This implies a non-trivial mechanism of quenching. For both molecules it was found that distance between impurities is smaller or equal to exciton diffusion length, which is the necessary condition for quenching. Following mechanism of quenching is proposed: exciton diffuses by hopping form one host molecule (DPVBi or TPD) to another through Förster resonant energy transfer in a random walk manner. If, during its lifetime, it comes to proximity of an impurity, a PL quenching process occurs. Findings of this study are important because they show that even a small amount of oxygen that penetrates a blue emitter layer would impair luminescence efficiency of a device. Moreover, the absorption of its own radiation would additionally contribute to the rate of degradation of a device. It is reasonable to expect that transport properties would also be affected when materials are used as a hole-transporting layer in OLEDs.
PB  - Atlantis Press, Paris
T2  - Proceedings of the IV Advanced Ceramics and Applications Conference
T1  - Interaction of UV Irradiation with Thin Films of Organic Molecules
EP  - 347
SP  - 317
DO  - 10.2991/978-94-6239-213-7_23
ER  - 

@inbook{
author = "Tomović, Aleksandar and Djurišić, Ivana and Žikić, Radomir and Pejić, Milan and Jovanović, Vladimir P.",
year = "2017",
abstract = "There is an ongoing interest in organic materials due to their application in various organic electronic devices. However stability of organic materials limits their potential use. They are prone to degradation both during the working life and storage. One of the main causes is extrinsic degradation, under the influence of oxygen and moisture. This problem can be solved by encapsulation of devices. However no encapsulation is perfect. This paper presents a study of interaction of thin films of well-known organic blue emitters, namely N,N′-bis(3-methylphenyl)-N,N′-bis(phenyl)benzidine (TPD) and 4,4′-bis(2,2-diphenylvinyl)-1,1′-biphenyl (DPVBi), with UV light in air. Films of both materials are stable in vacuum, but readily degrade in the presence of oxygen. Thus, the necessary condition for interaction (degradation) is the simultaneous presence of UV light and oxygen. Chemical analysis of irradiated films by mass and infrared spectroscopy revealed presence of oxidized species (impurities). These impurities are responsible for increased morphological stability of irradiated films and quenching of photoluminescence (PL). Only small amount of impurities, 0.4 % (0.2 %) for TPD (DPVBi), causes 50 % decrease of PL. This implies a non-trivial mechanism of quenching. For both molecules it was found that distance between impurities is smaller or equal to exciton diffusion length, which is the necessary condition for quenching. Following mechanism of quenching is proposed: exciton diffuses by hopping form one host molecule (DPVBi or TPD) to another through Förster resonant energy transfer in a random walk manner. If, during its lifetime, it comes to proximity of an impurity, a PL quenching process occurs. Findings of this study are important because they show that even a small amount of oxygen that penetrates a blue emitter layer would impair luminescence efficiency of a device. Moreover, the absorption of its own radiation would additionally contribute to the rate of degradation of a device. It is reasonable to expect that transport properties would also be affected when materials are used as a hole-transporting layer in OLEDs.",
publisher = "Atlantis Press, Paris",
journal = "Proceedings of the IV Advanced Ceramics and Applications Conference",
booktitle = "Interaction of UV Irradiation with Thin Films of Organic Molecules",
pages = "347-317",
doi = "10.2991/978-94-6239-213-7_23"
}

Tomović, A., Djurišić, I., Žikić, R., Pejić, M.,& Jovanović, V. P.. (2017). Interaction of UV Irradiation with Thin Films of Organic Molecules. in Proceedings of the IV Advanced Ceramics and Applications Conference
Atlantis Press, Paris., 317-347.
https://doi.org/10.2991/978-94-6239-213-7_23

Tomović A, Djurišić I, Žikić R, Pejić M, Jovanović VP. Interaction of UV Irradiation with Thin Films of Organic Molecules. in Proceedings of the IV Advanced Ceramics and Applications Conference. 2017;:317-347.
doi:10.2991/978-94-6239-213-7_23 .

