TY - JOUR
T1 - Improvement in the environmental stability of tris(8-hydroxyquinoline) aluminum by substitution of sulphonic acid in 8-hydroxyquinoline ligand
AU - Roy, V. A.L.
AU - Kwong, C. Y.
AU - Djurišić, A. B.
AU - Pode, R. B.
AU - Rao, T. K.Gundu
AU - Chan, W. K.
PY - 2004
Y1 - 2004
N2 - Tris (8-hydroxyquinoline) aluminum (Alq 3) is a commonly used electron transporting and/or light emitting material in organic light emitting diodes (OLEDs). However, it is well known that Alq 3 is very sensitive to atmosphere exposure and that photoluminescence of Alq 3 films decreases with the time of atmosphere exposure. Degradation is also a serious problem in Alq 3 based OLEDs. Several degradation mechanisms have been identified in these devices, including formation of unstable cationic species due to passage of holes. Therefore, there is lots of interest in improving the stability of Alq 3. We have synthesized Tris (8-hydroxyquinoline-5 sulphonic acid) aluminum (Al(qS) 3) in order to improve the stability. We performed electron spin resonance measurements on Alq 3 and Al(qS) 3 powders. Unlike Alq 3 which exhibited strong ESR signal, Al(qS) 3 produced no detectable ESR signal indicating absence of free radicals in this material. To test the environmental stability of Al(qS) 3 films, we have performed photoluminescence (PL) measurements in humid air at different temperatures and found that Al(qS) 3 exhibits improved stability. After comparing the stability of Alq 3 and Al(qS) 3 thin films, fabrication of the light emitting diodes with Al(qS) 3 emitting layer was attempted in order to compare the performance with Alq 3 based devices.
AB - Tris (8-hydroxyquinoline) aluminum (Alq 3) is a commonly used electron transporting and/or light emitting material in organic light emitting diodes (OLEDs). However, it is well known that Alq 3 is very sensitive to atmosphere exposure and that photoluminescence of Alq 3 films decreases with the time of atmosphere exposure. Degradation is also a serious problem in Alq 3 based OLEDs. Several degradation mechanisms have been identified in these devices, including formation of unstable cationic species due to passage of holes. Therefore, there is lots of interest in improving the stability of Alq 3. We have synthesized Tris (8-hydroxyquinoline-5 sulphonic acid) aluminum (Al(qS) 3) in order to improve the stability. We performed electron spin resonance measurements on Alq 3 and Al(qS) 3 powders. Unlike Alq 3 which exhibited strong ESR signal, Al(qS) 3 produced no detectable ESR signal indicating absence of free radicals in this material. To test the environmental stability of Al(qS) 3 films, we have performed photoluminescence (PL) measurements in humid air at different temperatures and found that Al(qS) 3 exhibits improved stability. After comparing the stability of Alq 3 and Al(qS) 3 thin films, fabrication of the light emitting diodes with Al(qS) 3 emitting layer was attempted in order to compare the performance with Alq 3 based devices.
UR - http://www.scopus.com/inward/record.url?scp=1942421326&partnerID=8YFLogxK
U2 - 10.1117/12.503009
DO - 10.1117/12.503009
M3 - Conference article
AN - SCOPUS:1942421326
SN - 0277-786X
VL - 5214
SP - 283
EP - 290
JO - Proceedings of SPIE - The International Society for Optical Engineering
JF - Proceedings of SPIE - The International Society for Optical Engineering
T2 - Organic Light-Emitting Materials and Devices VII
Y2 - 4 August 2003 through 6 August 2003
ER -