High‐Performance Zinc‐Lead Alloy Green Quasi‐2D Perovskite Light‐Emitting Diodes

Abstract Lead‐based perovskite light‐emitting diodes (PeLEDs) is gaining significant attention for their outstanding optoelectronic properties. However, the intrinsic lead toxicity in these materials presents serious environmental and health risks, limiting their further development. Here, highly efficient zinc‐lead alloy quasi‐2D perovskites are developed through Zn²⁺ substitution and additive engineering. The Zn²⁺ substitution improves tolerance factors, increases radiative recombination rates, and suppresses nonradiative recombination, thereby enhancing stability. Additionally, [bis(4‐methoxyphenyl) phosphinyloxy]carbamic acid tert‐butyl ester (BPCA) additive effectively passivates bromine vacancy defects and improves film quality. The successful Zn²⁺ substitution and additive passivation strategy results in a significantly increased photoluminescence quantum yield from 4.3 to 85.6%. Consequently, high‐performance zinc‐lead alloy green PeLEDs are achieved with a maximum current efficiency of 54.35 cd A⁻¹ and a peak external quantum efficiency of 22.49%, representing the highest performance among green PeLEDs with partial lead substitution. Moreover, the T₅₀ lifetime of Zn‐Lead alloy PeLEDs is ≈8.9 times longer than that of the pristine PeLEDs. The approach not only mitigates lead toxicity but also improves device efficiency and stability, representing a significant advancement toward safer and more sustainable perovskite‐based optoelectronic devices.