Carrier Multiplication and Hot-Carrier Cooling Dynamics in Quantum-Confined CsPbI3 Perovskite Nanocrystals

• DOI: 10.1021/acs.jpclett.0c00188
• Publication Date: 2020-02-21T06:52:33Z
• Authors: Muyu Cong; Bin Yang; Junsheng Chen; Feng Hong; Songqiu Yang; Weiqiao Deng; Keli Han
• Keywords: Multiple exciton generation

Carrier multiplication (CM) is an effective mechanism that makes it possible to use hot carriers (HCs) bypass the Shockley–Queisser limit for solar-cell efficiency. In this paper, we present a detailed study of both CM and HC cooling dynamics in quantum-confined CsPbI3 perovskite nanocrystals (NCs), using femtosecond transient absorption spectroscopy. Our results show barrierless CM, with efficiency exceeding 90%, can be achieved strongly confined NCs on time scale ≪200 fs. A low (∼40%), however, observed weakly NCs. suggests absence intrinsic phonon bottleneck Furthermore, biexciton Auger rate increased 4-fold compared These suggest enhanced likely originates from Coulomb coupling relaxed momentum conservation.