Significant improvements in power conversion efficiency have recently been reported in kesterite-based solar cells. A new approach to hydrogen annealing has been developed that enhances carrier collection with minimized defects in CZTS solar cells. This significant breakthrough has already led to new records in overall photovoltaic efficiencies, significantly closing the gap to commercial viability.
Achievement of New Efficiency Record
Researchers at the UNSW have attained a world record PCE of 13.2% in CZTS solar cells by incorporating hydrogen annealing. Hydrogen annealing consists of exposing material to a hydrogen-rich atmosphere to redistribute key elements within the structure. The approach drastically reduces the recombination of carriers and further enhances charge transport, which overcomes major limitations in kesterite-based photovoltaics in terms of efficiency.
Advantages of Hydrogen Annealing
Hydrogen annealing technique has several benefits:
Defect Passivation: Hydrogen atoms interact with defects in the CZTS absorber layer passivating them, thus reducing the energy losses
Optimized Transport of Carriers: Redistribution of sodium and oxygen optimizes pathways for charge transport
Better Lattice Matching: The treatment provides better structural material integrity, meaning that carriers get collected more effectively
Scalability: This method is friendly to large scale production and has the potential for application in other thin-film solar technologies.
Further Optimizations: PCE Attains 14.5%
A different publication in ACS Energy Letters analyzed the effects of low-temperature annealing on CdS:In/CZTSSe heterojunctions. The researchers concluded that the process promotes Cu, Zn, and Sn atoms’ migration into the interface to improve lattice matching. The improvement was associated with a further record-breaking PCE of 14.5%. This was the next big success in kesterite science.
Scope for Further Extension
Hydrogen annealing has proven to be a very effective process not only in CZTS, but also in other thin-film solar cells, like CIGS. Scientists believe this technique can be adapted to a variety of photovoltaic technologies to enhance efficiency while keeping cost-effectiveness and environmental sustainability in mind.
Future Research and Commercial Viability
The next objective for researchers is to take the CZTS solar cell efficiency past 15% while keeping affordability and scalability. Future improvements will focus on
Refine the annealing process to further improve defect passivation and carrier mobility.
Optimize material composition for better energy conversion.
Develop scalable manufacturing techniques to bring kesterite solar cells closer to widespread adoption.
The latest improvements in hydrogen annealing have increased the efficiency of kesterite-based solar cells. With researchers now achieving efficiencies above 13% and approaching 15%, this technology is emerging as a strong candidate for sustainable and cost-effective photovoltaics. Continued refinements in material processing and annealing techniques could soon make CZTS solar cells a competitive alternative in the renewable energy sector.