Researchers from Japan's Tokyo Institute of Technology, University of Oxford in the UK and Colorado State University in the U.S have shown that α-FAPbI₃, a promising solar cell material with a cubic perovskite structure that is metastable at room temperature, can be stabilized by introducing a pseudo-halide ion like thiocyanate (SCN^–) into its structure. The recent findings provide new insights into the stabilization of the α-phase via grain boundary and pseudo-halide engineering.

A material with good photophysical properties that has recently gained momentum is α-formamidinium lead iodide or α-FAPbI₃ (where FA⁺ = CH(NH₂)₂⁺), a crystalline solid with a cubic perovskite structure. Solar cells made of α-FAPbI₃ exhibit a remarkable 25.8% conversion efficiency and an energy gap of 1.48 eV. Unfortunately, α-FAPbI₃ is metastable at room temperature and undergoes a phase transition to δ-FAPbI₃ when triggered by water or light. The energy gap of δ-FAPbI₃ is much larger than the ideal value for solar cell applications, making the preservation of the α-phase crucial for practical purposes. To overcome this problem, the team of researchers, led by Associate Professor Takafumi Yamamoto from Tokyo Institute of Technology (Tokyo Tech), has recently presented a new strategy for stabilizing α-FAPbI₃.

According to reports, Panasonic is planning to sell windows made of “power-generating glass”, with perovskite solar cells integrated into transparent panes, to deliver power for homes. The module reportedly has a conversion efficacy of 17.9%, which is said to be the second highest worldwide for a perovskite cell larger than 800 sq. centimeters, ( after China’s UtmoLight - 18.6%).

Panasonic has been developing the cells since 2014 but only recently completed a test project, which consisted of installing the innovative glass on the balcony of a model home in its smart-town project in Kanagawa prefecture.