Impact of post-annealing temperature on silver bismuth sulfide quantum dot-sensitized solar cells fabricated by successive ionic layer adsorption and reaction method
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Date
2024-11-01
Authors
Rajakaruna, R. P. P. D.
Bandara, J.
Journal Title
Journal ISSN
Volume Title
Publisher
Postgraduate Institute of Science (PGIS), University of Peradeniya, Peradeniya ,Sri Lanka
Abstract
Nontoxic semiconductor materials are becoming increasingly used for solar cell fabrication and among them, silver bismuth sulfide (AgBiS₂) is a forefront ternary semiconductor material. AgBiS₂ nanocrystal has a high absorption coefficient, high mobility, and tunable bandgap. In this study, the performance of AgBiS₂ quantum dot-sensitized solar cells was investigated based on post-annealing temperature. AgBiS₂ quantum dots (QDs) were deposited on a TiO₂ mesoporous layer using the successive ionic layer adsorption and reaction (SILAR) method, with the optimal number of SILAR cycles being determined to be three. After deposition, AgBiS₂ QDs solar cells were kept overnight and subsequently annealed at 50, 100, 150 and 200 °C for one hour on a hotplate in ambient air. Raising the annealing temperature to 100 °C increased the short-circuit current density, open-circuit voltage, and fill factor. However, further increasing the annealing temperature resulted in degradation of solar cell performance. The cell with the configuration of FTO/m-TiO₂/AgBiS₂/polysulfide-electrolyte/Cu₂S-brass plate annealed at 100 °C has the maximum power conversion efficiency of 0.6%. The observed variations in solar cell performance of FTO/m-TiO₂/AgBiS₂/polysulfide-electrolyte/Cu₂S-brass plate electrodes have a direct relationship with the post-annealing temperature of AgBiS₂ QDs. Transmission electron microscopy study showed the formation of AgBiS₂ QDs with crystalline phases of 200 and 220 for the pre-annealed AgBiS₂ QDs at 100 °C, and Energy-dispersive X-ray spectroscopy data validated the presence of Ag, Bi, and S on the TiO₂ mesoporous layer. X-ray diffraction analysis revealed that post-annealing of AgBiS₂ film enhanced the 111 and 222 crystalline phases, while the 200 and 220 crystalline phases increased up to 100 °C and subsequently decreased. UV-Vis spectra revealed that increasing the annealing temperature up to 100 °C increased the absorption of AgBiS₂ QDs, whereas above 100 °C absorbance was reduced and the absorption peak was red shifted by 70 nm.
Description
Keywords
AgBiS₂ , Crystallinity , Nontoxic , Post-annealing
Citation
Proceedings of the Postgraduate Institute of Science Research Congress (RESCON) -2024, University of Peradeniya, P 183