Interfacial Electron Transfer in PbI₂@Single-Walled Carbon Nanotube van der Waals Heterostructures for High-Stability Self-Powered Photodetectors

Abstract

Acquiring a deep insight into the electron transfer mechanism and applications of one-dimensional (1D) van der Waals heterostructures (vdWHs) has always been a significant challenge. Herein, through direct observation using aberration-corrected transmission electron microscopy (AC-TEM), we verify the stable formation of a high-quality 1D heterostructure composed of PbI 2 @ single-walled carbon nanotubes (SWCNTs). The phenomenon of electron transfer between PbI 2 and SWCNT is elucidated through spectroscopic investigations, including Raman and X-ray photoelectron spectroscopy (XPS). Electrochemical testing indicates the electron transfer and enduring stability of 1D PbI 2 within SWCNTs. Moreover, leveraging the aforementioned electron transfer mechanism, we engineer self-powered photodetectors that exhibit exceptional photocurrent and a 3-order-of-magnitude switching ratio. Subsequently, we reveal its unique electron transfer behavior using Kelvin probe force microscopic (KPFM) tests. According to KPFM, the average surface potential of SWCNTs decreases by 80.6 mV after filling. Theoretical calculations illustrate a charge transfer of 0.02 e per unit cell. This work provides an effective strategy for the in-depth investigation and application of electron transfer in 1D vdWHs.

SiX2 (X = S, Se) Single Chains and (Si–Ge)X2 Quaternary Alloys

“…The use of carbon nanotubes (CNTs) and boron nitride nanotubes (BNNTs) as reaction templates for encapsulation has proven highly effective for synthesizing various nanostructures. − This innovative method enables the creation of a diverse array of vdW 1D materials by introducing various substances such as monoelements, perovskites, metal halides, carbides, and chalcogenides into the confined spaces of nanotubes. − In particular, the small inner diameter of the nanotubes is advantageous for synthesizing 1D chain structures because it limits the radial growth of the encapsulated material. This geometric confinement effect of nanotubes has provided the opportunity for the emergence of crystal structures and properties not found in their bulk form. − Furthermore, the protective sheaths formed by the nanotubes play a crucial role in shielding the encapsulated materials from degradation, thereby facilitating the investigation of various nanostructures.…”