In-depth understanding of catalytic mechanism in solar cells via synergistic effect of interfacial engineering and structural integration

Abstract

Establishing robust yet high-efficiency counter electrode (CE) is an essential challenge for dye-sensitized solar cells (DSSCs). The CE made of carbon-based catalysts is experimentally proved to be an ideal alternative for noble Pt metal in DSSCs. Nevertheless, its reaction mechanisms remain unclear because of the lack of comprehensive understanding of its physical and chemical properties. Here, the DSSC based on the Ni3B/NiO incorporating N-doped carbon hollow spheres (N-CHS) and RGO (N-CHS/(Ni3B/NiO)/RGO) CE achieved a high power conversion efficiency (PCE) of 9.57%, which is 26.92% higher than that of the DSSC based on Pt CE. This can be attributed to: Firstly, RGO further promotes the formation of the Ni3B/NiO heterostructure to enhance electrocatalytic performance. Secondly, N-doping stimulates catalytic activity, benefited from the generation of more defects. Ultimately, the structural advantage of N-CHS/(Ni3B/NiO)/RGO nanocomposites not only lead to a high density of interfaces between the Ni3B and NiO components while maximizing its use efficiency but also synergistically accelerate the kinetics, thus boosting the PCE. This article highlights a powerful strategy of interfacial engineering and structural integration to rationally design nano-functional materials in energy conversion related fields.