Attaining 15.1% Efficiency in Cu<sub>2</sub>ZnSnS<sub>4</sub> Solar Cells Under Indoor Conditions Through Sodium and Lithium Codoping
The rising demand for sustainable low‐power devices has driven interest in indoor photovoltaic (IPV) technologies for Internet of Things (IoT) applications. Composed of earth‐abundant and non‐toxic elements, Kesterite‐based Cu 2 ZnSnS 4 (CZTS) solar cells are highly attractive for IPV. This study systematically investigates the effects of sodium (Na), lithium (Li), and Na–Li co‐doping on solution‐processed CZTS devices. A comprehensive analysis reveals that Na‐doping substantially improves crystallinity and grain morphology, significantly boosting efficiency, whereas Li alone has minimal impact. Notably, Na–Li co‐doping achieves a 10.1% efficiency under AM 1.5G illumination, outperforming both the reference and singly doped devices. The co‐doping synergy arises from Na‐induced grain growth and Li‐induced defect passivation and carrier concentration regulation. These devices exhibit high adaptability under 20 different indoor lighting conditions representative of real‐world environments, achieving up to 15.1% power conversion efficiency under 3000 K illumination at 2.93 mW cm −2 ;—the highest reported indoor efficiency for CZTS cells. Their stable open‐circuit voltage, high fill factor, and consistent efficiency across various color temperatures and intensities underline their suitability for IPV applications. Future work should focus on improving bandgap alignment with indoor light spectra to further enhance the efficiency of this eco‐friendly technology for IoT energy solutions.
Authors
- Alejandro Navarro‐Güell
- Matteo Valentini (ORCID: https://orcid.org/0000-0001-8567-7624)
- Romain Scaffidi (ORCID: https://orcid.org/0000-0001-9766-1857)
- Sergio Giraldo (ORCID: https://orcid.org/0000-0003-4881-5041)
- David Payno (ORCID: https://orcid.org/0000-0003-1381-5121)
- Edgardo Saucedo (ORCID: https://orcid.org/0000-0003-2123-6162)
- Zacharie Jehl Li‐Kao (ORCID: https://orcid.org/0000-0002-2610-5973)
- Iván Caño (ORCID: https://orcid.org/0000-0003-4226-1527)
- Denis Flandre (ORCID: https://orcid.org/0000-0001-5298-5196)
- Yuancai Gong (ORCID: https://orcid.org/0000-0003-3548-9064)
- Claudia Malerba (ORCID: https://orcid.org/0000-0001-6976-3442)
- Alex Jiménez‐Arguijo (ORCID: https://orcid.org/0000-0002-3583-0958)
- Marcel Placidi (ORCID: https://orcid.org/0000-0001-5684-9669)
- Bart Vermang (ORCID: https://orcid.org/0000-0003-2669-2087)
- Alejandro Pérez‐Rodríguez (ORCID: https://orcid.org/0000-0002-3634-1355)
- Oriol Segura‐Blanch (ORCID: https://orcid.org/0000-0002-5041-5322)
Institutions
- National Agency for New Technologies, Energy and Sustainable Economic Development (IT)
- IMEC (BE)
- Institut de Recerca en Energia de Catalunya (ES)
- ENEA Casaccia Research Centre
- Universitat de Barcelona (ES)
- Hasselt University (BE)
- UCLouvain (BE)
- Universitat Politècnica de Catalunya (ES)
Publication Details
- Journal
- Solar RRL
- Published
- 2025-02-18
- DOI
- https://doi.org/10.1002/solr.202400756
- Citations
- 15
- Primary Topic
- Chalcogenide Semiconductor Thin Films
- Type
- article
- Field-Weighted Citation Impact
- 10.96
Funders
- European Commission
- Generalitat de Catalunya
- Federación Española de Enfermedades Raras
- Fonds Wetenschappelijk Onderzoek
- Institució Catalana de Recerca i Estudis Avançats
- Ministerio de Ciencia e Innovación
- Horizon 2020 Framework Programme
- Horizon 2020
- Agencia Estatal de Investigación