Effect of SnO2 Nanoparticles on Band Gap Energy of x(SnO2)-y(Ag)-β-Carotene/FTO Thin Film

Abstract

SnO2 shows higher electron mobility (100-200 cm2V-1s-1) than TiO2 (0.1-1.0 cm2V-1s-1), indicated that it has higher electron diffusion transport. As a result, it may minimize interfacial charge recombination losses to oxidized redox species in the electrolyte or solid-state hole transporter, thus enhancing solar cell device performance. Many researchers have done the synthesis of SnO2 by controlling morphologies and architectures to optimize solar cells performance. Unfortunately, it's just view of them investigated the properties of the composite SnO2 with metallic materials and its potentials for solar cell devices. In this work, SnO2 nanoparticles, Ag nanoparticles, and β-Carotene were composited with a various mass portion of SnO2 nanoparticles to control the band gap energy and the other optoelectronic properties. The composites subsequently were deposited on FTO substrates using spin coater. The thin film of SnO2-Ag-β-Carotene/FTO composites were characterized by UV-Vis, FTIR spectroscopy, and XRD measurements. We found that the maximum direct band gap energy of 3.74 eV was reached by the sample 20, while the minimum direct band gap energy of 3.54 eV was achieved by sample 15. The maximum indirect band gap of 1.59 eV resulted in sample 20. On the other hand, the minimum value of the indirect band gap is 1.27 eV achieved by sample 25. Both direct and indirect Tauc plot analysis showed that there was no significant influence of SnO2 mass portion on the band gap energy of SnO2-Ag-β Carotene composite thin film. But it was a fact that each mass fraction composites had different band gap energy. This fact can be used to control the band gap energy to optimize the use of SnO2 composite as DSSC electron transporting electrode. The FTIR spectroscopy and XRD result were also detail examined in this work.