Efforts to improve the efficiency of kesterite-based solar cells have shown progress, with researchers achieving a record power conversion efficiency (PCE) of 11.4 percent. A new approach using hydrogen annealing has been applied to enhance carrier collection in Cu₂ZnSnS₄ (CZTS) solar cells. This technique involves heating the material in a hydrogen-rich environment, which redistributes key elements and reduces energy losses. The findings indicate that hydrogen annealing could be a scalable method to enhance performance, making CZTS a viable option for tandem solar cells.

Hydrogen Annealing Improves Carrier Collection

According to a study published in Nature Energy, researchers at the University of New South Wales explored the impact of hydrogen annealing on CZTS solar cells. The process was found to redistribute sodium and oxygen within the material, reducing defects and enhancing carrier transport. Carrier recombination, a key challenge in CZTS cells, was mitigated, leading to improved efficiency.

Kaiwen Sun, senior author of the study, told Tech Xplore that the aim was to develop a sustainable and cost-effective alternative for next-generation photovoltaics. He explained that hydrogen plays a crucial role in passivating defects near the absorber surface, leading to improved carrier collection.

Potential for Wider Applications

Beyond CZTS, hydrogen annealing has demonstrated promise in enhancing other thin-film solar cell materials, such as copper indium gallium selenide (CIGS). Researchers believe this technique could be applied to various photovoltaic technologies to improve efficiency while maintaining environmental benefits.

Future work will focus on increasing the efficiency of CZTS solar cells beyond 15 percent while preserving their affordability and sustainability. Refinements in the annealing process and further material optimisations are expected to contribute to more efficient solar energy solutions.