Semiconducting halide perovskites are being studied for use as light-harvesting and light-emitting layers in photovoltaic, photochemical, and optoelectronic device applications. Interfaces, including free interfaces, grain boundaries, and those at electrical contacts all have a strong effect on local photocarrier dynamics. We demonstrate how Lewis bases can act as electron donating ligands to passivate free surfaces and grain boundaries to yield films with quasi-Fermi level splittings that exceed 96% of the Shockley-Queisser limit, consistent with measured internal photoluminescence quantum yields in excess of 90% in the archetypal methylammonium lead triiodide films. We also explore the role of the cation on carrier dynamics in halide perovskite nanocrystals, and find that the biexciton Auger rate appears sensitive to the choice of cation, providing insight into the origins of the unusual photophysics of these materials.

Interfaces, cations, and carrier dynamics in halide perovskites

255th National Meeting (2018)

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