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Design of a high-efficiency system with combined reflectors for a light-emitting diode front fog lamp
摘要： This paper provides a design method for a light-emitting diode front fog lamp system based on a freeform surface and an improved quadric surface. First, a light-receiving reflector is used to converge the light-emitting diode beam to form an equivalent lighting point. Then, the relationship between the point and the light pattern on the work surface is calculated, and the freeform surface is constructed based on Snell’s law and non-imaging optical theory. Finally, two compensated reflectors are added at both ends of the freeform surface to reflect the unutilized light to achieve the compensation effect. By application of combined reflectors, the light pattern at the work surface 25 m away can satisfy the requirement of ECE R19 Revision 7. Also, this system has the advantages of small size and high efficiency because lens or prism groups are avoided. And the utilization of a compensated surface also increases light efficiency. Finally, a prototype model is tested, which also meets the regulatory requirements.
关键词： freeform surface,front fog lamp,combined reflectors,light-emitting diode,high efficiency
更新于2025-09-19 17:13:59
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High efficiency color-temperature tunable organic light-emitting diode
摘要： In this study, we demonstrate a high-efficiency and high light-quality organic light-emitting diode (OLED) with color temperature tunable from the 1700 K of dusk-hue, 1900 K of candles and 2500 K of incandescent bulbs to 3000 K of warm-white light. The color-temperature tunable OLED device was achieved by utilizing a hybrid system and inserting a carrier modulation layer (CML) between the emission layers. In addition, the electron-rich charge transport properties of EML-1, facilitated via a 3 : 1 composition ratio of the 3P-T2T host to TPD-15 co-host, played a crucial role in tuning the desirable low-color temperature of the fabricated OLED devices. The current efficiency, power efficacy, and spectrum resemblance index (SRI) of the studied OLED are 40.2 cd/A, 40.3 lm W?1 and 82.2 at 1000 cd m?2, respectively. The resultant devices show great potential to advance the study and development of physiologically friendly lighting and enable a successful commercial OLED lighting product in the market.
关键词： organic light-emitting diode,physiologically friendly lighting,high light-quality,color temperature tunable,high efficiency
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE High Power Diode Lasers and Systems Conference (HPD) - Coventry, United Kingdom (2019.10.9-2019.10.10)] 2019 IEEE High Power Diode Lasers and Systems Conference (HPD) - High-power 1.5μm laser diodes for LIDAR applications
摘要： The development of high-power, high-efficiency 3.5 μm band lasers is crucial for various applications in optoelectronics, including medical diagnostics, environmental monitoring, and defense systems. This paper presents a novel approach to enhancing the performance of these lasers through the use of advanced semiconductor materials and innovative device architectures. Our experimental results demonstrate significant improvements in output power and efficiency, paving the way for next-generation optoelectronic devices.
关键词： semiconductor materials,device architectures,high-power,3.5 μm band lasers,high-efficiency,optoelectronics
更新于2025-09-16 10:30:52
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High Efficiency Solution-Processed Organic Light-Emitting Diodes with Tetradentate Platinum(II) Emitters
摘要： The realization of high efficiency solution-processed organic light-emitting diodes (OLEDs) by using phosphorescent tetradentate Pt(II) emitters and bipolar organic hosts is demonstrated in this work. To investigate the effect of organic host on the platinum dopant, the performances of solution-processed Pt-OLEDs with various combination between four tetradentate Pt(II) emitters, including two newly developed tetra-Pt-S2 and tetra-Pt-S3, and three bipolar organic hosts m-TPAPy, o-TPAPy, and o-CzPy, have been analyzed and compared. Among the tetradentate Pt(II) complexes studied in this work, tetra-Pt-S3 exhibited the best electroluminescent performance attributable to its bulky molecular scaffold structure, high emission quantum yield, and good solubility in common organic solvents. High external quantum efficiencies (EQEs) of up to 22.4% were achieved in the solution-processed OLED with tetra-Pt-S3 emitter and m-TPAPy host at the dopant concentration of 4 wt%. At a high luminance of 1000 cd m-2, the EQE of this device decreased slightly to 21.0%.
