Interface Engineering of Perovskite Quantum Dot/Carbon Nanotube Heterogeneous Films for Constructing High-Performance Photodetectors

Heterogeneous films consisting of single-walled carbon nanotubes (SWCNTs) and perovskite quantum dots (PQDs) have shown remarkable potential for high-performance photodetectors, leveraging the high carrier mobility of SWCNTs and the high absorption coefficient of PQDs. However, the dense coating of ligand molecules on synthesized PQDs substantially impedes interfacial contact between PQD films and SWCNT films, thereby hindering the separation of photogenerated excitons and the subsequent transfer of the separated holes at the heterogeneous interface, ultimately degrading the overall photoelectric performance of the films. Here, we systematically reduced the molecular density of organic ligands on as-prepared CsPbBr₃ quantum dots (QDs) by employing a mixed solvent of n-hexane and ethyl acetate to rinse the QDs, thereby enhancing interfacial contact between PQD and SWCNT films. This facilitates more efficient exciton separation and transfer, leading to superior optoelectronics performance of the heterogeneous films. Furthermore, increasing the density of SWCNT films enhances their contact area with QD films, further improving the efficiency of exciton separation and transfer and consequently boosting the responsivity of the constructed photodetectors. By optimizing the ligand molecular density on CsPbBr₃ QDs and the density of SWCNT films, a high-performance photodetector was developed, achieving a photoresponsivity of 1.6 × 10⁶ A/W and a detectivity of 3.1 × 10¹⁵ Jones, surpassing most previously reported CsPbBr₃ QD/SWCNT-based photodetectors. These results provide a pivotal strategy for advancing the development of carbon-based high-performance photodetectors.