Broadband photodetectors with self-driven functions have attracted intensive scientific interest due to their low energy consumption and high optical gain. However, high-performance broadband self-driven photodetectors are still a significant challenge due to the complex fabrication processes, environmental toxicity, high production costs of traditional 3D semiconductor materials and sharply raised contact resistance, severe interfacial recombination of 2D materials and 2D/3D mixed dimension heterojunction. Here, 1D p-Te/2D n-Bi2Te3 heterojunctions are constructed by the simple and low-cost hydrothermal method. 1D p-Te/2D n-Bi2Te3 devices are applied in photoelectrochemical (PEC) photodetectors, with their high performance attributed to the good interfacial contacts reducing interface recombination. The device demonstrated a broad wavelength range (365–850 nm) with an/ph//dark as high as 377.45. The RiD*, and external quantum efficiency (EQE) values of the device were as high as 12.07 mA/W, 5.87 × 1010 Jones, and 41.05%, respectively, which were significantly better than the performance of the prepared Bi2Te3 and Te devices. A comparison of the freshly fabricated device and the device after 30 days showed that 1D p-Te/2D n-Bi2Te3 had excellent stability with only 18.08% decay of photocurrent. It is anticipated that this work will provide new emerging material for future design and preparation of a high-performance self-driven broadband photodetector.
Cu-doped ZnO nanorods have been grown at 90°C for 90 min onto a quartz substrate pre-coated with a ZnO seed layer using a hydrothermal method. The influence of copper (Cu) precursor and concentration on the structural, morphological, and optical properties of ZnO nanorods was investigated. X-ray diffraction analysis revealed that the nanorods grown are highly crystalline with a hexagonal wurtzite crystal structure grown along the c-axis. The lattice strain is found to be compressive for all samples, where a minimum compressive strain of −0.114% was obtained when 1 at.% Cu was added from Cu(NO3)2. Scanning electron microscopy was used to investigate morphologies and the diameters of the grown nanorods. The morphological properties of the Cu-doped ZnO nanorods were influenced significantly by the presence of Cu impurities. Near-band edge (NBE) and a broad blue-green emission bands at around 378 and 545 nm, respectively, were observed in the photoluminescence spectra for all samples. The transmittance characteristics showed a slight increase in the visible range, where the total transmittance increased from approximately 80% for the nanorods doped with Cu(CH3COO)2 to approximately 90% for the nanorods that were doped with Cu(NO3)2.
The efficiency of photocatalytic hydrogen evolution is currently limited by poor light adsorption, rapid recombination of photogenerated carriers, and ineffective surface reaction rate. Although heterojunctions with innovative morphologies and structures can strengthen built‐in electric fields and maximize the separation of photogenerated charges. However, how to rational design of novel multidimensional structures to simultaneously improve the above three bottleneck problems is still a research imperative. Herein, a unique Cu 2 O─S@graphene oxide (GO)@Zn 0.67 Cd 0.33 S Three dimensional (3D) hollow heterostructure is designed and synthesized, which greatly extends the carrier lifetime and effectively promotes the separation of photogenerated charges. The H 2 production rate reached 48.5 mmol g −1 h −1 under visible light after loading Ni 2+ on the heterojunction surface, which is 97 times higher than that of pure Zn 0.67 Cd 0.33 S nanospheres. Furthermore, the H 2 production rate can reach 77.3 mmol g −1 h −1 without cooling, verifying the effectiveness of the photothermal effect. Meanwhile, in situ characterization and density flooding theory calculations reveal the efficient charge transfer at the p‐n 3D hollow heterojunction interface. This study not only reveals the detailed mechanism of photocatalytic hydrogen evolution in depth but also rationalizes the construction of superior 3D hollow heterojunctions, thus providing a universal strategy for the materials‐by‐design of high‐performance heterojunctions.
Self-powered full-spectrum photodetectors (PDs) offer numerous advantages, such as broad application fields, high precision, efficiency, and multi-functionality, which represent a highly promising and potentially valuable class of detectors for future development. However, insensitive response to solar-blind ultraviolet (UV) and complex and expensive preparation processes greatly limit their performance and practical application. In this study, a self-powered full-spectrum Bi2Se3/a-Ga2O3/p-Si heterojunction PD with high sensitivity for solar-blind UV band prepared by a simple and low-cost two-step synthesis method is presented. Experiments results reveal that the developed PD has an excellent performance, such as high sensitivity from 200 to 850 nm, and a responsivity of 1.38 mA/W as well as a detectivity of 3.22 × 1010 Jones under 254 nm light at zero bias. Additionally, the unencapsulated device displays exceptional stability and imaging capabilities. It is expected that Bi2Se3/a-Ga2O3/p-Si heterojunction PD with a simple and low-cost synthesis method has great potential for self-powered full-spectrum photodetectors.
15 December 2017 in ACS Sustainable Chemistry & Engineering