title: Selectively Modulating Triplet Exciton Formation in Host Materials for Highly Efficient Blue Electrophosphorescence.
abstract: The concept of limiting the triplet exciton formation to fundamentally alleviate triplet-involved quenching effects is introduced to construct host materials for highly efficient and stable blue phosphorescent organic light-emitting diodes (PhOLEDs). The low triplet exciton formation is realized by small triplet exciton formation fraction and rate with high binding energy and high reorganization energy of triplet exciton. Demonstrated in two analogue molecules in conventional donor-acceptor molecule structure for bipolar charge injection and transport with nearly the same frontier orbital energy levels and triplet excited energies, the new concept host material shows significantly suppressed triplet exciton formation in the host to avoid quenching effects, leading to much improved device efficiencies and stabilities. The low-voltage-driving blue PhOLED devices exhibit maximum efficiencies of 43.7 cd A(-1) for current efficiency, 32.7 lm W(-1) for power efficiency, and 20.7% for external quantum efficiency with low roll-off and remarkable relative quenching effect reduction ratio up to 41%. Our fundamental solution for preventing quenching effects of long-lived triplet excitons provides exciting opportunities for fabricating high-performance devices using the advanced host materials with intrinsically small triplet exciton formation cross section.
authors.affiliation: Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials, Jiangsu National Synergistic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications , 9 Wenyuan Road, Nanjing 210023, China.
authors.forename: Huanhuan
authors.initials: H
authors.lastname: Li
authors.affiliation: Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials, Jiangsu National Synergistic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications , 9 Wenyuan Road, Nanjing 210023, China.
authors.forename: Ran
authors.initials: R
authors.lastname: Bi
authors.affiliation: Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials, Jiangsu National Synergistic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications , 9 Wenyuan Road, Nanjing 210023, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Chen
authors.affiliation: Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials, Jiangsu National Synergistic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications , 9 Wenyuan Road, Nanjing 210023, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Yuan
authors.affiliation: Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials, Jiangsu National Synergistic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications , 9 Wenyuan Road, Nanjing 210023, China.
authors.forename: Runfeng
authors.initials: R
authors.lastname: Chen
authors.affiliation: Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials, Jiangsu National Synergistic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications , 9 Wenyuan Road, Nanjing 210023, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Tao
authors.affiliation: Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials, Jiangsu National Synergistic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications , 9 Wenyuan Road, Nanjing 210023, China.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials, Jiangsu National Synergistic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications , 9 Wenyuan Road, Nanjing 210023, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Zheng
authors.affiliation: Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials, Jiangsu National Synergistic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications , 9 Wenyuan Road, Nanjing 210023, China.|Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Jiangsu National Synergistic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (NanjingTech) , 30 South Puzhu Road, Nanjing 211816, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
keywords: PhOLEDs; exciton formation cross section; host material; singlet and triplet ratio