Laser scribing of Cd2SnO4-based CdTe polycrystalline solar cells

Abstract

Cd2SnO4-based CdTe solar cell is a potential technology to fabricate low cost and highly efficient thin film photovoltaic modules due to the excellent optical and electrical properties of Cd2SnO4 conductive transparent layer. However, the detailed research on patterning process is still deficient. In the present work, we developed laser scribing techniques to pattern the Cd2SnO4 thin film and the functional layers on top of the transparent conductive layer. By modifying the process and precisely adjusting the average energy density, the technique was further optimized to remove the upper layers completely without inducing any damage to the Cd2SnO4. The laser scribing process eliminates the exaggerated current density of CdTe solar cells contributed by the light absorption of the residual upper layers and as a result, device performance of the laser scribed cells could be precisely characterized. Besides, the isolative laser scribing of Cd2SnO4 layer and layers on top of Cd2SnO4 (window layer, absorption layer, back contact and metal electrode) is equal to the so-called P1, P2 and P3 steps in thin-film PV module production, which suggests that the whole set of laser scribing technique is applicable to the mass production of the Cd2SnO4-based CdTe solar cell modules.