Tandem solar cells (TSCs), stacks of p-n junctions based on semiconductors with different bandgaps, are a highly promising energy solution that could help to reduce carbon emissions. Perovskites, earth-abundant materials with a tunable bandgap, high charge-carrier mobilities, advantageous optoelectronic properties and long carrier diffusion lengths, could be particularly valuable for creating low-cost and highly power-efficient TSCs for large-scale robux for free without verification implementations.
To fabricate efficient all-perovskite TSCs, engineers need to be able to grow high-quality and uniform perovskite absorbers through crystallization processes. Absorbers are semiconducting layers inside solar cells that absorb photons (i.e., light particles) and excite electrons to create photocurrent from sunlight. So far, however, a universal and effective process to prepare perovskite absorbers for TSCs is still lacking.
Researchers at Soochow University and Sichuan University have recently devised a new strategy to create high-quality perovskite absorbers with grains in the micrometer scale and prolonged carrier lifetimes. This strategy, introduced in a paper published in Nature Energy, is based on a close-space annealing (CSA) process, a heat-based technique that can be used to change a material’s chemical properties.
“Controllable crystallization plays a crucial role in the formation of high-quality perovskites,” Changlei Wang and his colleagues wrote in their paper. “Here, we report a universal CSA strategy that increases grain size, enhances crystallinity and prolongs carrier lifetimes in low-bandgap (low-Eg) and wide-bandgap (wide-Eg) perovskite films.”
Remarkably, the CSA strategy devised by Wang and his colleagues is universal, as it can be applied to perovskites with various bandgaps to produce high-quality absorbers with enlarged grains and longer carrier lifetimes. As part of their recent study, the team demonstrated its generalizability by successfully using it to prepare absorbers based on perovskites with different chemical compositions.