Efficient planar heterojunction perovskite solar cells by vapour deposition

The use of organometal halide perovskites as the light-absorbing material in nanostructured solar cells has increased efficiency to practical levels; here it is shown that vapour deposition of the perovskite removes the need for complex nanostructures and will hence simplify large-scale manufacture. Solar cells made simpler Nanostructured solid-state solar cells that incorporate organometallic halide perovskites as the light-absorbing material have recently attained levels of power conversion efficiency that are attractive for practical applications. Now Mingzhen Liu et al . show that, when using vapour deposition rather than the usual solution processing to deposit the perovskite, high efficiencies can be achieved with these materials in even simpler device structures. By removing the need for complex nanostructures altogether, the prospects for large-scale manufacture are potentially enhanced. Many different photovoltaic technologies are being developed for large-scale solar energy conversion 1 , 2 , 3 , 4 . The wafer-based first-generation photovoltaic devices 1 have been followed by thin-film solid semiconductor absorber layers sandwiched between two charge-selective contacts 3 and nanostructured (or mesostructured) solar cells that rely on a distributed heterojunction to generate charge and to transport positive and negative charges in spatially separated phases 4 , 5 , 6 . Although many materials have been used in nanostructured devices, the goal of attaining high-efficiency thin-film solar cells in such a way has yet to be achieved 7 . Organometal halide perovskites have recently emerged as a promising material for high-efficiency nanostructured devices 8 , 9 , 10 , 11 . Here we show that nanostructuring is not necessary to achieve high efficiencies with this material: a simple planar heterojunction solar cell incorporating vapour-deposited perovskite as the absorbing layer can have solar-to-electrical power conversion efficiencies of over 15 per cent (as measured under simulated full sunlight). This demonstrates that perovskite absorbers can function at the highest efficiencies in simplified device architectures, without the need for complex nanostructures.