Photoluminescence Tuning Through Irradiation Defects in CH$_3$NH$_3$PbI$_3$ Perovskites

TL;DR

This study demonstrates that Helium ion irradiation can introduce defects in CH$_3$NH$_3$PbI$_3$ perovskites, which modify their photoluminescence properties and reveal their resilience and potential for defect engineering in optoelectronic applications.

Contribution

It presents a novel application of Helium ion irradiation for controlled defect introduction in perovskites, enhancing understanding of defect effects on light emission.

Findings

Irradiation defects modify photoluminescence properties.

Perovskites show resilience and even enhanced emission after irradiation.

Defect effects vary with temperature and crystal structure.

Abstract

Defect engineering is applied to hybrid (CH$_3$NH$_3$)PbI$_3$ organic-inorganic perovskites. These materials have become one of the most promising low-cost alternatives to traditional semiconductors in the field of photovoltaics and light emitting devices. We use here Helium ion irradiation at low energy as a tool for the controlled introduction of point defects in both single crystals and polycrystalline thin films. The irradiation defects modify the opto-electronic properties as probed using photoluminescence spectroscopy from 10K to room-temperature. 2 Contrary to usual semiconductors, we observe a very good resilience of the PL properties with irradiation, even associated to an enhancement of the optical emission at low temperature. We discuss these results in relation with the tetragonal to orthorhombic low-temperature phase transition below T=160 K. A comparison between spectra from single crystals and polycrystalline films, both with and without irradiation defects, allow a better understanding of the light emission mechanisms in both kinds of samples. We thereby evidence radiation hardness of these materials and the specificity of defects and their impact over light emission properties.