Photoluminescence Temperature Dependence, Dynamics, and Quantum Efficiencies in Mn²⁺-Doped CsPbCl₃ Perovskite Nanocrystals with Varied Dopant Concentration

Abstract

A series of Mn 2+ -doped CsPbCl 3 nanocrystals (NCs) was synthesized using reaction temperature and precursor concentration to tune Mn 2+ concentrations up to 14%, and then studied using variable-temperature photoluminescence (PL) spectroscopy. All doped NCs show Mn 2+ 4 T 1g → 6 A 1g d−d luminescence within the optical gap coexisting with excitonic luminescence at the NC absorption edge. Room-temperature Mn 2+ PL quantum yields increase with increased doping, reaching ∼60% at ∼3 ± 1% Mn 2+ before decreasing at higher concentrations. The low-doping regime is characterized by singleexponential PL decay with a concentration-independent lifetime of 1.8 ms, reflecting efficient luminescence of isolated Mn 2+ . At elevated doping, the decay is shorter, multiexponential, and concentration-dependent, reflecting the introduction of Mn 2+ −Mn 2+ dimers and energy migration to traps. A large, anomalous decrease in Mn 2+ PL intensity is observed with decreasing temperature, stemming from the strongly temperature-dependent exciton lifetime and slow exciton-to-Mn 2+ energy transfer, which combine to give a strongly temperature-dependent branching ratio for Mn 2+ sensitization.

Lead‐Free Semiconductors: Soft Chemistry, Dimensionality Control, and Manganese‐Doping of Germanium Halide Perovskites

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“…[51][52][53][54] Park et al observed strong photon antibunching as well as blinking behavior ascribed to charge/discharge events triggered by photoionization in CsPbBr 3 and CsPbI 3 . [56] Both transition metals [35,57] and rare earth metals [34] have been doped into CsPbX 3 , achieving quantum yields greater than 60 % and 170 %, respectively. [55] Pan et al first demonstrated lanthanide doping into CsPbCl 3 , showing improved quantum yield and luminescence bands across the visible and even into the near-IR region.…”

Caesium for Perovskite Solar Cells: An Overview

“…In this scenario, Mn 2+ doping is currently considered one of the leading strategies to modify the optical and magnetic functionalities of nanocrystals of various chalcogenide and oxide semiconductors . An interesting synergy between these materials chemistry features was proposed by Yuan et al., who synthesized a series of Mn 2+ ‐doped CsPbCl 3 nanocrystals using reaction temperature and precursor concentration to tune Mn 2+ content up to 14 % . The obtained nanocrystals showed Mn 2+ 4 T 1g → 6 A 1g d‐d luminescence within the optical gap coexisting with excitonic luminescence at the nanocrystals absorption edge, and quantum yields up to 62 % were observed for Mn 2+ concentrations of about 3 %.…”