Fundamental Light-Conversion Mechanisms in Metal Halide Perovskites for Photovoltaics*

Organic-inorganic metal halide perovskites have emerged as attractive materials for solar cells with power-conversion efficiencies now exceeding 22%. We discuss the fundamental processes that have enabled these materials to be such efficient light-harvesters and charge collectors.

We demonstrate that at the intrinsic limit, the mobility of charge-carriers is predominantly governed by interaction of carriers with optical vibrations of the lead halide lattice (Fröhlich interaction)^[1]. In the absence of trap-mediated charge recombination, band-to-band recombination will dominate losses near the Shockley-Queisser limit. We show that in methylammonium lead triiodide perovskite, such processes can be fully explained as the inverse of absorption,^[2] and exhibit a dynamic that is heavily influences by photon reabsorption inside the material.^[3] Finally, we demonstrate that in the absence of degradation, perovskite solar cells can exhibit appreciably higher energy-conversion efficiencies under solar concentration, where they exceed the Shockley-Queisser limit and exhibit elevated open-circuit voltages.^[4,5]

[1] A.D. Wright, C. Verdi, R.L. Milot, G. E. Eperon, M. A. Pérez-Osorio, H. J. Snaith, F. Giustino, M. B. Johnston, L. M. Herz, Nature Communications 2016, 7, 11755
[2] C. L. Davies, M. R. Filip, J. B. Patel, T. W. Crothers, C. Verdi, A. D. Wright, R. L. Milot, F. Giustino, M. B. Johnston, L. M. Herz, Nature Communications 2018, 9, 293
[3] T. W. Crothers, R. L. Milot, J. B. Patel, E. S. Parrott, J. Schlipf, P. Müller-Buschbaum, M. B. Johnston, L. M. Herz, Nano Letters 2017, 17, 5782
[4] Q. Lin, Z. Wang, H. J. Snaith, M. B. Johnston, L. M. Herz, Advanced Science 2018, 5 1700792
[5] Z. Wang, Q. Lin, B. Wenger, M. G. Christoforo, Y. H. Lin, M. T. Klug, M. B. Johnston, L. M. Herz, H. J. Snaith, Nature Energy 2018, 3, 855