Commitment Between Roughness and Crystallite Size in the Vanadium Oxide Thin Film opto-electrochemical Properties

The V2O5 thin films has been widely studied because it has application as ionic host in electrochromic and lithium-ion batteries, two technologies that have an intimate connection with sustainability as substitutes for fossil energies and as agents for improving energy efficiency. In electrochromic technology, V2O5 is applied as a passive electrode due to its high transmittance and small contrast, and its reversibility on electrochemical reactions. To contribute to increase the optical and charge efficiency of V2O5 thin film passive electrodes, were investigated in this work the influence of the morphological properties, crystallite size and roughness, on the reversible specific charge capacity and the respective optical responses. The films morphological properties were modified by varying their thickness to the nanoscale. The films were deposited by thermal evaporation from powdered V2O5. The crystallite size and surface roughness were measured respectively by XRD and AFM. The results showed that the charge capacity is directly proportional to the surface roughness and inversely proportional to the crystallite size. The film optical contrast and the nominal transmittance shows to be improved according to their morphological properties. In conclusion, the V2O5 opto-electrochemical properties can be improved, increasing the efficiency on the light control processes.

五氧化二钒(V₂O₅)薄膜已被广泛研究，因其可作为电致变色(electrochromic)与锂离子电池中的离子宿主材料；这两类技术作为化石能源的替代品与能源效率提升介质，与可持续发展有着紧密关联。在电致变色技术领域，五氧化二钒凭借高透过率、低对比度以及电化学反应可逆性，被用作惰性电极。为优化五氧化二钒薄膜惰性电极的光学与电荷效率，本研究探讨了形貌特性、晶粒尺寸与表面粗糙度对可逆比容量及对应光学响应的影响。本研究通过调控薄膜的纳米级厚度来改变其形貌特性，采用热蒸发法以五氧化二钒粉末为原料制备薄膜，并分别通过X射线衍射(XRD)与原子力显微镜(AFM)表征晶粒尺寸与表面粗糙度。结果表明，电荷容量与表面粗糙度呈正相关，与晶粒尺寸呈负相关；薄膜的光学对比度与标称透过率可随其形貌特性得到改善。综上，五氧化二钒的光电化学性能可得到优化，从而提升光调控过程的效率。