InP@ZnSe/ZnS-TMPD Core–Shell Quantum Dot Films with Filter Properties for Micro-Hyperspectral Imaging Applications

Quantum dot (QD) filters, characterized by miniaturization, customizability, and low-cost advantages, have emerged as dispersive components in the development of microhyperspectral cameras. In this research, InP QDs were encapsulated with a ZnS single-shell and a ZnSe/ZnS double-shell to synthesize InP@ZnS and InP@ZnSe/ZnS core–shell quantum dots (CSQDs). InP@ZnSe/ZnS CSQDs exhibited enhanced oxidation resistance, spectral stability, a high extinction coefficient, and good filtering performance. By optimizing the precursor ratio, precise control over the size and size distribution of InP CSQDs was achieved, enabling exceptional tunability of their filtering spectra. Moreover, the surface modification of InP@ZnSe/ZnS CSQDs with N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD) ligands effectively quenched their photoluminescence properties without sacrificing filtering performance. The structural and optical properties were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and UV–vis spectrophotometry, revealing critical structure–property correlations. The nontoxic colloidal QD filter arrays based on InP@ZnSe/ZnS-TMPD CSQDs demonstrated dual functional advantages: precise spectral tunability over the 400–800 nm range, and complete short-wavelength cutoff with 86% high-efficiency transmission in the long-wavelength region, with a spectral transition steepness of 1.18%/nm. First-principles calculations revealed that ZnSe middle shell improved the light absorption of InP CSQDs. The underlying mechanisms responsible for the good filtering capabilities, oxidation resistance, spectral stability, and broad spectral tunability of InP@ZnSe/ZnS CSQDs were systematically investigated in this study, and these findings may facilitate the practical application of QD-based microspectrometers.