Metal oxide barrier layers for terrestrial and space perovskite photovoltaics

Perovskite photovoltaics are attractive for both terrestrial and space applications. Although terrestrial conditions require durability against stressors such as moisture and partial shading, space poses different challenges: radiation, atomic oxygen, vacuum and high-temperature operation. Here we demonstrate a silicon oxide layer that hardens perovskite photovoltaics to critical space stressors. A 1-μm-thick silicon oxide layer evaporated atop the device contacts blocks 0.05 MeV protons at fluences of 10¹⁵ cm⁻² without a loss in power conversion efficiency, which results in a device lifetime increase in low Earth orbit by ×20 and in highly elliptical orbit by ×30. Silicon-oxide-protected Cs_0.05(MA_0.17FA_0.83)_0.95Pb(I_0.83Br_0.17)₃) (MA, methylammonium; FA, formamidinium cation) and CsPbI₂Br cells survive submergence in water and N,N-dimethylformamide. Furthermore, moisture tolerance of Sn-Pb and CsPbI₂Br devices is boosted. Devices are also found to retain power conversion efficiencies on exposure to alpha irradiation and atomic oxygen. This barrier technology is a step towards lightweight packaging designs for both space and terrestrial applications.