Heterojunction solar cell with 25.18% effectiveness, 85.42% fill factor

• Scientists in China have actually fabricated a heterojunction solar cell with a 244.63 cm2 Czochralski n-c-Si wafer. They used light soaking to improve the dark conductance of the hydrogenated amorphous silicon films.

Scientists from the Chinese Academy of Sciences (CAS) have actually constructed a heterojunction solar cell with extremely conductive boron-doped hydrogenated amorphous silicon (a-Si: H) thin films. They claim it reduces fill factor losses to a minimum.

"Our cells were conceived for applications in large-scale solar modules," researcher Wenzhu Liu told pv magazine.

The researchers fabricated the cell with a 244.63 cm2 Czochralski n-c-Si wafer given by China-based Sichuan Yongxiang Silicon Material Company. They used light soaking to improve the dark conductance of the a-Si: H films, in order to help the diffusion and also hopping of weakly bound hydrogen atoms, leading to effective boron tetrasilicide (B − Si4) doping.

"The light-soaking devices are made of LED arrays as well as were established by Chinese companies at our request," Liu claimed.

The researchers have discovered that boron doping, which originates from weakly bound hydrogen atoms, plays a crucial part in the development of metastable hydrogen setups in the a-Si: H films. Under conventional illumination conditions, the solar cell accomplished a power conversion efficiency of 25.18%, an open-circuit voltage of 749 mV, and also a fill factor of 85.42%, which the researchers described as the highest possible worths amongst two-side gotten in touch with silicon solar cells.

An encapsulated device was additionally able to retain 98.70% and also 97.59% of the fill factor and also performance, respectively, after 1,000 hrs. The researchers claimed that this demonstrates high stability versus extreme climate degradation factors.

The scientists defined the process in "Light-induced activation of boron doping in hydrogenated amorphous silicon for over 25% performance silicon solar cells," which was lately released in Nature Energy. "We participated in their design as well as now both the cells and also the light-soaking devices will certainly be available in the marketplace," said Liu.