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Effect of annealing temperature on silicon-based MoS <sub/>x</sub> thin film solar cells
摘要： A suitable annealing temperature was found by adopting the sol–gel method to prepare silicon-based molybdenum sulfide film heterojunction solar cells. As shown by the results, a change in the efficiency of the solar cells, which was attributed to the fact that as the annealing temperature rises, the degree of crystallization of the film increases continuously, the degree of order of the crystal particles goes up first and then goes down, and the temperature change affects the proportion of Mo in different valence states. By comparison, it was found that when the temperature reached 500 °C, the degree of order of the film was raised and the film was in the initial zone from the amorphous to the microcrystal phase change and the proportion of Mo 6+ was relatively large, increasing the conversion efficiency of the device power to 7.55% and laying a good basis for preparing high-performance solar batteries made in the two-dimensional materials. When the annealing temperature continues to rise, the intergranular defects increase, and the overall degree of order of the film decreases. Furthermore, the highly crystalline thin films and the improvement in the device efficiency can be controlled if we obtained the relationship between the annealing temperature and the layers of the two-dimensional materials.
关键词： annealing temperature,solar cells,crystallization,sol–gel method,silicon-based MoSx thin film
更新于2025-09-12 10:27:22
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Apparatus-dependent sol-gel synthesis of TiO <sub/>2</sub> nanoparticles for dye-sensitized solar cells
摘要： Synthesis of titanium dioxide nanoparticles (TiO2 NPs) has been done by sol-gel-hydrothermal colloidal route in two different apparatus; one being simple stainless steel (named as TiO2-B) and other being at constant temperature and pressure autoclave (named as TiO2-W). These TiO2 NPs were investigated by various characterization techniques such as scanning electron microscope (SEM), X-ray diffractometer (XRD), and photoluminescence spectrophotometer. Also, it was observed that the quality of the synthesized TiO2-W NPs is comparable with the commercial TiO2 NPs (TiO2-C), whereas the cost of synthesis is almost reduced to half. The synthesized TiO2 NPs are used as the photoanode in dye-sensitized solar cell (DSSC). DSSC with TiO2-W showed better power conversion efficiency as compared to DSSC with TiO2-B.
关键词： sol-gel,nanoparticles,dye-sensitized solar cells,TiO2
更新于2025-09-12 10:27:22
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Effects of Sn Incorporation in ZnO Thin Films on Properties of Perovskite Solar Cells
摘要： Properties of electron transporting layer (ETL) play an important role on photovoltaic performances of perovskite solar cells. In this work, effects of Sn incorporation on properties of ZnO-based perovskite solar cells were investigated. Sn-doped ZnO (TZO) thin film as ETL was prepared via a sol?gel method. With 5% atom doping, TZO film coated on an indium doped tin oxide (ITO) substrate provided comparable light transmittance with that of an undoped ZnO/ITO substrate. It was also found that the optical band gap of TZO film (3.30 eV) is slightly wider than that of the ZnO one (3.28 eV). These results suggest that Sn atoms probably incorporated into the ZnO crystal during the sol-gel method. The grains size of perovskite layer coated on TZO or ZnO films also showed variation. The perovskite crystal on the TZO thin film (average 300 nm) was larger than that of the one on ZnO thin film (average 277 nm). The preliminary results indicate that the perovskite solar cell based on TZO film provided higher power conversion efficiency (PCE) of 4.42 % than the ZnO-based device (3.16%). Short-circuit current density (Jsc), open-circuit voltage (Voc) and fill factor (FF) of TZO-based device were also higher than the ZnO-based device. This may be because TZO film may provide lower resistivity and better ETL/perovskite interface contact, confirmed by lower series resistance and higher shunt resistance of the TZO-based device. Finally, this work introduced a simple method to prepare TZO film at low temperature for photovoltaic application. It may help guide the development of flexible solar cells and other optoelectronic devices.
