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排序方式: 共有1201条查询结果,搜索用时 15 毫秒
1.
Efficient dye sensitized solar cells (DSSCs) are developed using phenoxazine (POZ) based organic dye (WS5) and graphene nanosheets (GNs) counter electrode (CE). Being organic, both these materials are used together to explore compatibility of organic materials in current DSSCs. Organic dye with POZ moiety is synthesized and graphene oxide nanosheets (GONs) are spin coated on FTO glass and thermally reduced afterwards. To increase the performance of WS5 through decreased dye aggregation, deoxycholic acid (DCA) is added to it. The results of adding DCA are observed and compared using UV–Vis spectroscopy, external quantum efficiency (EQE), electrochemical impedance spectroscopy (EIS) and photovoltaic conversion efficiency (PCE). Prepared organic dye based DSSC cell results in a high PCE of 6.61%. The optimized WS5 dye and GNs CE, shows PCE of 5.77% and the GNs CE compared to Pt CE results in almost identical charge transfer resistance value at the CE/electrolyte interface. Low cost of this designed organic dye and GNs and the PCE results indicate that this combination may result in the reduction of cost of current DSSCs and the realization that expensive and rare inorganic materials can be replaced with organic ones in future.  相似文献   
2.
  总被引:1,自引:0,他引:1  
To realize graphene-based electronics, bandgap opening of graphene has become one of the most important issues that urgently need to be addressed. Recent theoretical and experimental studies show that intentional doping of graphene with boron and nitrogen atoms is a promising route to open the bandgap, and the doped graphene might exhibit properties complementary to those of graphene and hexagonal boron nitride (h-BN), largely extending the applications of these materials in the areas of electronics and optics. This work demonstrates the conversion of graphene oxide nanosheets into boron carbonitride (BCN) nanosheets by reacting them with B(2) O(3) and ammonia at 900 to 1100 °C, by which the boron and nitrogen atoms are incorporated into the graphene lattice in randomly distributed BN nanodomains. The content of BN in BN-doped graphene nanosheets can be tuned by changing the reaction temperature, which in turn affects the optical bandgap of these nanosheets. Electrical measurements show that the BN-doped graphene nanosheet exhibits an ambipolar semiconductor behavior and the electrical bandgap is estimated to be ≈25.8 meV. This study provides a novel and simple route to synthesize BN-doped graphene nanosheets that may be useful for various optoelectronic applications.  相似文献   
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Patterned reduced graphene oxide (rGO) films with vertically aligned tip structures are fabricated by a straightforward self‐assembly method. The size, uniformity of the patterns, and alignment of the tips are successfully controlled according to the concentration of a GO/octadecylamine (ODA)‐dispersed solution. The surface energy difference between the GO/ODA solution and a self‐assembled water droplet is a critical parameter for determining the pattern structure. Numerous rGO nanosheets are formed so as to be vertically aligned with respect to the substrate during film fabrication at GO concentrations below 2.0 g/L. These samples provide high field‐emission characteristics. The patterned rGO arrays are highly flexible with preservation of the field emission properties, even at large bending angles. This is attributed to the high crystallinity, emitter density, and good chemical stability of the rGO arrays, as well as the strong interactions between the rGO arrays and the substrate.  相似文献   
5.
    
Micrometer‐sized electrochemical capacitors have recently attracted attention due to their possible applications in micro‐electronic devices. Here, a new approach to large‐scale fabrication of high‐capacitance, two‐dimensional MoS2 film‐based micro‐supercapacitors is demonstrated via simple and low‐cost spray painting of MoS2 nanosheets on Si/SiO2 chip and subsequent laser patterning. The obtained micro‐supercapacitors are well defined by ten interdigitated electrodes (five electrodes per polarity) with 4.5 mm length, 820 μm wide for each electrode, 200 μm spacing between two electrodes and the thickness of electrode is ~0.45 μm. The optimum MoS2‐based micro‐supercapacitor exhibits excellent electrochemical performance for energy storage with aqueous electrolytes, with a high area capacitance of 8 mF cm?2 (volumetric capacitance of 178 F cm?3) and excellent cyclic performance, superior to reported graphene‐based micro‐supercapacitors. This strategy could provide a good opportunity to develop various micro‐/nanosized energy storage devices to satisfy the requirements of portable, flexible, and transparent micro‐electronic devices.  相似文献   
6.
