Highly Responsive Ultraviolet Sensor Based on ZnS Quantum Dot Solid with Enhanced Photocurrent

Abstract

Detection of visible blind UV radiation is not only interesting but also of technologically important. Herein, we demonstrate the efficient detection of UV radiation by using cluster like ZnS quantum dot solid nanostructures prepared by simple reflux condensation technique. The short-chain ligand 3-mercaptopropionic acid (MPA) involved in the synthesis lead to the cluster like formation of ZnS quantum dots into solids upon prolonged synthesis conditions. The ZnS QD solid formation resulted in the strong delocalization of electronic wave function between the neighboring quantum dots. It increases the photocurrent value, which can be further confirmed by the decrease in the average lifetime values from 64 to 4.6 ns upon ZnS cluster like QD solid formation from ZnS QDs. The ZnS quantum dot solid based UV sensor shows good photocurrent response and a maximum responsivity of 0.31 (A/W) at a wavelength of 390 nm, is not only competitive when compared with previous reports but also better than ZnS and metal oxide-based photodetectors. The device exhibits a high current value under low-intensity UV light source and an on/off ratio of IUV/Idark = 413 at zero biasing voltage with a fast response. Further, photocurrent device has been constructed using ZnS quantum dot solid nanostructures with graphene hybrids as an active layer to improve the enhancement of photoresponsivity.

Zn–Al Layered Double Hydroxide Film Functionalized by a Luminescent Octahedral Molybdenum Cluster: Ultraviolet–Visible Photoconductivity Response

“…During the last few decades, the use of various wide band-gap semiconducting inorganic materials, such as ZnO, MoS2, ZnS, SiC for the light energy converters, has been mainly reported due to their simple structure and high photoconductive gain. [1][2][3][4] The visible (Vis) sensing photodetector using solar light energy became an interesting study for sustainable energy development goals. 5, However, the development of broadband photodetectors, having an efficient photoactivity in the UV-Vis light range, low cost, and environmentally friendly material and process, is facing many challenges for researchers.…”

Stable Lead-Free Silver Bismuth Iodide Perovskite Quantum Dots for UV Photodetection

“…The photocurrent devices contained a multilayered structure with (i) the electron transport layer consisting of commercial TiO 2 with average particle diameter around 50 nm (coated on the FTO substrate by doctor blade method), (ii) perovskite quantum dot active layer sensitizer (coated by spin coating technique), (iii) MoO 3 layer as a hole transport material in the device, and finally, aluminum metal electrode on top, fabricated by the reported methods. 37 The conduction band (CB) of TiO 2 is in a favorable position near the perovskite quantum dot conduction band (CB), to receive the photoexcited electrons from the perovskite quantum dots. Also, the perovskite QDs have a longer excited-state lifetime which will result in the increase of electron−hole pair population in the system.…”

Drug Release Profiles of Mitomycin C Encapsulated Quantum Dots–Chitosan Nanocarrier System for the Possible Treatment of Non-Muscle Invasive Bladder Cancer

“…The mixture was deposited onto the Cu grids covered with carbon film (200 mesh) using a disposable dropper and a standard filter paper was used to absorb the excess solvent according to Ribeiro et al [23]. Figure 3a shows the monodispersed spherical shape ZnS particles with average particle size of 4.66 nm [41]. Similarly, the HRTEM micrograph for Mn:ZnS exhibit spherical NPs with average particle size of 1.83 nm, as shown in (c).…”