太陽光電產氫反應器中MnxTi1-xO2薄膜電極之研究

The study of MnxTi1-xO2 film electrode in solar photoelectrical hydrogen production reactor

宋國輝(Guo-Hui Sung)

指導教授 ： 陳志臣

國立中央大學/工學院/材料科學與工程研究所/碩士(2007年)

摘要

本論文主要探討摻雜不同濃度Mn2+ 離子在不同退火溫度下之TiO2薄膜對光電流的影響。成膜方式主要以溶膠凝膠法，並以旋轉塗佈鍍製備TiO2薄膜，其優點在於製程簡單、成本低廉、產物品質佳且可提高摻雜物均勻性。TiO2薄膜有極佳物理及化學穩定性、高比表面積、高多孔性、高光電化學和光催化性質，但由於TiO2薄膜屬寬能隙，無法在可見光波段被吸收，藉由掺雜Mn2+ 離子以降低TiO2能隙，增加太陽光的吸收，提升光電流產生的效率。在MnxTi1-xO2薄膜中分別取x=0、0.02、0.05及0.1四種不同摻雜量，觀察在空氣氣氛下不同退火溫度對於MnxTi1-xO2的薄膜結構、吸收光譜、光電流性質的影響。本研究發現在550℃退火下，MnxTi1-xO2薄膜結晶性較佳；摻雜Mn2+ 離子後，能隙明顯降低，有利於太陽光的吸收，但會造成光激發後電子-電洞對的再結合效應，透過外加偏壓後能有效分離電子-電洞對，以提升光電流效率。當摻雜Mn2+ 離子濃度增加至10mol%（X＝0.1），在固定偏壓0.8V下，可產生最大光電流0.68 mA/cm2。

關鍵字

摻雜錳 ； 光電極 ； 溶膠-凝膠法 ； 二氧化鈦 ； 光電化學

並列摘要

In this study, we investigated the influence of Mn2+ doped TiO2 thin films ions under different temperature of annealing treatment on photocurrent. The TiO2 thin films were prepared by sol-gel spin coating. There are several advantages in this method like simplity process, lower cost, better product quality, and more dopant uniform. TiO2 has excellent physical and chemical stability, high specific surface area, high porosity, and high photoelectrochemical and photocatalytic activity. Since the undoped-TiO2 films have high energy gap, they are not useful in the visible range. In order to reduce energy gap, we have doped Mn2+ ions into TiO2 films and to enhance the absorption of the visible light. Furthermore, the sol-gel spin coating method was employed to prepare the MnxTi1-xO2 thin films, where x=0, 0.02, 0.05 0.1. We have also studied the structure, absorption spectra, and photocurrent of the MnxTi1-xO2 films in air atmosphere with different annealing temperature. We found that the TiO2 films have good structure with annealing temperature of 550℃ and the energy gap reduces after doping the Mn2+ ions. As results of TiO2 doped Mn2+ ions, the recombination of electrons and holes will be enhanced. In addition, a bias potential can be applied to accelerate the separation of photogenerate electrons and holes to improve efficiency of photocurrent. The TiO2 films with 10 mol% Mn2+ have a max photocurrent value of 0.68 mA/cm2 when annealing temperature was 550℃and the bias potential was 0.8 V.

並列關鍵字

PEC ； photoelectrochemical ； electrode ； Mn ； doping ； TiO2

參考文獻

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