Photoluminescence decay dynamics in γ-Ga2O3 nanocrystals: The role of exclusion distance at short time scales

•We made analytical models of donor-acceptor defect interactions in Ga2O3 nanocrystals.•Defect sites were randomly distributed on the surface or throughout the nanocrystal.•Models are in good agreement with PL decay data for exclusion distance of ca. 1nm.•Exclusion distance between donor and acceptor plays a key role at short decay times.•The role of exclusion distance is independently confirmed by Monte Carlo simulations.