Screen-printed particulate silicon devices for photovoltaic applications

A simple low temperature process for the preparation of particulate silicon devices is described. The process is based on the screen-printing of a paste containing silicon particles, adhesives and an organic binder on a metallized substrate. The formation of the rear contact, firing of the particulate silicon layer and sealing of the rear contact is performed in one step only by exposing the wet print to a well-defined temperature cycle. Subsequently a front Schottky electrode is applied by evaporation of a semi-transparent metal layer or by screen-printing rectifying contact pads on top of the particulate layer. Experimental results on small-area particulate silicon Schottky devices are reported showing that the process is capable of providing diodes with sharp current-voltage (I-V) characteristics. Finally, a novel structure for an efficient and predominantly red-sensitive particulate silicon p-n junction solar cell using pre-diffused particles is introduced.