Jiang Ji, Shi Mingming, Xia Zhengchang, Cheng Yong, Chu Zema, Zhang Wei, Li Jingzhen, Yin Zhigang, You Jingbi, Zhang Xingwang
Key Lab of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, P. R. China.
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, P. R. China.
Sci Adv. 2024 May 3;10(18):eadn5683. doi: 10.1126/sciadv.adn5683.
Perovskite light-emitting diodes (PeLEDs) have attracted great attention in recent years; however, the halogen vacancy defects in perovskite notably hamper the development of high-efficiency devices. Previously, large-sized passivation agents have been usually used, while the effect of defect passivation is limited due to the weak bonding or the large space steric hindrance. Here, we predict that the ultrasmall-sized formate (Fa) and acetate (Ac) have more efficient passivation ability because of the stronger binding with the perovskite, as demonstrated by density functional theory calculation. We introduce ultrasmall-sized cesium salts (CsFa/CsAc) into buried interface, which can also diffuse into the bulk, resulting in both buried interface and bulk passivation. In addition, the improved perovskite growth has been found due to the enhanced hydrophily after introducing CsFa/CsAc as additive. According to these advantages, a pure-red PeLED with 24.2% efficiency at 639 nm has been achieved.
近年来，钙钛矿发光二极管（PeLEDs）备受关注；然而，钙钛矿中的卤素空位缺陷显著阻碍了高效器件的发展。此前，通常使用大尺寸钝化剂，但由于键合较弱或空间位阻较大，缺陷钝化效果有限。在此，我们通过密度泛函理论计算表明，超小尺寸的甲酸盐（Fa）和乙酸盐（Ac）与钙钛矿的结合更强，具有更有效的钝化能力。我们将超小尺寸的铯盐（CsFa/CsAc）引入埋入界面，其也能扩散到体相中，从而实现埋入界面和体相的钝化。此外，发现引入CsFa/CsAc作为添加剂后，由于亲水性增强，钙钛矿的生长得到改善。基于这些优点，实现了在639nm处效率为24.2%的纯红色PeLED。
