Perovskite/crystalline silicon stack technology

Perovskite semiconductor materials are compounds whose band gaps can be tuned from 1.2 eV to 3.2 eV by tuning the composition. The band gap of the perovskite material is adjusted to about 1.68 eV, and the tandem solar cell is composed of a crystalline silicon material with a band gap of 1.12 eV through the stacking technology. It acts as a bottom cell to absorb long-wavelength low-energy photons. Sub-cells with different band gaps absorb light in different bands, which can reduce the thermal relaxation loss of photogenerated carriers and effectively improve the photoelectric conversion efficiency of solar cells.

The theoretical efficiency limit for single-crystalline silicon solar cells is 29.4%, the actual laboratory efficiency record is 26.7%, and the highest average efficiency for mass-produced cells is about 24.5%. The theoretical efficiency limit of perovskite/crystalline silicon double-junction tandem solar cells can be increased to 42.5%, and the actual laboratory efficiency record has reached 29.52%, which has exceeded the theoretical limit of single-crystalline silicon.

At present, the efficiency of the small-area perovskite/crystalline silicon tandem cell of the thermal energy technology team has exceeded 27%, and the accelerated aging life has exceeded 2000 hours. . In the next step, Thermal Energy plans to develop a complete process for preparing perovskite/crystalline silicon tandem solar cells on industrial-grade M6 (166 mm * 166 mm) silicon wafers, and achieve an efficiency target of 27% by the end of 2023.