Development of Key Technologies for Tandem Hybrid Perovskite Solar Cells

The solar cells based on hybrid lead halide perovskite have recently attracted massive attention due to their low manufacturing cost, lightweight, and excellent mechanical flexibility. Despite these advantages, further improvements in performance, lifetime, and large-scale manufacturing capability will need to be improved before commercialization. Notably, stacking two individual sub-cells with different absorption profiles into the multi-junction tandem architecture has been proven as an effective way to harvest broader range of the solar spectrum and to minimize the thermalization loss of photon energy, leading to high device performance. Nevertheless, successful application of this concept to perovskite solar cells has not been revealed. Over the past few years, we have made important breakthroughs in the development of highly-efficient and stable large-area perovskite solar cells. The obtained power conversion efficiencies (PCEs) from our group are among the highest value ever reported for perovskite solar cells under the same conditions. Furthering on our previous work, here we propose several new strategies to achieve high-performance, stable, large-area tandem perovskite solar cells based on cost-effective procedures in this project, where the following key technologies will be pursued: (1) materials innovation for developing transparent conductive layer, anti-reflection layer, perovskite active layer, interfacial layer, interconnection layer, and encapsulation layer; (2) interfacial modification for improving the contact properties at the interfaces; (3) device engineering for designing novel device architecture and for developing large-scale blade-coating techniques. To examine the feasibility of these techniques, the nanoscale characterization and optical modeling via transfer matrix method will be performed. The structure-properties relationship of the newly-developed materials and their impact on device characteristics will be systematically investigated, and the degradation mechanisms of the devices will also be studied. Upon completion of this project, we will provide fundamental scientific investigations and technological applications of perovskite solar cells. The resulting findings will not only open a new avenue for improving the practicality of solution-processed tandem perovskite solar cells, but also bring new insights into the development of novel functional materials for device applications.