An efficient organic and inorganic hybrid interlayer for high performance inverted red cadmium-free quantum dot
Nagarjuna Naik Mude1, Su Jeong Kim1, Raju Lampande1
1Department of Information Display, Kyung Hee University 26, Kyungheedae-ro, Dongdaemoon-gu Seoul 130-701 Republic of Korea jhkwon@khu.ac.kr.
Abstract:
The efficiency and device lifetime of quantum dot light-emitting diode (QLED) devices suffer from the charge imbalance issue resulting from excess electron injection from the ZnO electron transport layer (ETL) to the quantum dot (QD) emissive layer (EML). Herein we report 1,3-bis(9-phenyl-1,10-phenanthrolin-2-yl)benzene (BPPB) small molecule ETL blended ZnO as an interlayer in inverted red indium phosphide (InP) based QLEDs to slow down the ZnO ETL mobility. The device with ZnO : BPPB (15 wt%) shows 16.7% external quantum efficiency and 595 h lifetime (T 50) at 1000 cd m-2. Insertion of a thin hybrid interlayer reduces the electron injection to match the charge balance in the QD layer and also suppresses the interfacial exciton quenching between the ZnO ETL and QD EML.
