AUTHOR=Yuan Fang , Zhang Min , Zhu Chunrong , Liu Xiaoyun , Zhao Chenjing , Dai Jinfei , Dong Hua , Jiao Bo , Lan Xuguang , Wu Zhaoxin 

TITLE=Hole Transport Layer Free Perovskite Light-Emitting Diodes With High-Brightness and Air-Stability Based on Solution-Processed CsPbBr3-Cs4PbBr6 Composites Films

JOURNAL=Frontiers in Chemistry

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2022.828322

DOI=10.3389/fchem.2022.828322

ISSN=2296-2646

ABSTRACT=<p>Recently, perovskite light-emitting diodes (PeLEDs) have drew widespread attention due to their high efficiencies. However, because of the sensitivity to moisture and oxygen, perovskite luminescent layers are usually prepared in high-purity nitrogen environment, which increases the cost and process complexity of device preparation and seriously hindrances its commercialization of PeLED in lighting and display application. Herein, dual-phase all-inorganic composite CsPbBr<sub>3</sub>-Cs<sub>4</sub>PbBr<sub>6</sub> films are fabricated from CsBr-rich perovskite solutions by a simple one-step spin-coating method in the air with high humidity. Compared with the pure CsPbBr<sub>3</sub> film, the composite CsPbBr<sub>3</sub>-Cs<sub>4</sub>PbBr<sub>6</sub> film has much stronger photoluminescence emission and longer fluorescence lifetime, accompanied by increased photoluminescence quantum yield (33%). As a result, we obtained green PeLED devices without hole transport layer exhibiting a maximum brightness of 72,082 cd/m<sup>2</sup> and a maximum external quantum efficiency of about 2.45%, respectively. More importantly, the champion device shows excellent stability with operational half-lifetime exceeding 1,000 min under continuous operation in the air. The dual-phase all-inorganic composite CsPbBr<sub>3</sub>-Cs<sub>4</sub>PbBr<sub>6</sub> film shows attractive prospect for advanced light emission applications.</p>