Direct Growth of Multi‐Layer Graphene on Quartz Glass for High‐Performance Broadband Neutral Density Filter Applications

Abstract 2D layered materials, such as graphene, transition metal dichalcogenides, and hexagonal boron nitride (h‐BN), cover a broadband in the electromagnetic spectrum with wavelengths ranging from hundred nanometers to millimeters. Their applications in photonic and optoelectronic nano‐devices have been demonstrated frequently, while they still need to be extended to daily life related fields. Herein, this work demonstrates a brand new application of multi‐layer graphene directly grown on quartz glass as broadband neutral density filters (NDFs). The graphene‐based NDFs present nearly wavelength‐independent transmittances over a wavelength range of 400–2500 nm, affording great optical attenuation capacity in the long‐exposure photography. This work further shows that, MoX₂ (X = S, Se) and h‐BN directly grown on quartz glass can serve as optical cut‐off filters with different absorption edges located in the visible and deep‐ultraviolet ranges, respectively. The results are hereby expected to promote macroscopic optical applications of 2D layered materials and their heterostructures in high‐performance multi‐functional optical filters.