| 1. |
- Liu, Zhiying, et al.
(författare)
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Solution-Processable Nanotube/Polymer Composite for High-Performance TFTs
- 2011
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Ingår i: IEEE Electron Device Letters. - 0741-3106 .- 1558-0563. ; 32:9, s. 1299-1301
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Tidskriftsartikel (refereegranskat)abstract
- Thin-film field-effect transistors (TFTs) are readily fabricated using a semiconductor composite that is solution processed under ambient conditions for the conduction channel. The composite comprises single-walled carbon nanotubes (SWCNTs) embedded in poly-9,9' dioctyl-fluorene-co-bithiophene. Carrier mobility values approaching 10 cm(2)V(-1)s(-1) are obtained for the composite with relatively high SWCNT concentrations. When the SWCNT concentration is reduced for a large ON/OFF current ratio > 10(6), the mobility remains decent around 0.3 cm(2)V(-1)s(-1). The resultant TFTs display remarkable environmental and operational reliability. Nanotube-based composites are therefore of significance in printed electronics owing to their simplicity in device fabrication and competitiveness in device performance.
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| 2. |
- Zhang, Huotian, et al.
(författare)
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Reversible air-induced optical and electrical modulation of methylammonium lead bromide (MAPbBr(3)) single crystals
- 2017
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Ingår i: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 111:10
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Tidskriftsartikel (refereegranskat)abstract
- The photoluminescence (PL) variations of organic-inorganic hybrid lead halide perovskites in different atmospheres are well documented, while the fundamental mechanism still lacks comprehensive understandings. This study reports the reversible optical and electrical properties of methylammonium lead bromide (MAPbBr(3) or CH3NH3PbBr3) single crystals caused by air infiltration. With the change in the surrounding atmosphere from air to vacuum, the PL intensity of perovskite single crystals decreases, while the conductivity increases. By means of first-principles computational studies, the shallow trap states are considered as key elements in PL and conductivity changes. These results have important implications for the characterization and application of organic-inorganic hybrid lead halide perovskites in vacuum.
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| 3. |
- Cheng, W., et al.
(författare)
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Medial reward and lateral non-reward orbitofrontal cortex circuits change in opposite directions in depression
- 2016
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Ingår i: Brain. - : Oxford University Press. - 0006-8950 .- 1460-2156. ; 139:12, s. 3296-3309
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Tidskriftsartikel (refereegranskat)abstract
- The first brain-wide voxel-level resting state functional connectivity neuroimaging analysis of depression is reported, with 421 patients with major depressive disorder and 488 control subjects. Resting state functional connectivity between different voxels reflects correlations of activity between those voxels and is a fundamental tool in helping to understand the brain regions with altered connectivity and function in depression. One major circuit with altered functional connectivity involved the medial orbitofrontal cortex Brodmann area 13, which is implicated in reward, and which had reduced functional connectivity in depression with memory systems in the parahippocampal gyrus and medial temporal lobe, especially involving the perirhinal cortex Brodmann area 36 and entorhinal cortex Brodmann area 28. The Hamilton Depression Rating Scale scores were correlated with weakened functional connectivity of the medial orbitofrontal cortex Brodmann area 13. Thus in depression there is decreased reward-related and memory system functional connectivity, and this is related to the depressed symptoms. The lateral orbitofrontal cortex Brodmann area 47/12, involved in non-reward and punishing events, did not have this reduced functional connectivity with memory systems. Second, the lateral orbitofrontal cortex Brodmann area 47/12 had increased functional connectivity with the precuneus, the angular gyrus, and the temporal visual cortex Brodmann area 21. This enhanced functional connectivity of the non-reward/punishment system (Brodmann area 47/12) with the precuneus (involved in the sense of self and agency), and the angular gyrus (involved in language) is thus related to the explicit affectively negative sense of the self, and of self-esteem, in depression. A comparison of the functional connectivity in 185 depressed patients not receiving medication and 182 patients receiving medication showed that the functional connectivity of the lateral orbitofrontal cortex Brodmann area 47/12 with these three brain areas was lower in the medicated than the unmedicated patients. This is consistent with the hypothesis that the increased functional connectivity of the lateral orbitofrontal cortex Brodmann area 47/12 is related to depression. Relating the changes in cortical connectivity to our understanding of the functions of different parts of the orbitofrontal cortex in emotion helps to provide new insight into the brain changes related to depression.
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| 4. |
- Ling, Li, et al.
(författare)
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Precisely Controlled Hydration Water for Performance Improvement of Organic-Inorganic Perovskite Solar Cells
- 2016
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Ingår i: Advanced Functional Materials. - : Wiley-VCH Verlagsgesellschaft. - 1616-301X .- 1616-3028. ; 26:28, s. 5028-5034
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Tidskriftsartikel (refereegranskat)abstract
- Recently, intensive studies on the role of water molecule in the formation of organic-inorganic perovskite film have been reported. However, not only the contradictive phenomena but also the complex processing technique has hindered the widespread use of water molecule in perovskite preparation. Here the hydration water is introduced into the precursors instead of water. By precisely controlling the content of hydration water, a smoother and more uniform perovskite film is obtained through a simple one-step spin coating method. The improvement of perovskite film quality leads to highly efficient planar perovskite solar cells. Summing up the device studies and the investigation of morphology, crystallization, and optical properties, the impact of water molecule in the formation of perovskite crystal and consequences of device performance is understood. Due to its universal adaptability and simplified process, precise control of hydration water is therefore of great utility to high quality perovskite films fabrication and large-scale production of this upcoming photovoltaic technology.
