- 标题
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Oxygen-Defected Molybdenum Oxides Hierarchical Nanostructure Constructed by Atomic-Level Thickness Nanosheets as an Efficient Absorber for Solar Steam Generation
摘要： Solar steam generation is a potential approach for fresh water recycling, thus attracting increasing attention recently. To further promote water evaporation rate, some new materials need to be developed, such as plasmonic transition metal oxides. In this work, we report an oxygen-defected molybdenum oxides hierarchical nanostructure (MoOx HNS) composed of ultrathin nanosheets with atomic-level thickness, which is demonstrated as an efficient absorber for solar steam generation. Benefiting from broadband light absorption and special assembled architecture, the resulting MoOx HNS loaded on a PTFE membrane (MoOx HNS Membrane) exhibits excellent performance for boosting steam generation rate. Under 1 sun (1 kW m?2) illumination, the evaporation rate can reach at 1.255 kg m?2 h?1, with the energy conversion efficiency of 85.6%, which is one of the best performance compared with other desalination materials. Meanwhile, the MoOx HNS Membrane can achieve high-performance seawater desalination in both laboratorial and outdoor conditions. The enhanced water evaporation performance can be attributed to the synergistic effects of the efficient solar-to-thermal conversion and the unique channel structure. This work expands the scope of investigated materials which can be applied in seawater desalination system.
关键词： MoOx hierarchical nanostructure,seawater desalination,photothermal conversion,oxygen vacancies,solar steam generation
更新于2025-09-23 15:21:21
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Efficiency enhancement of TiOx electron-transporting layer-based ultrathin p-type c-Si solar cell by reactive sputtering of backside MoOx hole-transporting contact
摘要： The importance of efficient carrier selective transport at the backside contact significantly increases with thickness reduction of c-Si solar cells. Here, MoOx backside hole-transporting layer is fabricated on TiOx electron-transporting layer-based ultrathin c-Si solar cell with a final configuration of Ag/ITO/Mg/TiOx/45 μm p-type c-Si/MoOx/Ag by reactive magnetron sputtering method at room temperature. The effects of oxygen ratio and sputtering power on the film phase, bandgap, and surface roughness are investigated. Moreover, the contact performance between Ag and p-type c-Si is systematically studied and optimized by MoOx insertion. Based on the optimized MoOx thin film, the obtained totally dopant-free cell shows an enhancement of all cell parameters with a resultant high efficiency of 12.81%, which is about 12.8% relatively higher than that of conventional backside p+-based one (11.36%). In the combination of experiment and simulation processes, better performance of MoOx-based cell can be ascribed to the improvement of both electrical and optical performances of the device. The realization of MoOx-based contact at room temperature enables the solar cell fabrication under planar state possible, which can greatly avoid the bowing effect and reduce the yield losses and energy consumption during the fabrication of ultrathin c-Si solar cells.
关键词： reactive sputtering,c-Si solar cell,hole-transporting contact,MoOx,TiOx
更新于2025-09-23 15:21:01
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Energy band alignment in molybdenum oxide/ Cu(In,Ga)Se2 interface for high efficiency ultrathin Cu(In,Ga)Se2 solar cells from low-temperature growth
摘要： In this work, the molybdenum oxide (MoOx) was employed as a back contact layer to improve the device performance of ultrathin Cu(In,Ga)Se2 (CIGS) solar cells with CIGS absorber synthesized through the low-temperature three-stage co-evaporation process. This contribution focuses on the investigation of the inherent mechanisms and the improved device performance in detail. Our research shows that the energy band of the CIGS/Mo interface can be tuned and the Schottky barrier can be reduced. Compared with the reference sample without MoOx, the back barrier height of the new device with 10 nm MoOx enjoys a significant decrease from 43.83 meV to 15.98 meV because of the improvement of energy band structure. Meanwhile, the results of wxAMPS simulation corroborate that the energy band bends upward in the devices with appropriate thickness of MoOx films, which facilitates the carrier transportation and suppresses the recombination of charge carriers at the MoOx/Cu(In,Ga)Se2 interface. Moreover, the carriers can transport through the MoOx/CIGS interface by tunneling when the MoOx film is thin enough. Finally, by controlling the thicknesses of MoOx films, an efficiency of 10.38 % is achieved in 0.5 μm CIGS solar cells by optimizing the MoOx thickness under the low-temperature three-stage co-evaporation process.
