Defect-Dependent Nonradiative Carrier Recombination in Cesium Lead Halide Perovskite Quantum Dots: A Time-Domain Ab Initio Study

All-inorganic metal halide perovskite quantum dots (QDs), such as CsPbBr 3, exhibit high structural stability and promising optoelectronic properties. However, their performance is often limited by defect-mediated nonradiative recombination. The microscopic mechanisms, however, remain poorly understood. Here, we employ nonadiabatic molecular dynamics to reveal defect-dependent nonradiative recombination mechanisms in CsPbBr 3 QDs. By examining representative intrinsic defects, including Br vacancies (V Br ), Cs interstitials (Cs i ), and Pb Br antisites, we identify two distinct recombination regimes governed by coherence-dominated and lattice-coupled processes. Specifically, V Br causes only minor lattice distortion and weak electron–vibrational interactions, preserving electronic coherence and small nonadiabatic coupling, thus leading to moderately accelerated recombination. In contrast, Cs i and Pb Br induce pronounced lattice deformations that strongly couple with the defect state, enhancing nonadiabatic coupling and driving much faster carrier recombination. These results establish a mechanistic picture of defect-dependent carrier loss in CsPbBr 3 QDs and offer guidance for defect engineering in perovskite nanomaterials.