雙分離界面的階梯式有機太陽能電池

Cascade Organic Solar Cells with Two Exciton Dissociation Surfaces

何宗翰(Tzung-Han Ho)

指導教授 ： 陳永芳

共同指導教授 ： 林麗瓊 ； 陳貴賢(Kuei-Hsien Chen)

國立臺灣大學/理學院/物理研究所/碩士(2010年)

https://doi.org/10.6342/NTU.2010.03122

摘要

由於人類對化石燃料的過度使用，大量的二氧化碳排放造成全球溫度上升和氣候變遷，進而引起各地頻傳的災害。爲了解決這個問題，再生能源的開發已成爲刻不容緩的事情，其中又以太陽能發電最具潛力。有機太陽能電池從1986年開始快速發展，至今效率已可達7%，成爲各國能源領域新興的研究方向。

有機太陽能電池的改良主要分爲兩方面，一方面爲材料的改質，另一方面爲元件結構上的改進。本篇論文主要從元件結構上著手，嘗試將階梯式能階的概念實際應用到有機太陽能電池上。階梯式太陽能電池結構主要具有多激子分離界面、高光學吸收補償、無串聯電流限制、高激子利用效率的優點，但缺點爲必須以同時具有高電子與電洞傳輸性質的材料做爲中間層，而具備此特性的材料並不多見。從文獻搜尋發現，10,12-二十五二炔酸(PDA)具有高電子與電洞傳輸的特性，故選擇PDA做爲本實驗的中間層，再搭配Pentacene和C60形成階梯式有機太陽能電池結構。

元件的製作方面，首先在ITO玻璃上旋轉塗佈PEDOT:PSS做爲電洞傳導層，接著分別蒸鍍上Pentacene、PDA和C60做爲主動層，再蒸鍍上BCP做爲激子阻擋層，最後鍍上銀電極。除了PDA單體外，我們亦嘗試利用紫外光聚合PDA單體成爲高分子，及利用熱退火的方式對元件做處理，觀察對元件效率的影響。

實驗結果發現，當PDA加入Pentacene/C60組成的雙層結構中間形成階梯式結構時，Voc會比原先的雙層結構來得高，Jsc則會比原來結構低。目前Pentacene/PDA/C60階梯式結構的效率最高爲1.20%，約和Pentacene/C60雙層結構元件的1.14%相等。將來若能改善PDA分子的排列方向，效率亦有再提升的空間。

關鍵字

有機太陽能電池 ； 階梯式 ； 有機半導體 ； 10,12-二十五二炔酸 ； 並五苯 ； 碳六十

並列摘要

Due to the abuse of fossil fuel, there have been a lot of carbon dioxide exhausted into the air.The carbon dioxide will cause climate change and the temperature of earth to rise,which further result in many disasters in the world. To solve this problem, the research of renewable energy become more and more important, especially the development of solar cells.Organic solar cells had been developed quickly since 1986, the efficiency now is about 7%.

The improvement of organic solar cells is divided into two regions, one is the synthesis of new materials,the other is the amelioration of device structure. In this thesis,we focus on the improvement of device structure and try to apply the concept of cascade energy level to the fabrication of organic solar cell devices.Cascade-type organic solar cells have many advantages including large exciton dissociation surfaces, good optical compensation, no restriction of photocurrent, high exciton usage efficiency, etc.There is still a disadvantage that the middle layer material has to have high electron and hole mobility,but the materials having this property are very rare.We found that 10,12-PENTACOSADIYNOIC ACID(PDA) has this bipolar property, so we choose it as our middle layer material,and together with Pentacene and C60 to form the cascade-type organic solar cell.

To fabricate our device, first we spin-coat the PEDOT:PSS on the ITO glass as hole transport layer,then evaporate Pentacene, PDA and C60 as our active layer in turn,last evaporate BCP as the exciton blocking layer and silver as the electrode.Besides the PDA monomer, we also tried polymerizing the PDA monomer to polymer and annealing the devices to improve the performance of the devices.

We found that when inserting PDA into the interface of Pentacene/C60 bilayer structure to form the cascade-type structure,the Voc would increase and the Jsc would decrease. Until now the best efficiency of Pentacene/PDA/C60 cascade-type structure is 1.20%,which is nearly equal to the Pentacene/C60 bilayer device, whose efficiency is 1.14%. If we can improve the orientation of PDA molecules, the efficiency has a big chance to increase further in the future.

並列關鍵字

organic solar cell ； organic semiconductor ； cascade solar cell ； 10,12-Pentacosadiynoic acid ； pentacene ； C60

參考文獻

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