Effect of conductive substrate (working electrode) on the morphology of electrodeposited Cu2O

Cu2O thin fims were electrodeposited from a Cu(II) acetate solution containing 0.02 M<br>Copper(II) acetate (Cu(OAc)2) and 0.1 Msodium acetate (NaOAc) at pH 5.6, using three<br>different working conductive electrodes with approximately the same square resistance<br>-indium doped tin oxide glass (ITO/Glass), florine-doped tin oxide glass (FTO/Glass), and<br>Indium doped tin oxide Polyethylene terephthalate (ITO/PET)—under identical conditions<br>using a common growth condition. The Cu2O thin fims werecharacterized by means<br>ofscanning electron microscopy (SEM), x-raydiffraction (XRD),current density versus<br>growth time for Cu2O fims, and electrochemical impedance spectroscopy (EIS). The results<br>showed that the choice of substratematerials hasa crucial role in controlling of Cu2O growth.<br>The charge transfer resistance (Rct) of FTO/Glass-Cu2O exhibits the lowest value; this<br>means that FTO/Glass-Cu2O possess the highest electron transfer effiiency.All Cu2O fims<br>showed n-type semiconductor characteristic with charge carrier densities varying between<br>1.4 × 1018–1.2 × 1019 cm−3.本研究通过电沉积法制备氧化亚铜（Cu₂O）薄膜，电解液为pH 5.6的水溶液，其中包含0.02 M乙酸铜(II)（Copper(II) acetate, Cu(OAc)₂）与0.1 M乙酸钠（Sodium acetate, NaOAc）。实验选取三种方阻大致相当的导电工作电极：掺铟氧化锡玻璃（Indium doped tin oxide glass, ITO/Glass）、掺氟氧化锡玻璃（Fluorine-doped tin oxide glass, FTO/Glass）以及掺铟氧化锡聚对苯二甲酸乙二酯（Indium doped tin oxide Polyethylene terephthalate, ITO/PET），所有样品均在统一的生长条件下完成制备。 随后采用扫描电子显微镜（Scanning Electron Microscopy, SEM）、X射线衍射（X-ray Diffraction, XRD）、Cu₂O薄膜的电流密度-生长时间曲线以及电化学阻抗谱（Electrochemical Impedance Spectroscopy, EIS）对所制备的Cu₂O薄膜进行了系统表征。 研究结果表明，衬底材料的选择对Cu₂O的生长调控起着至关重要的作用。其中，FTO/Glass负载的Cu₂O薄膜的电荷转移电阻（Charge transfer resistance, Rct）最低，意味着该样品具备最高的电子传输效率。所有制备得到的Cu₂O薄膜均表现出n型半导体特性，其载流子浓度介于1.4 × 10¹⁸ 至 1.2 × 10¹⁹ cm⁻³之间。