Tomović, Aleksandar, Djurišić, Ivana, Žikić, Radomir, Pejić, Milan, Jovanović, Vladimir P., "Interaction of UV Irradiation with Thin Films of Organic Molecules" in Proceedings of the IV Advanced Ceramics and Applications Conference (2017):317-347,
https://doi.org/10.2991/978-94-6239-213-7_23 . .

TY  - JOUR
AU  - Tomović, Aleksandar
AU  - Jovanović, Vladimir P.
AU  - Djurišić, Ivana
AU  - PEJIĆ, MILAN M.
AU  - Cerovski, Viktor
AU  - BLESIĆ, SUZANA M.
AU  - Žikić, Radomir
PY  - 2015
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/1892
AB  - U ovom radu je prikazana studija mehanizma gašenja fotoluminescencije (FL) tankih amorfnih filmova N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)benzidine (TPD) izloženih UV zračenju u vazduhu. TPD je organski molekul koji se često koristi u izradi organskih svetlećih dioda (OLED). Prilikom izlaganja TPD filmova UV zračenju u vazduhu, dolazi do fotooksidacije TPD molekula, te iz tog razloga fotoluminescencija TPD filmova opada eksponencijalno sa vremenom osvetljavanja filmova, odnosno sa povećanjem koncentracije nečistoća nastalih usled fotooksidacije. Intenzitet fotoluminescencije opadne na polovinu svoje početne vrednosti u slučaju kada je 0.4 % nečistoća prisutno u filmu. U tom slučaju je srednje rastojanje između nečistoća (akceptora) šest puta veće od srednjeg rastojanja između TPD molekula (donora). Direktan dugodometni Forsterov transfer energije je odbačen kao mehanizam gašenja fotoluminescencije jer je spektralno preklapanje emisije donora i apsorpcije akceptora zanemarljivo. Iz ovog razloga je postulirana ekscitonska difuzija u TPD filmovima, analogno nalazima u postojećoj literaturi. Prisustvo produkata oksidacije je potvrđeno uz pomoć infracrvene (IR) spektroskopije. Takodje, izračunat je IR spektar koristeći teoriju funkcionala gustine (DFT) i dobijeno je dobro slaganje sa eksperimentalnim rezultatima.
AB  - The mechanism of photoluminescence (PL) quenching of thin amorphous N,N′-bis(3-methylphenyl)- N,N′-bis(phenyl)benzidine (TPD) films exposed to UV light in air is studied. TPD is small organic molecule widely used in production of organic light emmiting devices (OLEDs). Photoluminescence of TPD films decays exponentially with time of irradiation, i.e. with the increase of concentration of impurities (photo-oxidized TPD molecules) generated by UV irradiation in air. Intensity of PL decreases to half of its original value when the concentration of impurities reaches 0.4%. Average distance between impurities (acceptors) is almost an order of magnitude larger than average distance between host TPD molecules (donors). Direct long range Förster energy transfer is ruled out as the mechanism of PL quenching, as the overlap between donor and acceptor is lacking, and exciton self-diffusion in TPD films is postulated for the mechanism. The presence of oxidation products is confirmed by infrared (IR) spectroscopy. Vibrational spectra of TPD molecule and few other possible products of photo-oxidation of TPD molecule, obtained by density functional theory, are compared to experimental IR spectra.
PB  - Savez inženjera i tehničara Srbije, Beograd
T2  - TEHNIKA
T1  - Mehanizam gašenja fotoluminescencije u tankim filmovima N,N′-bis(3- methylphenyl)-N,N′-bis(phenyl)benzidine osvetljenih UV svetlošću u vazduhu
T1  - MECHANISM OF PHOTOLUMINESCENCE QUENCHING IN THIN FILMS OF N,N′-BIS(3- METHYLPHENYL)-N,N′-BIS(PHENYL)BENZIDINE IRRADIATED BY UV LIGHT IN AIR
EP  - 914
IS  - 6
SP  - 909
VL  - 70
DO  - 10.5937/tehnika1506909T
ER  - 

