Semi-transparent perovskite photovoltaic and solid-state electrochromic cells

Photovoltachromic devices combine photovoltaic and electrochromic features to enable adjustable transparency glazing, where the photovoltaic component supplies the power to drive the coloration. Such stand-alone, self-powered devices are of commercial interest for integration into windows and surfaces of buildings and vehicles. Here, we report for the first time some recent results in the design of liquid junction and solid state perovskite-based photovoltachromic devices, with self-adaptive transparency. This multifunctional devices are capable of producing electrical power by solar energy conversion as well as undergoing a chromic transition from neutral-color semitransparent to dark blue-tinted when irradiated with solar light, without any additional external bias. Recently, we demonstrated that the combination of semi-transparent perovskite photovoltaic and solid-state electrochromic cells enables fully solid-state photovoltachromic devices with a suitable visible transmittance as well as a 5.5% maximum light power conversion efficiency. These results represent a significant step towards the design of a smart building envelope and the building integration of photovoltaics.