Zero-Dimensional Lead-Free Halide Perovskites: From Structural Design to Optoelectronic Applications

Abstract

Lead-based halide perovskites have revolutionized optoelectronic technologies, yet their commercialization is hindered by lead toxicity and environmental instability. Zero-dimensional (0D) lead-free halide perovskites, featuring isolated metal halide clusters and tunable compositions, emerge as promising alternatives, combining high photoluminescence quantum yields, structural stability, and environmental friendliness. This review synthesizes the latest advances in 0D leadfree perovskites, detailing their crystal structures, electronic band characteristics, and unique photophysical properties driven by self-trapped exciton (STE) emissions. We summarize diverse synthesis strategies-including thermal injection, mechanochemical methods, and template-assisted growth that enable precise control over morphology and phase purity. The structure-property relationships underlying efficient luminescence and stability are dissected, alongside their applications in cutting-edge optoelectronics: X-ray scintillators with high detection sensitivity, anticounterfeiting materials with stimulus-responsive emission, self-powered ultraviolet photodetectors, and white light-emitting diodes (WLEDs) with high color rendering indices. Critical challenges, such as enhancing carrier mobility, suppressing humidity-induced degradation, and achieving scalable production, are addressed, alongside perspectives on future directions, including rational dopant design, heterostructure engineering, and functional integration for next-generation optoelectronic devices. This overview underscores 0D lead-free perovskites as a transformative class of materials for sustainable optoelectronics.