由於有機太陽能電池具有可撓性，大面積且製程容易的優點，在太陽能電池的領域得到很大的重視。而未來商業化，捲軸式連續製程(roll-to-roll process)必定是發展的重點，現今的有機太陽能電池元件大部分使用旋轉塗佈方式成膜，無法適用於捲軸式大量印刷方式，所以本實驗選用刮刀塗佈方式成膜，除了可結合捲軸式連續製程，未來也會朝大面積發展。
本研究除了電極之外本研究為全容易刮刀製程，結構為ITO / Cs2CO3 / P3HT:PCBM / PEDOT / Ag，但由於主動層使用1,2-Dichlorobenzene (DCB) 為溶劑成膜不均勻，會有內聚的現象產生，為了改善此現象，於溶劑DCB中以體積一比一的比例分別加入Chlorobenzene與n-Hexane，以共溶劑的方式解決了以DCB作為主動層溶劑時成膜不均的問題。使用不同種溶劑的元件經照光之後變化的趨勢不同，經許多量測分析後發現，不同溶劑的沸點以及溶解度會影響主動層P3HT與PCBM的排列與相分離，進而影響元件的特性
不同溶劑製做成元件後並進行持續照光，使用共溶劑DCB + Hexane 的元件效率可高達3.92%，共溶劑DCB + CB的效率則可到3.78%，都比使用純溶劑DCB的效率3.20%還高。。

Organic solar cells have attracted great attention, because of their properties of flexibility, large active area ,and simple fabrication process. Most of the organic solar cells use spin-coating process, but spin-coating process can’t apply to roll-to-roll process. We use blade-coating process to fabricate organic solar cell.
In this work, we use blade to coat the electron transport layer, active layer and hole transport layer. The active layer is a bulk heterojunction (BHJ) consisting of the blending of P3HT and PCBM .In the beginning, the active layer dissolved in DCB is non-uniform on electron transport layer. Hense we use co-solvent (DCB + Chlorobenzene , DCB + Hexane) to improve uniformity of the active layer. After many measurements, we discover that the boiling point and solubility of solvents play an important role in the phase separation of P3HT and PCBM. The improvement in photovoltaic response was attributed to the crystalline of P3HT and the change in surface composition of the active layer, which is more favorable for charge transport in inverted structures.
The performance of the devices is enhanced after light soaking continuously. The best efficiency of devices using co-solvent such as DCB + Hexane can reach to 3.92%.

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