关键词： ultrathin,Cu(In,Ga)Se2,MoOx,low-temperature,energy band
更新于2025-09-23 15:19:57
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Simulation of graded bandgap on backwall superstrate CIGS solar cells with MoOx electron reflection layer
摘要： A model of backwall superstrate CuInxGa(1?x)Se2 (CIGS) solar cell with MoOx as an electron reflection layer has been investigated by Solar Cell Capacitance Simulator (SCAPS). The influence of the CIGS absorber with different thicknesses on the performance of the CIGS solar cells with a flat bandgap structure is carefully analyzed. When the CIGS thickness is 400 nm, the device with 10 nm MoOx layer has the highest efficiency of 8.24%. To further increase the efficiency, a graded bandgap structure, near the MoOx layer, has been established, and the efficiency can be improved from 8.24% to 15.01% when the maximum bandgap value and the length of the graded region are 1.6 eV and 240 nm, respectively. The causes of efficiency enhancement by this graded bandgap structure are then studied. With an additional graded bangap structure in SCR, close to the CdS layer, the efficiency is slightly improved from 15.01% to 15.15%. Finally, the simulation results show that the efficiency can be increased from 15.15% to 16.26% when the thickness of MoOx is reduced from 10 nm to 1 nm.
关键词： backwall superstrate,MoOx,bandgap grading,CIGS solar cells,SCAPS
更新于2025-09-19 17:13:59
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Transmission Electron Microscopy and Electron Energy-Loss Spectroscopy Studies of Hole-Selective Molybdenum Oxide Contacts in Silicon Solar Cells
摘要： In this study, sub-stochiometric hole-selective molybdenum oxide (MoOx) contacts in crystalline silicon (c-Si) solar cells were investigated by a combination of transmission electron microscopy (TEM) and spatially-resolved electron energy-loss spectroscopy (SR-EELS). It was observed that a ≈ 4 nm SiOx interlayer grows at the MoOx/c-Si interface during the evaporation of MoOx over c-Si substrate. SR-EELS analyses revealed the presence of 1.5 nm diffused MoOx/ITO (indium tin oxide) interface in both as-deposited and annealed samples. Moreover, the presence of a 1 nm thin layer with a lower oxidation state of Mo was detected at SiOx/MoOx interface in as-deposited state which disappears upon annealing. Overall, it was evident that no hole-blocking interlayer is formed at MoOx/ITO interface during annealing and homogenization of the MoOx layer takes place during the annealing process. Furthermore, device simulations revealed that efficient hole collection is dependent on MoOx work function and that reduction in work function of MoOx results in loss of band bending and negatively impacts hole-selectivity.
关键词： silicon,electron energy-loss spectroscopy (EELS),hole-selective,transmission electron microscopy (TEM),molybdenum oxide (MoOx)
更新于2025-09-12 10:27:22
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[IEEE 2019 26th International Workshop on Active-Matrix Flatpanel Displays and Devices (AM-FPD) - Kyoto, Japan (2019.7.2-2019.7.5)] 2019 26th International Workshop on Active-Matrix Flatpanel Displays and Devices (AM-FPD) - Correlation between Roll-Off Phenomena and Carrier Injections for OLEDs
摘要： In organic light-emitting diodes (OLEDs), the roll-off phenomenon was observed in the EL efficiency - current density characteristics. Although the EL efficiency in the inverted OLED with HAT-CN was 1.5-2 times higher than that in the inverted OLED with MoOx, the former maximum EL efficiency was observed in the higher current density. On the other hand, the EL efficiency in the inverted OLEDs decreased rapidly after the maximum as compared with the conventional OLED. The roll-off was thought to depend on carrier injections.
