TY - JOUR
T1 - Interface and thickness tuning for blade coated small-molecule organic light-emitting diodes with high power efficiency
AU - Chang, Yu-Fan
AU - Chiu, Yu-Chian
AU - Chang, Hao-Wen
AU - Wang, Yi-Siang
AU - Shih, Yi-Lun
AU - Wu, Chih-Hao
AU - Liu, Yi-Lun
AU - Lin, Yu-Sheng
AU - Meng, Hsin-Fei
AU - Chi, Yun
AU - Huang, Heh-Lung
AU - Tseng, Mei-Rurng
AU - Lin, Hao-Wu
AU - Zan, Hsiao-Wen
AU - Horng, Sheng-Fu
AU - Juang, Jenh-Yih
PY - 2013/9/28
Y1 - 2013/9/28
N2 - We developed a general method based on fluorescence microscopy to characterize the interface dissolution in multi-layer organic light-emitting diodes (OLEDs) by blade coating. A sharp bi-layer edge was created before blade coating, with the bottom layer being insoluble and top layer soluble. After blade coating, fluorescence images showed that the edge of the top layer shifted when the layer dissolved completely, whereas the bottom layer's edge remained in place as a positioning mark. The dissolution depth was determined to be 15-20 nm when the emissive-layer host of 2,6-bis (3-(9H-carbazol-9-yl)phenyl) pyridine (26DCzPPy) was coated on the hole-transport layer of N,N′-bis(naphthalen-1-yl)-N,N′-bis(phenyl)-benzidine(NPB), which was consistent with a sudden drop in efficiency of orange OLEDs with layer thickness below 20 nm. Thus, the layer thickness of OLEDs was optimized to stay more than 20 nm for blade coating. For a two-color white OLED with the structure TCTA/26DCzPPy:PO-01-TB:FIrpic/TPBI, efficiency was 24 cd/A and 8.5 lm/W at 1000 cd/m2. For a three-color white OLED with Os(fptz)2(dhpm) added as the emitter, the efficiency was 12.3 cd/A and 3.7 lm/W at 1000 cd/m2. For a green device with the structure TCTA/26DCzPPy:Ir(mppy) 3/TPBI, the efficiency was 41.9 cd/A and 23.4 lm/W at 1000 cd/m2.
AB - We developed a general method based on fluorescence microscopy to characterize the interface dissolution in multi-layer organic light-emitting diodes (OLEDs) by blade coating. A sharp bi-layer edge was created before blade coating, with the bottom layer being insoluble and top layer soluble. After blade coating, fluorescence images showed that the edge of the top layer shifted when the layer dissolved completely, whereas the bottom layer's edge remained in place as a positioning mark. The dissolution depth was determined to be 15-20 nm when the emissive-layer host of 2,6-bis (3-(9H-carbazol-9-yl)phenyl) pyridine (26DCzPPy) was coated on the hole-transport layer of N,N′-bis(naphthalen-1-yl)-N,N′-bis(phenyl)-benzidine(NPB), which was consistent with a sudden drop in efficiency of orange OLEDs with layer thickness below 20 nm. Thus, the layer thickness of OLEDs was optimized to stay more than 20 nm for blade coating. For a two-color white OLED with the structure TCTA/26DCzPPy:PO-01-TB:FIrpic/TPBI, efficiency was 24 cd/A and 8.5 lm/W at 1000 cd/m2. For a three-color white OLED with Os(fptz)2(dhpm) added as the emitter, the efficiency was 12.3 cd/A and 3.7 lm/W at 1000 cd/m2. For a green device with the structure TCTA/26DCzPPy:Ir(mppy) 3/TPBI, the efficiency was 41.9 cd/A and 23.4 lm/W at 1000 cd/m2.
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U2 - 10.1063/1.4821881
DO - 10.1063/1.4821881
M3 - RGC 21 - Publication in refereed journal
SN - 0021-8979
VL - 114
JO - Journal of Applied Physics
JF - Journal of Applied Physics
IS - 12
M1 - 123101
ER -