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| 5. |
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| 6. |
- Lu, H., et al.
(författare)
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An optical dynamic study of MAPbBr3 single crystals passivated with MAPbCl3/I3-MAPbBr3 heterojunctions
- 2017
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry. - 1463-9076 .- 1463-9084. ; 19:6, s. 4516-4521
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Tidskriftsartikel (refereegranskat)abstract
- Recently, perovskite based solar cells have attracted lots of research interest, some of which is in the passivation of perovskite surfaces, particularly the heterojunction based surface passivation. In this study, the optical dynamics of MAPbBr3 single crystals with and without heterojunction passivation were studied systematically by means of a time-resolved spectroscopic technique for the first time. The emission lifetime of MAPbBr3 single crystals under two-photon (1064 nm) excitation is a few orders of magnitude longer than that measured under one-photon (355 nm or 532 nm) excitation. Interestingly, with surface passivation, the lifetime measured at 355 nm excitations could be tuned significantly, whereas the lifetime change under 1064 nm excitations was considerably less. Our results give a direct evidence of surface quench by comparing the lifetimes before and after surface passivation. Furthermore, the results demonstrate that proper MAPbCl3-MAPbBr3 heterojunctions can dramatically reduce the recombination channels in the surface region, which can be potentially useful for perovskite based solar cells, light emitting diodes (LED), and sensitive detectors.
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| 7. |
- Pang, Zhibo, et al.
(författare)
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Global Fresh Food Tracking Service Enabled by Wide Area Wireless Sensor Network
- 2010
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Ingår i: 2010 IEEE Sensors Applications Symposium, SAS 2010. - : IEEE Sensors Council. ; , s. 6-9
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Konferensbidrag (refereegranskat)abstract
- A global fresh food tracking service is presented, in which a set of primary environmental conditions for transport of fresh fruits and vegetables, including global position, temperature, relative humidity, concentrations of CO2, O2 and ethylene gases and 3-axis acceleration, is collected through mobile and remotely controllable wireless sensor nodes. Real time monitoring, tracking, alarming, close-loop controlling and information sharing could therefore be provided as WEB services with service oriented architecture. Fully functioned hardware modules, protocols and system software have been developed. A 50-day field test has been successfully carried out, proving the system concept and the robustness of hardware and software designed. Due to its worldwide deploy-ability and added-values to fresh food supply chain, it is feasible to establish a practical fresh food tracking service business.
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| 8. |
- You, Yintao, et al.
(författare)
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An organic multilevel non-volatile memory device based on multiple independent switching modes
- 2014
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Ingår i: Organic electronics. - : Elsevier BV. - 1566-1199 .- 1878-5530. ; 15:9, s. 1983-1989
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Tidskriftsartikel (refereegranskat)abstract
- The demand for higher data density memory structures is greater today than ever before. Multilevel resistive organic memory devices (OMD) provide an ideal solution, in being easily fabricated, cost-effective and at the same time promising high storage capacity. However, conventional methods for multilevel OMDs impose demanding requirements on material properties and attain only limited performance. We hereby provide an alternative design concept that combines multiple switching modes in one device to realize multilevel function. The device possesses a simple structure by using a ferroelectric phase-separated blend as the active layer. Two switching modes, the ferroelectric switching and the metallic filament switching, are realized simultaneously in this device, and enable a ternary storage function. The cross-section scanning electron microscope (SEM) images provide a strong evidence of the formation and annihilation of the metallic filament.
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| 9. |
- Yuan, S., et al.
(författare)
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High-gain broadband organolead trihalide perovskite photodetector based on a bipolar heterojunction phototransistor
- 2018
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Ingår i: Organic electronics. - : Elsevier. - 1566-1199 .- 1878-5530. ; 57, s. 7-13
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Tidskriftsartikel (refereegranskat)abstract
- Both a favorable material and designed structure are essential for a high-performance photodetector. For the excellent physical properties of organolead trihalide perovskites, with CH3NH3PbI3 films serving as a base layer, a bipolar heterojunction phototransistor-type perovskite photodetector is proposed. Benefiting from this bipolar heterojunction structure, which is characterized by high gain and low work voltage, an optimized device exhibits high performance with a photoresponsivity of 125 AW−1 and an external efficiency of 3.62 × 104% at 427 nm with a low work voltage of 0.7 V. Additionally, such phototransistors have a broad photoresponsivity from 360 to 820 nm. These results demonstrate that the bipolar heterojunction phototransistor, which is widely used in inorganic materials, is a promising structure for organolead trihalide perovskite optoelectronic devices, paving a new way for developing high-performance photodetectors.
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| 10. |
- Zhang, Wei, et al.
(författare)
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Hierarchical Design of a Low Power Standing Wave Oscillator Based Clock Distribution Network
- 2016
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Ingår i: 2016 2ND IEEE NORDIC CIRCUITS AND SYSTEMS CONFERENCE (NORCAS). - : IEEE conference proceedings. - 9781509010950
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Konferensbidrag (refereegranskat)abstract
- This paper introduces a hierarchical clock interconnection network with two-level bufferless standing wave resonant clock distribution to minimize the clock power consumption in a synchronous system. The first level is a serpentine network which consists of many coupled standing wave oscillators to distribute clock signals in the whole chip area. The second level is a group of fishbone architectures connected to the standing wave oscillators to route clock signals in the local areas. A clock synthesis flow for the fishbone architecture is also introduced to enable design automation. This fishbone architecture is studied through a pipelined floating-point fused multiply-add module under 28nm standard CMOS process. Simulation results show that, this architecture can reduce more than 30% clock power consumption compared with a traditional buffered clock network.
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