Study of solar cell fabrication using an electrostatic thick-film printing method

A novel thick-film circuit printing technique which is based on the electrostatic principle known as noncontact electrostatic thick-film printing was developed for the metallization of edge-defined film-fed growth (EFG) solar cells. The conventional thick-film solar cell inks were modified by adding 10-20% terpineol solvent. The effects of ink viscosity, applied voltages, nozzle diameter, and nozzle-to-substrate distance on line definition and ink-flow rate were investigated. A simple theoretical model was derived for the electrostatic ink ejection. The minimum line width obtained was 3 mm. Multilayer printing was able to be used to raise the line film thickness. The maximum line width obtained was about 20-30 mm for a single run. The system is now completely computercontrolled and capable of printing films onto solar cell substrates reliably, with a high degree of accuracy. Multiple-layer prints can be made with food layer-to-layer registration