Biexciton Auger recombination in mono-dispersed, quantum-confined CsPbBr3 perovskite nanocrystals obeys universal volume-scaling

摘要

Auger recombination has been a long-standing obstacle to many prospective applications of colloidal quantum dots (QDs) ranging from lasing,light-emitting diodes to bio-labeling.As such,understanding the physical underpinnings and scaling laws for Auger recombination is essential to these applications.Previous studies of biexciton Auger recombination in various QDs established a universal scaling of biexciton lifetime (τxx) with QD volume (Ⅴ):τxx =γV.However,recent measurements on perovskite nanocrystals (NCs),an emerging class of enablers for light harvesting and emitting applications,showed significant deviations from this universal scaling law,likely because the measured NCs are weakly-confined and also have relatively broad size-distributions.Here we study biexciton Auger recombination in mono-dispersed (size distributions within 1.7％-9.0％),quantum-confined CsPbBr3 NCs (with confinement energy up to 410 meV) synthesized using a latest approach based on thermodynamic equilibrium control.Our measurements clearly reproduce the volume-scaling of τxx in confined CsPbBr3 QDs.However,the scaling factor y (0.085 ± 0.001 psm3) is one order of magnitude lower than that reported for CdSe and PbSe QDs (1.00 ± 0.05 psm3),suggesting unique mechanisms enhancing Auger recombination rate in perovskite NCs.