Solution-processed Molybdenum Oxide Hole Transport Layer Stabilizes Organic Solar Cells

The hole transport layer (HTL) affects the device performance and stability of organic solar cells. In this work, a stable molybdenum oxide (MoOx) hole transport layer with low cost was prepared by adjusting the state of the precursor solution with an alcoholic solution of molybdenum acetylacetonate through an oxidant. The MoOx transport layer has good transmittance with a work function of 5.07 eV and higher surface energy. The PM6:Y6 devices using MoOx HTL achieve a high efficiency of 16.8%. MoOx HTL exhibits good applicability with excellent performance in both ternary and all-polymer systems. Air storage stability T-80 of the all-polymer device using MoOx HTL was over 600 h, much higher than 70 h of the PEDOT:PSS-based device, and its thermal stability at 85 degrees C and operational stability under light show better stability than that of the PEDOT:PSS hole transport layer. This work provides a facile and low-cost method to fabricate HTL for organic solar cells, which is beneficial to improve their efficiency and stability.