关键词： perovskite solar cells,electron transporting layer,photovoltaic performance,sol-gel method,Sn-doped ZnO
更新于2025-09-12 10:27:22
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Physical properties of cerium doped-yttrium iron garnet ultrathin films for photovoltaic application
摘要： In this study, cerium incorporated yttrium iron garnet ultrathin films (CexY3-xFe5O12) (where x = 0, 0.1, 0.3, and 0.5) were prepared by the sol-gel method, spin coating technique, and heat treatment on quartz substrates. The effect of Ce on structural properties, morphology of thin films surface, and optical properties was explored by X-ray diffraction (XRD), field emission microscopy (FESEM), and atomic force microscopy (AFM). According to the XRD results, the films were crystalline with the cubic phase, while the FESEM indicated the YIG nanoparticles with approximately spherical shapes. The growth process of crystallite in YIG nanoparticles was investigated by X-ray peak broadening. The Williamson-Hall (W–H) analysis was utilized to maintain the contributions of crystallite size on the peak broadening of Ce:YIG nanoparticles. The structural features of thin films such as strain and stress for all of the peaks of XRD were accurately determined from the uniform deformation model (UDM) according to the YIG cubic phase. According to the AFM pictures, it seemed that thin films had a continuous and smooth surface. The absorption and transmission were measured in the visible and infrared region from 400 to 1200 nm.
关键词： Structural features,Cerium yttrium iron garnet thin films,Photovoltaic application,Optical properties,Sol-gel
更新于2025-09-12 10:27:22
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Surface improvement investigation of sol–gel SiO <sub/>2</sub> cladding for waveguide device passivation
摘要： The sol–gel method is a well-known process for SiO2 formation on top of a semiconductor-based waveguide. This method does not require expensive equipment or SiH4 gas. However, it may result in difficulty with wet-etching, which prevents proper current injection into the semiconductor layer. We have investigated the surface condition of sol–gel SiO2 on top of Si, and have confirmed that the main causes of the anti-etching property might be due to the formation of a polymer layer after the curing process. To improve the surface condition, plasma ashing, in addition to 700 °C curing, is proposed. Regular wet etching of SiO2 layer on Si with a ratio of 1800 nm min?1 has been successfully confirmed.
关键词： SiO2,waveguide passivation,plasma ashing,sol–gel method,polymer layer,wet etching
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Saturable Absorption with CNT Coupled WGM and Fabrication of Er-Doped Microresonator for on-Chip Mode-Locked Laser
摘要： Mode-locked (ML) fiber lasers are becoming key components in industry, because they provide high performance while being relatively inexpensive. The generation of high-repetition rate pulses is gaining interest but it remains a challenge to achieve a GHz repetition rate with fiber lasers. On the other hand, whispering-gallery-mode (WGM) microresonators allow the strong confinement of light and miniaturizing an ML laser into a WGM microresonator will enable us to achieve a high pulse repetition rate, a small footprint and on-chip integrability. In this work, we explore the possibility of a passive ML laser with the system shown in Fig. 1(a). There are two key technologies involved; one is saturable absorption (SA) and the other is laser gain in a microresonator. First, we verified numerically that we could realize an ML laser with our proposed carbon nanotube (CNT) coupled erbium (Er) doped microresonator, and the result is shown in Fig. 1(b). We modelled our system with a nonlinear Schr?dinger equation, where we took gain and SA (also loss (Q), Kerr effect, and dispersion) into account [2]. The result shows that a self-starting ML is possible with microresonator parameters. Next, encouraged by the numerical result, we experimentally demonstrated SA in a microtoroid. We grew CNTs selectively on a silica microtoroid by chemical vapor deposition and investigated the SA behavior (Fig. 1(c)). By performing a pump-probe like experiment we successfully characterized the SA behavior in a microresonator system. This is the first demonstration of SA in a WGM microcavity system [1]. We then fabricated an Er-doped active microtoroid by using the sol-gel method. The sol-gel method is one way of forming silica from a metal alkoxide precursor. Although sol-gel has been widely used, it is still a challenge to fabricate high-quality defect-free film on a Si wafer that allows us to fabricate an ultrahigh-Q WGM microresonator. Figure 1(d)-(f) shows the fabricated films. We found optimum parameters and obtained a clean film as shown in Fig. 1(g). By using this film, we fabricated an Er-doped WGM microresonator, where the Q was 1.2×106 at 1480 nm (Fig. 1(h)). We obtained clear up-conversion luminescence when we pumped the cavity at 1480 nm, which constitutes the first step towards ML lasing in such a WGM microresonator. In summary, these results provide a promising approach for realizing an on-chip high repetition rate ML WGM microresonator.
