Zinc Stannate (Zn₂SnO₄)-Based Hybrid Composite Photoanode for Dye-Sensitized Solar Cell Application

Abstract

Improving the power conversation efficiency of dyesensitized solar cells (DSSCs) has become a challenge and a matter of interest for researchers. Designing a simple device structure with better performance by a cost-effective fabrication technique is essential for photovoltaic technology. This study emphasizes an alternative hybrid composite photoanode material for the DSSC devices. Pristine Zn 2 SnO 4 and Zn 2 SnO 4 -SnO 2 and Zn 2 SnO 4 -ZnO composites were synthesized by facile solid-state calcination to prepare the photoanode for DSSCs. The structural, surface morphological, optical, and band structural properties of the synthesized samples were studied. An attempt has been made to correlate the power conversion efficiency of the fabricated devices with the investigated properties. The X-ray diffraction analysis confirms the presence of multiphases that depend on the stoichiometric ratio of precursor materials. The surface morphology analysis reveals that the Zn 2 SnO 4 -SnO 2 and Zn 2 SnO 4 -ZnO composites exhibit microsheet and microrod structures, respectively. The composite materials show a higher amount of dye loading, leading to better performance than the pristine Zn 2 SnO 4 sample. A better band matching of the synthesized composite materials with other layers provides a higher carrier density. The composite photoanodes exhibit higher efficiency (6.26% for Zn 2 SnO 4 -SnO 2 and 4.48% for Zn 2 SnO 4 -ZnO) than the pristine Zn 2 SnO 4 photoanode (3.76%). The results indicate that the Zn 2 SnO 4 -based composites can be potential materials for photoanode applications.

Enhancing the perovskite solar cell performance by the interface modification of Zn–Sn–O compound heterostructures

“…A sample with an excess of Zn content (ZTO–ZnO) has relatively bigger particles, whereas a Sn excess sample (ZTO–SnO 2 ) shows homogeneous particle formation with dense film formation. 34 In the case of the pristine sample agglomerated particle formation leads to more surface roughness which can significantly affect the charge transfer process of the devices. It has been reported that the surface roughness of the thin film effectively controls the charge transfer process of the PSC device.…”

“…The detailed synthesis process has been reported in our earlier work. 34 In brief, the required amount of zinc and tin metallic powders were ball milled for 12 h in ethanol media to obtain homogenous composite powders. Subsequently, the obtained powders were annealed at 950 °C for 8 h in the presence of oxygen to obtain the final products.…”

“…An enhanced fill factor and current density were achieved due to a more surface-to-volume ratio of the dense and homogeneous surface morphology of the ZTO-SnO 2 sample compared to the surface morphology of the ZTO-ZnO sample. 34 The sheet-like surface morphology can promote effective charge transport at the interfaces between perovskite and ETL heterostructures. 28 The multiband structure of the heterostructure with other layers can be another cause for improved efficiency.…”

“…34 Therefore, the surface modification of the ETL influences the transfer process more effectively. 34 Transferring the charges in dense surface structures is relatively more accessible than in in-homogeneous/agglomerated surface structures. The mobility of charge carriers is affected by the agglomerated surface structure, whereas in dense surface structures, charge transfer occurs more effectively.…”

“…The FESEM images show a significant variation in surface morphologies based on their composition ratio (Fig.2(a)-(c)). A sample with an excess of Zn content (ZTO-ZnO) has relatively bigger particles, whereas a Sn excess sample (ZTO-SnO 2 ) shows homogeneous particle formation with dense film formation 34. In the…”