关键词： high efficiency,platinum complexes,organic light-emitting diodes,solution-process,bipolar organic host
更新于2025-09-16 10:30:52
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Non-halogenated-solvent-processed highly efficient organic solar cells with a record open circuit voltage enabled by noncovalently locked novel polymer donors
摘要： The relatively low open circuit voltage (Voc) of organic solar cells (OSCs) with narrow and ultra-narrow bandgap fused-ring electron acceptors limits further improvement of the OSCs. Simply down-shifting the highest occupied molecular orbital (HOMO) levels of the donors always results in the trade-off between the Voc and short circuit current (Jsc). In this work, we reported three novel noncovalently locked polymer donors based on different side-chain-modified benzodithiophene (BDT) units alternately copolymerized with an electron-deficient 3,30-dicarboxylate-substituted difluorotetrathiophene building block for efficient OSCs. Due to the existence of the electron-affinity moiety, deep HOMO levels are obtained for these copolymer donors, enabling the highest recorded Voc of 0.99 V when blended with the IT-4F acceptor. Meanwhile, intramolecular noncovalent interactions in these copolymers favor a preferential face-on orientation. Efficient charge transport and exciton dissociation under a low driving force are observed in these novel polymer donors. Consequently, the device processed from a non-halogenated solvent shows a high efficiency of 12.5% with simultaneously high Voc and Jsc, which is one of the highest performances of non-halogenated-solvent-processed OSCs to date. These results demonstrate that the synergistic effect of the energy band structure and molecular geometry can provide an effective molecular design strategy for high performance OSCs.
关键词： noncovalently locked polymer donors,organic solar cells,open circuit voltage,non-halogenated-solvent-processed,high efficiency
更新于2025-09-16 10:30:52
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Electrostatic potential dispersing pyrimidine-5-carbonitrile acceptor for high efficiency and long lifetime thermally activated delayed fluorescence organic light-emitting diodes
摘要： Pyrimidine-5-carbonitrile was developed as an electrostatic potential managing and strong acceptor moiety of thermally activated delayed fluorescence (TADF) emitters for high efficiency and long lifetime in devices. Two types of TADF emitters with the donor moiety extended from either the 2 or 4 position of the acceptor moiety were prepared to study the effect of the donor substitution position on the TADF characteristics of the TADF emitters. Comparison of the two types of TADF emitters suggested that the extension of the donor structure from the 4 position of the pyrimidine-5-carbonitrile acceptor is an effective way of enhancing the external quantum efficiency (EQE) and lifetime of the TADF devices. A high EQE of 19.8% and lifetime exceeding that of the state-of-the-art green TADF emitter were demonstrated using one of the pyrimidine-5-carbonitrile derived emitters through the uniformly distributed electrostatic potential.
关键词： organic light-emitting diodes,Pyrimidine-5-carbonitrile,thermally activated delayed fluorescence,electrostatic potential,high efficiency,long lifetime
更新于2025-09-16 10:30:52
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Design and Demonstration of High-Efficiency Quantum Well Solar Cells Employing Thin Strained Superlattices
摘要： Nanostructured quantum well and quantum dot III–V solar cells provide a pathway to implement advanced single-junction photovoltaic device designs that can capture energy typically lost in traditional solar cells. To realize such high-efficiency single-junction devices, nanostructured device designs must be developed that maximize the open circuit voltage by minimizing both non-radiative and radiative components of the diode dark current. In this work, a study of the impact of barrier thickness in strained multiple quantum well solar cell structures suggests that apparent radiative efficiency is suppressed, and the collection efficiency is enhanced, at a quantum well barrier thickness of 4 nm or less. The observed changes in measured infrared external quantum efficiency and relative luminescence intensity in these thin barrier structures is attributed to increased wavefunction coupling and enhanced carrier transport across the quantum well region typically associated with the formation of a superlattice under a built-in field. In describing these effects, a high efficiency (>26% AM1.5) single-junction quantum well solar cell is demonstrated in a device structure employing both a strained superlattice and a heterojunction emitter.
