Enhanced Photoluminescence of All-Inorganic Manganese Halide Perovskite-Analogue Nanocrystals by Lead Ion Incorporation
Qian Meng, Liya Zhou, Qi Pang, Xingli He, Tingying Wei, Jin Z. Zhang
Abstract
Herein, we develop an effective approach for incorporating lead (Pb) ions into manganese (Mn) halide perovskite-analogue nanocrystals (PA NCs) of CsMn(Cl/Br)3·2H2O via room-temperature supersaturation recrystallization. Pb2+-incorporated Mn-PA NCs exhibit strong orange emission upon UV light illumination, a peak centered at 600 nm assigned to Mn2+ transition (4T1g → 6A1g) with a photoluminescence quantum yield (PLQY) of 41.8% compared to the pristine Mn-PA NCs with very weak PL (PLQY = 0.10%). The significant enhancement of PLQY is attributed to the formation of [Mn(Cl/Br)4(OH)2]4––[Pb(Cl/Br)4(OH)2]4––[Mn(Cl/Br)4(OH)2]4– chain network structure, in which Pb2+ effectively dilutes the Mn2+ concentration to reduce magnetic coupling between Mn2+ pairs to relax the spin and parity selection rules. In addition, excited energy can effectively transfer from the [Pb(Cl/Br)4(OH)2]4– unit to Mn2+ luminescence centers owing to the low activation energy. Pb2+-incorporated PA NCs also exhibit excellent stability. The combined strong PL and high stability make Pb2+-incorporated Mn-based PA NCs an excellent candidate for potential optronic applications.