Halide Perovskites based Indoor Photovoltaics: Role of Composition Tuning and Interfacial Layers

With the explosive development of the Internet of Things (IoT) technology, indoor photovoltaics (IPVs) are becoming a promising candidate to sustainably power billions of wireless sensors for secured and smart buildings. Among the various photovoltaics technologies available today, halide perovskite-based IPVs are most promising for integration with IoT because of their excellent optoelectronic properties, easy and cost-effective processability using solution-based methods such as roll-to-roll printing, high specific power, and earth-abundance. The low intensity of the indoor light sources means the absence of beneficial light-induced trap filling of the perovskite photoactive layer. This demands stringent defect minimisation approaches at every functional layer to maximize the power conversion efficiency of IPVs and thereby reduce the efficiency gap (more than 20 % now) between the theoretically predicted and experimentally observed power conversion efficiency of IPVs. In this talk, I will discuss the effect of active layer composition tuning and the role of interfacial layers in maximizing efficiency and suppressing the hysteresis effects under indoor lighting. While tuning the composition of the halide perovskites we observed that the fast processing of the triple anion perovskite composition enables the retention of Chlorine and enhances the photovoltaic device performance under indoor lighting. The kinetics of chlorine incorporation/escape was investigated by in situ grazing incidence wide-angle X-ray scattering and correlated the Cl content with the photovoltaic device performance. The selection of organic vs oxide-based transport layers and the effect of light soaking and J-V hysteresis under indoor lighting will also be discussed in detail.