Effect of film thickness manganite-based on interfacial barrier of heterojunctions

Interracial barrier is a key factor that determines the performances of heterojunctions. In this work, we study the effect of manganite film thickness on the effective interracial barrier for La0.67Sr0.33MnO3/Nb：SrTiO3 junctions, The barrier is extracted from the forward current-voltage characteristics. Our results demonstrate that the barrier decreases gradually from -0.85 eV to -0.60 eV when the film thickness decreases from 150 nm to 2 nm. The overall value of the barrier is only about 50% of the corresponding one determined from the photovoltaic effect.     

WO3/g-C3N4异质结催化剂的制备及其氧化脱硫性能

以尿素和钨酸铵为原料采用浸渍法制备了金属氧化物三氧化钨（WO₃）与石墨相氮化碳（g-C₃N₄）异质结复合材料WO₃/g-C₃N₄。采用XRD、UV-vis、SEM、PL和XPS表征手段考察了催化剂的理化性质,发现WO₃与g-C₃N₄存在较好的相互作用和电子转移,保证了WO₃/g-C₃N₄本身所具有较高的氧化脱硫活性。以WO₃/g-C₃N₄作为催化剂,过氧化氢异丙苯为氧化剂,考察其光催化氧化脱硫性能,在反应温度80℃,O/S物质的量比为3.0的反应条件下,反应180 min,二苯并噻吩（DBT）转化率可以达到72.79%。通过游离基捕获实验,发现超氧自由基（·O₂^-）、电子（e^-）、羟基自由基（·OH）起到了促进反应速率的作用,并对该体系的反应机理进行了探讨。     

Calculations of two dimensional electron gas distributions in AlGaN/GaN material system

This paper presents calculating results of the two-dimensional electron gas (2DEG) distributions in AlGaN/GaN material system by solving the Schr\"{o}dinger and Poisson equations self-consistently. Due to high 2DEG density in the AlGaN/GaN heterojunction interface, the exchange correlation potential should be considered among the potential energy item of Schr\"{o}dinger equation. Analysis of the exchange correlation potential is given. The dependencies of the conduction band edge, 2DEG density on the Al mole fraction are presented. The polarization fields have strong influence on 2DEG density in the AlGaN/GaN heterojunction, so the dependency of the conduction band edge on the polarization is also given.     

Review on the Properties of Boron-Doped Diamond and One-Dimensional-Metal-Oxide Based P-N Heterojunction

This review is mainly focused on the optoelectronic properties of diamond-based one-dimensional-metal-oxide heterojunction. First, we briefly introduce the research progress on one-dimensional (1D)-metal-oxide heterojunctions and the features of the p-type boron-doped diamond (BDD) film; then, we discuss the use of three oxide types (ZnO, TiO₂ and WO₃) in diamond-based-1D-metal-oxide heterojunctions, including fabrication, epitaxial growth, photocatalytic properties, electrical transport behavior and negative differential resistance behavior, especially at higher temperatures. Finally, we discuss the challenges and future trends in this research area. The discussed results of about 10 years’ research on high-performance diamond-based heterojunctions will contribute to the further development of photoelectric nano-devices for high-temperature and high-power applications.     

Biohybrid Organic Heterostructure Based on Chlorophyll-Bacteriochlorophyll Aggregates for Ecofriendly Hydrogen Production

Hydrogen energy is an abundant, clean, sustainable and environmentally friendly renewable energy source. Therefore, the production of hydrogen by photocatalytically splitting water on semiconductors has been considered in recent years as a promising and sustainable strategy for converting solar energy into chemical energy to replace conventional energy sources and to solve the growing problem of environmental pollution and the global energy crisis. However, highly efficient solar-driven photocatalytic hydrogen production remains a huge challenge due to the poor visible light response of available photocatalytic materials and the low efficiency of separation and transfer of photogenerated electron-hole pairs. In the present work, organic heterojunction structures based on bacteriochlorophyll (BChl) and chlorophyll (Chl) molecules were introduced and used for solar-driven photocatalytic hydrogen production from water under visible light. Also, noble metal-free photocatalyst was successfully constructed on Ti₃C₂T_x nanosheets by simple successive deposition of Chl and BChl, which was used for the photocatalytic splitting water to hydrogen evolution reaction (HER). The results show that the optimal BChl@Chl@Ti₃C₂T_x composite has a high HER performance with 114 μmol/h/g_cat, which is much higher than the BChl@Ti₃C₂T_x and Chl@Ti₃C₂T_x composites.     

