Opportunity of lead-free metal halide perovskites for electroluminescence

<p>Lead halide perovskites (LHPs), which have demonstrated exceptional optical and electrical properties are promising candidates for electroluminescent light-emitting diodes (LEDs). However, concerns about the toxicity and stability have hindered their commercialization. In recent years, lead-free metal halide perovskites (LFMHPs) have emerged as promising alternatives, and significant progress has already been made in developing LFMHP-based LEDs. Nevertheless, their device performance is still inferior to that of well-developed LHP-based counterparts. To fully exploit LED applications and boost device performance, in this review, we provide a comprehensive overview of the currently explored different metal-based LFMHPs. We mainly focus on the preparation methods, crystal structure, optical properties, and LED applications of these materials. Furthermore, we conclude with a discussion regarding the key challenges and potential prospects in this field. We hope that this review will inspire more extensive research on LFMHPs from a new perspective and promote practical applications of LFMHP-based LEDs in multiple directions of current and future research.</p>