Rational Ion Migration Management for Long-Term Stable Blue Perovskite Light-Emitting Diodes

点击翻译按钮获取中文摘要

Metal halide perovskites, which possess high conductivity, high photoluminescence quantum efficiency and color purity, are ideal emitters for cost-effective light-emitting diodes (LEDs). Although EQEs of perovskite LEDs (PeLEDs) emitting in red and green have been boosted to over 25 % recently, approaching that of prevailing OLED and QLEDs, it is still a great challenge to achieve high efficiency blue PeLEDs. More importantly, overcoming poor operational lifetime of PeLEDs (around 10 hours for blue PeLEDs), which is thought to originate from severe ion migration induced by electric field in perovskite emitters and interfacial degradation, is a key for further development of PeLEDs and future applications in displays and lighting. The objective of RAIMM is achieving pure blue PeLEDs (emitting from 465 to 475 nm) with EQEs exceeding 20 % and significantly improved lifetime over 1,000 hours @100 cd/m2. My strategies are using several powerful characterizations (e.g., in-situ PL, in-situ EL imaging, PL&EL, etc.) to reveal a clear degradation mechanism of perovskite emitters and PeLEDs. Accordingly, I will introduce different processing additives to achieve highly emissive perovskite emitters with much suppressed ion migration. With the stable perovskite emitters, new device structures will be designed to stabilize the interfacial contacts and decrease turn-on voltages of PeLEDs. This strategy will minimize the electrical fields across the PeLEDs and limit ion penetration through charge transporting layers. Finally, I will be able to achieve high efficiency pure blue PeLEDs with lifetime over 1,000 h, representing a milestone in PeLEDs community. I will collaborate with Helio Display Materials to demonstrate the first all perovskite-based prototype display with Rec. 2020 color gamut. I believe our results will dramatically accelerate the progress of PeLEDs and stimulate further breakthroughs in other perovskite optoelectronic devices.