Lead-free halide perovskites for photovoltaic smart windows

For over half a century, the biggest photovoltaic (PV) market has been conquered by silicon PV technology but recent years have witnessed perovskites as promising solar cell materials with manifold applications. Day-to-day energy needs can be pleased by the use of materials that harvest solar energy. Thermo-responsive change in the colour exhibited by many of the perovskites have got applied in the groundwork of solar powered smart windows. Thermal comfort level inside the building is very important which mainly depends on the windows and it can be achieved by thermochromic perovskites owing to the flexibility of their crystal structure in response to temperature, therefore these can be leading candidates in the field of smart energy gadgets. Besides all these, there are some limitations like toxicity of the metal atom used in the thermochromic perovskite, preparation methods, stability issues, power conversion efficiencies etc. Designing such perovskite material for tackling current challenges is a key area of research among researchers in the photovoltaic sector. This review mainly centres on the lead-free thermochromic perovskite materials, easy and cost-effective preparation method for solar powered smart window application.