Application of Thin Film Ultralow-Power Lead-Free Perovskite Solar Energy Harvesters in Power Management Systems

M. Aleksandrova, I. Pandiev (Tech. Univ. Sofia, Bulgaria)

Lead-free thin film perovskite solar cell is fabricated and characterized in terms of short-term stability at temperature and light exposure intensity variations. The performance of the proposed energy harvesting element is analyzed for its applicability to charge a supercapacitor. Two possible power management systems are studied and recommendation for using is given based on the charging rate. It is found that the combination of quantum dots with lead-free perovskites expands the absorption in the visible spectrum below 500 nm, which improves the spectral sensitivity of the cell and stabilizes its response at white light. It is found that the power processing system with discrete components exhibits maximum charging rate of 1.2 mV/min, vs. 53 μV/min obtained with monolithic DC-DC convertor, which results in faster reaching the full capacity of the supercapacitor for less than 5 hours (the typical charging time of the selected storage element). The temperature instability of the output electrical power during this time is 1.8 %/oC at maximum light intensity of 10 000 cd/m2. This is superior, when compared to the non-perovskite thin film solar cells, exhibiting typical instability values of 2-2.2 %/oC.