以溶液製程沉積氧化鎢改善載子傳輸之有機異質接面太陽能電池研究

Abstract

本論文主要研究內容為有機太陽能電池，主動層材料利用P3HT混合PCBM的塊材異質接面為主體結構，從傳統結構、傳統結構加入三氧化鎢、氧化鎢(WOx) 等，討論不同結構及參數對於效率的影響，並試從本實驗室所架設之噴墨系統噴製氧化鎢作為電洞傳導層的可行性。 在傳統結構電池的製作中，在藉由升高主動層材料的混合時溫度及兩階段旋轉塗佈速度，使得兩種材料均勻度上升並且與基板的附著力增加，解決旋轉塗佈時溶質溶劑連帶分離及附著力不足導致薄膜破裂等成膜性差劣的狀況，將電池效率從不到0.1 %提升到目前平均1.0 %左右。而在加入三氧化鎢之後，其可能因為液滴沉積的方式造成三氧化鎢厚度太厚而使得電阻上升而反造成校的下降。氧化鎢的部分則利用兩種配置溶液的方法，在以雙氧水為溶劑的例子，可以看到其主動層表面粗糙度受下層氧化鎢顆粒的影響，而提高了表變粗糙度，進而提升電洞傳導層與主洞層間接觸面積因而提高效率，得到1.2 %及1.4 %的轉換效率，但同時也發現整體元件的使用可靠度可能受雙氧水的問題而加劇氧化。最後提出以異丙醇做為氧化鎢顆粒的最終溶劑，得到不錯的顆粒分布，同時也減輕前述的積聚的現象。 此溶液製成使得有機太陽能電池能以大面積製作、低成本、低材料消耗、製成簡易的優點，同時也利用液態沉積氧化鎢的方式，可製作出以無機材料取代傳統高分子材料的方式，以利後續無機、有機等相關整合的應用。

This thesis is about using P3HT:PCBM as active layer material to be main structure of organic bulk heterojunction solar cell, including conventional structure and conventional structure hybrid with tungsten oxides as hole transportation layer (HTL). In fabrication of conventional structure solar cell, by heating up the solution of the active layer material and two-steps of spin coating speed can improve the uniformity of solution and adhesion between active layer and substrate, solving the separation solute from solvent and enhancing film property by improving the adhesion. The conversion efficiency was improved from less than 0.1 % to 1.0 % in average. By adding tungsten trioxide, because of using drop-evaporate method to form tungsten trioxide film, the thickness can’t be easily controlled so that the resistance may be get higher then drop down the efficiency. About forming tungsten oxide (WOx) film, we use hydrogen peroxide to change the oxidation number of tungsten. By enlarge the roughness of ITO surface, the contact between ITO and active layer get better and improve the efficiency from 1.0 % to 1.4 %. But the electrode would be affected by the instability of the tungsten oxide solution and the stability of the device couldn’t sustain for a long time. By replacing the solvent from hydrogen peroxide to isopropyl alcohol, the efficiency drops down because of the aggregation of the active layer. Due to the poor uniformity of active layer, there’s no lots of carrier can transport from device to load. All fabrication by solution methods for organic solar cell can be cheap, simple, and scalable in large area producing for future industries.