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A.pptx
- 2. Nanostructures • Specific growth conditions lead to different structures with different properties • Nanowires/Nanotubes • Nanobelts • Nanocombs • Nanosprings • Nanocages • Nanoflowers • Nanoflakes • Nanohelix • Nanoneedles • 1D structures • Diameter: 1-100 nanometers (10-9 m) • Length: microns (10-6 m) • Typical aspect ratios of 1000 or more. • Nanorods: small aspect ratios • Nanowires: large aspect ratios
- 3. Why Zinc Oxide? Why ZnO? Could be prepared at low temperature with high quality/performance Act as traps for the electrons and guarantee a better efficiency Easy to perform, economical & and very abundant on the earth's crust Introduce an additional energy levels inside the oxide band gap. Solves the problem related to photo-corrosion of zinc oxide which becomes more stable High thermal & excellent chemical stability and good electrical conductivity Can be produced in various shapes with different deposition technique
- 4. What is HSCs? HYBRIDSOLARCELLS(HSCs) Combine advantages of both organic/polymers and inorganic semiconductors. Consist of conjugated polymers that absorb light as the donor and transport holes. Inorganic materials are used as the acceptor and electron transporter in the structure. Have a potential for low-cost by roll-to-roll processing but also for scalable solar power conversion. It mimics the photosynthesis process by absorbing natural light. A promising solution to future energy concerns because of their material and simple structure The performance was determined by photoconversion efficiency in percentage (%)
- 5. Applications of HSCs Building Integrated Photovoltaic Indoor Appliances Mobile Charger Hyundai Blue Will Concept Car Roof Mounted DSSCs Solar Backpack Solar Tent Flexible DSSCs for Military
- 6. Problemsof HSCs Bilayer Structure HSCs Low power conversion efficiency due to the limited D/A interface area; poor mixing) [Brian R. Saunders et al]. The conjugated polymers have short exciton diffusion lengths (4–20 nm) [M. Theander et al]. The morphology structure which was fixed by the oriented nanostructures can provide the device with a good stability. Vertically aligned electron acceptor channels normally improve the device performance by facilitating the transport of charge carriers to electrodes and minimizing the charge recombination. Objectives Problems & Objectives Bulk Heterojunction HSCs Disordered structures lead to a serious recombination and instability of the morphological structure in the active layer [J. Bouclé et al]. High level of recombination of free electrons with oxidized dye molecules that is caused by low electron transfers [K.M. Coakley et al]. To synthesize self-organized and vertically aligned ZAO nanowires by microwave assisted sonication approach. To fabricate ordered architecture of HSCs using vertically aligned ZAO nanowires
Hinweis der Redaktion
- ZnO has the richest family of nanostructures among all materials
- Zinc oxide is an inorganic compound with the formula ZnO. It exists in white powder which is insoluble in water. It is used as an additive in numerous materials and products including food supplements, tyres (vulcanization process as an accelerator and activator - to achieve improved elasticity, tensile strength, hardness and weather resistance.), plastics, ceramics, glass, cement, lubricants, paints, ointments, batteries, baby powder, and widely used in cosmetics. Between 2003 and 2014, the scientific committees of the European Commission, released several opinions on the use of ZnO in cosmetics which can lead to lung toxicity and inflammation. Some tests suggest that this could also lead to cancer. In view of this, the European cosmetics regulation lays down to not using titanium dioxide or zinc oxide nanoparticles in applications that would lead to any significant inhalation exposure such as powders or sprayable products. So, it is suggested that both forms of the substance should be authorised at a maximum concentration of 25 %. So, ……we have too many product in our market right now… Wide-bandgap materials have several characteristics that make them useful compared to narrower bandgap materials. The higher energy gap gives devices the ability to operate at higher temperatures, as bandgaps typically shrink with increasing temperature, which can be problematic when using conventional semiconductors. ZnO is transparent to visible light and can be made highly conductive by doping.