@article{
author = "Tomović, Aleksandar and Jovanović, Vladimir P. and Djurišić, Ivana and PEJIĆ, MILAN M. and Cerovski, Viktor and BLESIĆ, SUZANA M. and Žikić, Radomir",
year = "2015",
abstract = "U ovom radu je prikazana studija mehanizma gašenja fotoluminescencije (FL) tankih amorfnih filmova N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)benzidine (TPD) izloženih UV zračenju u vazduhu. TPD je organski molekul koji se često koristi u izradi organskih svetlećih dioda (OLED). Prilikom izlaganja TPD filmova UV zračenju u vazduhu, dolazi do fotooksidacije TPD molekula, te iz tog razloga fotoluminescencija TPD filmova opada eksponencijalno sa vremenom osvetljavanja filmova, odnosno sa povećanjem koncentracije nečistoća nastalih usled fotooksidacije. Intenzitet fotoluminescencije opadne na polovinu svoje početne vrednosti u slučaju kada je 0.4 % nečistoća prisutno u filmu. U tom slučaju je srednje rastojanje između nečistoća (akceptora) šest puta veće od srednjeg rastojanja između TPD molekula (donora). Direktan dugodometni Forsterov transfer energije je odbačen kao mehanizam gašenja fotoluminescencije jer je spektralno preklapanje emisije donora i apsorpcije akceptora zanemarljivo. Iz ovog razloga je postulirana ekscitonska difuzija u TPD filmovima, analogno nalazima u postojećoj literaturi. Prisustvo produkata oksidacije je potvrđeno uz pomoć infracrvene (IR) spektroskopije. Takodje, izračunat je IR spektar koristeći teoriju funkcionala gustine (DFT) i dobijeno je dobro slaganje sa eksperimentalnim rezultatima., The mechanism of photoluminescence (PL) quenching of thin amorphous N,N′-bis(3-methylphenyl)- N,N′-bis(phenyl)benzidine (TPD) films exposed to UV light in air is studied. TPD is small organic molecule widely used in production of organic light emmiting devices (OLEDs). Photoluminescence of TPD films decays exponentially with time of irradiation, i.e. with the increase of concentration of impurities (photo-oxidized TPD molecules) generated by UV irradiation in air. Intensity of PL decreases to half of its original value when the concentration of impurities reaches 0.4%. Average distance between impurities (acceptors) is almost an order of magnitude larger than average distance between host TPD molecules (donors). Direct long range Förster energy transfer is ruled out as the mechanism of PL quenching, as the overlap between donor and acceptor is lacking, and exciton self-diffusion in TPD films is postulated for the mechanism. The presence of oxidation products is confirmed by infrared (IR) spectroscopy. Vibrational spectra of TPD molecule and few other possible products of photo-oxidation of TPD molecule, obtained by density functional theory, are compared to experimental IR spectra.",
publisher = "Savez inženjera i tehničara Srbije, Beograd",
journal = "TEHNIKA",
title = "Mehanizam gašenja fotoluminescencije u tankim filmovima N,N′-bis(3- methylphenyl)-N,N′-bis(phenyl)benzidine osvetljenih UV svetlošću u vazduhu, MECHANISM OF PHOTOLUMINESCENCE QUENCHING IN THIN FILMS OF N,N′-BIS(3- METHYLPHENYL)-N,N′-BIS(PHENYL)BENZIDINE IRRADIATED BY UV LIGHT IN AIR",
pages = "914-909",
number = "6",
volume = "70",
doi = "10.5937/tehnika1506909T"
}

