Magnetic field effects in non-magnetic luminescent materials: from organic semiconductors to halide perovskites

Cong Tao,Jian-Pu Wang,Lin Zhu,Mei-Ling Niu,Jing-Min Wang,Qi-Ming Peng

doi:10.7498/aps.71.20211872

Abstract

Magnetic field effects (MFEs) are used to describe the changes of the photophysical properties (including photoluminescence, electroluminescence, injectedcurrent, photocurrent, etc.) when materials and devices are subjected to the external magnetic field. The MFEs in non-magnetic luminescent materials and devices were first observed in organic semiconductor. In the past two decades, the effects have been studied extensively as an emerging physical phenomenon, and also used as a unique experimental method to explore the processes such as charge transport, carrier recombination, and spin polarization in organic semiconductors. Recent studies have found that the MFEs can also be observed in metal halide perovskites with strong spin-orbital coupling. Besides, for expanding the research domain of MFEs, these findings can also be utilized to study the physical mechanism in metal halide perovskites, and then provide an insight into the improving of the performance of perovskite devices. In this review, we focus on the magnetic field effects on the electroluminescence and photoluminescence changes of organic semiconductors and halide perovskites. We review the mainstream of theoretical models and representative experimental phenomena which have been found to date, and comparatively analyze the luminescence behaviors of organic semiconductors and halide perovskites under magnetic fields. It is expected that this review can provide some ideas for the research on the MFEs of organic semiconductors and halideperovskites, and contribute to the research of luminescence in organic materials and halideperovskites.

Highlights

The excited states in OLED determined by the interactions between carriers.[38]
(a) MPL of the perovskite film with different excitation intensities at room temperature; (b) MC of the perovskite solar cell with different excitation intensities; (c) linear characteristics of positive MC and negative MPL; (d) schematic diagram of the electron-hole pair model in perovskites.[33]

Summary

Introduction

光(electroluminescence,EL)、光电流(photocurrent,PC)、注入电流等的强度, 导致磁光致发光(MPL)[3]、磁电致发光(MEL)[4]、磁光电流(MPC)[5]、磁物理学家 Kalinowski 等人首次在有机发光二极管(organic light-emitting diode, OLED)中探测到了磁场效应[11],一个中等大小的磁场(< 0.5 T)就能够显著地图 1 基于 Alq3 的 OLED(a)电致发光和(b)电流的磁场效应[11] Fig. 1. The magnetic field effects on (a) electroluminescence and (b) current of Alq3-based 在过去的几十年里,有机半导体光电器件得到了广泛的研究。其中 OLED 因其柔性可卷曲、可视角度大、对比度高、色域广等优势,取得了巨大的成功,已经广泛应用于智能手机、个人电脑、车载显示等。2003 年 Kalinowski 等人发现, 基于小分子材料 Alq3 的 OLED 在最大 300 mT 外加磁场下,其发光和电流分别增加了 5%和 3%,即 MEL 和 MC 分别为 5%和 3%(图 1(a)(b))[11]。由于该 OLED 不含有磁性材料,因此当人们得知一个较小的磁场就能够显著改变器件的光电性质时,磁场效应立刻成为了领域内的一个热点。

Results

Conclusion