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Heat-Recovery Solar Cell
摘要： Heat-recovery (HERC) solar cell—a concept of solar cells utilizing the heat for improving the power conversion e?ciency—is presented. HERC solar cell, characterized by an absorber hotter than electrodes, recovers heat as electricity to have high conversion e?ciency exceeding the detailed balance limit when carrier-energy ?ltering is employed. Being di?erent from hot-carrier solar cells, HERC solar cell does not require fast carrier extraction within the thermalization time, which largely improves its feasibility (feasible even with Si). An increment in the conversion e?ciency originates from thermoelectricity produced by the temperature di?erence. Requirements for materials of the ?ltering layers are also given based on a nonideal device simulation with the thermoelectric properties.
关键词： Si solar cells,Heat-recovery solar cell,carrier-energy filtering,thermoelectricity,power conversion efficiency
更新于2025-09-11 14:15:04
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A Molecular Design Strategy in Developing Titanyl Phthalocyanines as Dopant-Free Hole Transporting Materials for Perovskite Solar Cells: Peripheral or Non-Peripheral Substituents?
摘要： We demonstrate a molecular design strategy to enhance the efficiency of phthalocyanine (Pc) based hole transporting materials (HTMs) in perovskite solar cells (PSCs). Herein, two titanyl phthalocyanine (TiOPc) derivatives are designed and applied as dopant-free HTMs in planar n-i-p structured PSCs. The newly developed TiOPc compounds possess eight n-hexylthio groups attached to either peripheral (P-SC6-TiOPc) or non-peripheral (NP-SC6-TiOPc) positions of the Pc ring. Utilizing these dopant-free HTMs in PSCs with a mixed cation perovskite as the light absorbing material and tin oxide (SnO2) as the electron transporting material (ETM) results in a considerably enhanced efficiency for NP-SC6-TiOPc based devices compared to PSCs using P-SC6-TiOPc. Hence, all the photovoltaic parameters, including power conversion efficiency (PCE), fill factor, open circuit voltage and short-circuit current density are remarkably improved from 5.33 ± 1.01%, 33.34 ± 3.45%, 0.92 ± 0.18 V, and 17.33 ± 2.08 mA cm-2 to 15.83 ± 0.44%, 69.03 ± 1.59%, 1.05 ± 0.01 V, and 21.80 ± 0.36 mA cm-2, respectively, when using the non-peripheral substituted TiOPc derivative as the HTM in a PSC. Experimental and computational analysis suggests more compact molecular packing for NP-SC6-TiOPc than P-SC6-TiOPc in the solid state due to stronger π-π interactions, leading to thin films with better quality and higher performance in hole extraction and transportation. PSCs with NP-SC6-TiOPc also offer much higher long-term stability than P-SC6-TiOPc based devices, under ambient conditions with a relative humidity of 75%.
关键词： non-peripheral substituents,titanyl phthalocyanines,perovskite solar cells,power conversion efficiency,hole transporting materials
更新于2025-09-11 14:15:04
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Regioregularity and Electron Deficiency Control of Unsymmetric Diketopyrrolopyrrole Copolymers for Organic Photovoltaics
摘要： Manipulating the electron deficiency and controlling the regioregularity of π-conjugated polymers are important for the fine-tuning of their electronic and electrochemical properties to make them suitable for an organic solar cell. Here, we report such a molecular design of unsymmetric diketopyrrolopyrrole (DPP) based copolymers with different aromatic side units of either thiophene (Th), pyridine (Py), or fluorobenzene (FBz). The unsymmetric electron acceptors of Th?DPP?Py and Th?DPP?FBz were polymerized with the electron donor of two-dimensional benzobisthiophene (BDT-Th), affording two regiorandom DPP copolymers. They exhibited contrasting molecular orbital levels and bulk heterojunction morphology in methanofullerene-blended films, leading to power conversion efficiencies of 3.75 and 0.18%, respectively. We further synthesized a regioregular DPP copolymer via sandwiching the centrosymmetric BDT-Th unit by two Th?DPP?Py units in an axisymmetric manner. The extensive characterization through morphology observation, X-ray diffraction, and space-charge-limited current mobilities highlight the case-dependent positive/negative effects of regioregularity and electron deficiency control.
