Bandgap-universal passivation enables stable perovskite solar cells with low photovoltage loss
The efficiency and longevity of metal-halide perovskite solar cells are typically dictated by nonradiative defect-mediated charge recombination.
In this work*, a team of researchers from this department, the Department of Physics at Oxford and Materials Science and Engineering at Sheffield, and the Hong Kong University of Science and Technology, demonstrate a vapour-based amino-silane passivation that reduces photovoltage deficits to around 100 millivolts (>90% of the thermodynamic limit) in perovskite solar cells of bandgaps between 1.6 and 1.8 electron volts, which is crucial for tandem applications.
A primary-, secondary-, or tertiary-amino-silane alone negatively or barely affected perovskite crystallinity and charge transport, but amino-silanes that incorporate primary and secondary amines yield up to a 60-fold increase in photoluminescence quantum yield and preserve long-range conduction.
Amino-silane-treated devices retained 95% power conversion efficiency for more than 1,500 hours under full-spectrum sunlight at 85oC and open-circuit conditions in ambient air with a relative humidity of 50 - 60%.
*Science: 'Bandgap-universal passivation enables stable perovskite solar cells with low photovoltage loss'.
