Controlling Nucleation and Growth of Metal Halide Perovskite Thin Films for High-Efficiency Perovskite Solar Cells.
Metal halide perovskite thin films can be crystallized via a broad range of solution-based routes. However, the quality of the final films is strongly dependent upon small changes in solution composition and processing parameters. Here, this study demonstrates that a fractional substitution of PbCl2with PbI2in the 3CH3NH3I:PbCl2mixed-halide starting solution has a profound influence upon the ensuing thin-film crystallization. The presence of PbI2in the precursor induces a uniform distribution of regular quadrilateral-shaped CH3NH3PbI3perovskite crystals in as-cast films, which subsequently grow to form pinhole-free perovskite films with highly crystalline domains. With this new formulation of 3CH3NH3I:0.98PbCl2:0.02PbI2, this study achieves a 19.1% current-voltage measured power conversion efficiency and a 17.2% stabilized power output in regular planar heterojunction solar cells.
Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, UK.
Nobuya
N
Sakai
Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, UK.
Zhiping
Z
Wang
Mathematical Institute, University of Oxford, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford, OX2 6GG, UK.
Victor M
VM
Burlakov
Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, UK.
Jongchul
J
Lim
Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, UK.
David
D
McMeekin
Center for Energy Studies, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India.
Sandeep
S
Pathak
Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, UK.
Henry J
HJ
Snaith
lead halide mix; nucleation; perovskite photovoltaics; thin-film crystallization