Ultrathin layered double hydroxide nanosheets prepared by original precursor method for photoelectrochemical photodetectors

Layered double hydroxides (LDHs) are widely used owing to their unique alternating anionic and cationic layered two-dimensional (2D) structures. However, studies on the preparation of 2D LDH nanosheets with uniform thickness and their photodetectors are limited. In this study, two novel ultrathin LDH (Ca-In and Ca-Al LDH) nanosheets are peeled off from precursor bimetallic phosphides through the original precursor method. Both Ca-In and Ca-Al LDH nanosheets demonstrate a uniform thickness distribution with an average thickness of 3–4 nm, micron-level lateral sizes, and moderate bandgap. Owing to its broad light absorption range, hydrophilicity, and stability, Ca-In and Ca-Al LDH nanosheets are applied for the first time in photoelectrochemical photodetectors, realizing a wide range of light detection from ultraviolet (365 nm) to visible light (635 nm). Moreover, the fabricated photodetectors exhibit excellent cycle stability, and the average photocurrent density shows no reduction after 70 days. Therefore, this study provides an effective method to prepare 2D Ca-In and Ca-Al LDH nanosheets with uniform thickness and photoelectric application prospects.