Characteristics of polymer semiconductor film prepared by evaporative spray deposition using ultra-dilute solution (ESDUS): application to polymer photovoltaic cells

Organic photovoltaics (OPV) with junction controlled structure are prepared by the evaporative spray deposition using ultra-diluted solution (ESDUS) method with different donor polymer(p) and acceptor fullerene(n) ratio solution. In order to demonstrate the ideal junction, we fabricate the polymer solar cells with single junction(p/n), pin-layered junction (pin) or bulk-heterojunction (BHJ) active layer. The photovoltaic performance is dramatically varied with its junction. And the pin junction has best performance under the sunlight due to its good carrier generation and transport. And also we investigated the temperature dependence of the active layer morphologies at each substrate temperature 60 − 160 °C during its spray-depositing. The domain of active layer became smaller with increasing substrate temperature. The pin-layered cell sprayed at 120 °C gives best photovoltaic performance. Thus, ESDUS enables us to control the junction and morphologies of active layer.