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Tuning Bandgap of Mixed-Halide Perovskite for Improved Photovoltaic Performance Under Monochromatic-Light Illumination
摘要： Organic–inorganic halide perovskites have emerged as promising materials for optoelectronic devices. This paper focuses on a new application field for perovskite materials as monochromatic-light conversion devices. First the optical properties of organic–inorganic perovskite semiconductors with bandgaps varying from near-infrared to visible at room temperature are presented. Two types of hybrid organic–inorganic mixed-halide perovskites, (FAPbI3)x(MAPbBr3)1-x and FA0.85MA0.15Pb(IxBr1-x)3, are adopted for bandgap tuning, an approximate linear variation of bandgaps with the x value is obtained. The relationship between thin film composition and device performance are investigated. Based on the results of the above bandgap tuning, two kinds of devices with bandgap near the wavelength of 683 nm are characterized under monochromatic-light illumination. A conversion efficiency of up to 40% under 60 mW cm?2 monochromatic-light illumination is achieved. The results confirm that the perovskite films exhibit sharp optical absorption edge, enabling highly efficient monochromatic-light conversion device.
关键词： monochromatic-light,hybrid mixed-halide perovskites,bandgap tuning,photovoltaic performance
更新于2025-11-25 10:30:42
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Hierarchical TiO <sub/>2</sub> microspheres composed with nanoparticle-decorated nanorods for the enhanced photovoltaic performance in dye-sensitized solar cells
摘要： Hierarchical TiO2 microspheres composed of nanoparticle-decorated nanorods (NP-MS) were successfully prepared with a two-step solvothermal method. There were three benefits associated with the use of NP-MS as a photoanode material. The decoration of nanoparticles improved the specific surface area and directly enhanced the dye loading ability. Rutile nanorods serving as electron transport paths resulted in fast electron transport and inhibited the charge recombination process. The three-dimensional hierarchical NP-MS structure supplied a strong light scattering capability and good connectivity. Thus, the hierarchical NP-MS combined the beneficial properties of improved scattering capability, dye loading ability, electron transport and inhibited charge recombination. Attributed to these advantages, a photoelectric conversion efficiency of up to 7.32% was obtained with the NP-MS film-based photoanode, resulting in a 43.5% enhancement compared to the efficiency of the P25 film-based photoanode (5.10%) at a similar thickness. Compared to traditional photoanodes with scattering layers or scattering centers, the fabrication process for single layered photoanodes with enhanced scattering capability was very simple. We believe the strategy would be beneficial for the easy fabrication of efficient dye-sensitized solar cells.
关键词： electron transport,dye-sensitized solar cells,solvothermal method,Hierarchical TiO2 microspheres,photovoltaic performance
更新于2025-11-14 17:04:02
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Improved photovoltaic performance of perovskite solar cells by utilizing down-conversion NaYF <sub/>4</sub> :Eu <sup>3+</sup> nanophosphors
摘要： Perovskite solar cells assembled with titanium dioxide electron transport layer exhibited brilliant photovoltaic properties due to titanium dioxide having a high electron mobility, appropriate energy level alignment and easy fabrication procedure. However, inherent instability exists in titanium dioxide-based perovskite solar cells because of the ultraviolet photocatalytic activity of titanium dioxide. This results in recombination at the interface of titanium dioxide/perovskite. In this report, the down-conversion nanocrystals film made of europium-doped sodium yttrium fluoride was deposited on the non-conducting side of the conducting glass. The down-conversion nanocrystal layer could absorb high energy ultraviolet photons and converted them to visible light. The layer not only extended the spectral response range for perovskite solar cells but also alleviated the photocatalytic activity of titanium dioxide. The perovskite solar cells with the down-conversion nanocrystals film generated average power conversion efficiency yield of 19.99%, which is much better than that of the device without the down-conversion nanocrystals film (16.99%). The best power conversion efficiency for the device with the down-conversion nanocrystals film was 20.17%. In addition, perovskite solar cells with the down-conversion nanocrystals film showed a small hysteresis.
关键词： titanium dioxide,down-conversion,NaYF4:Eu3+ nanophosphors,photovoltaic performance,perovskite solar cells
更新于2025-11-14 17:04:02
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Efficient Dye-Sensitized Solar Cells Composed of Nanostructural ZnO Doped with Ti
摘要： Photoanode materials with optimized particle sizes, excellent surface area and dye loading capability are preferred in good-performance dye sensitized solar cells. Herein, we report on an efficient dye-sensitized mesoporous photoanode of Ti doped zinc oxide (Ti-ZnO) through a facile hydrothermal method. The crystallinity, morphology, surface area, optical and electrochemical properties of the Ti-ZnO were investigated using X-ray photoelectron spectroscopy, transmission electron microscopy and X-ray diffraction. It was observed that Ti-ZnO nanoparticles with a high surface area of 131.85 m2 g?1 and a controlled band gap, exhibited considerably increased light harvesting efficiency, dye loading capability, and achieved comparable solar cell performance at a typical nanocrystalline ZnO photoanode.
