Cesium Doping for Performance Improvement of Lead(II)-acetate-Based Perovskite Solar Cells.

Min-Seok Han,Jinho Yoon,Xuewen Liu,Eun-Cheol Lee,Zhihai Liu

doi:10.3390/ma14020363

Abstract

Lead(II)-acetate (Pb(Ac)2) is a promising lead source for the preparation of organolead trihalide perovskite materials, which avoids the use of inconvenient anti-solvent treatment. In this study, we investigated the effect of cesium doping on the performance of Pb(Ac)2-based perovskite solar cells (PSCs). We demonstrate that the quality of the CH3NH3PbI3 perovskite film was improved with increased crystallinity and reduced pinholes by doping the perovskite with 5 mol% cesium. As a result, the power conversion efficiency (PCE) of the PSCs was improved from 14.1% to 15.57% (on average), which was mainly induced by the significant enhancements in short-circuit current density and fill factor. A PCE of 18.02% was achieved for the champion device of cesium-doped Pb(Ac)2-based PSCs with negligible hysteresis and a stable output. Our results indicate that cesium doping is an effective approach for improving the performance of Pb(Ac)2-based PSCs.

Highlights

Our results demonstrate the superior effect of cesium doping on the performance improvement of Pb(Ac)2 -based perovskite solar cells (PSCs)
When the perovskite was doped with 2.5 mol% cesium, the power conversion efficiency (PCE) increased to 15.04%
With 5 mol% cesium doping, the PCE further increased to 15.57%, which was mainly induced by the significant improvements in Jsc and fill factor (FF)

Summary

Introduction

Formamidinium (FA+ ), and X = Cl− , Br− , or I− ) have attracted considerable attention because of their tunable bandgap, high light absorption coefficient, and long exciton diffusion length over one micrometer [1]. In 2009 [2], perovskite solar cells (PSCs) have been intensively investigated, with rapid improvement in power conversion efficiency (PCE) to above 25.5% [3,4,5,6,7,8]. PSCs are considered one of the most promising candidates for next-generation solar energy devices. In order to obtain a high-quality perovskite film with a uniform morphology, an anti-solvent treatment is needed for the one-step spin-coating process [10]

Methods

Results

Conclusion