Detection of Single Charge Trapping Defects in Semiconductor Particles by Evaluating Photon Antibunching in Delayed Photoluminescence

[Image: see text] Time-resolved analysis of photon cross-correlation function g((2))(τ) is applied to photoluminescence (PL) of individual submicrometer size MAPbI(3) perovskite crystals. Surprisingly, an antibunching effect in the long-living tail of PL is observed, while the prompt PL obeys the photon statistics typical for a classical emitter. We propose that antibunched photons from the PL decay tail originate from radiative recombination of detrapped charge carriers which were initially captured by a very limited number (down to one) of shallow defect states. The concentration of these trapping sites is estimated to be in the range 10(13)–10(16) cm(–3). In principle, photon correlations can be also caused by highly nonlinear Auger recombination processes; however, in our case it requires unrealistically large Auger recombination coefficients. The potential of the time-resolved g((2))(0) for unambiguous identification of charge rerecombination processes in semiconductors considering the actual number of charge carries and defects states per particle is demonstrated.