Scalable, Low-Temperature Fabrication of High-Performance Perovskite Solar Modules and Their Application to Photo-Rechargeable Batteries

A fabrication of perovskite solar cells (PSCs) by scalable processes in large-area is prerequisite for the PSCs to fully utilize the inherent advantages of perovskite such as superior charge-transport properties, high absorption coefficient, flexible and light-weight form factors. Large-area perovskite solar modules (PSMs) can be utilized in self-powered personal mobility and electronics, smart textiles, custom-shaped building-integrated photovoltaics, and so on.<br/>Although several demonstrations of scalable production of PSCs have been reported, successful demonstration of fully scalable production of large-area PSMs is still lacking. The major obstacles are uniform wet-film formation via scalable process in large-area, and complete phase conversion of perovskite precursor to photoactive phase. Therefore, reliable scalable production methods should be established including wet-film formation and phase conversion steps.<br/>In addition, the direct integration of energy generation and storage devices have attracted a lot of interest recently in order to correspond to the fluctuation of power input from the Sun and increasing demand for self-powered electronics. However, inherent mismatch of voltage and current range for charging and discharge from PSCs to Li-based batteries is a major obstacle to realize the direct integration between them. Additionally, power output from PSCs under continuous light illumination, and storage capacity from charging-discharging cycles from Li-ion batteries should be retained.<br/>In this work, we successfully demonstrate high-performance PSMs and photo-rechargeable batteries by directly integrating PSMs and Li-ion batteries in a single substrate. All the layers constituting PSMs can be fabricated via solution shearing coating, with optimized rheological and interfacial properties, at a low temperature (&lt;160 °C). An electron transporting layer (ETL) is designed to be uniform and compact in large-area, by systematically investigating the effect of leaving group in sol-gel precursor and applying an optimal tin precursor with organic crosslinkers. As a result, high-efficiency over 24% can be achieved, retaining over 90% relative efficiency compared to initial one after over 2000 h. Complete conversion of perovskite precursor to photoactive phase in a large area can be achieved via careful selection of proper antisolvent and bathing in it.<br/>PSMs are carefully designed to have a proper area and structure to exactly match the charging voltage-current range of high-capacity Li-ion batteries. Consequently, over 20% efficiency of PSMs and over 14% of overall charging to storage efficiency can be achieved. The photo-charging can be repeatedly conducted over 50 cycles because of stable power output and storage of integrated PSMs and Li-ion batteries.