TY  - JOUR
AU  - Tomović, Aleksandar
AU  - Markesević, N.
AU  - Scarpellini, M.
AU  - Bovio, S.
AU  - Lucenti, E.
AU  - Milani, P.
AU  - Žikić, Radomir
AU  - Jovanović, Vladimir P.
AU  - Srdanov, V. I.
PY  - 2014
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/812
AB  - Owing to their low glass transition temperature, T-g, amorphous thin films of N,N'-bis(3-methylphenyl)-N,N'bis(phenyl)benzidine (TPD) undergo morphological changes even at room temperature. It has been noticed previously that exposure to UV light can increase apparent T-g of TPD films and thus stabilize their morphology. However, the reason behind increase in structural stability was not examined at the time. Here we present evidence that TPD molecules undergo photo-oxidation in air when exposed to lambda approximate to 350 nm radiation and that less than 5% of the photo-oxidized species are needed to prevent dewetting of thin TPD films. We propose that photo-oxidized TPD species bind strongly to both ordinary TPD molecules and to terminal hydroxyl groups at the substrate surface, which decreases mobility of TPD molecules and makes thin TPD film less prone to morphology changes.
PB  - Elsevier Science Sa, Lausanne
T2  - Thin Solid Films
T1  - Stabilization of N,N '-bis(3-methylphenyl)-N,N '-bis(phenyl)benzidine thin film morphology with UV light
EP  - 103
SP  - 99
VL  - 562
DO  - 10.1016/j.tsf.2014.03.081
ER  - 

@article{
author = "Tomović, Aleksandar and Markesević, N. and Scarpellini, M. and Bovio, S. and Lucenti, E. and Milani, P. and Žikić, Radomir and Jovanović, Vladimir P. and Srdanov, V. I.",
year = "2014",
abstract = "Owing to their low glass transition temperature, T-g, amorphous thin films of N,N'-bis(3-methylphenyl)-N,N'bis(phenyl)benzidine (TPD) undergo morphological changes even at room temperature. It has been noticed previously that exposure to UV light can increase apparent T-g of TPD films and thus stabilize their morphology. However, the reason behind increase in structural stability was not examined at the time. Here we present evidence that TPD molecules undergo photo-oxidation in air when exposed to lambda approximate to 350 nm radiation and that less than 5% of the photo-oxidized species are needed to prevent dewetting of thin TPD films. We propose that photo-oxidized TPD species bind strongly to both ordinary TPD molecules and to terminal hydroxyl groups at the substrate surface, which decreases mobility of TPD molecules and makes thin TPD film less prone to morphology changes.",
publisher = "Elsevier Science Sa, Lausanne",
journal = "Thin Solid Films",
title = "Stabilization of N,N '-bis(3-methylphenyl)-N,N '-bis(phenyl)benzidine thin film morphology with UV light",
pages = "103-99",
volume = "562",
doi = "10.1016/j.tsf.2014.03.081"
}

Tomović, A., Markesević, N., Scarpellini, M., Bovio, S., Lucenti, E., Milani, P., Žikić, R., Jovanović, V. P.,& Srdanov, V. I.. (2014). Stabilization of N,N '-bis(3-methylphenyl)-N,N '-bis(phenyl)benzidine thin film morphology with UV light. in Thin Solid Films
Elsevier Science Sa, Lausanne., 562, 99-103.
https://doi.org/10.1016/j.tsf.2014.03.081

Tomović A, Markesević N, Scarpellini M, Bovio S, Lucenti E, Milani P, Žikić R, Jovanović VP, Srdanov VI. Stabilization of N,N '-bis(3-methylphenyl)-N,N '-bis(phenyl)benzidine thin film morphology with UV light. in Thin Solid Films. 2014;562:99-103.
doi:10.1016/j.tsf.2014.03.081 .

Tomović, Aleksandar, Markesević, N., Scarpellini, M., Bovio, S., Lucenti, E., Milani, P., Žikić, Radomir, Jovanović, Vladimir P., Srdanov, V. I., "Stabilization of N,N '-bis(3-methylphenyl)-N,N '-bis(phenyl)benzidine thin film morphology with UV light" in Thin Solid Films, 562 (2014):99-103,
https://doi.org/10.1016/j.tsf.2014.03.081 . .

