| 摘要: | 本實驗主要是合成新的有機染料以spiro[cyclopenta[2,1-b:3,4-b’] dithiophene-4,9’- fluorene]為分子結構中間之架橋(spacer)，分別以diphenylamine、bis(4-methoxyphenyl)amine和carbazol作為推電子基，cyanoacrylic acid為拉電子基。並分別用核磁共振光譜儀(NMR)、質譜儀鑑定化合物之結構；紫外/可見光光譜儀、螢光光譜儀鑑定化合物之吸收、放光波長及染料在溶劑中之穩定度；由循環電位儀計算得知化合物之HOMO、LUMO值；並將染料製作染料敏化太陽能電池(dye - sensitized solar cells，DSSCs)探討其光電轉換效率。其中以carbazol為推電子基之spirofluorenebithiophene染料所製作之染料敏化太陽能電池，在AM 1.5太陽光(100 mW/cm2)照射下，其光電轉換效率(η)為3.4 %，短路電流(Jsc) 8.65 mA cm-2；開路電壓(Voc) 0.57 V；fill factor (FF) 0.70。 實驗結果顯示，有螺旋結構π共軛架橋，染料光穩定度顯著提昇，染料的吸收波長較長、消光係數亦增加，但螺旋的立體障礙結構大幅降低染料在二氧化鈦表面之覆蓋率，是造成所製作的太陽能電池光電轉換效率不及沒有螺旋結構染料之染料敏化太陽能電池的原因。 New organic dyes that contain spiro [cyclopenta[2,1-b:3,4-b'] dithiophene-4,9'-fluorene] conjugate spacer between arylamine donor (diphenylamine, bis(4-methoxyphenyl) amine and carbazol) and the cyanoacrylic acid acceptor have been synthesized. These compounds are characterized by 1H NMR, 13C NMR, mass spectrometry, UV / visible spectrometer, fluorescent spectrometer and cyclic voltametry in the estimation of HOMO and LUMO energy levels. These dyes were developed as the sensitizers for the application in dye-sensitized TiO2 nanocrystalline solar sells (DSSCs). A power conversion efficiency (ηPCE) of 3.4 % was determined with the DSSC based on 6-(5-(4-(9H-carbazol-9-yl)phenyl)thiophen-6-yl)spiro[cyclopenta[2,1-b:3,4-b’]dithiophene-4,9’-fluorene]-2-cyanoacrylic acid (SCZ) under simulated AM 1.5 G irradiation (100 mW / cm2): short-circuit current density (Jsc) of 8.65 mA cm-2; open-circuit voltage (Voc) of 0.57 V; fill factor (FF) of 0.70. The experimental results show that the DSSC dyes possess spirofluorenyl group enhance the photo-stability, molar extinction coefficient, and the red-shifting of UV-visible absorption wavelength. Nevertheless, compared with the bithiophene centered DSSC dyes, the steric hindrance of the spirofluorenyl group impedes the dye adsorption on TiO2 and hence decrease the power conversion efficiency of DSSCs. |