Tomović, A., Jovanović, V. P., Djurišić, I., PEJIĆ, M. M., Cerovski, V., BLESIĆ, S. M.,& Žikić, R.. (2015). Mehanizam gašenja fotoluminescencije u tankim filmovima N,N′-bis(3- methylphenyl)-N,N′-bis(phenyl)benzidine osvetljenih UV svetlošću u vazduhu. in TEHNIKA
Savez inženjera i tehničara Srbije, Beograd., 70(6), 909-914.
https://doi.org/10.5937/tehnika1506909T

Tomović A, Jovanović VP, Djurišić I, PEJIĆ MM, Cerovski V, BLESIĆ SM, Žikić R. Mehanizam gašenja fotoluminescencije u tankim filmovima N,N′-bis(3- methylphenyl)-N,N′-bis(phenyl)benzidine osvetljenih UV svetlošću u vazduhu. in TEHNIKA. 2015;70(6):909-914.
doi:10.5937/tehnika1506909T .

Tomović, Aleksandar, Jovanović, Vladimir P., Djurišić, Ivana, PEJIĆ, MILAN M., Cerovski, Viktor, BLESIĆ, SUZANA M., Žikić, Radomir, "Mehanizam gašenja fotoluminescencije u tankim filmovima N,N′-bis(3- methylphenyl)-N,N′-bis(phenyl)benzidine osvetljenih UV svetlošću u vazduhu" in TEHNIKA, 70, no. 6 (2015):909-914,
https://doi.org/10.5937/tehnika1506909T . .

TY  - JOUR
AU  - Tomović, Aleksandar
AU  - Jovanović, Vladimir P.
AU  - Djurišić, Ivana
AU  - Cerovski, Viktor
AU  - Nastasijević, Branislav
AU  - Veielović, S. R.
AU  - Radulović, K.
AU  - Žikić, Radomir
PY  - 2015
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/876
AB  - The photoluminescence (PL) quenching mechanism of UV light and air-exposed amorphous thin films of 4,4'-bis(2,2-diphenylvinyl)-1,1'-biphenyl (DPVBi), a well-known hole-transport material used in organic light-emitting diodes, is studied. Thin films of DPVBi are stable when exposed to UV light in vacuum but tend to degrade if oxygen is present simultaneously. This is evident from the changes in UV-vis absorption spectra of the latter, showing that degradation rate of DPVBi films is linearly proportional to both oxygen concentration and UV light intensity. Mass spectrometry study of such films revealed a number of different oxygen-containing molecules and fragments of DPVBi thus confirming apparent photo-oxidation process. Also, DFT study of molecular DPVBi with and without oxygen was carried out, the IR spectra calculated for the lowest energy molecules found and the results are compared with the experiment. The most sensitive to photo-oxidation is DPVBi photoluminescence, which decays exponentially with respect to the concentration of photo-oxidized DPVBi molecules (impurities). The PL quantum yield of DPVBi thin film drops to a half of its original value for 0.2% of the impurities present, at which point an average distance between DPVBi molecules (the donors) and photo-oxidized DPVBi species (acceptors) is an order of magnitude larger than the separation between two adjacent molecules. This implies a need for a long-range Forster energy transfer, which we rule out based on the lack of a donor-acceptor spectral overlap. The apparent discrepancy can be removed by postulating exciton self-diffusion in DPVBi thin films, for which there is supporting evidence in existing literature.
PB  - Elsevier, Amsterdam
T2  - Journal of Luminescence
T1  - Fast photoluminescence quenching in thin films of 4,4 '-bis(2,2-diphenylvinyl)-1,1 '-biphenyl exposed to air
EP  - 210
SP  - 204
VL  - 167
DO  - 10.1016/j.jlumin.2015.06.036
ER  - 

