Controlling Nucleation and Growth of Metal Halide Perovskite Thin Films for High-Efficiency Perovskite Solar Cells

Nobuya Sakai; Zhiping Wang; Victor M Burlakov; Jongchul Lim; David McMeekin; Sandeep Pathak; Henry J Snaith

doi:10.1002/smll.201602808

Controlling Nucleation and Growth of Metal Halide Perovskite Thin Films for High-Efficiency Perovskite Solar Cells

Small. 2017 Apr;13(14). doi: 10.1002/smll.201602808. Epub 2017 Feb 2.

Authors

Nobuya Sakai¹, Zhiping Wang¹, Victor M Burlakov², Jongchul Lim¹, David McMeekin¹, Sandeep Pathak³, Henry J Snaith¹

Affiliations

¹ Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, UK.
² Mathematical Institute, University of Oxford, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford, OX2 6GG, UK.
³ Center for Energy Studies, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India.

PMID: 28151573
DOI: 10.1002/smll.201602808

Abstract

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 PbCl₂ with PbI₂ in the 3CH₃ NH₃ I:PbCl₂ mixed-halide starting solution has a profound influence upon the ensuing thin-film crystallization. The presence of PbI₂ in the precursor induces a uniform distribution of regular quadrilateral-shaped CH₃ NH₃ PbI₃ perovskite crystals in as-cast films, which subsequently grow to form pinhole-free perovskite films with highly crystalline domains. With this new formulation of 3CH₃ NH₃ I: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.

Keywords: lead halide mix; nucleation; perovskite photovoltaics; thin-film crystallization.

Publication types

Research Support, Non-U.S. Gov't