Highly Efficient, Solution-Processed Organic Light-Emitting Diodes Based on Thermally Activated Delayed-Fluorescence Emitter with a Mixed Polymer Interlayer Yanwei Liu Xiaofang Wei Zhiyi Li Jianjun Liu Ruifang Wang Xiaoxiao Hu Pengfei Wang Yukiko Yamada-Takamura Ting Qi Ying Wang 10.1021/acsaem.7b00131.s001 https://acs.figshare.com/articles/journal_contribution/Highly_Efficient_Solution-Processed_Organic_Light-Emitting_Diodes_Based_on_Thermally_Activated_Delayed-Fluorescence_Emitter_with_a_Mixed_Polymer_Interlayer/5873511 The efficiency of solution-processed organic light-emitting diodes based on pure organic thermally activated delayed-fluorescence (TADF) emitters is limited by the hole-injection/severe exciton quenching of poly­(styrenesulfonate)-doped poly­(3,4-ethylenedioxythiophene) (PEDOT:PSS) and the exction quenching of TADF emitters due to the self-aggregation. In order to effectively enhance the hole-injection from PEDOT:PSS and to alleviate the exciton quenching of the PEDOT:PSS, the mixed interlayer of poly­(9-vinylcarbazole) (PVK) and poly­[(9,9-dioctylfluorenyl-2,7-diyl)-<i>co</i>-(4,4′-(<i>N</i>-(4-s-butylphenyl)­diphenylamine)) (TFB) was inserted between emitting layer (EML) and the PEDOT:PSS layer. Additionally, the cohost of 3′,5′-di­(carbazol-9-yl)-[1,1′-biphenyl]-3,5-dicarbonitrile (DCzDCN) and bis­(3,5-di­(9<i>H</i>-carbazol-9-yl)­phenyl)­diphenylsilane (SimCP2) was used to suppress the self-aggregation of the TADF emitter of 2-(9-phenyl-9<i>H</i>-carbazol-3-yl)-10,10-dioxide-9 thioxanthone (TXO-PhCz) and tune the charge carrier transport. By optimizing the mix ratio, highly efficient, solution-processed, green-emitting TADF-OLEDs with the hole-transport layer (HTL) of TFB:PVK (1:1) and the EML host of DCzDCN:SimCP2 (1:2) can be turned on at 4 V and can show a maximum current efficiency (CE) of 55.6 cd/A, a maximum power efficiency (PE) of 47.2 lm/W, and an external quantum efficiency (EQE) of 18.86%. The devices are among the most efficient OLEDs fabricated by solution-processed methods. These results indicate that the employment of a mixed HTL and EML cohost is a promising way toward the high-efficiency solution-processed OLEDs. 2018-01-29 00:00:00 carbazol -3-yl thioxanthone EML cohost PE mix ratio power efficiency hole-injection EQE TADF emitter self-aggregation TADF emitters PEDOT high-efficiency solution-processed OLEDs exction quenching light-emitting diodes HTL hole-transport layer poly quantum efficiency carbazol -9-yl DCzDCN PVK Mixed Polymer Interlayer CE exciton quenching Solution-Processed Organic Light-Emitting Diodes solution-processed methods EML host 4 V green-emitting TADF-OLEDs charge carrier transport Thermally Activated Delayed-Fluorescence Emitter TFB