Abstract
Organic solar cells have recently attracted much attention due to their potential for low-cost, flexible, large active area solar energy harvesting devices and simple fabrication process. We used blade-coating technique to fabricate large-area organic solar cells. Blade-coating technique not only reducing the usage of material but also has the potential toward roll-to-roll process. In this study, we used blade-coating process to deposit the hole transport layer and active layer. The active layer was a bulk heterojunction (BHJ) consisting of P3HT and PCBM. We overcame the THF solution diffusion into active region by using a graver to define the active region. Then the non-uniformity of hole transport layer was improved by two times coating in different blade speed. However, the thickness of active layer will affect the device performance. We tried many different concentration of P3HT:PCBM solution and different blade speed to find the optimal thickness of active area. And we found that high blade speed leads to increased layer thickness and larger non-uniformity. The best power conversion efficiency of devices using 29mg/ml P3HT:PCBM solution with optimal annealing condition can reach to 3.27% (single cell:6.3cm2) and 2.9% (five cells in series:31.5cm2).