关键词： quantum well solar cells,III–V solar cells,strained superlattices,photovoltaic devices,high-efficiency
更新于2025-09-16 10:30:52
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An Overview of the Photovoltaic Industry Status and Perspective in China
摘要： Photovoltaic (PV) is developing rapidly in China, and the installed capacity and PV module shipping capacity are the first in the world. However, with the changes in the global economic environment and the uncertainty of China’s PV policy, especially after the 531 new policy, China PV has started a new cycle. To understand the laws of the development of photovoltaics in China better, the article first introduces the distribution of China’s solar resources, sorts out the development process of China’s PV, focuses on the development of China’s PV Top-runner project, and emphasizes the role of advanced technology in the application of the Top-runner project for grid parity and industrial development. Then it expounds the evolution of PV module technology, inverter technology and System design technology, and analyzes the development status of photovoltaic industry chain and production of Chinese PV enterprises. Finally, it summarizes and predicts the development trend of China’s PV industry and gives recommendations for China’s PV development.
关键词： high efficiency module,top runner Project,bifacial module,grid parity,Levelized cost of energy (LCOE),bright project,PV poverty alleviation program
更新于2025-09-16 10:30:52
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Management of losses (thermalization-transmission) in the Si-QDs inside 3Ca??SiC to design an ultra-high-efficiency solar cell
摘要： Thermalization loss is one of the major losses in the single junction solar cells. Here, 3C–SiC as a wide bandgap semiconductor is used to manage this loss. To prevent the transmission of low energy photons, the intermediate bands inside the forbidden band gap is used. To do this, silicon quantum dots inside silicon carbide is suggested. At first, the detailed balance calculations are carried out to determine the efficiency limits of a cell with one and two mini-bands. Optical simulation using 3D FEM solution of the Schrodinger equation is done to obtain mini-bands, wave functions, and hence the optical absorption coefficient. Dimension parameters of a QD array like radius, inter-dot spacing, and array size are optimized to obtain a maximum efficiency. Inter-band and inter-sub-band absorption coefficient are calculated. That applied to determine the optimum characteristic of a QD–based intermediate band solar cell. The photocurrent increases as the inter-dot spaces decrease. Suitable radiuses and inter-dot spaces are found to obtain a high absorption coefficient and hence higher photocurrent. Finally, the effect of non-radiative recombination on the device performances is simulated. These results provide significant information to design a three-dimensional QDs based intermediate band solar cells.
关键词： Intermediate band,Super lattice,Silicon carbide,Multi-band,3D schrodinger,Si/SiC quantum dot,High efficiency
更新于2025-09-16 10:30:52
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TiO2 hierarchical nanowire-P25 particulate composite photoanodes in combination with N-doped mesoporous carbon/Ti counter electrodes for high performance quantum dot-sensitized solar cells
摘要： The time-consuming transport of photo-generated electrons across conventional photoanode film, composed of disordered P25 TiO2 nanoparticulates, is one of the main bottlenecks to improve the performance of quantum dot-sensitized solar cells (QDSCs). A convenient and effective method was developed for the preparation of high performance photoanodes based on composite paste composed of conventional P25 TiO2 nanoparticulates and TiO2 hierarchical nanowires (HNW) for QDSCs. The shortened transport path in the composite photoanode brings forward suppressed charge recombination processes at the interfaces between photoanode and electrolyte, and improved photovoltaic performance of the resulting solar cells. Through optimizing the composite photoanode and the adoption of N-doped mesoporous carbon/Ti counter electrodes, average power conversion efficiency of Zn-Cu-In-Se (ZCISe) QDSCs was increased from 12.77% corresponding to conventional P25 photoanodes to 13.43% (Jsc = 27.38 mA cm?2, Voc = 0.764 V, and FF = 0.642) corresponding to photoanodes with HNW/P25 weight ratio of 0.1%. Furthermore, this composite photoanode is also effective in improving the photovoltaic performance of QDSCs under different QD sensitizers (such as Zn-Cu-In-S (ZCIS) QDs) as well as different counter electrodes (such as Cu2S/brass).
关键词： TiO2 hierarchical nanowires,Quantum dot-sensitized solar cells,Composite photoanode,High efficiency
更新于2025-09-16 10:30:52