The Experts below are selected from a list of 20271 Experts worldwide ranked by ideXlab platform
Joop Schoonman - One of the best experts on this subject based on the ideXlab platform.
-
preparation and characterization of sno2 and cu doped sno2 thin films using electrostatic Spray Deposition esd
Journal of The European Ceramic Society, 2007Co-Authors: Robert C. Van Landschoot, Joop Schoonman, Matei C Ghimbeu, Martine LumbrerasAbstract:Tin (IV) oxide thin films were deposited on platinum-coated alumina substrates by means of electrostatic Spray Deposition (ESD) technique using as precursor solution tin chloride pentahydrate (SnCl4·5H2O) in ethanol. The influence of the Deposition parameters (temperature, time and flow rate) and copper addition on the morphology and microstructure of the films was studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy, respectively. The tetragonal rutile phase is evidenced by X-ray diffraction (XRD) with no other phases observed. The size of the particles calculated from the XRD peaks are in the nanometer range (7–10 nm) which is in good agreement with the transmission electron microscopy (TEM) results. The Raman spectra indeed revealed that the SnO2 films are crystallized in the rutile tetragonal phase and furthermore a peak shift and a decrease of the peaks intensity can be remarked for the films doped with CuO.
-
Tungsten trioxide thin films prepared by electrostatic Spray Deposition technique
Thin Solid Films, 2007Co-Authors: Camelia Matei Ghimbeu, Robert C. Van Landschoot, Joop Schoonman, Martine LumbrerasAbstract:Tungsten trioxide (WO3) thin films deposited on a Pt-coated alumina substrate using the electrostatic Spray Deposition (ESD) technique is reported in this paper. As precursor solution, tungsten (VI) ethoxide in ethanol was used. The morphology and the microstructure of the films were studied using scanning electron microscopy coupled with energy dispersive X-ray analysis, transmission electron microscopy, X-ray diffraction, and Raman spectroscopy. Dense to porous morphologies were obtained by tuning the Deposition temperature. Impedance spectroscopy and current-voltage measurements were used to study the electrical behaviour of the films in air, in temperature range 300-500????C. The activation energy was estimated from Arrhenius plots. Considering the obtained results, the ESD technique proved to be an effective technique for the fabrication of porous tungsten trioxide thin films. ?? 2007.
-
morphology of calcium phosphate coatings for biomedical applications deposited using electrostatic Spray Deposition
Thin Solid Films, 2006Co-Authors: Sander C G Leeuwenburgh, Joop Schoonman, M C Heine, J G C Wolke, Sotiris E Pratsinis, John A JansenAbstract:Abstract Electrostatic Spray Deposition (ESD) of biomedical calcium phosphate (CaP) coatings was investigated by in situ measurements of droplet sizes and velocities using Phase Doppler Anemometry. Processing parameters, related to the ESD-apparatus as well as the composition of the precursor solutions, were varied (Deposition temperature, nozzle-to-substrate distance, nozzle geometry, and composition of the precursor solution). Thereafter, morphological characteristics of these ESD-derived CaP coatings were correlated with measured droplet characteristics. By varying physical apparatus-related parameters such as the nozzle-to-substrate distance and the Deposition temperature, it was observed that electroSprayed butyl carbitol droplets did not shrink during droplet flight towards the heated substrate. Nevertheless, coatings with a different surface morphology were obtained, varying from microporous structures with coalesced pore walls to isolated rings on top of dense or grainy underlayers. The chemical composition of the precursor solutions and the mixing characteristics of the calcium and phosphate precursor components strongly influenced the initial droplet sizes, precipitation kinetics of the CaP solute, and subsequent coating morphology. Unique, reticular coatings can be deposited at a Deposition rate of 3.2 μm/h, which have a graded structure consisting of a dense underlayer, a submicron-porous intermediate layer, and a roughened toplayer revealing droplet-derived features such as isolated rings or coalesced, hollow surface pits.
-
Nanocomposite three-dimensional solar cells obtained by chemical Spray Deposition
Nano Letters, 2005Co-Authors: Marian Nanu, Joop Schoonman, Albert GoossensAbstract:The present study is focused on low-cost preparation of thin film TiO2/CuInS2 nanocomposite three-dimensional (3D) solar cells. With the aid of a simple Spray Deposition method, we have been able to obtain 3D solar cells, with a remarkable energy conversion efficiency of 5%. The new 3D solar cell design has the potential to breakdown the price barrier and to open up new production technologies for low-cost photovoltaic solar cells.
-
Electrostatic Spray Deposition (ESD) of calcium phosphate coatings.
