Effects of Ga doping and hollow structure on the band-structures and photovoltaic properties of SnO2 photoanode dye-sensitized solar cells

Abstract

The photon-to-electricity conversion properties of the prepared photoanode based on SnO₂ nanocrystals, which are assembled as the rough hollow microspheres (RHMs), are improved by aliovalent Ga³⁺ doping. The conduction band (CB) of the doped SnO₂ shifts negatively with increasing the Ga content from 1 to 5 mol% gradually. Moreover, the prepared Ga-doped SnO₂ photoanode shows an advantage in repressing the charge recombination. As a result, both the negative shift of the CB and repressed charge recombination enhance the open-circuit photovoltage (V_oc) and the short-circuit photocurrent (J_sc) of the DSSCs, and the power conversion efficiency (η) is increased by 80% at 3 mol% Ga-doping SnO₂ to compare with the undoped SnO₂ for DSSCs (AM 1.5, 100 mW cm⁻²). After treating the samples with TiCl₄, an overall photoconversion efficiency (approximately 7.11%) for SnO₂ based DSSCs is achieved.