Circularly polarized organic light-emitting diode(CP-OLED) has attracted increasing interest for its efficient ability to generate circularly polarized light directly. So far, many CP-OLEDs were successfully fabricate...Circularly polarized organic light-emitting diode(CP-OLED) has attracted increasing interest for its efficient ability to generate circularly polarized light directly. So far, many CP-OLEDs were successfully fabricated with chiral emitters or chiral hosts. In this study, a new strategy based on chiral electron transporting layer is proposed to construct CP-OLEDs. A pair of chiral electron transporting materials, 1,3,5-tris((R/S)-4-isopropyl-4,5-dihydrooxazol-2-yl)benzene((R/S)-TOx^(i)Pr), are firstly designed and synthesized. The crystalline films of(R/S)-TOx^(i)Pr show circularly polarized photoluminescence with photoluminescence dissymmetry factors of-0.067 and +0.041, respectively. The CP-OLEDs based on(R/S)-TOx^(i)Pr and three types of achiral emitters all exhibit circularly polarized electroluminescence, showing feasibility and strong versatility of this new strategy. The mechanism is attributed to in-situ electrical excitation instead of simply light filtering of non-circularly polarized light. This work demonstrates a new approach for realizing circularly polarized electroluminescence which may provide a valuable strategy to develop CP-OLEDs.展开更多
White organic light-emitting diodes(WOLEDs)is a new generation of lighting technology and has stimulated wide-ranging studies.Despite the advantage of simple device structure,single-emitting-layer WOLEDs(SEL-WOLEDs)st...White organic light-emitting diodes(WOLEDs)is a new generation of lighting technology and has stimulated wide-ranging studies.Despite the advantage of simple device structure,single-emitting-layer WOLEDs(SEL-WOLEDs)still face the challenges of difficult material screening and fine energy level regulation.Herein,we report efficient SEL-WOLEDs with a sky-blue emitting cerium(Ⅲ)complex Ce-TBO2Et and an orange-red emitting europium(Ⅱ)complex Eu(Tp2Et)2 as the emitters,showing a maximum external quantum efficiency of 15.9%and Commission Internationale de l'Eclairage coordinates of(0.33,0.39)at various luminances.Most importantly,the electroluminescence mechanism of direct hole capture and hindered energy transfer between the two emitters facilitate a manageable weight doping concentration of 5%for Eu(Tp2Et)2,avoiding the low concentration(<1%)of the low-energy emitter in typical SEL-WOLEDs.Our results indicate that d-f transition emitters may circumvent fine energy level regulation and provide development potential for SEL-WOLEDs.展开更多
基金supported by the National Natural Science Foundation of China (92156016, U23A20593 and 22071003)the National Key R&D Program of China (2021YFB3500400, 2021YFB3501800 and 2022YFB3503700)the China Postdoctoral Science Foundation (2023TQ0004)。
文摘Circularly polarized organic light-emitting diode(CP-OLED) has attracted increasing interest for its efficient ability to generate circularly polarized light directly. So far, many CP-OLEDs were successfully fabricated with chiral emitters or chiral hosts. In this study, a new strategy based on chiral electron transporting layer is proposed to construct CP-OLEDs. A pair of chiral electron transporting materials, 1,3,5-tris((R/S)-4-isopropyl-4,5-dihydrooxazol-2-yl)benzene((R/S)-TOx^(i)Pr), are firstly designed and synthesized. The crystalline films of(R/S)-TOx^(i)Pr show circularly polarized photoluminescence with photoluminescence dissymmetry factors of-0.067 and +0.041, respectively. The CP-OLEDs based on(R/S)-TOx^(i)Pr and three types of achiral emitters all exhibit circularly polarized electroluminescence, showing feasibility and strong versatility of this new strategy. The mechanism is attributed to in-situ electrical excitation instead of simply light filtering of non-circularly polarized light. This work demonstrates a new approach for realizing circularly polarized electroluminescence which may provide a valuable strategy to develop CP-OLEDs.
基金This work was supported by the National Natural Science Foundation of China(22071003,62104013,and 92156016)the National Key R&D PProgramof China(2021YFB3500400,2021YFB3501800,and 2022YFB3503702)the Beijing Natural Science Foundation(2202015).
文摘White organic light-emitting diodes(WOLEDs)is a new generation of lighting technology and has stimulated wide-ranging studies.Despite the advantage of simple device structure,single-emitting-layer WOLEDs(SEL-WOLEDs)still face the challenges of difficult material screening and fine energy level regulation.Herein,we report efficient SEL-WOLEDs with a sky-blue emitting cerium(Ⅲ)complex Ce-TBO2Et and an orange-red emitting europium(Ⅱ)complex Eu(Tp2Et)2 as the emitters,showing a maximum external quantum efficiency of 15.9%and Commission Internationale de l'Eclairage coordinates of(0.33,0.39)at various luminances.Most importantly,the electroluminescence mechanism of direct hole capture and hindered energy transfer between the two emitters facilitate a manageable weight doping concentration of 5%for Eu(Tp2Et)2,avoiding the low concentration(<1%)of the low-energy emitter in typical SEL-WOLEDs.Our results indicate that d-f transition emitters may circumvent fine energy level regulation and provide development potential for SEL-WOLEDs.
