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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Demonstrating the GaInP/GaAs Three-Terminal Heterojunction Bipolar Transistor Solar Cell
摘要： The three-terminal heterojunction bipolar transistor solar cell (HBTSC) concept enables the realization of a monolithic double-junction device with individual current extraction. We present an HBTSC realized by a heterojunction of GaInP and GaAs. The one-sun open-circuit voltage (VOC ) of the top and bottom junctions are 1.33 V and 0.99 V, respectively, while ?ll factors (FF) are above 80%. At one-sun illumination, reducing one junction’s bias from VOC to maximum power point degrades the performance of the other junction only slightly (< 0.5% ef?ciency loss). These results demonstrate the potential of the HBTSC concept to produce high-ef?ciency independently connected double-junction solar cells.
关键词： photovoltaic cells,independent current,multi terminal,gallium indium phosphide,gallium arsenide,double junction
更新于2025-09-23 15:21:01
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Toward Efficient Triple-Junction Polymer Solar Cells through Rational Selection of Middle Cells
摘要： The photon energy losses of polymer solar cells (PSCs) routinely drag their experimental power conversion efficiencies (PCEs) far below the theoretical limits. We report herein efficient triple-junction PSCs (TJ-PSCs) with mitigated energy losses through rational selection of subcells. We reveal that avoiding strong photon competition between the front and middle cells is critical in balancing the absorption rate among subcells with realistic layer thicknesses. Efficient TJ-PSCs are achieved by stacking a front cell of PBDB-T-2F:PC71BM, a middle cell of PBDB-T:HF-TCIC, and a rear cell of PTB7-Th: IEICO-4F in series and connecting them with two functional interconnection layers. A PCE of 13.09% is obtained from champion devices, representing one of the best TJ-PSCs among the reported studies. It accounts for a 35% improvement in efficiency over those of single-junction PSCs with the same absorption range, which is mainly attributed to the reduced nonabsorbing and thermalization losses of TJ-PSCs.
关键词： polymer solar cells,photon energy losses,power conversion efficiencies,nonfullerene acceptors,triple-junction
更新于2025-09-23 15:21:01
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Thermal Assessment of Laminar Flow Liquid Cooling Blocks for LED Circuit Boards Used in Automotive Headlight Assemblies
摘要： This research work presents a comparative thermal performance assessment of the laminar flow cooling blocks produced for automotive headlight assembly using a high power Light Emitting Diode (LED) chip. A three-dimensional numerical model with conjugate heat transfer in solid and fluid domains was used. Laminar flow was considered in the present analysis. The validation of the numerical model was realized by using the measured data from the test rig. It was observed that substantial temperature variations were occurred around the LED chip owing to volumetric heat generation. The cooling board with lower height performs better thermal performance but higher pressure drop for the same mass flow rates. The cooling board with the finned cover plate performs better thermal performance but results in an increased pressure drop for the same mass flow rates. Increasing the power of the LED results in higher temperature values for the same mass flow rates. The junction temperature is highly dependent on the mass flow rates and LED power. It can be controlled by means of the mass flow rate of the coolant fluid. New Nusselt number correlations are proposed for laminar flow mini-channel liquid cooling block applications.
关键词： laminar flow,CFD,LED chip,finned plate,junction temperature,automotive headlight,liquid cooling
更新于2025-09-23 15:21:01
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Enhanced Photoelectrochemical Water Oxidation from CdTe Photoanodes Annealed with CdCl2
摘要： CdTe absorbs sunlight up to 830 nm and has the potential to promote efficient photoelectrochemical (PEC) water splitting. However, most CdTe photoanodes and CdTe photocathodes show positive and negative photocurrent onset potentials for water oxidation and reduction, respectively, and are thus unable to drive PEC water splitting without external applied biases. In this work, we enhanced the activity of a CdTe photoanode having an internal p-n junction during PEC water oxidation by applying a CdCl2 annealing treatment together with surface modifications. The resulting CdTe photoanode generated photocurrents of 1.8 and 5.4 mA cm-2 at 0.6 and 1.2 VRHE, respectively, with a photoanodic current onset potential of 0.22 VRHE under simulated sunlight (AM 1.5G). The CdCl2 annealing increased the grain sizes in this material and lowered the density of grain boundaries, allowing for more efficient charge separation. Consequently, a two-electrode tandem PEC cell comprising a CdTe-based photoanode and photocathode split water without any external bias at a solar-to-hydrogen conversion efficiency of 0.51% at the beginning of the reaction.
