Alkesh B. Patel

Large-area uniform MoSe₂@WSe₂ HS prepared by EPD, achieves better catalytic activity, HER, and supercapacitor performance.

The two-dimensional pristine tin selenide (SnSe), possessing desirable optical, thermal, electrical, and optoelectronic characteristics, is the future nanomaterial of technological applications. In the present study, SnSe nanosingle crystals were grown using the direct vapor transport (DVT) method. The chemical composition, morphological analysis, crystalline phase, crystallinity, optical properties, vibrational modes, and oxidation states of the elements of the grown crystals are verified by energy-dispersive X-ray analysis (EDAX), X-ray photoelectron spectroscopy (XPS), optical microscopy–scanning electron microscopy (SEM), photoluminescence (PL), Raman, and X-ray diffraction. For the optoelectronic study of grown crystals, the current–voltage characteristic was measured. A photodetector based on single-crystalline SnSe is fabricated and studied under visible light with an on/off period of 10 s. The device designates excellent photocurrent and responsivity. Moreover, the photoelectrochemical (PEC) visible-light photoresponse of the SnSe single crystals was also studied. The photovoltaic output parameters like the open-circuit voltage (V_oc), short-circuit current (I_sc), fill factor (FF), and efficiency (η%) for the cell were determined. The grown crystal shows the highest photocurrent of 1.31 μA under an illumination of 120 mW/cm². Mott–Schottky plots helped in the redox analysis and energy band location. The Nyquist plot is also plotted to study electrochemical impedance. The work demonstrated the potential application of SnSe nanosingle crystals in the field of optoelectronic visible-light conditions.

The solar response ability and low-cost fabrication of the photoanode are important factors for the effective output of the photoelectrochemical system. Modification of the photoanode by which its ability to absorb irradiation can be manipulated has gained tremendous attention. Here, we demonstrated the MoSe2, WSe2, and MoSe2/WSe2 nanocrystal thin films prepared by the liquid-phase exfoliated and electrophoresis methods. Atomic force microscopy and high-resolution transmission electron microscopy show that the liquid exfoliated nanocrystals have a few layered dimensions with good crystallinity. Scanning electron microscopy demonstrated uniform distribution and randomly oriented nanocrystals, having a homogeneous shape and size. X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectra confirm the equal contribution of MoSe2 and WSe2 nanocrystals in the formation of the MoSe2/WSe2 heterojunction. Because of superior absorption of MoSe2/WSe2 heterojunction in the visible region and type-II heterojunction band alignment, in situ measurement of heterojunction electrode shows almost 1.5 times incident photo-to-current conversion efficiency and photoresponsivity in comparison to individual material electrodes. Our result clearly indicates the influence of heterojunction formation between liquid exfoliated nanocrystals on effective separation of photogenerated exciton and enhances charge carrier transfer, which leads to the improvement in photoelectrochemical performance. Liquid exfoliated nanosheet-based heterojunction is attractive as efficient photoanodes for the photoelectrochemical systems.

Group II-VI Compounds have emerged out as most suitable in the class of photo sensitive material. They represent a strong position in terms of their applications in the field of detectors as well as photo voltaic devices. Cadmium telluride is the prime member of this Group, because of high acceptance of this material as active component in opto-electronic devices. In this paper we report preparation and characterization of CdTe thin films by using a most economical screen printing technique in association with sintering at 510°C temperature. Surface morphology and smoothness are prime parameters of any deposited to be used as an active region of devices. Thus, we studied of the screen printed thin film by means of atomic force microscopy (AFM) and scanning electron microscopy (SEM) for this purpose. However, growth processes induced intrinsic defects in fabricated films work as charge traps and affect the conduction process significantly. So the conduction mechanism of deposited CdTe thin film is studied under dark as well as illuminated conditions. It is found that the deposited films showed the space charge limited conduction (SCLC) mechanism and hence various parameters of space charge limited conduction (SCLC) of CdTe film were evaluated and discussed and the photo responsive resistance is also presented in this paper.