Evaluation of CsPbBr3 Nanocrystals for Laser Cooling

Much effort has gone into realizing laser cooling with solids over the last two decades. Multiple attempts have been made with systems that include rare-earth doped glasses, GaAs heterostructures, CdS nanobelts and hybrid perovskite nanoplatelets. Here we suggest that CsPbBr3 perovskite nanocrystals may eventually lead to verifiable demonstrations of condensed phase laser cooling. The highest emission quantum yield we have realized in CsPbBr3 nanocrystal ensembles is 99.9% at room temperature. This value lies above the critical quantum yield for CsPbBr3, needed to realize laser cooling. We also find that associated CsPbBr3 nanocrystal emission up-conversion efficiencies are large and are 75% and 32% for laser detuning energies of 24 meV and 105 meV.