Evidence for Barrierless Auger Recombination in PbSe Nanocrystals: A Pressure-Dependent Study of Transient Optical Absorption

We report rates of Auger recombination (AR) in zero-dimensional (0D) PbSe nanocrystals as a function of energy gap (Eg) by using applied hydrostatic pressure to controllably shift E(g) according to the bulk deformation potential. Our studies reveal that the rate of AR in nanocrystals is insensitive to energy gap, which is in contrast with bulk semiconductors where this rate shows exponential dependence on E(g). These measurements represent the first direct experimental evidence that AR in 0D nanomaterials is barrierless, in distinction from bulk semiconductors.