Polymer solar cells: screen-printing as a novel deposition technique

Screen-printing is studied as deposition technique for conjugated material based layers. For light emitting diode applications poly(2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene) (MEH-PPV) is applied. For this material, batches with different molecular weight and different solution concentrations are subjected to theology measurements. Also the influence of several printing parameters like squeegee speed and pressure, snap-off distance and mesh size of the screen on the film formation and final thickness is investigated. It is shown that for each material batch and solution concentration specific printer settings have to be used to obtain active layers that are suitable for opto-electronic applications. Photovoltaics based on the principle of bulk donor-acceptor heterojunction are also tested using a blend of MEH-PPV mixed with the C-60-derivative (6,6)-phenyl C-61-butyric acid methyl ester (PCBM). Promising results have been obtained showing that screen-printing can be a suitable technique for the deposition of the active layer of polymer solar cells.