High‐Entropy Lead‐Free Organic–Inorganic Hybrid Perovskites Exhibiting Broad Absorption and Bright Golden Emission for LEDs

Abstract Metal halide perovskite nanomaterials are attractive for optoelectronic applications due to their exceptional optoelectronic properties; however, lead toxicity and stability issues significantly limit their practical use. High‐entropy materials (HEMs) leverage multi‐principal component synergy to form configurational entropy‐stabilized solid solutions, exhibiting unique physicochemical properties and superior stability arising from atomic‐scale chemical disorder and reconstructed local electronic states. Nevertheless, their luminescence efficiency often requires improvement. Here, we report the room‐temperature synthesis of a novel organic–inorganic hybrid high‐entropy perovskite, (TEA) 2 (Zr 0.18 Te 0.22 Hf 0.2 Sn 0.3 Pt 0.1 )Cl 6 (TEA = tetraethylammonium). Exploiting the synergistic effects among five diverse B‐site cations, this material exhibits broad‐spectrum–excitable broadband emission, producing a distinct golden light. The study demonstrates that this material retains 80% of its initial photoluminescence intensity after 1 h of continuous ultraviolet irradiation and maintains 60% of its original emission intensity even when heated to 340 K. Furthermore, its facile room‐temperature synthesis facilitates promising applications, such as in light‐emitting diodes and x‐ray detection. These findings provide crucial insights for advancing the development of efficient and stable novel optoelectronic materials.