Electrical and photoelectrical behaviour of heterojunctions based on novel oligomeric metal complexes

Naringenin‐based Schiff base ligands with 4‐aminobenzoic hydrazide were obtained as a unilateral form ( L¹ ). The ligand was oligomerized by oxidative polycondensation reaction with NaOCl as an oxidant in an aqueous alkaline medium at 90 °C to form a functional oligomer ( L² ), and its transition metal complexes such as those with Cu(II), Ni(II) and Zn(II) were prepared. The monomer and the oligomeric compounds were characterized using various techniques. Optical and electrical properties of the complexes were also investigated. All compounds showed indirect band gaps and they can be accepted as being in the semiconductor class. Organic–inorganic hybrid devices were obtained using n‐Si inorganic semiconductor and the complexes. The characteristic parameters of the devices were determined using current–voltage (I–V) and capacitance–voltage measurements in the dark. Photoelectrical properties of the devices were investigated using I–V measurements under a solar simulator with an AM1.5 global filter. Copyright © 2015 John Wiley & Sons, Ltd.     

Photocatalytic Nanoheterostructures and Chemically Bonded Junctions Made by Solution-Based Approaches

While single compound semiconductors were initially used for photocatalysis, combining two compounds to form a heterojunction significantly increases the photocatalysis performance. This review will outline how heterojunctions are superior, explain the different heterostructure architectures assembled from nanoparticles, and discuss the importance of achieving a large and quality contact in the junction, the heterojunction. Reference is made to methods for increasing the charge carrier performance and reducing recombination. Solution-based synthesis approaches, have been selected as the preferred route of manufacture, for the low cost scalability, and ability to combine a larger number of compounds. The main objective of this review article is to provide insight to the range of chemical solution-based methods for forming chemically bonded junction in nanoheterostructures for photocatalysis. Methods include chemical precipitation, impregnation, chemical bath deposition, hot injection, solvothermal, photo-deposition, electrochemical deposition, cation exchange and linker assisted assembly. The synthesis of different photocatalysts is addressed for each synthesis method. Solution synthesis is offered for coupling oxide semiconductors (i.e. TiO₂, ZnO, WO₃, Fe₂O₃, BiVO₄) with other oxides or metal chalcogenide quantum dots or metallic plasmonic nanoparticles.     

有机太阳能电池简介与展望

太阳能是一种非常重要的可再生能源。将太阳能转化为电能的有机太阳能电池,因其具有重量轻,柔韧性好,可以进行大面积、低成本的柔性制备等优点,为解决未来全球的能源问题提供了一种选择。简要介绍了有机太阳能电池的发展、性能参数、工作机理和应用实例。     

Incorporation of liquid crystalline triphenylene derivative in bulk heterojunction solar cell with molybdenum oxide as buffer layer for improved efficiency

We report efficient bulk heterojunction solar cells fabricated by inserting a discotic triphenylene derivative into poly (3-hexylthiophene): [6, 6]- phenyl-C61-butyric acid methyl ester. A layer of molybdenum oxide was inserted between anode and active layer. Power conversion efficiency of 2.0% was achieved for these photovoltaic solar cells containing self-organised discotic liquid crystals in the active layer under one sun condition. The influence of varying the thickness of liquid crystal layer and annealing on these solar cells was also studied. Post annealing the bulk heterojunction devices with discotic liquid crystal layer of thickness 20 nm in them yielded an open circuit voltage of 0.41 V, short circuit current density of 17.0 mA cm^?2, a Fill factor of 0.35 and power conversion efficiency of 2.5%.