Abstract
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%.