Promoting Phase Transition in Quasi‐2D Perovskites For High‐Performance Pure‐Red LEDs

• DOI: 10.1002/adma.202503704
• Publication Date: 2025-05-03T14:45:41Z
• Authors: Ao Yu; Jianglong Wang; Yiming Huo; Shouyu Wang; Xin Zhang; Tingwei He; Shaopeng Yang; Yuanzhi Jiang; Li Zhang; Zhenyang Liu; Mingjian Yuan; Changjiu Sun
• Keywords: Quantum yield; Quantum Efficiency

Abstract Layered quasi‐two‐dimensional (quasi‐2D) halide perovskites have emerged as a promising platform for high‐efficiency electroluminescence. Narrowing the multi‐quantum well distribution and eliminating wide‐bandgap 2D phases are crucial achieving flat energy landscape, minimizing loss, ensuring high‐color‐purity emission. Here, it is demonstrated that solution‐processed quasi‐2D perovskite films with broad component distributions arise from an incomplete kinetic transition low‐ n ( , quantum thickness) to high‐ phases. To address this, acetate anion treatment strategy proposed, which induces competitive coordination between anion, bulky spacer cation, inorganic layer, thereby facilitating insertion of octahedral precursor ions promoting phase transition. This results in enhanced color purity, efficient transfer, high photoluminescence yield. The fabricated light emitting diode (PeLED) exhibits emission peak at 641 nm external efficiency (EQE) 25.3%, representing one most pure‐red PeLEDs. also showcases versatility different wavelengths.