The objective of this research is to determine the optimum condition coating of semi conducting layer in low cost organic solar cells. We have already determined 5 conditions of coating thin films includes type of electron transporting solution, number of electron transporting layer, concentration of electron transporting solution, drop coating volume of electron transporting layer and speed coating of active layer. All of thin film layers on ITO glass have coated by convective coating technique and type of structure solar cell for this investigation is conventional structure solar cells. The results have shown that the optimum condition of coating from 5 conditions such as the optimum electron transporting layer solution is isopropanol (IPA). The optimum number of electron transporting layer is 1 layer, the optimum composition of electron transporting material with solvent of TiOx in IPA is 1:8. The optimum drop coating volume of electron transporting layer is 40 µl and the optimum speed coating of active layer between PCDTBT:PCBM is 2000 µm/sec, respectively. From the experiment, convective coating technique has performed to show efficiency of technique by low drop volume and give high transforming efficiency. Therefore, this coating technique has potential in manufacturing high scale.
Keywords: electron transporting layer; active layer; convective coating technique; low cost organic solar cells