Spent coffee ground-derived CQDs for enhanced bifacial DSSC Photoanodes: a stokes shift approach to boost current density and charge transfer efficiency

Citation

Lawal, Ismail and Shafie, Suhaidi and Pandey, Shyam S. and Jaafar, Haslina and Mustafa, Mohd Amrallah and Kamarudin, Mazliana Ahmad and Abdulmalik, Ibrahim Onuwe and Babani, Suleiman and Mohd Bello, Abdulrahman and Mohd Noor, Ikhwan Syafiq (2026) Spent coffee ground-derived CQDs for enhanced bifacial DSSC Photoanodes: a stokes shift approach to boost current density and charge transfer efficiency. Materials Letters, 418. art. no. 140844. pp. 1-4. ISSN 0167-577X; eISSN: 1873-4979

Abstract

This study explores spent coffee ground–derived carbon quantum dots (CQDs) as Stokes-shift additives for bifacial dye-sensitized solar cells (DSSCs). Microwave-synthesized SCG-CQDs exhibit red emission at ∼630 nm upon 400 nm excitation, enabling spectral down-conversion that complements the N719 dye's absorption. CQDs (2.5–10.0 mg/mL) were incorporated into ∼8 μm TiCl₄-treated translucent TiO₂ photoanodes. The optimal device (5.0 mg/mL) delivered a cumulative bifacial efficiency of 5.13%, with charge-collection efficiencies of 68.26% (front) and 66.92% (back), and photocurrent densities of 14.70 and 1.66 mA cm−2, respectively, demonstrating enhanced spectral utilization and reduced interfacial electron recombination tendencies.

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Additional Metadata

Item Type:	Article
Subject:	Materials Science (all)
Subject:	Condensed Matter Physics
Subject:	Mechanics of Materials
Divisions:	Faculty of Engineering Faculty of Science Centre for Foundation Studies in Science of Universiti Putra Malaysia Institute of Nanoscience and Nanotechnology
DOI Number:	https://doi.org/10.1016/j.matlet.2026.140844
Publisher:	Elsevier B.V.
Keywords:	Charge density; Compact layer; Cqd modified photoanode; Spent coffee ground waste
Sustainable Development Goals (SDGs):	SDG 7: Affordable and Clean Energy, SDG 9: Industry, Innovation and Infrastructure, SDG 12: Responsible Consumption and Production
Depositing User:	Ms. Siti Radziah Mohamed@mahmod
Date Deposited:	30 Jul 2026 02:20
Last Modified:	30 Jul 2026 02:20
Altmetrics:	https://www.altmetric.com/details.php?domain=psasir.upm.edu.my&doi=10.1016/j.matlet.2026.140844
URI:	http://psasir.upm.edu.my/id/eprint/125966
Statistic Details:	View Download Statistic

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