TY  - CONF
AU  - Tomović, Aleksandar
AU  - Markesevic, Nemanja
AU  - Jovanović, Vladimir P.
AU  - Žikić, Radomir
AU  - Scarpellini, M.
AU  - Lucenti, E.
AU  - Milani, P.
AU  - Srdanov, V. I.
PY  - 2013
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/2167
AB  - Triphenyldiamine (TPD) or N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)benzdine is a well known hole-transporting material often used in electroluminescent devices. In bulk material glass transition temperature TTPDg ~ 60°C [1] is rather low and for sufficiently thin films (thickness d ~ 30 nm) deposited on a fused-silica substrate, dewetting occurs even at room temperature [2]. Morphological changes, which are often related to low Tg, lead to degradation of device performance in which thin film s are incorporated. That is why it is interesting to find a way to stabilize thin films. Following a brief report [3] on increased stability of UV irradiated TPD films, we focused on elucidating the underlying mechanism, since an explanation of chemical changes on molecular level has not yet been given. Thin amorphous TPD films were produced in physical vapor deposition (PVO) process on a fused silica or glass substrates. Immediately after evaporation one half of each sample was exposed to UV light under ambient conditions in order to compare effects of irradiation on a single film. Illuminated and non-illuminated areas of films are characterized using UV-visible spectroscopy and atomic force microscopy (AFM). Decrease in absorption bands intensity was observed after irradiation, indicating a chemical change in the sample. AFM study clearly shows that dewetting process at room temperature is stopped for irradiated samples thinner than 30nm. Illuminated samples remained stable even after few weeks of storage under ambient conditions and after 24h exposure to temperatures T > TTPDg. From proton nuclear magnetic resonance and mass spectrometry measurements, we find that photo-excited TPD reacts with oxygen from air, which leads to oxidation and hydroxylation of small amount of TPD molecules. W e conclude that increased thermal stability of irradiated
films is due to hydrogen bonding among TPD molecules and molecules formed in hydroxylation process.
PB  - Fakultet tehničkih nauka, Novi Sad
C3  - APOSTILLE workshop 02: Printed, flexible and nano electronics, Novi Sad
T1  - Towards the mechanisam of stabilization of TPD thin films with UV light
SP  - 23
UR  - https://hdl.handle.net/21.15107/rcub_rimsi_2167
ER  - 

@conference{
author = "Tomović, Aleksandar and Markesevic, Nemanja and Jovanović, Vladimir P. and Žikić, Radomir and Scarpellini, M. and Lucenti, E. and Milani, P. and Srdanov, V. I.",
year = "2013",
abstract = "Triphenyldiamine (TPD) or N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)benzdine is a well known hole-transporting material often used in electroluminescent devices. In bulk material glass transition temperature TTPDg ~ 60°C [1] is rather low and for sufficiently thin films (thickness d ~ 30 nm) deposited on a fused-silica substrate, dewetting occurs even at room temperature [2]. Morphological changes, which are often related to low Tg, lead to degradation of device performance in which thin film s are incorporated. That is why it is interesting to find a way to stabilize thin films. Following a brief report [3] on increased stability of UV irradiated TPD films, we focused on elucidating the underlying mechanism, since an explanation of chemical changes on molecular level has not yet been given. Thin amorphous TPD films were produced in physical vapor deposition (PVO) process on a fused silica or glass substrates. Immediately after evaporation one half of each sample was exposed to UV light under ambient conditions in order to compare effects of irradiation on a single film. Illuminated and non-illuminated areas of films are characterized using UV-visible spectroscopy and atomic force microscopy (AFM). Decrease in absorption bands intensity was observed after irradiation, indicating a chemical change in the sample. AFM study clearly shows that dewetting process at room temperature is stopped for irradiated samples thinner than 30nm. Illuminated samples remained stable even after few weeks of storage under ambient conditions and after 24h exposure to temperatures T > TTPDg. From proton nuclear magnetic resonance and mass spectrometry measurements, we find that photo-excited TPD reacts with oxygen from air, which leads to oxidation and hydroxylation of small amount of TPD molecules. W e conclude that increased thermal stability of irradiated
films is due to hydrogen bonding among TPD molecules and molecules formed in hydroxylation process.",
publisher = "Fakultet tehničkih nauka, Novi Sad",
journal = "APOSTILLE workshop 02: Printed, flexible and nano electronics, Novi Sad",
title = "Towards the mechanisam of stabilization of TPD thin films with UV light",
pages = "23",
url = "https://hdl.handle.net/21.15107/rcub_rimsi_2167"
}

Tomović, A., Markesevic, N., Jovanović, V. P., Žikić, R., Scarpellini, M., Lucenti, E., Milani, P.,& Srdanov, V. I.. (2013). Towards the mechanisam of stabilization of TPD thin films with UV light. in APOSTILLE workshop 02: Printed, flexible and nano electronics, Novi Sad
Fakultet tehničkih nauka, Novi Sad., 23.
https://hdl.handle.net/21.15107/rcub_rimsi_2167

Tomović A, Markesevic N, Jovanović VP, Žikić R, Scarpellini M, Lucenti E, Milani P, Srdanov VI. Towards the mechanisam of stabilization of TPD thin films with UV light. in APOSTILLE workshop 02: Printed, flexible and nano electronics, Novi Sad. 2013;:23.
https://hdl.handle.net/21.15107/rcub_rimsi_2167 .

