1 华南理工大学 发光材料与器件国家重点实验室，广东 广州 510640
2 东莞伏安光电科技有限公司，广东 广州 510006
3 沈阳工业大学 石油化工学院，辽宁 辽阳 111003
蓝光OLED材料是电致发光领域的关键和难点。基于高能激发态转换的“热激子”材料表现出优异蓝光材料的潜能。本文通过调节给受体的推拉电子能力，以蒽为核心构筑单元、三苯基苯为弱给体、苯氰基为受体，设计合成了一种新型D?π?A结构分子TACN。扭曲的三苯基苯提供了高度扭曲的分子构象，有效减弱了聚集态下的猝灭效应，因此TACN表现出高的荧光量子产率（聚集态下47%）。实验结果和理论分析表明，TACN具备“热激子”特征，其大的T2?T1能隙（1.45 eV）有效阻碍了从T2到T1的内转换（IC）过程，而小的T2?S1能差（0.18 eV，T2> S1）有利于促进反向系间窜越（RISC）过程。基于TACN的非掺杂器件表现出深蓝色发射（λmax= 444 nm），半峰宽（FWHM）为59 nm，色坐标为（0.17，0.13）。其最大外量子效率（EQEmax）为8.3%，相应的激子利用率（EUE）最高为88.7%。
有机发光二极管 热激子 蓝光材料 蒽 反向系间窜越 organic light emitting diodes hot exciton blue emitter anthracene reverse intersystem crossing
Author Affiliations
Abstract
1 College of Chemistry, Jilin University, Changchun 130012, China
2 State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun 130012, China
3
4 State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun 130012, China
We investigate terahertz radiation (T-rays) from a pentacene organic diode at room temperature. The quantum chemistry calculation for frequency-related Huang–Rhys factor of pentacene is also carried out. The results demonstrate that the T-rays can come from a bending vibration of pentacene skeleton after the energy of pentacene exciton transferring to the vibrational excited state via electron–phonon coupling. Frequency and natural bond orbital analytics of pentacene and its derivatives are performed in order to explain the result and develop new materials to get higher emission. This work provides a new way to produce T-rays with a simple device at room temperature.
230.0230 Optical devices 250.0250 Optoelectronics 310.0310 Thin films Chinese Optics Letters
2015, 13(1): 012301
