本研究導入一垂直於基板的二氧化鈦單晶奈米柱陣列(TiO2 nanorod array)作為電子受體，提供電子一直接的傳導路徑，再利用旋轉塗佈法注入聚(3-己基噻吩) [poly(3-hexylthiophene-2,5-diyl), P3HT]作為電子施體，組裝P3HT/TiO2奈米柱異質接面太陽能電池。繼以釕(Ruthenium, Ru)有機金屬染料與二氫吲哚(Indoline)有機染料修飾二氧化鈦奈米柱表面，藉以改善電池中有機與無機之介面不相容的問題。此外，亦加入四-特-丁基吡啶 (4-tert-butylpyridine, TBP) 處理於二氧化鈦奈米柱表面，並分別探討染料和TBP對介面修飾之影響。利用循環伏安法(cyclic voltammetry, CV)及表面電位顯微鏡(Kelvin probe force microscope, KPM)定義費米能階(Fermi level)對齊(aligned)後各層材料之能階位置，證明高吸光係數之染料與P3HT可同時提供光電流。利用時間解析光激螢光光譜(time-resolved photoluminescence, TRPL)及電化學交流阻抗分析(electrochemical impedance spectroscopic, EIS)分別分析電荷轉移與再結合特性。經由TBP進一步處理D149修飾介面之元件，促使P3HT的光電子能有效的在介面分離，同時也抑制了逆反應發生的機率及降低電子的傳輸阻力。在二氧化鈦奈米柱長度為650 nm下，此元件之最佳效率達1.9 %，其Voc= 0.50 V，Jsc= 6.76 mA/cm2，而FF= 0.56。此外，經D149介面修飾之元件，進一步將二氧化鈦奈米柱長度增長為1.5 µm，效率可達2.63 %。

TiO2 nanorod (NR) array/poly(3-hexylthiophene) (P3HT) heterojunction solar cells have been fabricated in this study. The vertically aligned single crystal TiO2 nanorod (NR) array was synthesized on the FTO substrate by hydrothermal method. Significant enhancement of the cell efficiency is achieved by interfacial modification using Ruthenium dye and Indoline dye as well as further treating with 4-tert-butylpyridine (TBP). Cyclic voltammetry (CV) and Kelvin probe force microscope (KPM) are employed to determine the aligned energy level diagrams of the devices. Both dye molecule and P3HT contributing to photocurrent generation of the interface-modified heterojunction solar cells is therefore concluded according to the energy level diagrams. Moreover, the charge separation and recombination in the interface-modified TiO2 NR array/P3HT heterojunction solar cells are investigated by time-resolved photoluminescence (TRPL) and electrochemical impedance spectroscopic (EIS). With a TiO2 NR thickness of 650 nm, the D149/TBP-modified TiO2 NR array/P3HT heterojunction solar cell possesses an efficiency of 1.9 % with a short circuit current density (Jsc) of 6.76 mA/cm2, an open circuit voltage (Voc) of 0.5 V, and a fill factor (FF) of 0.56. The enrichment of cell performance is attributed to the enhancement of charge separation and suppression of recombination at TiO2 NR/P3HT interface and improvement of electron transporting in TiO2 NR by the modification of effective dye and TBP. A efficiency of 2.63 % is further achieved in the D149-modified cell by elongating the TiO2 NR thickness to 1.5 µm.

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