Researchers at Soochow University and Sichuan University have recently developed a strategy to create high-quality perovskite absorbers with grains in micrometer scale and enhanced carrier lifetime.
Generally, the engineers should be able to grow high-quality and uniform perovskite absorbers through the crystallization process to fabricate Tandem solar cells (TSCs). The absorbers in the solar cells are semiconducting layers that absorb photons and excite electrons to create photocurrent.
The newly designed strategy is based on the close-space annealing (CSA) process. It is a heat-based technique used to alter the chemical property of a material. The CSA strategy devised by the team is universal and can be applied to perovskites with different bandgaps. It will help to produce high-quality absorbers with longer carrier lifetimes. The researchers also demonstrated that the strategy can be generalized while preparing perovskite absorbers with different chemical compositions.
The new strategy of the CSA process makes the perovskites releases the solvents relatively slowly, causing the growth of grains. The grains then merge with the neighboring crystals, forming efficient single-junction perovskite solar cells (PVSCs).
“By placing the intermediate-phase perovskite films with their faces towards solvent-permeable covers during the annealing process, high-quality perovskite absorber layers are obtained with a slowed solvent releasing process, enabling fabrication of efficient single-junction perovskite solar cells (PVSCs) and all-perovskite tandem solar cells,” Wang and his colleagues stated in their research paper.
The early evaluations of the strategy enabled the researchers to create highly performing perovskite absorbers with low and wide bandgaps. These absorbers were used in fabricating 4-T and 2-T all perovskite Tandem Solar Cells (TSCs). These TSCs illustrated remarkable power conversion efficiencies.
The CSA strategy proposed by Wang and his colleagues can be used to create enhanced absorbers at lower cost. Also these can be used to create efficient TSCs that are purely based on perovskites. This could lead to large-scale implementation as effective energy solutions.