The effects of electronic impurities and electron-hole recombination dynamics on large-grain organic-inorganic perovskite photovoltaic efficiencies

Jean-Christophe Blancon (1) , Wanyie Nie (1) , Amanda J. Neukirch (1) , Gautam Gupta (1) , Sergei Tretiak (1) , Laurent Cognet (2) , Aditya D. Mohite (1) , Jared J. Crochet (1)

1 LANL - Los Alamos National Laboratory
2 LP2N - Laboratoire Photonique, Numérique et Nanosciences

Organometallic perovskites have attracted considerable attention after promising developments in energy harvesting and other optoelectronic applications. However, further optimization will require a deeper understanding of the intrinsic photo-physics of materials with relevant structural characteristics. Here we investigate the dynamics of photogenerated charge carriers in large-area grain organometallic perovskite thin films via confocal time-resolved photoluminescence spectroscopy. It is found that the bimolecular recombination of free charges is the dominant decay mechanism at excitation densities relevant for photovoltaic applications. Bimolecular coefficients are found to be on the order of 10-9 cm3/s, comparable to typical direct-gap semiconductors, yet significantly smaller than theoretically expected. We also demonstrate that there is no degradation in carrier transport in these thin films due to electronic impurities. Suppressed electron-hole recombination and transport that is not limited by deep level defects provide a microscopic model for the superior performance of large-area grain hybrid perovskites for photovoltaic applications.

Domaines: Biophysique [physics.bio-ph]

Jean-Christophe Blancon, Wanyie Nie, Amanda J. Neukirch, Gautam Gupta, Sergei Tretiak, et al.. The effects of electronic impurities and electron-hole recombination dynamics on large-grain organic-inorganic perovskite photovoltaic efficiencies . Advanced Functional Materials, 2016, 26 (24), pp.4283. ⟨10.1002/adfm.201505324⟩. ⟨hal-01390068⟩