Journal of biomedical materials research. Part A, 2003Co-Authors: Sander C G Leeuwenburgh, J. Wolke, Joop Schoonman, J JansenAbstract:Using electrostatic Spray Deposition (ESD), thin calcium phosphate layers were deposited onto commercially pure cp-Ti substrates. ESD is a thin-film technique that enables the Deposition of inorganic thin films onto metallic substrates using a simple and cheap experimental set-up. The results show that coating structure and morphology can be tailored by choosing the appropriate combination of Deposition parameters. Scanning electron microscopy revealed that various surface morphologies, ranging from dense to very porous coatings, can be obtained. Particularly interesting was a unique reticular coating morphology characterized by a three-dimensionally interconnected pore network. X-ray diffraction (XRD) and Fourier transform infrared spectrometry (FTIR) analyses showed that crystalline carbonate apatite coatings were formed after heat treatment of as-deposited ESD coatings.
C.-h. Chen - One of the best experts on this subject based on the ideXlab platform.
-
electrostatic Spray Deposition of spinel li4ti5o12 thin films for rechargeable lithium batteries
Solid State Communications, 2005Co-Authors: Jianglan Shui, C.-h. ChenAbstract:Abstract Spinel Li 4 Ti 5 O 12 thin films are important for the fabrication of rechargeable lithium microbatteries. Porous thin films of Li 4 Ti 5 O 12 were prepared by electrostatic Spray Deposition (ESD) technique with lithium acetate and titanium butoxide as the precursors. The structures of these films were analyzed by scanning electron microscopy and X-ray diffraction. Coin-type cells with a liquid electrolyte were made with the Li 4 Ti 5 O 12 films against metallic lithium. Their electrochemical performance was investigated by means of galvanostatic cell cycling, cyclic voltammetry and Ac impedance spectroscopy. It was found that pure spinel phase of Li 4 Ti 5 O 12 was obtained. After annealing at the optimal temperature of 700 °C, the films can deliver a reversible specific capacity of about 150 mAh/g with excellent capacity retention after 70 cycles. Their electrochemical characteristics were quite comparable with those of the Li 4 Ti 5 O 12 laminate electrodes containing carbon black additive.
-
electrostatic sol Spray Deposition essd and characterisation of nanostructured tio2 thin films
Thin Solid Films, 1999Co-Authors: C.-h. Chen, E.m. Kelder, Joop SchoonmanAbstract:Abstract A novel film fabrication technique, i.e. electrostatic sol-Spray Deposition (ESSD), has been used in this study to prepare TiO 2 thin films of various surface morphologies and crystalline structures. Scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and UV/Vis absorption spectroscopy were employed to characterize the as-deposited and annealed TiO 2 thin films. It has been found that silicon dopant can increase the anatase-to-rutile phase transformation temperature up to about 1050°C. Two possible mechanisms are proposed to explain the phase stabilisation effect, i.e. reduction of the oxygen vacancy concentration by dissolution of SiO 2 in the TiO 2 lattice and segregation of a SiO 2 second phase. The energy bandgap of amorphous SiO 2 doped TiO 2 films decreases with increasing annealing temperature.
-
Electrostatic sol-Spray Deposition of nanostructured ceramic thin films
Journal of Aerosol Science, 1999Co-Authors: C.-h. Chen, M. H J Emond, E.m. Kelder, Ben De Meester, Joop SchoonmanAbstract:ElectroSpraying has been developed into an electrostatic Spray Deposition technique for the Deposition of ceramic thin films. The cone-jet Spraying mode appears to be the most preferable for this purpose, and the domain where the cone-jet mode exists was found to depend strongly on the nozzle design. A nozzle with a large diameter and a tilted outlet widens the windows for both the applied high DC voltage and the flow rates of a precursor liquid keeping the cone-jet mode intact. The results of three nozzle designs are compared, one of which has been selected for feeding two different precursor liquids simultaneously. With three relevant sols as precursor liquids, nanostructured thin films of ZnO, ZrO2, and Al2O3have been deposited. Their morphologies are dependent on the preparation of the precursor sols and the Deposition temperature. Highly porous films were obtained by using a high Deposition temperature and a sol prepared from a metal alkoxide or a metal acetate.