关键词： Photoanode,Overall water splitting,Photoelectrochemistry,p-n junction,CdCl2 treatment
更新于2025-09-23 15:21:01
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Construction of n-TiO2/p-Ag2O Junction on Carbon Fiber Cloth with Visa??NIR Photoresponse as a Filter-Membrane-Shaped Photocatalyst
摘要： The development of effective and reusable photocatalysts with broad-spectra activity has attracted attention. Herein, we have constructed n-TiO2/p-Ag2O junction on carbon fiber (CF) cloth as an efficient and recyclable photocatalyst. With CF cloth as the substrate, TiO2 nanorods (length: 1–2 μm) are prepared by a hydrothermal process, and the in-situ growth of Ag2O nanoparticles (10–20 nm) is then realized by chemical bath deposition route. The flexible CF/TiO2/Ag2O cloth (area: 4 × 4 cm2) shows a broad and strong photo-absorption (200–1000 nm). Under the illumination of visible-light (λ > 400 nm), CF/TiO2/Ag2O cloth can efficiently eliminate 99.2% rhodamine B (RhB), 99.4% acid orange 7 (AO7), 87.6% bisphenol A (BPA), and 89.5% hexavalent chromium (Cr6+) in 100 min, superior to CF/Ag2O cloth (83.5% RhB, 60.0% AO7, 31.2% BPA and 41.8% Cr6+). In particular, under the NIR-light illumination (980 nm laser), CF/TiO2/Ag2O cloth can remove 70.9% AO7 and 60.0% Cr6+ in 100 min, which are significantly higher than those by CF/Ag2O cloth (19.8% AO7 and 18.9% Cr6+). In addition, CF/TiO2/Ag2O cloth (diameter: 10 cm), as a filter-membrane, can effectively wipe off 94.4% flowing RhB solution (rate: ~ 1 L h? 1) at 6th filtering/degrading grade. Thus, CF/TiO2/Ag2O cloth can be used as a Vis–NIR-responded filter-membrane-shaped photocatalyst with high-efficiency for purifying wastewater.
关键词： n-TiO2/p-Ag2O junction,Filter-membrane,Photocatalyst,Vis-NIR photoresponse,Carbon fiber cloth
更新于2025-09-23 15:21:01
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Solar cell based on vertical graphene nano hills directly grown on silicon
摘要： We demonstrate a solar cell application based on vertical graphene nano hills (VGNH) directly grown without using a catalyst. The photovoltaic device based on VGNH grown on top of interfacial layer Al2O3 is compared with that on top of bare silicon by critically analyzing its electrical properties. The role of the interfacial layer is to minimize surface recombination and enhance its built-in potential. Our key process is simple to fabricate large-area devices, avoiding an unreliable transfer process. In addition, the thickness of VGNH is optimized and the surface texturing of silicon is performed to overcome the crucial problem of the high reflectivity of silicon. A low reflectivity of thick layers of VGNH is achieved with low series resistance despite of the vertical structure, which is beneficial for high photocurrent. A higher work function of VGNH ~ 4.7 eV is measured by KPFM. The conversion efficiency of 10.97% is achieved with an active area of 0.9 cm2 by co-doping with PEDOT: PSS and inorganic acid HNO3. Moreover, the photo-responsivity of the VGNH-based device is estimated as 1.196 AW-1 under deep ultraviolet light.
关键词： vertical graphene,graphene doping,graphene nano hills,directly grown graphene,solar cell,anti-reflecting coating,Schottky junction
更新于2025-09-23 15:21:01
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Detectors on the Basis of High-Purity Epitaxial GaAs Layers for Spectrometry of X and Gamma Rays
摘要： The characteristics of detectors of soft-X and γ rays based on high-purity epitaxial GaAs layers are discussed. The characteristics of detectors with different rectifying contacts are compared, that is, those with a Schottky barrier and a p–n junction. The spectral characteristics of the manufactured detectors that were obtained under the irradiation by 57Co and 241Am sources at different bias voltages and in a photovoltaic mode and the simulation results using the Geant 3.21 software package are presented.