关键词： carrier injections,HAT-CN,roll-off phenomenon,OLED,EL efficiency,MoOx
更新于2025-09-12 10:27:22
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Thermal stability improvement of metal oxide-based contacts for silicon heterojunction solar cells
摘要： Metal oxides are interesting materials for use as carrier-selective contacts for the fabrication of doping-free silicon solar cells. In particular, MoOx and TiOx have been successfully used as hole and electron selective contacts in silicon solar cells, respectively. However, it is of paramount importance that good thermal stability is achieved in such contacts. In our work, we combined i-a-Si:H/MoOx based hole contacts with electron contacts featuring i-a-Si:H/TiOx/low work function metal (ATOM) to fabricate doping-free cells, termed MolyATOM cells. We found that the thermal stability of the ATOM contact was improved when the i-a-Si:H was annealed (300°C for 20 min in N2) before depositing TiOx (i.e. pre-TiOx annealing), which reduces the hydrogen content in i-a-Si:H by about 27 %rel, and thereby the H-related degradation of the ATOM contact characteristics. Moreover, it was found that reducing the thickness of the low-work function metal on top of the TiOx enhanced the thermal stability of the ATOM contact. With these adaptations, the MolyATOM cell efficiency was improved by 3.5 %abs, with the highest efficiency of 17.6%. Moreover, the cells show improved thermal stability after the above-mentioned pre-TiOx annealing, which is confirmed by annealing tests at cell level as well as damp-heat tests at module level. The insights of this study could be used to tailor other metal-oxide based electron or hole contacts.
关键词： Doping-free cells,Passivating contact,MoOx,Thermal stability,TiOx,Annealing
更新于2025-09-11 14:15:04
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[IEEE 2019 26th International Workshop on Active-Matrix Flatpanel Displays and Devices (AM-FPD) - Kyoto, Japan (2019.7.2-2019.7.5)] 2019 26th International Workshop on Active-Matrix Flatpanel Displays and Devices (AM-FPD) - Influence of molybdenum oxide thickness, electronic structure, and work function on the performance of hole selective silicon heterojunction solar cells
摘要： Ultra-thin MoOx is capable of exhibiting high work function (< 6 eV), large band gaps (< 3 eV) are benefiting for surface passivation and hole selectivity layer in silicon solar cells instead of the doped layers due to high parasitic absorption. Importantly, MoOx electronic structure by oxygen dilution during the evaporation have influence to the MoOx work function and hence reduce hole injection. XPS study confirmed the electronic structure and chemical composition of the evaporated and annealed (Ar and O2 atmosphere) MoOx sample. TEM showed a clear interface contact between the ITO/MoOx/a-SiH(i) layers and no diffusion between the layers after annealed at 140 oC. Fabricated 10 nm thick MoOx/n-Si solar cells archived an efficiency of 20.04%, FF of 73.79 % and Jsc of 38.40 mA/cm2. A sever degradation in FF and Jsc was noticed by increasing the MoOx thickness due to diffusion of layers and high parasitic absorption of MoOx.
关键词： work function,silicon heterojunction solar cells,thickness,MoOx,electronic structure
更新于2025-09-11 14:15:04
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Synthesis and electrochromic properties of molybdenum oxide films
摘要： Molybdenum oxide (MoOx) thin films were prepared by pulse DC sputtering using a molybdenum target and their optical and electrochromic properties were investigated. These MoOx thin films were reactively sputter-deposited at various oxygen flow rates. The effects of the oxygen flow rate on the growth and microstructure of the molybdenum oxide films were examined using X-ray diffractometry (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The optical density and modulation of the MoOx films were analyzed using a UV/VIS spectrophotometer (UV-visible). Electrochromic tests were conducted using an electrochemical analyzer. Experimental results reveal that the electrochromic properties depended strongly on the crystalline phase, thickness, chemical composition and microstructure, which were controlled by varying the oxygen flow rate.
关键词： Pulse DC sputtering,Oxygen flow rates,Electrochromic tests,MoOx thin films
更新于2025-09-04 15:30:14