Reviewed by Lexie CornerMar 26 2025
A research team from the Department of Energy Science and Engineering at DGIST, in collaboration with researchers from UNIST, has developed a technology to significantly improve the efficiency of environmentally friendly solar cells. The new approach resulted in an 8.26 % increase in power conversion efficiency compared to traditional solar cells. This discovery is expected to accelerate the commercialization of next-generation sustainable solar cells.
Image Credit: leolintang/Shutterstock.com
Silver bismuth sulfide (AgBiS2) nanocrystals have recently gained attention as a potential material for sustainable solar cells. Unlike conventional high-efficiency solar cells, which contain toxic heavy metals like lead and cadmium, silver bismuth sulfide is non-toxic and abundant as a raw material. However, it faces a challenge in that its efficiency drops significantly when the material becomes too thick, impairing the flow of electricity.
To address this issue, the research team developed a thin film with a mixed structure designed to improve electrical conductivity. By chemically modifying the silver bismuth sulfide nanocrystals, the team created a layer with distinct donor and acceptor properties, which enhanced the efficiency of electrical flow.
As a result, the performance of the solar cell improved, and its efficiency increased by 8.26 % when they produced a 65 nm light-absorbing layer twice as thick as conventional ones. This improvement corresponds to extending the operation time of an LED lightbulb by over two hours or enabling a smartphone to be charged four or five times.
This research has greatly increased the charge diffusion length by allowing the donor and acceptor to coexist in the same layer of the AgBiS2 solar cell, thus maintaining performance even in thicker layers. We expect this eco-friendly technology to be applied to various high-efficiency solar cells in the future.
Choi Jong-min, Professor, Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science and Technology
DGIST Energy Science and Engineering students Kim Hae-jung and Park Jin-young, along with UNIST combined Master's and doctoral program student Choi Ye-jin, led the collaborative study between DGIST Professor Choi's team and UNIST Professor Kwon Oh-hoon's team.
The study was funded by the Ministry of Science and ICT, the Nanomaterial Technology Development Program of the National Research Foundation of Korea (NRF), and the Basic Laboratory Program of the NRF.
Journal Reference:
Kim, H. J., et al. (2025) Homogeneously Blended Donor and Acceptor AgBiS2 Nanocrystal Inks Enable High‐Performance Eco‐Friendly Solar Cells with Enhanced Carrier Diffusion Length. Advanced Energy Materials. doi.org/10.1002/aenm.202404552.