Ag@TiO2核殼型奈米複合材料應用於染料敏化太陽能電池之研究

Ag@TiO2 Core-Shell type nanocomposites for Dye-sensitized solar cell

蕭新翰(Hsin-Han Hsiao)

指導教授 ： 張合 ； 魏大華

國立臺北科技大學/機電學院/機電整合研究所/碩士(2013年)

https://doi.org/10.6841/NTUT.2013.00339

摘要

本本研究主要是利用改善後之溶膠凝膠法，於低溫的環境下合成二氧化鈦奈米粒子並將其與銀奈米金屬結合，形成以奈米金屬為內核、二氧化鈦完整包覆於外表的核殼型奈米複合材料，探討合成條件對於粒徑、結構、表面特性等性質的影響，並應用在染料敏化太陽能電池之光陽極，量測其封裝完成之光電轉換效率、紫外光遮蔽、光電化學反應等應用的分析探討。藉由化學還原法合成出純銀奈米金屬，將醇氧鈦前驅鹽之酒精溶液與銀奈米金屬溶液混合，使二氧化鈦完整包覆於奈米銀奈米金屬表面，合成出銀@二氧化鈦核殼型複合材料，將此製備銀@二氧化鈦核殼型複合材料粉末，與Triton X-100以及PEG均勻混合後，利用旋轉塗佈機塗佈於參氟二氧化錫導電基板(FTO) 透明導電玻璃上，而完成染料敏化太陽能電池光電極之製備。
銀@二氧化鈦核殼型複合材料結構，藉由銀奈米粒子具有之表面電漿共振的特性，能夠吸收可見光激發電子電洞，而且純金屬和二氧化鈦N型半導體接觸，會於介面形成蕭特基能階彎曲之現象，因此可有效的將電池之光電反應從紫外光延伸至可見光區域，僅吸收可見光能量即可激發電子電洞對進行光電化學反應。
而完整的二氧化鈦包覆於銀奈米金屬表面可有效保護內部金屬不受外在環境的侵蝕，使其能兼具銀奈米金屬優點，以及二氧化鈦奈米光電材料的特性，並可有效延長材料使用壽命。此外，本研究將銀@二氧化鈦核殼型複合材料處理得到之粉末，利用旋轉塗佈機塗佈於FTO導電玻璃上，經過450℃之熱處理後，將試片隔絕光源浸泡染料24小時，經由實驗結果顯示，其完成染料敏化太陽能電池之封裝結構光電轉換效率可達3.67%。
另外，以不同比例Ag@TiO2核殼型奈米複合材料奈米粉末與Degussa P25TiO2奈米顆粒混合，在比例3：7時有著最佳光電轉換效率5.5%；進而增加光陽極薄膜厚度可達到最佳28μm膜厚，進而提升11.2%，光電轉換效率為6.06%。而相較於純Degussa P25TiO2奈米顆粒26μm，效率提升了17%。

關鍵字

染料敏化太陽能 ； 光電極 ； 銀@二氧化鈦核殼複合材料 ； 溶膠凝膠法

並列摘要

This study employed improved sol-gel method to synthesize nanoparticle of TiO2 and combined it with silver nanometal under low temperature, forming a core-shell nanocomposite which had the nanometal as the core and the TiO2 as the intact coating, in order to explore the effect of synthesis conditions on particle size, structure, and surface characteristics. The material prepared was then packaged to serve as photoanode of the dye-sensitized solar cell, and its application to photoelectric conversion efficiency, UV shielding, and photoelectrochemical reaction were then measured for analysis and discussion.Pure silver nanometal was generated by chemical reduction method, and then its solution was blended with alcoholic solution of alcohol titanium oxide precursor salt to allow TiO2 to coat on surface of the silver nanometal and synthesize Ag@TiO2 core-shell composite. Powder of the Ag@TiO2 core-shell composite was then mixed with Triton X-100 and PEG uniformly and coated on a transparent conductive glass made of fluorine-doped tin oxide conductive substrate (FTO) using a rotary coating machine, so preparation of photoanode of dye-sensitized solar cell was finished.
With its structure, silver nanoparticle of Ag@TiO2 core-shell has the characteristic of surface plasma resonance and so can absorb visible light to excite electron-hole. In addition, contact between pure metal and N-shaped TiO2 semiconductor occur the phenomenon of Shottky energy level bend on the interface, so photoelectronic reaction of the cell expands from UV to visible light area. It excites electron-hole pairs to start photoelectrochemical reaction by absorbing only visible light. The intact coating on the surface of silver nanometal effectively protects the interior metal from the corrosion caused by the external the environment. Thus it has the advantage of silver nanometal and the characteristic of TiO2 nano photoelectric material, in which way it prolongs life of the material.Furthermore, this study coated the powder of Ag@TiO2 core-shell composite to FTO conductive glass with a rotary coating machine. After heat treatment at 450℃, the specimen was soaked in dye in light-isolated environment for 24 hours. In subsequent experiment, the result shows thatthe package structure of the dye-sensitized solar cell had photoelectric conversion efficiency up to 3.67%.
Besides, when differential proportions of Ag@TiO2 core-shell composite was mixed with Degussa P25 TiO2nanoparticle, the ratio 3:7 generated the best photoelectric conversion efficiency, 5.5%, which further increased film thickness of the photoanode up the optimum 28μm, by 11.2%, generating 6.06% of photoelectric convervision efficiency, an increase of 17% in comparison with mixture of Degussa P25TiO2 nanoparticle.

並列關鍵字

dye-sensitizedsolar cell ； photoanode ； Ag@TiO2 core-shell composite ； sol-gel method

參考文獻

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