Enhanced Photoluminescence of All-Inorganic Manganese Halide Perovskite-Analogue Nanocrystals by Lead Ion Incorporation

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 ·2H 2 O via room-temperature supersaturation recrystallization. Pb 2+ -incorporated Mn-PA NCs exhibit strong orange emission upon UV light illumination, a peak centered at 600 nm assigned to Mn 2+ transition ( 4 T 1g → 6 A 1g ) 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 Pb 2+ effectively dilutes the Mn 2+ concentration to reduce magnetic coupling between Mn 2+ 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 Mn 2+ luminescence centers owing to the low activation energy. Pb 2+ -incorporated PA NCs also exhibit excellent stability. The combined strong PL and high stability make Pb 2+ -incorporated Mn-based PA NCs an excellent candidate for potential optronic applications.