Vividly colorful hybrid perovskite solar cells by doctor-blade coating with perovskite photonic nanostructures†
The colors of solar cells are very important when adopting them for future indoor and outdoor light energy harvesting devices with smart designs. Here we report the formation of vividly colorful hybrid organometal trihalide perovskite solar cells by a low-cost and scalable doctor-blade coating method. The perovskite films have a combination of a hundred micrometer size large domain structure and a concentric ring photonics structure in each domain which generates the vivid color. The convection during precursor solution drying in the doctor-blade coating process has been found to be responsible for the formation of the large domains and the coffee-ring like perovskite photonic structures after solvent drying, whose periodicity can be well tuned by the substrate temperature and the precursor solution concentration. Both the perovskite films and the finished devices are very colorful, and the efficiency of the vividly colorful solar cells is close to the optimized doctor-blade coated perovskite solar cell.