1D CsPbBr₃@SWCNTs van der Waals Heterostructures for Negative Dual‐Band Photodetectors

The application of 1D halide perovskite heterostructures based on single‐walled carbon nanotubes (SWCNTs) is always an unresolved challenge. Herein, for the first time, 1D van der Waals heterostructures based on CsPbBr 3 encapsulated within semiconducting SWCNTs (CPB@s‐SWCNTs) are engineered for negative dual‐band photodetectors via inner and outer charge‐transfer engineering. The individual CPB@SWCNT device exhibits a negative light response and achieves a significant n‐doping effect. Theoretical calculations illustrate that the electrons transferred from CPB to SWCNT are 0.61 e per cell. More importantly, the CPB@s‐SWCNTs are successfully separated, and large‐area CPB@s‐SWCNTs film devices exhibit obvious negative light response (−10.3 A W −1 ) at 3 V at 510 nm. Interestingly, integrated CPB@s‐SWCNTs film with SrTiO 3 substrate device shows negative dual‐band light detection (−5.8 A W −1 at 520 nm and −5.2 A W −1 at 400 nm). Kelvin probe force microscope tests indicate that electrons are transferred from CPB and SrTiO 3 to SWCNTs through inner filling and outer integration. This work not only provides a general strategy for the separation, assembly, and device integration of halide perovskite‐filled SWCNTs, but also expands their application in optoelectronic devices.