Covalent functionalization of transition metal dichalcogenides with perylene for light harvesting devices

This study investigates the optical and electronic properties of eight two-dimensional transition metal chalcogenides (TMDs)—MoS2, WS2, MoSe2, WSe2, MoTe2, WTe2, MoO2, and WO2—covalently functionalized with perylene, forming zero-dimensional/two-dimensional hybrid materials. Comprehensive characterization was conducted using techniques including XPS, Raman, EDX, TEM, and AFM. Optical properties were assessed using UV-Vis-NIR absorption and photoluminescence spectroscopy, while electronic properties were examined through cyclic voltammetry and field-effect transistor devices. Notably, the spectroscopic signatures of isolated perylene predominate in the hybrid materials, while WSe2 and MoSe2 displayed a novel band in the near-IR region, and MoTe2 exhibited enhanced conductivity. Perylene significantly boosted absorption between 400–600 nm, leading to remarkable improvements in the photoresponse and responsivities showing values exceeding 2 × 105 % and 2 × 104 mA W−1 , respectively. The presented hybrid materials rival the best examples of non-covalent functionalization, underscoring the potential of covalent functionalization as a powerful technique for further tailoring the optical and electronic properties of 2D materials.