关键词： bandgap energy,dye-sensitized solar cell,photovoltaic performance,Ti doped ZnO
更新于2025-11-14 17:04:02
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Synthesis of CoNi bimetallic alloy nanoparticles wrapped in nitrogen-doped graphite-like carbon shells and their electrocatalytic activity when used in a counter electrode for dye-sensitized solar cells
摘要： Nanoparticles of the bimetallic alloy CoNi wrapped in nitrogen-doped graphite-like carbon shells and dispersed on nitrogen-doped graphite-like carbon sheets (CoxNi1?x@NC) were synthesized by calcining CoNi metal–organic frameworks that were prepared through a facile solvothermal reaction using various raw-material molar ratios Co:Ni and CoNi:ethylenedinitrilotetraacetic acid. After depositing CoxNi1?x@NC for use as a counter electrode film in dye-sensitized solar cells, it was found that the electrocatalytic activity of the CoxNi1?x@NC counter electrode towards triiodide reduction could be optimized by simply tuning the molar ratios (Co:Ni and CoNi:ethylenedinitrilotetraacetic acid) appropriately during CoxNi1?x@NC synthesis. Cells that utilized a CoxNi1?x@NC counter electrode exhibited strong chemical-composition-dependent photovoltaic performance. Under optimal conditions, the CoxNi1?x@NC counter electrode presented an impressive energy conversion efficiency of 3.58%, suggesting that it is a highly promising counter electrode for application in dye-sensitized solar cells. This counter electrode has the advantages that it is considerably less expensive than a Pt counter electrode and that it provides the basis for the design and preparation of other inexpensive and efficient counter electrodes to replace Pt.
关键词： Photovoltaic performance,Dye-sensitized solar cells,CoNi alloy bimetallic nanoparticles,Counter electrode,Electrocatalytic activity
更新于2025-11-14 17:04:02
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Grafting cobalt sulfide on graphene nanosheets as a counterelectrode for dye-sensitized solar cells
摘要： In the present work a composite counter electrode of graphene nanosheets grafted cobalt sulfide was fabricated through a facile synthetic route, in which cobalt sulfide nanoparticles were successfully grafted on the surface of graphene nanosheets. Used as a counter electrode in DSSC, a power conversion efficiency of 7.28% can be achieved. Such a result might be contributed to the facts that this counter electrode composed of graphene nanosheets grafted cobalt sulfide has a good stability and electrochemical catalytic performance toward triiodide reduction reaction.
关键词： photovoltaic performance,graphene nanosheets,cobalt sulfide,counterelectrode,Dye-sensitized solar cell
更新于2025-11-14 17:04:02
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Performance modeling and analysis of high-concentration multi-junction photovoltaics using advanced hybrid cooling systems
摘要： This paper presents the performance modeling and analysis of the high-concentration multi-junction photovoltaic cells, using either constant-width one-section or two-stepwise microchannels-jet impingement hybrid cooling system. The performance simulation and analysis of the cells are conducted using a three dimensional-Computational Fluid Dynamics program for various operating parameters, including water flow rate (100–1300 mL/min.), inlet water temperature (10–80 °C), and heat flux (10–90 W/cm2 corresponding to concentration ratios of 250–2250). The thermal and electrical characteristics of the cells are correlated in dimensionless form as functions of the direct normal irradiance and the operating and geometrical parameters of the hybrid cooling systems. The developed high-quality explicit performance model correlations assist in the design, performance prediction, and selection of operation strategy of photovoltaic cells. The results indicated that the generated and net output power is directly proportional to the applied heat flux (concentration ratio) and inversely proportional to the inlet water temperature. Temperature uniformity of the photovoltaic base enhances with the water flow rate, deteriorates with heat flux, and less affected by the inlet temperature, particularly for the two-sections cooling system. The pumping power increases with water flow rate and decreases as both inlet temperature or heat flux increases. Heat transfer characteristics enhance significantly with water flow rate, moderately with inlet water temperature and slightly with heat flux.
