Silicon Ink selective emitter solar cells for optimum module performance

Innovalight´s Cougar™ Platform is a selective emitter (SE) process based on a screen-printed patternof Silicon Ink. The Cougar Platform has been licensed to several leading solar companies. The performance gain from the Cougar SE process is well documented at the cell level [1]. In this report we describe the optimization of the Cougar cell for photovoltaic (PV) modules. Ray tracing modeling [2] has been used to optimize the performance of encapsulated Cougar cells, taking into account the optical properties of surface texture, encapsulant materials, and cell anti-reflection coating layers. Anti-reflection coatings are made from silicon nitride (SiN_x), the optical characteristics of which were determined from ellipsometry and UV-Vis spectroscopy. Modeling predicts different cell-to-module (CTM) values for short-circuit current (I_sc), depending on the SiN_x characteristics. Mini-modules were constructed to verify modeling results. In addition to optical modeling, fill factor losses in the mini-modules are investigated and analyzed. Accelerated lifetime testing was also performed. The Cougar Platform shows equivalent reliability performance compared to traditional, homogeneous emitter (HE) solar cells.