摘要
针对我国有机发光二极管(OLED)显示领域对低成本、高性能材料及简约器件制备工艺的重大迫切需求,提出不含贵重金属的纯有机材料体系及相关器件研究计划;开发并完善自主知识产权的新一代发光材料/主体材料体系,使发光效率和寿命达到实用化的水平;掌握新一代发光材料的发光机制、构效关系、激发态过程及其调控规律,实现兼顾结构简单、高效率、长寿命的新型器件结构,明确其内在物理机制和规律,为高性能材料和器件开发提供科学指导和解决方案,并在此基础上实现显示器件的优化设计、集成和可控制备.
Organic light-emitting diodes （OLEDs） have been a research focus for almost 30 years because of their great potential applications in fiat-panel displays, solid-state lighting, and wearable electronics. The recombination of holes and electrons within the devices under electrical excitation typically generates 25% singlet excitons and 75% triplet excitons. However, only 25% singlet excitons can be utilized to emit light, and the other 75% triplet excitons are generally wasted through non-radiative transition to give a maximum internal quantum efficiency of about 25% for the first generation fluorescent OLEDs. To improve the internal quantum efficiency, phosphorescent materials have been utilized to exploit the non-radiative triplet state by introducing noble heavy metal atoms like iridium （Ir） and platinum （Pt） to increase spin-orbit interactions. Overall electroluminescence （EL） internal quantum efficiency has been successfully improved to 100% since both singlet and triplet excitons could be harvested due to their radiative triplet excitons and efficient intersystem crossing （ISC） from the singlet excited state to the triplet excited state. Nevertheless, noble metals are indispensable for those phosphorescent materials, which are expensive and nonrenewable. In the past few years, metal-free thermally activated delayed fluorescence （TADF） emitters that can also realize 100% exciton utilization through efficient reverse intersystem crossing （RISC） of triplet excitons are regarded as promising materials for next-generation OLEDs. Besides, the intersystem crossing of excitons between higher energy Tm and Sn with close energy levels may also happen in hybridized local and charge-transfer （HLCT） excited state, where the local excited （LE） state contributes to a high efficiency fluorescence radiative decay, while the charge transfer （CT） state ensures the generation of singlet excitons in high yield through the reverse intersystem crossing from high-lying CT-based triplet excited
出处
《科学通报》
EI
CAS
CSCD
北大核心
2016年第32期3448-3452,共5页
Chinese Science Bulletin
基金
国家重点研发计划战略性先进电子材料重点专项(2016YFB0401000)资助
关键词
有机发光二极管
有机发光材料
激发态
稳定性
显示器件
organic light-emitting diodes, organic light-emitting materials, excited state, stability, display panel
