MoS₂ / WS₂ Nanosheets and Quantum Dots for Sensing Hemin and Fabrication of Self-Powered Photodetectors

Abstract

In this study, it was found that transition metal dichalcogenide (TMDC)-based nanosheets (NSs) and quantum dots (QDs) provide a versatile platform for designing chemosensors and photodetectors. As proof-of-concept, its multifunctionality was demonstrated by preparing MoS 2 and WS 2 NSs and QDs by the probe sonication method that works as a fluorescence quenching indicator for hemin, and its combination with hemin are efficient photoactive material for fabricating selfpowered photodetectors. For instance, at 23.8 μM concentration of hemin, the quenching efficiencies were observed to be 74, 93, 91, and 94% for MoS 2 NSs, MoS 2 QDs, WS 2 NSs, and WS 2 QDs, respectively. The sensing process is selective and applicable to real samples. In addition, the combination of MoS 2 and WS 2 nanomaterials with hemin collected from the sensing experiments was utilized for facile fabrication of photodetectors that exhibits responsivities of 0.95 and 2641 AW −1 cm −2 at 0 V for MoS 2 QDs/hemin and WS 2 QDs/hemin, respectively. The devices show high detectivities of 5.99 × 10 13 and 1.87 × 10 14 Jones. The parameters are significant at 0 V, and hence, the devices possess signature characteristics of self-powered photodetectors. The working mechanism for both sensing and photodetection was found to be due to fluorescence resonance energy transfer and electrostatic interaction between the nanomaterials and hemin. The idea of using the resultant solution from the sensing experiments for device fabrication and the findings were not reported earlier. Therefore, it will help in developing cost-effective platforms for sensing different components with biological importance, as well as in fabricating energy efficient photodetectors.