Kesterite tech news - monthly briefing
Part of: Future and breakthrough technologies stock
Monthly Summary: Kesterite (CZTS/CZTSSe) Photovoltaic Research (October 2026)
Overview October 2026 was a landmark month for kesterite-based thin-film photovoltaics, characterized by significant breakthroughs in power conversion efficiency (PCE), scalability, and specialized applications. Research focused heavily on overcoming the "open-circuit voltage deficit" and interface recombination issues that have historically hindered the commercialization of these earth-abundant, non-toxic materials.
Key Trends and Major Events
- Record-Breaking Efficiency: A major milestone was reached by the Chinese Academy of Sciences (CAS), which achieved a certified 13.0% efficiency on a 10.5 cm² mini-module using a formamide-based molecular coordination strategy, signaling a transition from laboratory-scale cells to viable module production.
- Indoor Photovoltaic (IPV) Dominance: Kesterite technology is emerging as a leading candidate for powering the Internet of Things (IoT). Researchers at the Universitat Politècnica de Catalunya (UPC) reported record indoor efficiencies of up to 18% by tuning bandgaps to match LED spectra, positioning kesterite as a sustainable alternative to lead-halide perovskites.
- Tandem Cell Architectures: There is a growing trend toward integrating kesterite as a bottom-cell absorber in tandem configurations. Innovations include carbon-electrode monolithic designs and all-chalcogenide four-terminal architectures, which aim to eliminate noble metals and toxic materials while maximizing spectral harvesting.
Technical Advancements and Engineering Strategies
- Interface Engineering: Multiple studies identified the back-contact interface as a critical bottleneck. Solutions included the use of ultrathin MoS₂ layers, SnS barrier interlayers, and sacrificial Cu₂O–Bi₂O₃ interlayers to suppress decomposition and improve charge carrier transport.
- Doping and Compositional Control: Advanced chemical engineering strategies, such as chromium (Cr³⁺) cation doping and precursor doping source layers (PDSL), were successfully deployed to mitigate bulk defects and copper-zinc (Cu-Zn) antisite defects.
- Crystallization Management: The Bilayer Composition-Modulated Sulfurization (BCMS) technique demonstrated success in governing copper redistribution, leading to improved crystallization and reduced voltage deficits in wide-bandgap cells.
Positive and Negative Signals
- Positive Signals:
- Spontaneous Performance Gains: A study revealed that sodium (Na) ion migration during storage can lead to "self-healing" effects, increasing efficiency from 13.02% to 14.37% over 90 days.
- Scalability: The successful demonstration of large-area mini-modules confirms that kesterite processing is becoming increasingly compatible with industrial manufacturing requirements.
- Negative Signals:
- Passivation Limitations: Research from the University of Bristol indicated that standard alkali post-deposition treatments (PDTs)—widely used in CIGS manufacturing—can actually degrade kesterite performance, suggesting that legacy thin-film techniques cannot be applied blindly to kesterite architectures.
- Persistent Challenges: Despite progress, the industry continues to grapple with compositional inhomogeneity and the inherent toxicity of buffer layers like cadmium sulfide (CdS), driving a strong push toward zinc-based (ZnS, ZTO) alternatives.