Fabrication of Spray-Coated Semitransparent Organic Solar Cells

We investigated a promising, low-cost method for fabrication of semitransparent organic solar cells by mass production. The active layer of the organic solar cells was added by spray coating with a dual action airbrush. The solution for the active layer was prepared from a rigorously blended poly(3-hexylthiophene-2,5-diyl) (P3HT) and (6,6)-Phenyl-C61 butyric acid methyl ester (PCBM) in 1,2-dichlorobenzene, and the surface morphology of the spray-coated active layer depending on the concentration of the P3HT and PCBM was investigated. The semitransparency achieved, came from the use of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) as the conductive polymer electrode. For comparison, spin-coated solar cells were also fabricated. Power-conversion efficiency and transparency was achieved from the lower cost spray-coating method that was comparable to those by the traditional spin-coating method. The best spray-coated solar cell exhibited power-conversion efficiency of 1.9% (average or 1.7%) while the best spin-coated solar cell was 2.0% (average of 1.6%), when both were measured under the AM1.5G spectrum 100 mW/cm
²
light. Transmittance of the spray-coated solar cell was 52.2% while that of the spin-coated solar cell was 51.2%.