In-situ growth and immobilization of CdS nanoparticles onto functionalized MoS2: preparation, characterization and fabrication of photoelectrochemical cells

Abstract

A facile strategy for the controllable growth of CdS nanoparticles at the periphery of MoS 2 en route the preparation of electron donor‐acceptor nanoensembles is developed. Precisely, the carboxylic group of α‐lipoic acid, as addend of the modified MoS 2 obtained upon 1,2‐dithiolane functionalization, was employed as anchor site for the in‐situ preparation and immobilization of the CdS nanoparticles in an one‐pot two‐step process. The newly prepared MoS 2 /CdS hybrid material was characterized by complementary spectroscopic, thermal and microscopy imaging means. Absorption spectroscopy was employed to register the formation of MoS 2 /CdS, by observing a broad shoulder centered at 420 nm due to CdS nanoparticles, while the excitonic bands of MoS 2 were also evident. Moreover, based on the efficient quenching of the characteristic fluorescence emission of CdS at 725 nm by the presence of MoS 2 , strong electronic interactions at the excited state between the two species within the ensemble were identified. Photoelectrochemical assays of MoS 2 /CdS thin‐film electrodes revealed a prompt, steady and reproducible anodic photoresponse during repeated on‐off cycles of illumination. A significant zero‐current photopotential of ‐540 mV and an anodic photocurrent of 1 μA were observed, underlining improved charge‐separation and electron transport from CdS to MoS 2 . The superior performance of the charge‐transfer processes in MoS 2 /CdS is of direct interest for the fabrication of photoelectrochemical and optoelectronic devices.