关键词： diketopyrrolopyrrole,organic photovoltaics,electron deficiency,regioregularity,power conversion efficiency
更新于2025-09-11 14:15:04
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Novel photo-voltaic device based on Bi1?xLaxFeO3 perovskite films with higher efficiency
摘要： Photovoltaic cells using polycrystalline La substituted bismuth iron oxide, Bi1?xLaxFeO3, (0.1 ≤ x ≤ 0.4), films as the light harvesting component were investigated in this work. A novel cell set-up utilizing a double layered TiO2 film as top contact and a thin layer of quasi-solid polymer electrolyte as back contact was used and a significant enhancement in cell efficiency was observed for assemblies based on x ≥ 0.2 samples, coincident with a structural transition of Bi1?xLaxFeO3 from ferroelectric to non-ferroelectric. The power conversion efficiency of the PV device was 0.13% for the cell with x = 0.2 at 1 sun irradiation. The short circuit current density for this La composition was 0.35 mA cm?2. A hysteretic behaviour was observed for higher La compositions when the scanning is from open-circuit (OP) to short-circuit (SC) which may be attributed to polarization effects. The results at x ≥ 0.2 show an improved performance with respect to BiFeO3 based systems, suggesting the stabilization of the non-ferroelectric crystal structure leads either to a more efficient separation of photo-generated electron–hole pairs and/or enhanced charge transport. The findings represent a step towards the realisation of facile to fabricate, inorganic solid state photovoltaic devices.
关键词： ferroelectric,Photovoltaic cells,power conversion efficiency,quasi-solid polymer electrolyte,Bi1?xLaxFeO3,non-ferroelectric,TiO2
更新于2025-09-10 09:29:36
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Numerical simulation of carrier transporting layer free planar perovskite cells
摘要： One of challenging issues in research on planar perovskite solar cells (PSCs) is to design a device structure as simple as possible with high device performance, being beneficial to decreasing process complexity, improving device stability and reducing fabrication cost. In this work, concerning two categories of configurations, p-CH3NH3PbI3 based hole transporting layer (HTL) free planar PSCs, as well as p-CH3NH3PbI3 based HTL- free and electron transporting layer (ETL) free planar PSCs were modeled and simulated by AFORS-HET software, and the performances of these PSCs were analyzed in detail. Several factors or parameters that influence the performance of PSCs were concerned in the models, such as interface defect layer, trap density of the perovskite layer, series resistance and shunt resistance. The yielded power conversion efficiency (PCE) of HTL-free PSCs with the configurations of ZnO:Al/ZnO/CH3NH3PbI3 and ZnO:Al/TiO2/CH3NH3PbI3 were 14.36% and 16.92%, respectively. Three transparent conductive oxide (TCO) materials, i.e. ZnO:Al, FTO and ITO, were directly combined with p-type CH3NH3PbI3 to form ZnO:Al/CH3NH3PbI3, FTO/CH3NH3PbI3 and ITO/CH3NH3PbI3 carrier transporting layer free PSCs, with the PCE up to 15.91%, 15.48% and 6.42%, respectively. This evaluation indicates the high performances of some both HTL-free and ETL-free, carrier transporting layer free, planar PSCs with TCO/perovskite heterojunctions, an extremely simple device structure. This could be because photo-generated carriers can be effectively separated by built-in electric field and transported from p-n heterojunctions to electrodes in TCO/CH3NH3PbI3 heterojunction solar cells.
关键词： Planar perovskite solar cells,HTL-free,Power conversion efficiency,TCO/ETL/CH3NH3PbI3,TCO/CH3NH3PbI3,ETL-free
更新于2025-09-10 09:29:36
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<b>Compatibility of Anfis controller and FPGA in solar power generation for a domestic oad
摘要： Among other soft computing techniques, the Adaptive Neuro Fuzzy Inference System (Anfis) gives a significant and advantageous result in solar power generation, especially in tracking the maximum power point. Due to the dynamic nature of solar irradiance and temperature, efficient energy conversion is not possible. However, advancements in the areas of artificial intelligence have made it possible to overcome the hurdles. The Maximum Power Point Tracking (MPPT) technique adopting the advantages of Anfis has been proven to be more successful with a fast dynamic response and high accuracy. The complete system is modeled using Matlab/Simulink; the hardware results are validated with the benefits of Field Programmable Logic Array (FPGA) instead of ordinary micro-controllers.