Tomović, Aleksandar, Markesevic, Nemanja, Jovanović, Vladimir P., Žikić, Radomir, Scarpellini, M., Lucenti, E., Milani, P., Srdanov, V. I., "Towards the mechanisam of stabilization of TPD thin films with UV light" in APOSTILLE workshop 02: Printed, flexible and nano electronics, Novi Sad (2013):23,
https://hdl.handle.net/21.15107/rcub_rimsi_2167 .

TY  - CONF
AU  - Markesevic, Nemanja
AU  - Jovanović, Vladimir P.
AU  - Žikić, Radomir
AU  - Scarpellini, M.
AU  - Lucenti, E.
AU  - Milani, P.
AU  - Srdanov, V. I.
PY  - 2011
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/2163
AB  - N,N´-Bis(3-methylphenyl)-N,N’dyphenilbenzidine (TPD) is a hole-transport material used in
electroluminescent devices whose glass transition temperature, Tg, depends on the film thickness.[1] For sufficiently thin films (d<30 nm), dewetting of amorphous TPD films deposited on a on fused silica or an ITO substrate occurs even at room temperature.[2] Following a brief report on increased thermal stability of UV irradiated TPD films,[3] we investigated the underlying mechanism responsible for it. From proton NMR and mass spectrometry measurements, coupled with morphology (AFM) and spectroscopy (UV-VIS) studies, we find that photo-excited TPD species react with oxygen in air. This leads to partially oxidized TPD films whose increased thermal stability we ascribe to stronger hydrogen bonding of photo-oxidized TPD species with hydrophilic substrates.
PB  - Institute of physics, Pregrevica 118, Belgrade, Serbia
PB  - CIMAINA, Università di Milano, Via Celoria 16, 20133 Milano, Italy
PB  - 3 Institute for Terahertz Science and Technology, University of California Santa Barbara, Santa Barbara CA 93106
C3  - XVIII Symposium on Condensed Matter Physics - SFKM 2011, Belgrade
T1  - Altering Glass Transition of TPD thin Films with UV Light
SP  - 105
UR  - https://hdl.handle.net/21.15107/rcub_rimsi_2163
ER  - 

@conference{
author = "Markesevic, Nemanja and Jovanović, Vladimir P. and Žikić, Radomir and Scarpellini, M. and Lucenti, E. and Milani, P. and Srdanov, V. I.",
year = "2011",
abstract = "N,N´-Bis(3-methylphenyl)-N,N’dyphenilbenzidine (TPD) is a hole-transport material used in
electroluminescent devices whose glass transition temperature, Tg, depends on the film thickness.[1] For sufficiently thin films (d<30 nm), dewetting of amorphous TPD films deposited on a on fused silica or an ITO substrate occurs even at room temperature.[2] Following a brief report on increased thermal stability of UV irradiated TPD films,[3] we investigated the underlying mechanism responsible for it. From proton NMR and mass spectrometry measurements, coupled with morphology (AFM) and spectroscopy (UV-VIS) studies, we find that photo-excited TPD species react with oxygen in air. This leads to partially oxidized TPD films whose increased thermal stability we ascribe to stronger hydrogen bonding of photo-oxidized TPD species with hydrophilic substrates.",
publisher = "Institute of physics, Pregrevica 118, Belgrade, Serbia, CIMAINA, Università di Milano, Via Celoria 16, 20133 Milano, Italy, 3 Institute for Terahertz Science and Technology, University of California Santa Barbara, Santa Barbara CA 93106",
journal = "XVIII Symposium on Condensed Matter Physics - SFKM 2011, Belgrade",
title = "Altering Glass Transition of TPD thin Films with UV Light",
pages = "105",
url = "https://hdl.handle.net/21.15107/rcub_rimsi_2163"
}

Markesevic, N., Jovanović, V. P., Žikić, R., Scarpellini, M., Lucenti, E., Milani, P.,& Srdanov, V. I.. (2011). Altering Glass Transition of TPD thin Films with UV Light. in XVIII Symposium on Condensed Matter Physics - SFKM 2011, Belgrade
Institute of physics, Pregrevica 118, Belgrade, Serbia., 105.
https://hdl.handle.net/21.15107/rcub_rimsi_2163

Markesevic N, Jovanović VP, Žikić R, Scarpellini M, Lucenti E, Milani P, Srdanov VI. Altering Glass Transition of TPD thin Films with UV Light. in XVIII Symposium on Condensed Matter Physics - SFKM 2011, Belgrade. 2011;:105.
https://hdl.handle.net/21.15107/rcub_rimsi_2163 .

Markesevic, Nemanja, Jovanović, Vladimir P., Žikić, Radomir, Scarpellini, M., Lucenti, E., Milani, P., Srdanov, V. I., "Altering Glass Transition of TPD thin Films with UV Light" in XVIII Symposium on Condensed Matter Physics - SFKM 2011, Belgrade (2011):105,
https://hdl.handle.net/21.15107/rcub_rimsi_2163 .