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Communications Chemistry , Article number: (2026)
We are providing an unedited version of this manuscript to give early access to its findings. Before final publication, the manuscript will undergo further editing. Please note there may be errors present which affect the content, and all legal disclaimers apply.
Two carbazole-based donor–acceptor dyes, CBZ-Gly and CBZ-EG, featuring glycerol- and ethylene glycol-like side chains, were designed and synthesized to achieve synergistic compatibility with DES-based electrolytes, and systematically investigate their impact on DSSCs performance. These dyes were tested in DSSCs employing two neat deep eutectic solvent (DES) electrolytes (choline chloride/ethylene glycol and choline chloride/glycerol) under both simulated sunlight (AM 1.5G) and indoor lighting (1000 lux). By combining molecular-level dye design with a tailored DES-based electrolyte, we achieved an improvement in long-term device stability over several months and demonstrated a record indoor power conversion efficiency of 9.4%, thereby establishing a new benchmark for fully sustainable, DES-based DSSCs under low-light conditions.
The authors declare that all data supporting the findings of this study are available within the paper and its supplementary information files.
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The authors thank the Ministero dell’Università e della Ricerca (PRIN2022 Mendeleev, Project no.2022KMS84P funded by European Union—NextGenerationEU, Piano Nazionale di Ripresa e Resilienza (PNRR) M4 C2 I.1.1 CUP H53D23004590006), Ministero dell’Ambiente e della Sicurezza Energetica (SOLE-H2, Project RSH2A_000004—CUP: F57G25000080006, funded by European Union—NextGenerationEU, Piano Nazionale di Ripresa e Resilienza (PNRR) Missione 2 Componente 2 Investimento 3.5—D.D. 279 05/08/2025, and Sustainable Mobility Center (CNMS-MOST) funded by European Union—NextGenerationEU, Piano Nazionale di Ripresa e Resilienza (PNRR) Missione 4 Componente 2, Investimento 1.4—D.D. 1033 17/06/2022, CNMS – CN_00000023- CUP: H43C22000510001) for financial support. Open Access publishing facilitated by Università degli Studi di Milano-Bicocca, as part of the Wiley – CRUI-CARE agreement.
Department of Materials Science, Solar Energy Research Center MIB-SOLAR and INSTM Milano-Bicocca Research Unit University of Milano-Bicocca, Milano, Italy
Giorgia Salerno, Chiara Liliana Boldrini, Norberto Manfredi, Ottavia Bettucci & Alessandro Abbotto
Department of Information and Electrical Engineering and Applied Mathematics (DIEM), University of Salerno, Fisciano, SA, Italy
Giorgia Salerno
Dipartimento di Farmacia–Scienze del Farmaco, Università degli Studi di Bari “Aldo Moro”, Bari, Italy
Vito Capriati
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G.S. and O.B. synthesized and characterized the dyes. G.S. and C.B. investigated the solar cells by EIS and performed the IPCE measurements. G.S., O.B. and C.B. fabricated, optimized and characterized the solar cells. N.M. supported the photovoltaic data analysis. V.C. supported the DES data interpretation. A.A. and O.B. conceived the main conceptual idea, conceived and planned the experiments, interpreted the results and wrote the manuscript, with contributions from all authors. All authors have given approval to the final version of the manuscript.
Correspondence to Ottavia Bettucci or Alessandro Abbotto.
The authors declare no competing interests.
Communications Chemistry thanks Sergey Dayneko and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. A peer review file is available.
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Salerno, G., Boldrini, C.L., Manfredi, N. et al. Advancing dye–DES synergies in dye-sensitized solar cells for improved indoor efficiency and long-term stability under sustainable conditions. Commun Chem (2026). https://doi.org/10.1038/s42004-025-01821-7
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