Electrophoretic‐Driven In Situ Polymerization Depositing High‐Quality Perovskite Films for Photodetectors

Abstract Perovskite quantum dots (PQDs) have wide applications in optoelectronic devices due to their excellent stability and processability. However, PQD films are still seeking to overcome the problems of disorder and porosity. This seriously hinders the carrier transport and the application of PQDs in photodetectors (PDs). In this work, the electrophoretic deposition (EPD) method is employed to fabricate PQDs with conjugated linoleic acid (CLA) as the ligands, and the highly oriented and dense films are obtained. In addition, CLA molecules can polymerize during electrophoresis, which shortens the quantum dot spacing. It facilitates carrier transport while improving the stability of the film. PDs prepared by electrophoresis have a high detectivity ( D *) up to 5.1 × 10 12 Jones, which is 3.9 times higher than PDs prepared by spin coating (1.3 × 10 12 Jones) and reaches the highest record under the same conditions. In addition, the device exhibits a remarkable stability, maintaining 95% of the initial performance when left in the air for 3 months. This work provides a new perspective on the assembly of PQDs in the application of optoelectronic devices.