Colloidal Sb<sup>3+</sup>-Doped Cs<sub>2</sub>InCl<sub>5</sub>·H<sub>2</sub>O Perovskite Nanocrystals with Temperature-Dependent Luminescence
Anuraj S. Kshirsagar, Habibul Arfin, Srijita Banerjee, Barnali Mondal, Angshuman Nag
Abstract
Bulk crystals of Sb3+-doped A2InX5·H2O (A = Cs, Rb; X = Cl, Br) zero-dimensional (0D) perovskites exhibit a high photoluminescence (PL) quantum yield. Can we prepare their colloidal nanocrystals (NCs)? Such solution-processed nanocrystals will be useful for ink-based and thin-film technologies. Here, we present a facile route to synthesize colloidal Sb3+-doped Cs2InCl5·H2O NCs and explore their optical properties. Sb3+ ions with 5s2 outermost electrons yield intense (quantum yield 39%) green light emission. Temperature-dependent (6.5–300 K) PL provides a mechanistic origin of the excitation and emission processes. At room temperature, the undoped NCs emit blue light (2.8 eV, 435 nm) through localized defects, but below 200 K, near band-edge UV–blue emission (3.15 eV, 394 nm) is observed. Sb3+ doping introduces a new transition from relaxed excited 3P1* to 1S0 state yielding green emission with a long (1.94 μs) lifetime. Colloidal Sb3+-doped Cs2InCl5·H2O NCs emitting intense green light along with a large Stokes shift and a long PL lifetime have potentials for solution-processed light-emitting applications.