目的 研发含纳米结构Co3O4中间层的Ti/Co3O4/RuO2-IrO2阳极,并对其电化学析氧性能进行研究,以提升Ti/RuO2-IrO2金属氧化物阳极的电化学析氧性能。方法 在Ti基底上电沉积制备Co(OH)2,烧结形成Co3O4纳米片结构,随后采用热分解工艺在Ti/Co3O4表面制备RuO2-IrO2电催化层,从而构建了Ti/Co3O4/ RuO2-IrO2复合阳极。使用透射电子显微镜(TEM)、扫描电子显微镜(SEM)、X-射线衍射仪(XRD)和电化学工作站对涂层的微观表面形貌、物相组成、电化学性能等进行观察与分析。结果 SEM显示出Ti/Co3O4纳米片上RuO2-IrO2的负载量随涂刷次数增加逐渐增多,最终完全遮盖Co3O4纳米片中间层。且随着RuO2- IrO2前驱体溶液涂覆次数的增加,XRD观察到RuO2-IrO2衍射峰强度在逐渐增大。TEM测试显示Co3O4中间层是由纳米颗粒堆叠组成且具有多孔结构。电化学极化曲线测试表明,涂覆三次RuO2-IrO2层的含Co3O4中间层阳极析氧电位最低,当电流密度达到10 mA/cm2时,析氧电位仅为1.326 V(vs. SCE),低于无中间层的Ti/RuO2-IrO2阳极(1.413 V)。循环伏安测试表明,Ti/Co3O4/RuO2-IrO2阳极的伏安电量达到62.83 mC/cm2,相较于Ti/RuO2-IrO2阳极的23.65 mC/cm2提高了166%。稳定性能试验表明,在经过1 000次循环稳定性试验后,加入Co3O4纳米片中间层的复合阳极的伏安电量降低了35.94%,低于无中间层阳极48.88%的伏安电量损耗率。循环极化试验后的Ti/Co3O4/RuO2-IrO2复合阳极的电化学活性仍明显优于循环极化试验前的Ti/RuO2-IrO2阳极。结论 Co3O4纳米片中间层的加入使得Ti/Co3O4/RuO2-IrO2阳极的电催化析氧性能和稳定性都得到了提升。  相似文献   
7.
张娅  王锐  文思斯  周燚洒  薛健  王海辉 《化工学报》2021,72(12):6188-6202
石墨相氮化碳(g-C3N4)纳米片由于具有本征孔、高孔密度、高稳定性、高力学强度、大比表面积、化学环境可调节等特性,在气体分离、渗透汽化、脱盐等膜分离工艺中具有独特的优势,从而引起了研究人员的广泛关注。本文介绍了g-C3N4纳米片的结构和性质,总结了g-C3N4纳米片的制备方法,阐述了不同形式的g-C3N4纳米片基分离膜,讨论了g-C3N4纳米片膜在分离中的应用,提出了g-C3N4纳米片膜的存在的问题和未来的发展趋势。  相似文献   
8.
We fabricate freely suspended nanosheets of molybdenum disulphide (MoS2) which are characterized by quantitative optical microscopy and high-resolution friction force microscopy. We study the elastic deformation of freely suspended nanosheets of MoS2 using an atomic force microscope. The Young''s modulus and the initial pre-tension of the nanosheets are determined by performing a nanoscopic version of a bending test experiment. MoS2 sheets show high elasticity and an extremely high Young''s modulus (0.30 TPa, 50% larger than steel). These results make them a potential alternative to graphene in applications requiring flexible semiconductor materials.PACS, 73.61.Le, other inorganic semiconductors, 68.65.Ac, multilayers, 62.20.de, elastic moduli, 81.40.Jj, elasticity and anelasticity, stress-strain relations.  相似文献   
9.
《Ceramics International》2023,49(6):9307-9315
In this study, we fabricated mechanically deformable thermoelectric sponges comprising transition metal dichalcogenides (TMDs) and polyethyleneimine (PEI) through a layer-by-layer (LBL) self-assembly technique for a thermoelectric power supply for electronic skin. Chemically exfoliated molybdenum sulfide (MoS2) and niobium diselenide (NbSe2) were prepared as p- and n-type room-temperature thermoelectric materials, respectively, and deposited on a melamine sponge via electrostatic bonding with PEI to obtain stable mechanical stretchability and low thermal conductivity. Five bilayers of LBL self-assembled thermoelectric sponges exhibited an enhanced thermoelectric performance and figure of merit, which resulted from the improvement in the Seebeck coefficient compared with that of pristine chemically exfoliated TMDs owing to the energy filtering effect and the extremely low thermal conductivity owing to the phonon scattering effect at several created interfaces and the porous structure of the sponge. Additionally, the thermoelectric sponges showed mechanical stability during operation under stretching and compression and mechanical durability over 10,000 cycles under 30% tensile strain. Finally, based on the proposed thermoelectric sponge, a power patch that can be installed on the back of a hand to produce electrical energy in real time was successfully demonstrated.  相似文献   
10.
    
Direct ethanol fuel cells hold great promise as a power source. However, their commercialization is limited by anode catalysts with insufficient selectivity toward a complete oxidation of ethanol for a high energy density, as well as sluggish catalytic kinetics and low stability. To optimize the catalytic performance, rationally tuning surface structure or interface structure is highly desired. Herein, a facile route is reported to the synthesis of Rh nanosheets-supported tetrahedral Rh nanocrystals (Rh THs/NSs), which possess self-supporting homogeneous interface between Rh tetrahedrons and Rh nanosheets. Due to full leverage of the structural advantages within the given structure and construction of interfaces, the Rh THs/NSs can serve as highly active electro-catalysts with excellent mass activity and selectivity toward ethanol electro-oxidation. The in situ Fourier transform infrared reflection spectroscopy showed the Rh THs/NSs exhibit the highest C1 pathway selectivity of 23.2%, far exceeding that of Rh nanotetrahedra and Rh nanosheets. Density function theory calculations further demonstrated that self-interface between Rh nanosheets and tetrahedra is beneficial for C-C bond cleavage of ethanol. Meanwhile, the self-supporting of 2D nanosheets greatly enhance the stability of tetrahedra, which improves the catalytic stability.  相似文献   
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