Evaluation of an innovative liquid barrier layer in laser-structured screens for enhanced solar cell metallization

A strategy to further improve the screen-printing process focuses on reducing silver consumption per cell by minimizing the width of the printed electrical contacts by using laser technology to optimize the screen openings. In recent years, laser-structured screens with a polyimide (PI) barrier layer have gained prominence due to their significantly higher lifetime. In this work, we build upon the state-of-the-art by creating a prototype screen comprising of a new liquid photopolymer barrier layer, combined with conventional PI, resulting in a ‘hybrid barrier layer’. The aim of this work was to laser structure a full grid layout on the prototype and determine whether the hybrid barrier layer offers additional benefits, such as narrower fingers with reduced paste spreading. We successfully lasered a busbarless grid layout comprising of 120 fingers onto the prototype screen. This process was completed in just 10 minutes, and the laser-structured screen openings were tapered. For comparison, we used an industry standard screen coated only with PI as a reference. The average printed contact width of the prototype was approximately 23 μm, comparable to the average 21 μm of the reference. Also, a low wet silver laydown of 9 mg was applied to print the front side cell layout. The core widths of the printed fingers were measured to be 18 μm for the prototype and 16 μm for the reference screen. Both screens exhibited paste spreading of 5 μm. These results proves that the prototype is on par with an industry standard screen coated with PI. • Laser structuring on screen with an innovative barrier layer done in 10 min 16 s. • Average finger width printed from the laser opening was 23 μm. • Reduced wet silver laydown of 9 mg was applied on the front side cell layout. • Comparable print results with an industry standard reference screen.