디스펜싱 인쇄를 이용한 듀얼 인쇄된 결정질 실리콘 태양전지 제작에 관한 연구

Abstract

There have been strong industrial demands to adopt thin crystalline silicon solar cell wafers with high emitter sheet resistance, and reduce the consumption of silver paste per wafer, in order to cut down material costs and increase cell efficiency. To meet these industrial demands, double printing was attempted, where the first layer of finger electrodes was screen-printed and then busbars with the second layer of finger electrodes were screen-printed again, but it was found difficult to precisely superimpose two printed layers due to the distorted screen. Dual printing with separately screen-printed busbars and finger electrodes has been more vividly explored because it requires less alignment accuracy between two printing steps. However, screen printing is considered less suitable for thin crystalline silicon solar cell wafers. In this study, dual printing with screen-printed busbars in the first printing step and then non-contact dispensing printed finger electrodes was adopted and the influence of silver paste compositions was systematically studied. At the end, a plausible mechanism to explain cell efficiency dependency on the silver paste compositions is proposed.