Broadened and Enhanced Photoresponse of TiO 2 Nanotubes Through Progressive Copper Modulation
Juncai Wu, Shanhaotai Liu, Zhengyun Tian, Haoyu Jiang, Liqing Bu, Jinchen Yao, Jinshan Chen, Fayu Wu, Qingru LiuABSTRACT
To address the challenges of limited visible light absorption and severe charge carrier recombination in TiO 2 nanotube arrays, this study proposes a homologous modification strategy. By leveraging the unique photoelectric properties and bio‐functional advantages of copper‐based materials, we introduced them into the TiO 2 nanotube system and constructed two distinct composites through regulating the chemical state modulation of copper: the Cu@TiO 2 composite and its homologous CuO@TiO 2 composite (derived from the oxidation of Cu). Monochromatic light selective excitation was employed to accurately identify the actual dominant mechanisms in both composite systems and quantitatively evaluate the extension of their photoresponse ranges. Comparative results show that the Cu@TiO 2 composite extends its photoresponse range to 540 nm through surface plasmon resonance (SPR) effects, increasing the photocurrent density from 2.8 × 10 − 4 A·cm − 2 to 3.8 × 10 − 4 A·cm − 2 . The CuO@TiO 2 composite further redshifts the absorption edge to 640 nm and significantly enhances the photocurrent density from 2.9 × 10 − 4 to 4.2 × 10 − 4 A·cm − 2 by interfacial charge separation from Type‐II band alignment. As the research object evolves from Cu@TiO 2 to CuO@TiO 2 , the glucose detection sensitivity progressively improves, reaching 36.8 and 48.2 µA·cm − 2 ·mM − 1 , respectively.