关键词： DC-AC power conversion,MPPT,FPGA,Anfis controller,solar power generation
更新于2025-09-09 09:28:46
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Tandems in the thick of it
摘要： Two-terminal all-perovskite tandem structures are promising as low-cost yet highly efficient solar cells, but their development is limited by the poor quality of the low bandgap absorber layer. Now, a processing method has been shown to enable the production of uniform, thick tin–lead perovskite layers, which translate into improved photovoltaic parameters.
关键词： perovskite photovoltaics,low bandgap absorber,power conversion efficiency,tin–lead perovskite,tandem solar cells
更新于2025-09-09 09:28:46
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Dimensionality engineering of hybrid halide perovskite light absorbers
摘要： Hybrid halide perovskite solar cells were first demonstrated in 2009 with cell efficiency quickly soaring from below 10% to more than 23% in a few years. Halide perovskites have the desirable processing simplicity but are very fragile when exposed to water and heat. This fragility represents a great challenge for the achievement of their full practical potential in photovoltaic technologies. To address this problem, here we review the recent development of the mixed-dimensional perovskites, whereby the trade-off between power conversion efficiency and stability of the material can be finely tuned using organic amine cations with different sizes and functionalities.
关键词： hybrid halide perovskite,organic amine cations,stability,mixed-dimensional perovskites,solar cells,power conversion efficiency
更新于2025-09-09 09:28:46
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GaN Power Devices – Current Status and Future Directions
摘要： Power conversion losses are pervasive in all areas of electricity consumption, including motion control, lighting, air conditioning, and computation technology. To minimize losses, high efficiency switches are required for the fundamental power conversion units (motors, inverters, and generators) that drive the components. The workhorse of this industry has been silicon-based power switches, but that technology has matured to the fundamental material limits. As a wide bandgap semiconductor, the GaN materials system represents a critical technology for next-generation electronics in many applications due to the high breakdown field, high mobility, and chemical and thermal stability. Devices based on GaN are already well-known to many of us and are used in our daily lives, primarily as the core technology behind solid state lighting based on the GaN light emitting diode (LED), for which Nakamura, Amano, and Akasaki won the Nobel Prize in 2014. In addition GaN-based high electron mobility transistors (HEMTs) have been widely commercialized as RF power amplifiers for communications and radar applications. However, GaN-based devices are relatively nascent in the power conversion field, as most device technology has been dominated by Si and, recently, SiC. Power devices have unique requirements, such as normally-off behavior for fail-safe operation and high field management for high voltage operation, that have proven notoriously difficult in this system, thus an extension of HEMT designs and processing knowledge is not possible.
关键词： power devices,GaN,vertical GaN devices,power conversion,HEMTs
更新于2025-09-04 15:30:14
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[ASME ASME 2015 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems collocated with the ASME 2015 13th International Conference on Nanochannels, Microchannels, and Minichannels - San Francisco, California, USA (Monday 6 July 2015)] Volume 1: Thermal Management - A Study on the Thermo-Fluid Simulation Model Using Porous Media in the Power Conversion System
摘要： When converting an electric power by an insulated-gate bipolar transistor (IGBT) module, the problem which is the heat generation in the IGBT module should be prudently considered in the design process. As an engineer reviews the cooling performance of power semi-conductor devices only at the component level, it is difficult to predict the reduction of airflow rates in the heat sink when power semi-conductor devices including the heat sink are integrated into the power conversion system. As the porous media model is adopted in the IGBT stack of the PCS, the problem that the meshes are heavily concentrated in the IGBT module including the heat sink, air, and IGBT/ diode chips can be evaded and the airflow rate which is reflected in the effect of flow resistance by all interior structures including the IGBT module is calculated. For the outdoor type PCS, the hotspot temperature on the heat sink of the simulation and experiment is 99.3 and 101.6 Celsius, respectively. The proposed numerical simulation model considerably accurately predicts the hotspot temperature on the heat sink and can earn benefits in terms of efforts of mesh generation and computation time.
关键词： porous media model,heat sink,thermo-fluid simulation,power conversion system,IGBT module
更新于2025-09-04 15:30:14