V₂O₅ as Hole Transporting Material\nfor Efficient All Inorganic Sb₂S₃ Solar Cells

Abstract

This\nresearch demonstrates that V₂O₅ is able\nto serve as hole transporting material to substitute organic transporting\nmaterials for Sb₂S₃ solar cells, offering all\ninorganic solar cells. The V₂O₅ thin film is\nprepared by thermal decomposition of spin-coated vanadium­(V) triisopropoxide\noxide solution. Mechanistic investigation shows that heat treatment\nof V₂O₅ layer has crucial influence on the power\nconversion efficiency of device. Low temperature annealing is unable\nto remove the organic molecules that increases the charge transfer\nresistance, while high temperature treatment leads to the increase\nof work function of V₂O₅ that blocks hole transporting\nfrom Sb₂S₃ to V₂O₅. Electrochemical\nand compositional characterizations show that the interfacial contact\nof V₂O₅/Sb₂S₃ can be essentially\nimproved with appropriate annealing. The optimized power conversion\nefficiency of device based on Sb₂S₃/V₂O₅ heterojunction reaches 4.8%, which is the highest power\nconversion efficiency in full inorganic Sb₂S₃-based solar cells with planar heterojunction solar cells. Furthermore,\nthe employment of V₂O₅ as hole transporting\nmaterial leads to significant improvement in moisture stability compared\nwith the device based organic hole transporting material. Our research\nprovides a material choice for the development of full inorganic solar\ncells based on Sb₂S₃, Sb₂(S,Se)₃, and Sb₂Se₃.