关键词： photovoltaic mode,Geant 3.21,Schottky barrier,high-purity epitaxial GaAs layers,spectrometry,X and Gamma Rays,p–n junction
更新于2025-09-23 15:21:01
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[IEEE 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Shanghai (2018.8.8-2018.8.11)] 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Research on Thermal Analysis of Iris Recognition Module Package Structure
摘要： The existing iris recognition module is realized by assembly, which has large volume, high power consumption. The iris recognition module does not conform to the light and thin development trend of integrated circuits. Therefore, the industry is considering building a new iris recognition module from the bare chip and micro interconnect technology. The new module integrates a number of bare chips and passive devices in a limited space, and its thermal performance becomes more complex. It performance systematically. In this paper, thermal performance of the iris recognition module is systematically studied by the finite element method, and the influence of the thermal power of the chip, the thermal conductivity of the material and the area of PCB on the temperature and thermal resistance of the package are discussed. The results show that the thermal conductivity of chip material, the thermal power consumption of chip and the area of PCB have significant influence on packaging junction and thermal resistance of package. Package junction temperature and thermal resistance first decrease rapidly with the heat transfer coefficient of the package material, and then gradually tends to be horizontal, The effect of PCB area on the thermal performance of packaging is similar to that of the loading material, and the thermal dissipation power of the package is linearly increasing with the junction temperature of the package, and it has a horizontal linear relationship with the thermal resistance of the package.
关键词： microinterconnection technology,iris identification module,package junction temperature,package thermal resistance
更新于2025-09-23 15:21:01
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Selective growth of monolayer semiconductors for diverse synaptic junctions
摘要： The information computation through synapse networks in the brain plays a vital role for cognitive behaviors such as image/video recognition, self-learning, and decision-making. Achieving proper synaptic networks by conventional semiconductor and memristive devices has encountered critical issues such as the spatial density requiring a number of transistors for one synapse, reliable filament formation in memristors, or emulating diverse excitatory and inhibitory synaptic plasticity with two-terminal device geometry. Here, we report selective growth of variously doped MoS2 with controllable conductance plasticity, which can be used for emulating diverse synaptic junctions. The conductance plasticity in the monolayer MoS2 was found to originate from resistive-heating near the junctions with electrodes in the two-terminal device geometry and the carrier-concentration-dependent metal-insulator transition in the MoS2 channel. A spatiotemporal synaptic summation is demonstrated where the firing of a proper postsynaptic membrane potential can be designed for cognitive processes. Compared with previously reported three terminal synaptic devices with atomically thin materials, our two-terminal devices with flexible synaptic strengths have advantages for integrating three-dimensional neuronal networks. This provides a new insight on two-dimensional materials as a promising arena for integrated synaptic functionalities in artificial neural networks.
关键词： chemical vapor deposition,metal-insulator transition,defects engineering,two dimensional materials,synaptic junction
更新于2025-09-23 15:21:01
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Self-Powered Solar-Blind Photodetectors Based on <i>?±</i> / <i>?2</i> Phase Junction of
摘要： Self-powered Ga2O3-based solar-blind photodetectors have received attention recently due to the increased demand for energy saving, miniaturization, and high efficiency in devices. An ideal device structure consisting of a Ga2O3-based p-n junction is still difficult to obtain, since p-type doping is a major challenge. Although self-powered devices based on heterojunction are promising, there are two fatal disadvantages: (1) photosensitivity of the non-solar-blind region, on account of the narrower band gap of the heterojunction materials; and (2) poor quality of the epitaxial film due to lattice mismatch. In view of the various polymorphs of Ga2O3, we propose constructing a structure consisting of a Ga2O3 phase junction with α and β phases (α/β phase junction) for self-powered solar-blind photodetectors. The small lattice mismatch and similar band gap between α- and β-Ga2O3 will solve the two problems outlined above. The formation of α- and β-Ga2O3 is expected to result in a type-II band alignment, promoting separation of photogenerated carriers, which transfer through the junction to the corresponding electrodes. Herein, the α/β phase junction of Ga2O3 vertically aligned nanorod arrays with a thickness-controllable β-Ga2O3 shell layer are fabricated by a low-cost and simple process of hydrothermal and postannealing treatment. Two different types of self-powered α/β-Ga2O3 phase junction-based photodetectors, in the form of solid-state type and photoelectrochemical type, are constructed and realized. Our analysis shows that the constructed photodetectors are capable of highly efficient detection of solar-blind signal without any bias voltage. This work demonstrates the usefulness of using the α/β-Ga2O3 phase junction in a self-powered solar-blind photodetector, which is not only energy efficient, but also potentially workable in outer space, at the south and north pole, and other harsh environments without external power for a long time.
关键词： solar-blind photodetectors,phase junction,Ga2O3,α/β phase junction,self-powered
更新于2025-09-23 15:19:57