Unlocking High‐Performance in All‐Organic Solar Cells by the Development of Organic Electrodes with No Acid and High‐Temperature Treatment and the Effective Preparation Thereof on Organic Multilayer Films

Abstract Solar panels are difficult to dispose of and environmentally unfriendly because they contain potentially hazardous compounds and materials that are difficult to dispose of or recycle. As such, all‐organic solar cells (AOSCs), which comprise only organic materials, have received considerable attention as environmentally friendly alternatives. Although the use of AOSCs will resolve the issue of solar cell disposal, the production of high‐performance AOSCs remains a challenge (power conversion efficiency (PCE) currently ≈4%) because organic electrodes exhibit limited conductivity and are difficult to fabricate without damaging organic plastic substrates and multilayered organic semiconducting materials. Herein the development of AOSCs is reported with PCEs more than twice those of previously reported AOSCs on PET substrates (8.7%). The key to achieving this is the development of organic electrodes with high conductivity and which require no acid doping or high‐temperature heating, thus avoiding damage to the plastic substrates. Moreover, the top‐electrode lamination method developed herein, which does not damage the bottom organic layers of AOSCs, also contributes to the production of high‐performance AOSCs. In addition, the use of bioplastic substrates is explored to demonstrate the feasibility of producing environmentally friendly solar cells with good photovoltaic performance (PCE: 8.6%), thus suggesting that the electrodes and lamination method developed are effective for producing high‐performance AOSCs.