Impact of defects on exciton diffusion in organic light-emitting diodes

被引：4

作者：

Ingram, Grayson L. ^{[1
]}

Lu, Zheng-Hong ^{[1
]}

机构：

[1] Univ Toronto, Dept Mat Sci & Engn, Toronto, ON M5S 3E4, Canada

来源：

ORGANIC ELECTRONICS | 2017年 / 50卷

基金：

加拿大自然科学与工程研究理事会;

关键词：

Exciton diffusion; Electroluminescence; Organic light emitting device; Defect; Singlet; POLARON-INDUCED AGGREGATION; CONJUGATED POLYMERS; CRYSTALLINE ORDER; ENERGY-TRANSFER; DEVICES; SINGLET; ELECTROLUMINESCENCE; SEMICONDUCTORS; DEPENDENCE; LENGTH;

D O I：

10.1016/j.orgel.2017.07.017

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

The impact of defect concentration and current density on the effective singlet exciton diffusion length in 4'-bis(carbazol-9-yl) biphenyl (CBP) is quantified by analyzing the electroluminescent characteristics of several sets of OLEDs. The defect concentration and effective diffusion length are determined through fitting of the defect and CBP emission bands in the electroluminescence spectra under constant current operation using an analytical model derived based on the competition between exciton diffusion and energy transfer to defects. Defect concentrations of 3 +/- 1 Chi 10(18) cm (- 3), 2 +/- 1 Chi 10(18) cm (- 3) and 0.3 +/- 0.7 Chi 10(18) cm (- 3) are calculated in three sets of OLEDs, in which the effective diffusion length decreases as the defect concentration increases. Modelling the dependence of the effective diffusion length on defect concentration a " defect free" diffusion length of 4.5 +/- 0.3 nm is obtained for CBP singlet excitons in these devices operated under low current density. We also show that the driving voltage scales linearly with the defect concentration. (C) 2017 Elsevier B. V. All rights reserved.

引用

页码：48 / 54

页数：7