USTC makes breakthrough in solar cell efficiency

A research group led by Prof. CHEN Tao and Prof. ZHU Changfei, and their collaborator Prof. HAO Xiaojing at UNSW, developed a hydrothermal deposition method for the synthesis of antimony selenosulfide for solar cell applications. With this absorber material, the solar cell break the 10% benchmark efficiency barrier. This result has been published in Nature Energy entitled "Hydrothermal deposition of antimony selenosulfide thin films enables solar cells with 10% efficiency".

Antimony selenosulfide, Sb2(S,Se)3, as the ROHS-compliant and earth-abundant light harvesting material, has received increasing interests during the past few years. The band gap of Sb2(S,Se)3 is tunable in the range of 1.1-1.7 eV, satisfying the requirement for optimal sunlight harvesting.

In addition, Sb2(S,Se)3 possesses high extinction coefficient and the film thickness of about 500 nanometers can absorb sufficient light irradiation. With these advantages, the Sb2(S,Se)3 is a promising energy material for the applications of light-weight and portable electricity generation devices.

Consider that Sb2(S,Se)3 is consisted of earth-abundant elements and with the excellent stability, the improvement in breaking 10% benchmark efficiency will set a ground for commercialization path. In this study, the authors found that the hydrothermal deposition at supercritical condition enables the generation of compact and flat film with homogeneous element distribution in the lateral direction.

These superior characteristics allow the efficient carrier transport and suppression of the detrimental recombination. With further optimizations of the band gap, cation/anion ratio, crystal orientation and defect properties, the device successfully achieves a record power conversion efficiency.

The reviewer of this paper highly praised this work, commenting that "This paper presents a landmark efficiency value for Sb2(S,Se)3 solar cells breaking the 10% barrier.", "This achievement sheds new light on the investigation and application of Sb2(S,Se)3 ...".

The co-first authors of this articles are Dr. RONG feng, Dr. WANG Xiaomin and LIAN Weitao, from the School of Chemistry and Materials Science of University of Science and Technology of China.

The co-corresponding authors are ZHU Changfei (USTC), HAO Xiaojing (UNSW) and CHEN Tao (USTC). Collaborators also include Prof. YANG Shangfeng at USTC, Prof. XING Guichuan at University of Macau, Prof. CHEN Shiyou at the East China Normal University and so on.