@article{
author = "Tomović, Aleksandar and Jovanović, Vladimir P. and Djurišić, Ivana and Cerovski, Viktor and Nastasijević, Branislav and Veielović, S. R. and Radulović, K. and Žikić, Radomir",
year = "2015",
abstract = "The photoluminescence (PL) quenching mechanism of UV light and air-exposed amorphous thin films of 4,4'-bis(2,2-diphenylvinyl)-1,1'-biphenyl (DPVBi), a well-known hole-transport material used in organic light-emitting diodes, is studied. Thin films of DPVBi are stable when exposed to UV light in vacuum but tend to degrade if oxygen is present simultaneously. This is evident from the changes in UV-vis absorption spectra of the latter, showing that degradation rate of DPVBi films is linearly proportional to both oxygen concentration and UV light intensity. Mass spectrometry study of such films revealed a number of different oxygen-containing molecules and fragments of DPVBi thus confirming apparent photo-oxidation process. Also, DFT study of molecular DPVBi with and without oxygen was carried out, the IR spectra calculated for the lowest energy molecules found and the results are compared with the experiment. The most sensitive to photo-oxidation is DPVBi photoluminescence, which decays exponentially with respect to the concentration of photo-oxidized DPVBi molecules (impurities). The PL quantum yield of DPVBi thin film drops to a half of its original value for 0.2% of the impurities present, at which point an average distance between DPVBi molecules (the donors) and photo-oxidized DPVBi species (acceptors) is an order of magnitude larger than the separation between two adjacent molecules. This implies a need for a long-range Forster energy transfer, which we rule out based on the lack of a donor-acceptor spectral overlap. The apparent discrepancy can be removed by postulating exciton self-diffusion in DPVBi thin films, for which there is supporting evidence in existing literature.",
publisher = "Elsevier, Amsterdam",
journal = "Journal of Luminescence",
title = "Fast photoluminescence quenching in thin films of 4,4 '-bis(2,2-diphenylvinyl)-1,1 '-biphenyl exposed to air",
pages = "210-204",
volume = "167",
doi = "10.1016/j.jlumin.2015.06.036"
}

Tomović, A., Jovanović, V. P., Djurišić, I., Cerovski, V., Nastasijević, B., Veielović, S. R., Radulović, K.,& Žikić, R.. (2015). Fast photoluminescence quenching in thin films of 4,4 '-bis(2,2-diphenylvinyl)-1,1 '-biphenyl exposed to air. in Journal of Luminescence
Elsevier, Amsterdam., 167, 204-210.
https://doi.org/10.1016/j.jlumin.2015.06.036

Tomović A, Jovanović VP, Djurišić I, Cerovski V, Nastasijević B, Veielović SR, Radulović K, Žikić R. Fast photoluminescence quenching in thin films of 4,4 '-bis(2,2-diphenylvinyl)-1,1 '-biphenyl exposed to air. in Journal of Luminescence. 2015;167:204-210.
doi:10.1016/j.jlumin.2015.06.036 .

Tomović, Aleksandar, Jovanović, Vladimir P., Djurišić, Ivana, Cerovski, Viktor, Nastasijević, Branislav, Veielović, S. R., Radulović, K., Žikić, Radomir, "Fast photoluminescence quenching in thin films of 4,4 '-bis(2,2-diphenylvinyl)-1,1 '-biphenyl exposed to air" in Journal of Luminescence, 167 (2015):204-210,
https://doi.org/10.1016/j.jlumin.2015.06.036 . .

TY  - JOUR
AU  - Tomović, Aleksandar
AU  - Jovanović, Vladimir P.
AU  - Djurišić, Ivana
AU  - Cerovski, Viktor
AU  - Nastasijević, Branislav
AU  - Veličković, Suzana
AU  - Radulović, Katarina
AU  - Žikić, Radomir
AU  - Srdanov, Vojislav I.
PY  - 2014
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/1902
AB  - We studied degradation of 4,4′-bis(2,2′diphenyl vinyl)-1,1′-biphenyl (DPVBi), well know OLED material. Thermally evaporated thin films of DPVBi were irradiated with UV light in ambient, vacuum and under different oxygen pressures. The cause of degradation is reaction between UV excited DPVBi molecules and oxygen, via formation of singlet oxygen or electron transfer from excited DPVBi to molecular oxygen. Reaction rates depend on oxygen concentration and UV light intensity. These reactions lead to formation of oxidized species as evidenced by ASAP and MALDI-TOF mass spectroscopy. Photoluminescence quenching has two parts. One part is reversible and may imply formation of charge transfer complexes and the other is irreversible, caused by formation of oxidized species. IR and absorption spectra are studied by Density Functional Theory and results compared with the experiment.
PB  - Materials Research Society of Serbia
T2  - THE SIXTEENTH ANNUAL CONFERENCE YUCOMAT 2014 Programme and The Book of Abstracts
T1  - Degradation of thin 4,4′-bis(2,2′diphenyl vinyl)-1,1′-biphenyl films by UV light
SP  - 100
UR  - https://hdl.handle.net/21.15107/rcub_rimsi_1902
ER  - 