关键词： saturable absorption,sol-gel method,carbon nanotube,whispering-gallery-mode microresonators,erbium-doped microresonator,Mode-locked fiber lasers
更新于2025-09-11 14:15:04
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Multi-mode optical coded patterns enabled by upconversion nanoparticles and photonic crystals
摘要： The Al-Zr-ZnO films was deposited on the surface of n-Si (111) by sol-gel method. The results showed that the average grain size of Al-Zr-ZnO films decreases due to ion doping concentration. Based on XPS analysis, the surface defect oxygen of Al-Zr-ZnO films decreases. As for graphene/ Al-Zr-ZnO Schottky contact, barrier height increased and ideality factor decreased with the increasing of Al ion or Zr ion doping, indicating that the rectifying characteristics of graphene/Al-Zr-ZnO Schottky contacts was enhanced due to ion co-doping. It can be explained that oxygen vacancies of Al-Zr-ZnO films decreases due to the ion doping and weakens Fermi level pinning.
关键词： sol-gel method,Ion doping,Al-Zr-ZnO films,electrical properties,graphene
更新于2025-09-11 14:15:04
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Systematic Comparison of Thermal Annealing and Laser Treatment of TiO2 Thin Films Prepared by Sol-Gel Processing
摘要： Thin films with titania composition were prepared on glass substrates by dip-coating from coating solutions based on soluble precursor powders. The as-dried deposits were thermally annealed in a furnace and irradiated by a CO2 laser, respectively. Oven temperature can systematically be correlated to laser power density in terms of film thickness and refractive index. Results indicate that the formation of anatase and rutile critically depends on the different treatment conditions. Some specific microstructural features that originate from the laser irradiation are highlighted.
关键词： Laser annealing,Sol-gel processing,Thermal curing,Thin films,TiO2
更新于2025-09-11 14:15:04
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UV-Ozone Modified Sol-Gel Processed ZnO for Improved Diketopyrrolopyrrole-Based Hybrid Photodetectors
摘要： Organic-inorganic interfaces in photodiodes have recently gathered significant interest due to the realization of intrinsic p-n junctions and unique physical properties. Nanopatterned sol-gel ZnO films provide an alternate path for fullerene-free organic photodetectors. However, naturally occurring oxygen vacancies in ZnO often act as trap sites and can degrade device performance if left unchecked. Here, we focus on the role of UV-ozone treatment for filling oxygen vacancies in sol-gel processed ZnO for improving the hybrid interface with thienothiophene linked diketopyrrolopyrrole (DPP) films. The ZnO films are characterized by x-ray diffraction, ultraviolet photoelectron spectroscopy (UPS), cross-sectional electron microscope images, and electron energy loss spectroscopy (EELS). UV-ozone treatment shows no change in the crystal structure, but UPS indicates that the treated films are more resistive and have a higher oxygen concentration at the surface. The EELS spectra show gradual passivation of oxygen vacancies within the bulk of the ZnO films. Fullerene-free photodetectors fabricated from ZnO:DPP interfaces show dark currents reduced by half and photoresponsivities nearly doubled, on average, when the ZnO surface is UV-ozone treated compared to non-treated ZnO films, indicating this simple technique to be excellent for improving photodiode performance when ZnO is used as an electron transport layer.
关键词： ZnO,UV-Ozone,Defects,Sol-Gel,Donor-Acceptor Copolymer,Photodiode
更新于2025-09-11 14:15:04
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AIP Conference Proceedings [AIP Publishing 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Fes, Morocco (25–27 March 2019)] 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Electrical and optical analysis of a spray coated transparent conductive adhesive for two-terminal silicon based tandem solar cells
摘要： This work presents the results of the electrical and optical characterization of a new transparent conductive adhesive (TCA) that combines the techniques of spray pyrolysis and a sol-gel like process. This approach is of particular interest since the adhesive itself forms both the electrical and the mechanical interconnection of the bonded sub-cells. The electrical and optical characterization of the developed TCA shows a minimum connecting resistivity of 17 ?cm2 and a simulated reflection at the Si-TCA interface of ≈ 20%. By coating both substrate surfaces with a TiO2 anti reflection coating (ARC), the reflectance at the Si-TCA interface was successfully reduced down to <5%. The efficiency potential of a glued dual junction device was simulated in dependence of the electrical and optical properties of the TCA. The reported values of 17 ?cm2 connecting resistivity and 20% reflection limit the device efficiency to 22.3% (71% of the maximum achievable efficiency). Reducing the reflection to below 5%, as practically demonstrated in this paper, allows to increase this value to 25.3% (>80% of maximum), while additionally reducing the connecting resistivity to 10 ?cm2 or 1 ?cm2 allows for a further increase to 27.3% and 30.0%, respectively.
关键词： reflection losses,sol-gel process,tandem solar cells,connecting resistivity,TiO2 anti reflection coating,electrical characterization,transparent conductive adhesive,optical characterization,spray pyrolysis
更新于2025-09-11 14:15:04