Cost-effective Sb-doped SnO2 films as stable and efficient alternative transparent conducting electrodes for dye-sensitized solar cells

Abstract

Indium tin oxide (ITO) is a ubiquitous transparent conducting oxide (TCO) used in various optoelectronic devices, owing to its high optical transmittance and high electrical conductivity. The rarity of indium metal in the earth's crust leads to a significant increase in the production cost of ITO, thereby triggering the quest for novel alternative materials. In this scenario, undoped SnO₂ (TO) and Sb (antimony)-doped SnO₂ (ATO) large-area thin films have been deposited using a facile cost-effective spray pyrolysis technique, where ATO qualified as an efficient alternative TCO in DSSCs. Intriguingly, the doping of Sb in the SnO₂ lattice without structural change leads to an improvement in the properties and performance of DSSCs. The surface of the ATO conductive electrode increases the hydrophilicity due to high surface roughness compared to that of the undoped tin oxide (TO) electrode. A figure of merit of 8.23 × 10⁻³ Ω⁻¹ with a low sheet resistance value of 12.18 Ω □⁻¹ and a transmittance of 80% at 550 nm was achieved for doped electrodes on par with that of commercial ITO (1.52 × 10⁻³ Ω⁻¹). Moreover, the ATO conductive electrode shows a lower resistivity of 6.09 × 10⁻⁴ Ω cm, higher carrier concentration (6.20 × 10²⁰ cm⁻³), low mobility (16.49 cm² V⁻¹ s⁻¹) and thermal stability of the sheet resistance up to 400 °C (sheet resistance = 14 Ω □⁻¹, after thermal treatment) when compared to the undoped TO electrode. The fabricated DSSC using the spray-deposited ATO conductive electrode exhibits a maximum efficiency of 4.05%. These promising results indicate its viability as an efficient alternative TCO electrode for optoelectronic device applications.