摻雜硼酸之混相二氧化鈦奈米顆粒特性與染料敏化太陽能電池之應用

本文中利用在混相的二氧化鈦奈米顆粒當中摻雜不同重量百分比的硼酸，並從中探討其表面結構、缺陷狀態、光激發螢光的特性以及光電轉換效率的表現。從X光繞射的測量結果觀察摻雜硼酸後的二氧化鈦奈米顆粒的晶格尺寸以及混相中的金紅石相比例在不同濃度硼酸摻雜之後的變化。在二氧化鈦薄膜分析量測，利用紫外光/可見光進行分析出二氧化鈦摻雜硼酸後的能帶間隙會縮減，而且會因此延展可見光的吸收範圍，未摻雜硼酸的二氧化鈦則呈現出會吸收大量的紫外光的結果。摻雜硼酸後，硼離子會削減Ti4+的數量，造成氧缺陷的產生，進而影響電子在染料敏化太陽能電池中的傳導性，多餘的電子源自於二氧化鈦的氧缺，此現象影響了能帶中的導帶會往價帶靠近並驅使光電子從金紅石相的導帶走向能量較低的銳鈦礦相束縛區域，接著分散電荷而產生更多光電流及短路電流。電化學阻抗找出摻雜硼酸的二氧化鈦工作電極與電解液之間的RK值較小，即兩者之間的電子重組能力較強會影響到電子傳導，但是其電子生命週期以及電子數目都是較高，分別為19.7ms以及2.1´1018 cm-3。

關鍵字

電子特性；光伏特性；光激發光光譜； X光繞射分析；氧缺陷

並列摘要

In this study, using different boron weight percentages on mixed-phase (anatase and rutile) TiO2 nanoparticles were prepared to investigate structure morphology, defect states, luminescence properties and energy conversion. The result shows boron doping crystallite size and increases the rutile-phase percentage in an anatase matrix. Decreasing the band gap by boron doping can expand the absorption to the visible region, when undoped TiO2 exhibits high UV absorption. Oxygen vacancy defects are generated by boron ions reducing Ti+4 and influence electron transport on dye-sensitized solar cells. Excess electrons originating from the oxygen vacancies of doped TiO2 affect a downward shift in the conduction band edge and prompt the transfer of photoelectrons from the conduction band of the rutile phase to the lower energy anatase trapping sites; they separate charges to enhance the photocurrent and Jsc. Even though the resistance of the electron recombination (Rk) between doped TiO2 photoanode and the electrolyte for the doped TiO2 sample is lower, but a longer electron lifetime (τ) of 19.7 ms with a higher electron density (ns) of 2.1´1018 cm-3 contributes to high solar conversion efficiency.

並列關鍵字

oxygen vacancy ； photoluminescence ； energy dispersive analysis of X-rays ； Electronic characterization ； Photovoltaic

參考文獻

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摻雜硼酸之混相二氧化鈦奈米顆粒特性與染料敏化太陽能電池之應用

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