{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,19]],"date-time":"2026-08-19T04:28:03Z","timestamp":1787113683305,"version":"build-2736575974"},"reference-count":44,"publisher":"MDPI AG","issue":"16","license":[{"start":{"date-parts":[[2026,8,17]],"date-time":"2026-08-17T00:00:00Z","timestamp":1786924800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Italian Ministry of the Environment and the Energy Security"},{"name":"National Recovery and Resilience Plan"},{"DOI":"10.13039\/501100000780","name":"European Union","doi-asserted-by":"crossref","award":["IR0000027"],"award-info":[{"award-number":["IR0000027"]}],"id":[{"id":"10.13039\/501100000780","id-type":"DOI","asserted-by":"crossref"}]},{"award":["IR0000027"],"award-info":[{"award-number":["IR0000027"]}],"id":[{"id":"https:\/\/ror.org\/019w4f821","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nanomaterials"],"abstract":"<jats:p>The development of indoor photovoltaic devices for powering Internet of Things (IoT) sensors requires low-cost and sustainable components, making dye-sensitized solar cells (DSSCs) an ideal candidate for artificial light harvesting. The counter electrode plays a critical role in transferring electrons and catalyzing the reduction in the redox electrolyte. However, the traditional use of expensive and scarce platinum (Pt) limits the cost-effective, large-scale commercialization of these devices. While carbon-based materials offer a highly porous, conductive, and abundant alternative, commercial carbon pastes frequently require energy-intensive high-temperature sintering. In this study, we propose a sustainable, low-temperature, and screen-printable carbon composite counter electrode (LoT-HPC) using bio-derived hydroxypropyl cellulose (HPC) as a highly effective binder. Rheological characterizations confirm that the formulated LoT-HPC ink possesses an ideal shear-thinning profile and rapid structural recovery, ensuring excellent printability and film homogeneity. By comparing the custom LoT-HPC composite against a commercial high-temperature screen-printed graphite paste (HT-Elco) and a standard sputtered Pt-FTO electrode, we demonstrate the structural and electrocatalytic advantages of this material. When integrated into full DSSC devices and evaluated under low indoor illumination (1000 lux), the LoT-HPC cell delivers a power conversion efficiency (PCE) of 14.8% and a high short-circuit current density of 103.9 \u00b5A cm\u22122. Furthermore, the custom device demonstrated exceptional operational stability, retaining 98.6% of its initial efficiency (from 14.8% to 14.6%) after 200 h of continuous light-soaking and J-V cycling under 1000 lux. Ultimately, the successful implementation of the HPC binder enables the low-temperature fabrication of sustainable carbon counter electrodes without the need for energy-intensive thermal treatments, presenting a highly scalable pathway for indoor DSSC manufacturing.<\/jats:p>","DOI":"10.3390\/nano16161007","type":"journal-article","created":{"date-parts":[[2026,8,17]],"date-time":"2026-08-17T08:05:41Z","timestamp":1786953941000},"page":"1007","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Hydroxypropyl Cellulose as an Effective Binder for Low-Temperature Screen-Printed Porous Carbon Counter Electrodes for Indoor Dye-Sensitized Solar Cells"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5278-8758","authenticated-orcid":false,"given":"Roberto","family":"Speranza","sequence":"first","affiliation":[{"name":"Department of Applied Science and Technologies, Politecnico di Torino, Corso Duca Degli Abruzzi 24, 10129 Torino, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Elisa","family":"Morale","sequence":"additional","affiliation":[{"name":"Department of Applied Science and Technologies, Politecnico di Torino, Corso Duca Degli Abruzzi 24, 10129 Torino, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Filippo","family":"Sergiacomi","sequence":"additional","affiliation":[{"name":"Department of Applied Science and Technologies, Politecnico di Torino, Corso Duca Degli Abruzzi 24, 10129 Torino, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0007-0989-0678","authenticated-orcid":false,"given":"Angelica","family":"Bisceglie","sequence":"additional","affiliation":[{"name":"Department of Applied Science and Technologies, Politecnico di Torino, Corso Duca Degli Abruzzi 24, 10129 Torino, Italy"},{"name":"Center for Sustainable Future Technologies, Istituto Italiano di Tecnologia, 10129 Torino, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1661-6494","authenticated-orcid":false,"given":"Giorgio","family":"Mogli","sequence":"additional","affiliation":[{"name":"Department of Applied Science and Technologies, Politecnico di Torino, Corso Duca Degli Abruzzi 24, 10129 Torino, Italy"},{"name":"Center for Sustainable Future Technologies, Istituto Italiano di Tecnologia, 10129 Torino, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0001-6351-0628","authenticated-orcid":false,"given":"Simone","family":"Martellone","sequence":"additional","affiliation":[{"name":"Department of Applied Science and Technologies, Politecnico di Torino, Corso Duca Degli Abruzzi 24, 10129 Torino, Italy"},{"name":"Center for Sustainable Future Technologies, Istituto Italiano di Tecnologia, 10129 Torino, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4100-9661","authenticated-orcid":false,"given":"Andrea","family":"Lamberti","sequence":"additional","affiliation":[{"name":"Department of Applied Science and Technologies, Politecnico di Torino, Corso Duca Degli Abruzzi 24, 10129 Torino, Italy"},{"name":"Center for Sustainable Future Technologies, Istituto Italiano di Tecnologia, 10129 Torino, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"269","DOI":"10.1109\/JIOT.2017.2647881","article-title":"IoT Considerations, Requirements, and Architectures for Smart Buildings\u2014Energy Optimization and Next-Generation Building Management Systems","volume":"4","author":"Minoli","year":"2017","journal-title":"IEEE Internet Things J."},{"key":"ref_2","unstructured":"Sinha, S. 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