Varadharajaperumal, S.Alagarasan, D.Sripan, C.Ganesan, R.Satyanarayan, M.N.Hegde, G.2026-02-052021Materials Research Bulletin, 2021, 133, , pp. -255408https://doi.org/10.1016/j.materresbull.2020.111081https://idr.nitk.ac.in/handle/123456789/23513Surface level sulphur (S) doped TiO<inf>2</inf> nanorods (S-TNRs) were fabricated via toxic-free novel three-step processes such as low-temperature hydrothermal method followed by thermal evaporation (S layer) and post-annealing (350 °C, 450 °C and 550 °C) techniques. Present work focuses on the comprehensive studies of surface level doping, structure, morphology and compositional properties of different temperature annealed S-TNRs for CZTS thin-film (Au/CZTS/S-TNRs/TNRs/FTO) solar cells. The oxidation states of incorporated S atoms in the TiO<inf>2</inf> matrix were identified from X-ray photoelector spectroscopy (XPS) analysis. A reduction in bandgap for 350 °C annealed S-TNRs film was observed from UV-Vis spectroscopy. The electrical characteristics showed the fabricated solar cells strongly depend on the S-TNRs annealing temperature. Proposed technique would be useful in effective and controlled (surface level) doping of S atoms into any desired nanostructured metal oxides for optoelectronic applications and, further useful in fabricating cadmium (Cd) free buffer layer in chalcogenide solar cells. © 2020 Elsevier LtdAnnealingBuffer layersHeterojunctionsMorphologyNanorodsOxide mineralsSemiconductor dopingSulfurTemperatureThermal evaporationThin filmsTitanium dioxideUltraviolet visible spectroscopyAnnealing temperaturesChalcogenide solar cellsCompositional propertiesElectrical characteristicLow-temperature hydrothermal methodsNanostructured metalsOptoelectronic applicationsUV-vis spectroscopyThin film solar cells