关键词： Photovoltaic performance modeling,High-concentration multi-junction photovoltaic,Operating parameters,Microchannels heat sink,Electrical power correlations
更新于2025-09-23 15:21:01
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Photovoltaic parameters and stability study of HTM-free mixed-cation perovskite solar cells by incorporating additives to absorbing layers
摘要： In this study, quick route-coating is practiced to substitute methyl ammonium (MA) cation with formamidinium (FA) at different ratios. Through optimizing the MA:FA ratio, a maximum power conversion efficiency (PCE) of 8.31% is achieved for holes transporting material-free MA0.8FA0.2PbI3 mixed PSCs with the JSC of 19.02 mA/cm2, VOC of 0.859 V and FF of 50.88%. Then, to improve the performance, stability and carrier transport dynamic, various additives (PVA, PVP, PEG and EC) are incorporated into the perovskite layer. The treatment of perovskites with additives has proved to cause significant changes in the surface roughness, charge accumulation, charge transport, charge transport resistance, photovoltaic performance and cell stability. PCE of the PSCs mixed with PVA, PVP, EC and PEG optimally reaches 12.76%, 11.28%, 10.38% and 8.92%, respectively. Among the additives, EC and PVP provide better stability owing to the excellent interaction between the functional group of the additives and the perovskite. Surface modification and charge transport also occur better with those two additives.
关键词： Charge transport,Perovskite solar cells,Stability,Additives,Photovoltaic performance
更新于2025-09-23 15:21:01
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Charge Density Modulation on Asymmetric Fused-Ring Acceptors for High-Efficiency Photovoltaic Solar Cells
摘要： Charge density modulation on thieno[2'',3'':5',6']-s-indaceno[2',1':4,5]dithieno[3,2-b:2’,3’-d]pyrrole (IPT) core has been conducted for a systematic study of its impact on the electronic structure, molecular packing and photovoltaic performance of asymmetric fused-ring acceptors (FRAs). Herein, a series of IPT-based FRAs (ca. IN-4F, INO-4F, IPT-4F and IPCl-4F) are designed by adopting a corresponding side-chain of 2-ethylhexyl, 2-ethylhexyloxy, hydrogen or chloro onto IPT core. Enhanced electron-withdrawing side-chains contract the optical bandgap but lower the lowest unoccupied molecular orbital (LUMO) level, which yields a trade-off between JSC and VOC in organic solar cells (OSCs). Furthermore, the FRAs exhibit tuned miscibility and crystallinity, reflected on the FF and JSC values of the OSCs. By pairing with polymer donor PM6, IPT-4F based devices achieve the highest PCE of 14.62% with balanced VOC of 0.88 V and JSC of 22.15 mA cm-2 and high FF of 75.01%. Our research demonstrates that electronic density modulation on asymmetric FRAs is an effective way to systematically optimize the device parameters in pursuit of high performance OSCs.
关键词： asymmetric fused-ring acceptors,Charge density modulation,electron-withdrawing side-chains,organic solar cells,photovoltaic performance
更新于2025-09-23 15:21:01
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Quantum dot material engineering boosting quantum dot sensitized solar cells efficiency over 13%
摘要： The intrinsic electronic structure and crystalline quality of quantum dot (QD) light-harvesting materials are among the primary reasons in determining the photovoltaic performance of resulting QD sensitized solar cells (QDSCs). Undoubtedly, exploiting appropriate high-quality QDs is a crucial route to improve the performance of QDSCs. In order to reduce the density of trap state defects, a ZnSe shell layer with wider bandgap is overgrown around the light-harvesting star material Zn-Cu-In-Se (ZCISe) alloy QDs to form the type-I core/shell structured ZCIS/ZnSe. Through this QD material engineering, average power conversion efficiency (PCE) of QDSCs was improved from 9.54% corresponding to pristine CuInSe2, to 12.49% from alloyed ZCISe, and to 13.71% for core/shell structured ZCISe/ZnSe QDs. A certified PCE of 13.49% has been obtained for the ZCIS/ZnSe QDSCs under AM 1.5G one sun irradiation. This value is a new record efficiency for QDSCs. The remarkable enhancement of photovoltaic performance for ZCIS/ZnSe-based QDSCs vs. ZCISe ones is mainly ascribed to the reduced density of trap state defects, which favours the suppression of charge recombination at photoanode/electrolyte interfaces and hence improves the photovoltage and fill factor, particularly. The steady state optical spectroscopy, diode ideality factor, transient absorption, and electrochemical impedance spectroscopy characterizations confirm that the formed type-I core/shell structure can reduce the density of trap state defects and suppress charge recombination and improve the photovoltaic performance of the resulting cells. This work demonstrates the great potential of QD material engineering in improving the photovoltaic performance of QDSCs.
关键词： sensitized solar cells,photovoltaic performance,quantum dot,ZnSe,Zn-Cu-In-Se
更新于2025-09-23 15:21:01