Spectroscopic study on the impact of methylammonium iodide loading time on the electronic properties in perovskite thin films

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Detail(s)

Original languageEnglish
Pages (from-to)561-567
Journal / PublicationJournal of Materials Chemistry A
Volume4
Issue number2
Online published24 Nov 2015
Publication statusPublished - 14 Jan 2016

Abstract

Solution processed metal-organic halide perovskite photovoltaic devices have recently drawn tremendous attention due to their simplicity of fabrication and high efficiency. Despite numerous reports on optimizing perovskite films with different fabrication approaches, there is limited understanding on the correlation between sensitive processing conditions and the microstructural and electronic properties of perovskite films. Here we combine several opto-electrical spectroscopy techniques to investigate the methylammonium iodide (MAI) loading time effect on the doping density profile and uncoordinated ions in resulting CH3NH3PbI3 perovskite thin films. We find that even in a very short period of different loading times within two minutes, there is a significant impact on the device power conversion efficiency (PCE) from 2% to over 15%. It is found that the doping density profile is inhomogeneous across the perovskite film with too short MAI loading time, resulting in an S-shape in the current density-voltage (J-V) characteristics. On the other hand, devices with too long loading time have excess uncoordinated ions attributed to the J-V hysteresis. By using combined spectroscopy techniques to pinpoint the electronic properties in perovskite films, this work would shed light on the understanding of the controversial origins of the reported S-shape and hysteresis in perovskite photovoltaic cells.

Citation Format(s)

Spectroscopic study on the impact of methylammonium iodide loading time on the electronic properties in perovskite thin films. / Cheng, Yuanhang; Li, Ho-Wa; Zhang, Jinfeng; Yang, Qing-Dan; Liu, Taili; Guan, Zhiqiang; Qing, Jian; Lee, Chun-Sing; Tsang, Sai-Wing.

In: Journal of Materials Chemistry A, Vol. 4, No. 2, 14.01.2016, p. 561-567.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review