http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/5715 Sun, 13 Sep 2026 14:50:12 GMT 2026-09-13T14:50:12Z http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/13013 Title: Palmyrah Seed-Derived Activated Charcoal/TiO₂ Composites as a Counter Electrode for Dye-Sensitized Solar Cells Authors: Rajaramanan, T.; Umayangani Weerasinghe, M.I.; Kumara, G.R.A.; Senthilnanthanan, M.; Ravirajan, P.; Velauthapillai, D. Abstract: Platinum (Pt) is a widely used counter electrode (CE) material in dye-sensitized solar cells (DSSCs) due to its excellent catalytic properties. However, the steep cost limits its widespread adoption. This has spurred researchers to focus on carbon-based materials, which are abundant and economically viable alternatives. In this study, charcoal was derived from palmyrah seeds and activated by a simple thermal shock method involving rapid water immersion. This palmyrah seed-based activated charcoal (AC) was then combined with TiO2 to create a novel composite paste, enhancing amalgamation between carbon particles and adhesion of the carbon particles on the FTO glass substrate. XPS analysis confirmed the successful formation of the palmyrah seed-derived charcoal. Raman spectroscopic analysis revealed that the palmyrah seed-based AC showcases a graphite nature, a trait retained even in the composite film formed with TiO2. A DSSC was fabricated employing the as-prepared AC/TiO2 composite as the CE, N719 dye-coated TiO2 as the photoanode and an redox couple as the electrolyte. While the optimized AC/TiO2 (80:20) composite CE annealed at 400 °C demonstrated a power conversion efficiency (PCE) of 4.85%, an encouraging result relative to the PCE of a commercial Pt CE (6.88%), the AC/TiO2 composite offers a cost-effective and eco-friendly alternative, with potential for future optimization. Moreover, the device with the AC/TiO2 composite CE displayed notable catalytic reduction of to Ι– and greatest stability compared to the DSSC fabricated with Pt CE. Wed, 01 Jan 2025 00:00:00 GMT http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/13013 2025-01-01T00:00:00Z http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/13012 Title: MS2/TiO2 (M = Co, Sn and Ni) electrodes for electrocatalytic and photocatalytic water splitting Authors: Shanmugaratnam, S.; Srinivasan, S.; Yuvakkumar, R.; Oltedal, V.M.; Ravirajan, P.; Shivatharsiny, Y.; Velauthapillai, D. Abstract: Exploring an efficient and stable nanocatalyst for water splitting is a highly desirable, but still a challenging goal. Herein, we synthesized different metalchalcogenides (MS2: M = Co, Ni, Sn) embedded with TiO2 that form nanocomposites by the facile hydrothermal method for water splitting. The crystallinity and phases of the prepared materials were confirmed by X-Ray diffractive spectra; the morphology of the particles was studied by Scanning Electron Microscopy; and their superior catalytic performance in electrochemical and photocatalytic activity were examined using electrochemical characterization and photocatalytic experiments, respectively. In electrochemical processes, compared with bare TiO2, 10 wt% CoS2/TiO2, SnS2/TiO2, and NiS2/TiO2 nanocomposites exhibited high current densities with low Tafel slope values in hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). In addition, the amounts of hydrogen evolution in electrocatalysis and photocatalysis reactions were examined. These results show that metalchalcogenide (MS2) embedded with TiO2 nanocomposites electrodes are highly promising candidates to be used as efficient electro and photocatalysts for the water splitting process Wed, 01 Jan 2025 00:00:00 GMT http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/13012 2025-01-01T00:00:00Z http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/12960 Title: Mitigation of Self-p-Doping and Off-Centering Effect in Tin Perovskite via Strontium Doping Authors: Frasca, C.; Alippi, P.; Schwiddessen, R.; Prashanthan, K.; Nasti, G.; Zuo, S.; Ur Rehman, M.O.; Aldamasy, M.H.; Hartono, N.T.P.; Musiienko, A.; Abate, A. Abstract: Tin-based perovskite solar cells offer a less toxic alternative to their lead-based counterparts. Despite their promising optoelectronic properties, their performances still lag behind, with the highest power conversion efficiencies reaching around 15%. This efficiency limitation arises primarily from electronic defects leading to self-p-doping and stereochemical activity of the Sn(II) ion, which distorts the atomic arrangement in the material. In this study, we investigate the effect of strontium doping in tin-based perovskite on the distortion of the material’s structure and its optoelectronic properties. Using a combination of Density Functional Theory calculations and experiments, we demonstrate that strontium doping reduces p-doping and structural strain. This approach improves the efficiency from 6.3% in undoped devices to 7.5% in doped devices without relying on dimethyl sulfoxide, a harmful solvent for tin-based perovskites. This method could enable precise control of tin off-centering and self-p-doping, advancing the development of efficient and stable tin perovskite solar cells. Wed, 01 Jan 2025 00:00:00 GMT http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/12960 2025-01-01T00:00:00Z http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/12959 Title: Tailored Crystallization Dynamics for Efficient and Stable DMSO-Free Tin Perovskite Solar Cells Authors: Zuo, S.; Tarasov, A.; Frohloff, L.; Prashanthan, K.; Ruske, F.; Lounasvuori, M.; Frasca, C.; Dallmann, A.; Zu, F.; Mathies, F.; Scheler, F.; Hartono, N.T.P.; Guixiang, L.; Jinzhao, L.; Simmonds, M.; Wenhui, L.; Koch, N.; Albrecht, S.; Meng, L.; Unger, E.; Aldanmasy, M.H.; Musiienko, A.; Abate, A. Abstract: Tin perovskite solar cells are emerging as a sustainable lead-free alternative in thin film photovoltaics. DMSO-free processed tin perovskites are gaining interest due to the detrimental effects of DMSO on tin oxidation. However, replacing DMSO with other solvents remains challenging due to the accelerated crystallization dynamics in non-DMSO systems. In this study, the crystallization process in a DMSO-free solvent system is regulated by managing the transition from the sol-gel phase to the solid film. Specifically, piperazine dihydriodide (PDAI) and 4-tert-butylpyridine (tBP) are utilized to coordinately tune the colloidal chemistry through forming large pre-nucleation clusters in perovskite ink, further, facilitating the film formation process. By combining tBP and PDAI, a controllable crystallization rate is achieved as evidenced by in situ photoluminescence (PL) measurement during spin-coating. As a result, tin perovskite films show high crystallinity and improved microstructure. Devices treated with tBP+PDAI exhibit a champion power conversion efficiency of 7.8% and excellent stability without observable degradation for over 3000 h stored in the N2 glovebox. These findings advance understanding and managing crystallization in DMSO-free solvents processed tin perovskite solar cells. Wed, 01 Jan 2025 00:00:00 GMT http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/12959 2025-01-01T00:00:00Z