Gravure‐Printed ZnO in Fully Roll‐to‐Roll Printed Inverted Organic Solar Cells: Optimization of Adhesion and Performance

Abstract We present a gravure printing process for zinc oxide (ZnO) nanoparticle ink to be used as a hole‐blocking layer in inverted organic solar cells, enabling the production of patterned devices with freedom of design. The printability of the ink is optimized in a pilot‐scale roll‐to‐roll (R2R) process, leading to smooth layers having a thickness of few tens of nanometers. The properties of the printed ZnO film are further optimized using R2R post‐printing plasma treatment, which leads to increased adhesion and power conversion efficiency (PCE). The functionality of the printed ZnO layer is demonstrated in fully R2R‐printed inverted solar cells showing high performance (2.9 % mean PCE).