Lead‐free halide perovskites for efficient light‐emitting devices

Abstract Lead halide perovskites exhibit promising optoelectronic properties for optoelectronic applications, but their commercialization remains limited by significant challenges, particularly the reliance on toxic lead. Accordingly, the pursuit of lead‐free perovskite light emitters has become a compelling research focus. In this review, we systematically analyze the design strategies of lead‐free perovskite emitters across different dimensional architectures and metal cations from monovalent to tetravalent, highlighting recent advances toward efficient light‐emitting devices. We further examine the relationships between elemental selection and optoelectronic properties, and discuss remaining challenges and future research directions, with emphasis on flexible materials development and device fabrication. Additionally, we summarize commonly used A‐site cations and discuss how their design principles cooperate with different metal‐valence frameworks to regulate dimensionality, excited‐state behavior, and device‐relevant properties, thereby linking molecular engineering with representative lead‐free luminescent perovskites and their key applications.