Strong Efficiency Enhancement of Eu ³⁺ -Induced Polystyrene- <i>b</i> -Poly(acrylic acid) Nanoaggregates on Bladed Organic Polymer Solar Cells through Doping the Electron Transport Layer

To develop large-area polymer solar cells (LA-PSC), blading technology is thought to be the most effective current method. However, it faces critical challenges with respect to efficiency and stability in air during preparation and use. In this work, we focus on the interface engineering between the active layer and aluminum anode of LA-PSC through doping the original electron transport layer by an effective photon quantum energy conversion material of Eu3+-induced polystyrene-b-poly(acrylic acid) (merely referred to as EIPA). To optimize the electron transport layer (ETL), laboratory-prepared amphiphilic EIPA powder was fully dissolved in the original solution for the electron transport layer at a concentration of 0.5 mg/mL and used as the new electron transport layer. After doping, the interfacial contact of the electron transport layer to both the active layer and the electrode was improved, with a water contact angle decrease from 93° to 85.5°. This is beneficial for electron extraction and transport at the interface. Furthermore, the absorption and conversion of ultraviolet light by europium can protect Poly[(9,9-bis(3′-(N,N-dimethyl)-propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] dibromide(PFN-Br), mitigating device degradation and enhancing operational stability. After being stored under normal indoor light conditions for 500 h in air, the ETL doped with EIPA retained 82.02% of its initial efficiency. The optimized device exhibited significant improvements in power conversion efficiency (PCE), achieving up to 11.78% on average, representing a 11.6% increase in PCE over the original device efficiency of 10.65%. This confirms that optimizing the electron transport layer can effectively enhance the efficiency and stability of organic solar cells.