Highly Efficient All-Solid-State WO3-Perovskite Photovoltachromic Cells for Single-Glass Smart Windows

Current developments and challenges in energy-efficient windows for building integration relate to the design and realization of high-performance, durable electrochromic devices and semitransparent photovoltaic cells. Photovoltachromic devices combine the photovoltaic and electrochromic functionalities in a self-powered, stand-alone smart device enabling energy production from sunlight and adaptive daylight modulation without any additional external power supply. Herein, we present for the first time the features of an all-solid-state photovoltachromic device assembled entirely on a single-glass substrate with a simplified structure in which high-performance perovskite solar cells are capable of driving autonomously a fast (c.a. 15 s) and deep coloration of the electrochromic unit (Δ T avt = 22%; Δ T 650 = 30%). Such a multifunctional single-substrate device guarantees high aesthetics and transparency exhibiting increased photovoltaic performances with superior light power conversion efficiency (maximum 12.2%) when compared with the quasi-solid and solid-state photovoltachromics. The integration of an all-solid-state EC unit with semitransparent perovskite solar cells on a single-substrate photovoltachromic module allows for smart energy management by the dynamic control of solar radiation, enabling at the same time the generation of surplus energy by a PV system for additional uses or under cloudy conditions and less sunny hours of the day.