Suchergebnisse

Self-powered ultraviolet (UV) photodetectors have attracted considerable attention in recent years because of their vast applications in the military and civil fields. Among them, self-powered UV photodetectors based on p-n heterojunction low-dimensional nanostructures are a very attractive research field due to combining the advantages of low-dimensional semiconductor nanostructures (such as large specific surface area, excellent carrier transmission channel, and larger photoconductive gain) with the feature of working independently without an external power source. In this review, a selection of recent developments focused on improving the performance of self-powered UV photodetectors based on p-n heterojunction low-dimensional nanostructures from different aspects are summarized. It is expected that more novel, dexterous, and intelligent photodetectors will be developed as soon as possible on the basis of these works.

Photoelectrochemical (PEC) water-splitting offers a promising method to convert the intermittent solar energy into renewable and storable chemical energy. However, the most studied semiconductors generally exhibit a poor PEC performance including low photocurrent, small photovoltage, and/or large onset potential. In this work, we demonstrate a significant enhancement of photovoltage and photocurrent together with a substantial decrease of onset potential by introducing electrocatalytic and p-type NiO nanoclusters on an n-type cubic silicon carbide (3C-SiC) photoanode. Under AM1.5G 100 mW cm(-2) illumination, the NiO-coated 3C-SiC photoanode exhibits a photocurrent density of 1.01 mA cm(-2) at 0.55 V versus reversible hydrogen electrode (V-RHE), a very low onset potential of 0.20 V-RHE and a high fill factor of 57% for PEC water splitting. Moreover, the 3C-SiC/NiO photoanode shows a high photovoltage of 1.0 V, which is the highest value among reported photovoltages. The faradaic efficiency measurements demonstrate that NiO also protects the 3C-SiC surface against photo-corrosion. The impedance measurements evidence that the 3C-SiC/NiO photoanode facilitates the charge transfer for water oxidation. The valence-band position measurements confirm the formation of the 3C-SiC/NiO p-n heterojunction, which promotes the separation of the photogenerated carriers and reduces carrier recombination, thus resulting in enhanced solar water-splitting. ; Funding Agencies|Swedish Research Council (Vetenskapsradet) [621-2014-5461, 2018-04670, 621-2014-5825]; Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (FORMAS) [2016-00559]; Swedish Foundation for International Cooperation in Research and Higher Education (STINT) [CH2016-6722]; AForsk Foundation [16-399]; Stiftelsen Olle Engkvist Byggmastare [189-0243]; EU project CHALLENGE; Knut and Alice Wallenberg Foundation [KAW 2014.0276]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO Mat LiU) [2009 00971]

A simple chemical method for producing ZnO/ CuO/ CdS nanoparticles using a chemical route (SILAR) method has been utilized. XRD patterns show hexagonal structures for ZnO, spheres, and cubic-formed CuO/CdS nanoparticles. Nanoparticles showed a blue shift in their UV-VIS energy band edge with (3.7, 3, and 3.2) eV for ZnO, CuO, and CdS. The morphology of ZnO, CuO, and CdS nanoparticles is investigated using scanning electronic microscopy (SEM). The XRD pattern reveals that the crystallites size are 15–30 nm. Photoluminescence reveals a yellow-green (520 nm) region for ZnO, a blue (380 nm) region for CuO, and a red (440 nm) region for CdS. The CdS wideband gap restricts its application. In this manner, we combined ZnO, CdS, and CuO for the band gap design of the heterojunction and to get improved optoelectronic properties. Present results show that heterojunctions could be useful for long-term usage and effective photodiode applications.