@article{
author = "Tomović, Aleksandar and Jovanović, Vladimir P. and Djurišić, Ivana and Cerovski, Viktor and Nastasijević, Branislav and Veličković, Suzana and Radulović, Katarina and Žikić, Radomir and Srdanov, Vojislav I.",
year = "2014",
abstract = "We studied degradation of 4,4′-bis(2,2′diphenyl vinyl)-1,1′-biphenyl (DPVBi), well know OLED material. Thermally evaporated thin films of DPVBi were irradiated with UV light in ambient, vacuum and under different oxygen pressures. The cause of degradation is reaction between UV excited DPVBi molecules and oxygen, via formation of singlet oxygen or electron transfer from excited DPVBi to molecular oxygen. Reaction rates depend on oxygen concentration and UV light intensity. These reactions lead to formation of oxidized species as evidenced by ASAP and MALDI-TOF mass spectroscopy. Photoluminescence quenching has two parts. One part is reversible and may imply formation of charge transfer complexes and the other is irreversible, caused by formation of oxidized species. IR and absorption spectra are studied by Density Functional Theory and results compared with the experiment.",
publisher = "Materials Research Society of Serbia",
journal = "THE SIXTEENTH ANNUAL CONFERENCE YUCOMAT 2014 Programme and The Book of Abstracts",
title = "Degradation of thin 4,4′-bis(2,2′diphenyl vinyl)-1,1′-biphenyl films by UV light",
pages = "100",
url = "https://hdl.handle.net/21.15107/rcub_rimsi_1902"
}

Tomović, A., Jovanović, V. P., Djurišić, I., Cerovski, V., Nastasijević, B., Veličković, S., Radulović, K., Žikić, R.,& Srdanov, V. I.. (2014). Degradation of thin 4,4′-bis(2,2′diphenyl vinyl)-1,1′-biphenyl films by UV light. in THE SIXTEENTH ANNUAL CONFERENCE YUCOMAT 2014 Programme and The Book of Abstracts
Materials Research Society of Serbia., 100.
https://hdl.handle.net/21.15107/rcub_rimsi_1902

Tomović A, Jovanović VP, Djurišić I, Cerovski V, Nastasijević B, Veličković S, Radulović K, Žikić R, Srdanov VI. Degradation of thin 4,4′-bis(2,2′diphenyl vinyl)-1,1′-biphenyl films by UV light. in THE SIXTEENTH ANNUAL CONFERENCE YUCOMAT 2014 Programme and The Book of Abstracts. 2014;:100.
https://hdl.handle.net/21.15107/rcub_rimsi_1902 .

Tomović, Aleksandar, Jovanović, Vladimir P., Djurišić, Ivana, Cerovski, Viktor, Nastasijević, Branislav, Veličković, Suzana, Radulović, Katarina, Žikić, Radomir, Srdanov, Vojislav I., "Degradation of thin 4,4′-bis(2,2′diphenyl vinyl)-1,1′-biphenyl films by UV light" in THE SIXTEENTH ANNUAL CONFERENCE YUCOMAT 2014 Programme and The Book of Abstracts (2014):100,
https://hdl.handle.net/21.15107/rcub_rimsi_1902 .