Tin-based perovskite light-emitting diodes: Progress and perspective

Abstract

Lead-based perovskites exhibit exceptional optoelectronic properties, making them highly suitable for light-emitting diodes (LEDs). However, their intrinsic toxicity, primarily arising from soluble Pb²⁺ ions, poses significant environmental and regulatory barriers to large-scale commercialization. Tin-based perovskites have emerged as the most promising lead-free alternatives, retaining favorable charge transport properties and tunable bandgaps while substantially reducing ecotoxicological and human health risks. Nevertheless, the external quantum efficiency (EQE) of tin-based perovskite LEDs (PeLEDs) remains capped at ∼20%, reflecting a pronounced performance gap relative to state-of-the-art lead-based counterparts. In this review, we systematically summarize the fundamental structural motifs and photophysical behavior of tin-based perovskites to identify the root causes limiting film quality, particularly Sn²⁺ oxidation under ambient conditions and uncontrolled crystallization kinetics during film formation. We then outline recent device-level advances, including rational ligand engineering, interfacial dipole modulation, and compositional grading that have enabled measurable EQE improvements. Moreover, we evaluate the practical viability of tin-based emitters in next-generation optoelectronic applications, with an emphasis on narrowband pure-red displays and near-infrared optical communication. Finally, we highlight three persistent mechanistic challenges: (i) severe nonradiative recombination and imbalanced charge injection stemming from facile Sn²⁺ oxidation and inherent p-type self-doping; (ii) pronounced efficiency roll-off at elevated current densities driven by Auger recombination and localized Joule heating; and (iii) intrinsic operational instability under continuous optoelectronic and thermal stress. We conclude by proposing a unified research framework that integrates rational materials design, machine learning-guided high-throughput screening, and scalable fabrication paradigms to guide the development of tin-based PeLEDs. This roadmap aims to achieve efficiencies and operational robustness comparable to lead-based devices, thereby enabling truly sustainable high-performance optoelectronics.