1,720,966 research outputs found
Nanocarbon Based Polymer Solar Cells
No full text有機高分子太陽能電池具有低成本、可撓曲且能大面積製造的優勢，因而吸引大家廣泛的興趣。然而，目前高分子太陽能電池在應用上還有一些不利的因素，其陽極材料氧化銦錫透明電極不易撓曲且價格日益升高，電洞傳輸層PEDOT:PSS 有吸濕性且容易在紫外光下衰退，陰極的低功函數金屬則是在大氣中容易氧化不穩定。因此，此研究的目的是利用奈米碳材穩定的化學性質以及其良好的導電和可撓曲特性，藉以取代原本高分子太陽能電池中陰陽極和電洞傳輸層的材料，發展出以奈米碳材為基材的高分子太陽能電池。其一是以一維奈米碳管為透明導電電極，二維氧化態石墨烯為電洞傳輸層，兩者結合做為高分子太陽能電池的陽極平台，此元件表現出與一般元件接近的光電轉換效率，且具有可撓曲、可水溶液製程且大面積製造的優點。另外則是分別以n型及p型摻雜後的石墨烯做為太陽能電池中的陰陽極，發展出可以用roll-to-roll連續卷軸生產方式的元件，加上其半透明且可撓曲的優點，更有利於未來低成本製造和多元的應用。這兩種以奈米碳材維基材的高分子太陽能電池，成功結合了奈米碳材與高分子太陽能電池的優點，充分展現了其未來在生產及實際應用上的潛力。Polymer solar cells have attracted a great interest for fabricating low-cost large-area mechanically flexible photovoltaic devices compared to the conventional inorganic counterparts. But the conventionally used ITO anode, PEDOT:PSS, and the low work function metal cathode all have its own shortcomings, hindering the devices from practical application. In this research, we would like to demonstrate new architectures of polymer solar cells based on allotropes of carbon nanomaterials, by utilizing p-type doped graphene or single walled carbon nanotube (SWNT) thin film as the anode, graphene oxide (GO) as the hole transport layer, n-type doping graphene as the cathode, and fullerene derivative PCBM/P3HT bulk heterojunctions as the photoactive layer. The photovoltaic device based on the solution processed SWNT/GO platform has exhibited good power conversion efficiency of 3.1% as compared to the conventional device (PCE=3.57%). And the new innovation of polymer solar cell based on all-graphene electrodes provides a potential route to develop a flexible, semitransparent photovoltaic device which can be fully integrated with the low-cost, roll-to-roll fabrication process. By overcoming the drawbacks of polymer solar cells, these two approaches have shown the potential of serving the long-term solutions for the future energy supply
Solution-Processable Graphene Oxide as an Efficient Hole Transport Layer in Polymer Solar Cells
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Machine Learning Predictions of Block Copolymer Self‐Assembly
No full textDirected self-assembly of block copolymers is a key enabler for nanofabrication of devices with sub-10 nm feature sizes, allowing patterning far below the resolution limit of conventional photolithography. Among all the process steps involved in block copolymer self-assembly, solvent annealing plays a dominant role in determining the film morphology and pattern quality, yet the interplay of the multiple parameters during solvent annealing, including the initial thickness, swelling, time, and solvent ratio, makes it difficult to predict and control the resultant self-assembled pattern. Here, machine learning tools are applied to analyze the solvent annealing process and predict the effect of process parameters on morphology and defectivity. Two neural networks are constructed and trained, yielding accurate prediction of the final morphology in agreement with experimental data. A ridge regression model is constructed to identify the critical parameters that determine the quality of line/space patterns. These results illustrate the potential of machine learning to inform nanomanufacturing processes.
Domain configurations in Co/Pd and L10-FePt nanowire arrays with perpendicular magnetic anisotropy
No full textPerpendicular magnetic anisotropy [Co/Pd][subscript 15] and L1[subscript 0]-FePt nanowire arrays of period 63 nm with linewidths 38 nm and 27 nm and film thickness 27 nm and 20 nm respectively were fabricated using a self-assembled PS-b-PDMS diblock copolymer film as a lithographic mask. The wires are predicted to support Néel walls in the Co/Pd and Bloch walls in the FePt. Magnetostatic interactions from nearest neighbor nanowires promote a ground state configuration consisting of alternating up and down magnetization in adjacent wires. This was observed over ∼75% of the Co/Pd wires after ac-demagnetization but was less prevalent in the FePt because the ratio of interaction field to switching field was much smaller. Interactions also led to correlations in the domain wall positions in adjacent Co/Pd nanowires. The reversal process was characterized by nucleation of reverse domains, followed at higher fields by propagation of the domains along the nanowires. These narrow wires provide model system for exploring domain wall structure and dynamics in perpendicular anisotropy systems.National Science Foundation (U.S.) (NSF MRSEC, award DMR1419807)Singapore. Agency for Science, Technology and Research ((A*STAR) International Fellowship grant)Semiconductor Research Corporation. Center for Spintronic Materials, Interfaces, and Novel Architecture
Enhanced infrared light harvesting of inorganic nanocrystal photovoltaic and photodetector on graphene electrode
No full textQuantum Dot Light-Emitting Diode Using Solution-Processable Graphene Oxide as the Anode Interfacial Layer
No full textTransport behavior and negative magnetoresistance in chemically reduced graphene oxide nanofilms
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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