吲哚啉染料運用在多種後處理二氧化鈦奈米管薄膜陣列的染料敏化太陽能電池元件

Abstract

本論文研究目的為研究並提升吲哚啉染料於二氧化鈦奈米管吸咐性質並應用於染料敏化太陽能電池以提高能源轉換效率。吲哚啉染料分子為有機染料，其相較於金屬染料具有較便宜、高消光係數、易調整吸收光譜等優點。實驗中我們發現溶解於第三丁醇及甲醇中之吲哚啉染料在二氧化鈦奈米管上具有較佳的吸附性質，對吲哚啉染料敏化太陽能電池較佳的光電極長度約為18.5μm。針對二氧化鈦奈米管做各種後處理以增加吲哚啉分子在奈米管上的吸附量，經過TiCl4處理的二氧化鈦奈米管具有最高的吸附量，而經過鹽酸處理後將第二次燒結溫度500℃時經水熱處理後的二氧化鈦奈米管具有最高的效率並且吸附量也有提升，二氧化鈦奈米管分別經過水熱處理、鹽酸處理的吸附量也都有提升。經過X光繞射圖譜判定在銳鈦礦上的結晶強度各種處理都有加強的結果，二氧化鈦奈米管光電極經過各種處理後與吲哚啉分子間的鍵結方式並未改變，經由電化學頻譜分析後所得結果可以更加清楚瞭解到除了吸附量上升加強效率外還有其他加強的因素。將吲哚啉染料分子運用到可撓式結構上，可以量測到吲哚啉分子在二氧化鈦上的吸收光譜，會有紅移以及藍移現象，使得吸收光譜寬化，有利於吸收光子。在可撓式結構上效率較差主要是由於填充因子減少許多，但是可以利用經過水熱後的二氧化鈦奈米管的親水性較佳，讓PDMS可有效的滲透入奈米管的內部作為阻擋層，減低ITO與電解液間的漏電。

In this thesis, we study and improve the adsorption of an indoline dye, D149, on the titanium dioxide nanotubes for application in dye-sensitized solar cells to improve the energy conversion efficiency. D149 is an organic dye, which is cheaper than conventional ruthenium dyes, and it has higher extinction coefficient. In our experiment, we found the dye loading on the TiO2 nanotubes increased when D149 was dissolved in tert-butanol with methanol. The length of the titanium dioxide nanotubes of approximately 18.5 μm is prefered for D149-sensitized solar cell. We applied different post-processing nanotubes to increase the amount of D149 adsorbed on the nanotubes. TiCl4 treatment resulted into the highest amount of adsorption, and treatment of HCl trimming with hydrothermal process for titanium dioxide nanotubes showed the most efficient charge collection. According to the infrared spectroscopy, the post treatments did not change the chemical bonding between the indoline dye and the nanotubes. Based on electrochemical impedance analysis, the performance of the D149-sensitized nanotube solar cells was known to be improved by the post treatment due to the increased dye loading and the enhanced charge collection efficiency of the nanotubes. The absorption spectrum of D149 adsorbed on titania nanotubes was directly measured by transferring the nanotubes to a transparent substrate by poly-dimethylsilane (PDMS). The spectrum of D149 showed simultaneous red shift and blue shift when adsorbed on the nanotubes, which broaden the absorption spectrum. The red shift of D149 adsorbed on the nanotubes was observed to be stronger than the red shift of D149 adsorbed on nanopartibles. This could be caused by the more regular arrangement of D149 adsorbed on the sidewall of the nanotubes. As a result, the red shift of the D149 was influenced by certain post treatment of the nanotubes because of the roughened nanotube surface.