-
functional ceramic films with reticular structures prepared by electrostatic Spray Deposition technique
Journal of The Electrochemical Society, 1997Co-Authors: C.-h. Chen, E.m. Kelder, Joop SchoonmanAbstract:During the study of the electrostatic Spray Deposition technique, porous LiCoO{sub 2} thin layers with reticular structures were formed. This discovery has been successfully extended to many other important ceramic materials used in electrochemical devices such as LiMn{sub 2}O{sub 4}, LiNiO{sub 2}, LiCoO{sub 2}, Li{sub 3}PO{sub 4}, Li{sub 0.1}BPO{sub 4}, CoO, MnO{sub 2}, TiO{sub 2}, LaCoO{sub 3}, and SnO{sub 2} {center_dot} MnO{sub 2}. The pore size of these layers can be varied by adjusting the feed rate and/or the composition of the precursor solution. These reticular films are expected to have various applications in electrochemical devices, catalysts, and inorganic membranes.
-
Unique porous LiCoO2 thin layers prepared by electrostatic Spray Deposition
Journal of Materials Science, 1996Co-Authors: C.-h. Chen, E.m. Kelder, Joop SchoonmanAbstract:Electrostatic Spray Deposition (ESD) technique was used to fabricate thin LiCoO2 layers on a metal substrate. A unique, highly porous structure with a narrow pore-size distribution around 1 lain was obtained at 230~ using acetates as precursors and a mixture of ethanol (15 vol%) and butyl carbitol (85 vol%) as solvent. The pores were three-dimensionally interconnected. This structure was thermally stable at temperatures up to 600 ~ At small flow rates of the precursor solution, a nearly linear relation was found between pore size and flow rate. At Deposition temperatures above 230 ~ the porous structure disappeared. A possible formation mechanism for the porous structure has been proposed. 1.
Zhurong Liang - One of the best experts on this subject based on the ideXlab platform.
-
fast preparation of uniform large grain size perovskite thin film in air condition via Spray Deposition method for high efficient planar solar cells
Solar Energy Materials and Solar Cells, 2017Co-Authors: Zhurong Liang, Zhisheng Chai, Hu JinAbstract:Spray Deposition has been demonstrated to be a promising method to prepare perovskite thin film with many advantages, such as easy and processable under fully ambient condition, which is suitable for large-scale production. In this work, we reveal two typical Spray Deposition process of rapid and slow solvent evaporation. It is emphasized that the rapid solvent evaporation process is essential to avoid dendritic crystal and obtain dense perovskite thin film without pin-holes, which can be realized with a suitable substrate temperature. With optimized Spray conditions including flow rate of precursor solution and carrier gas pressure, a dense and uniform perovskite layer with full surface coverage was immediately formed in similar to 5 s without any post-annealing process. The as-fabricated planar heterojunction solar cell achieved a power conversion efficiency (PCE) of 13.54% with 300 +/- 30 nm in thickness of perovskite layer. To the best of our knowledge, this result is the highest value for the CH3NH3PbI3 perovskite solar cells fabricated in air condition with high humidity up to 50%.
-
a large grain size perovskite thin film with a dense structure for planar heterojunction solar cells via Spray Deposition under ambient conditions
RSC Advances, 2015Co-Authors: Zhurong Liang, Junxia Wang, Shaohong Zhang, Xueqing Xu, Nan Wang, Xin Wang, Zhuoneng Bi, Gang Xu, Ningyi Yuan, Jianning DingAbstract:Organometal halide perovskites have emerged as promising light absorbers for third-generation photovoltaics. Herein we developed a facile Spray Deposition process to prepare high-quality perovskite films without any post-annealing under ambient conditions with a high humidity of up to 50%. The as-prepared perovskite films exhibit large grain sizes up to micrometers and full surface coverage. These desirable features significantly enhance the light harvesting efficiency and reduce charge recombination. Furthermore, the morphology and film thickness can be easily controlled by varying the precursor concentration or scanning times during Spray Deposition. The as-fabricated planar heterojunction solar cells with an optimized perovskite film thickness exhibited a power conversion efficiency of ∼7.89%, which is expected to be further improved with the increase of substrate temperature, the utilization of more compatible substrates, and the optimization of the hole-transport layer and device structure. This simple low-temperature manufacturing process provides a novel strategy for the scalable and fast fabrication of high-quality absorber layers for efficient perovskite based solar cells. The film formation mechanism regarding the nucleation and growth of perovskite films with desirable morphology is also discussed.
-
a facile Spray Deposition route for uniform perovskite solar cells processed in air
International Photonics and OptoElectronics (2015) paper JW3A.20, 2015Co-Authors: Zhurong Liang, Junxia WangAbstract:In this work, we developed a facile Spray Deposition process to prepare perovskite films with full surface coverage and large grain size up to micrometers under ambient condition with high humidity up to 50%.
Suk Goo Yoon - One of the best experts on this subject based on the ideXlab platform.
-
highly nanotextured β bi2o3 pillars by electrostatic Spray Deposition as photoanodes for solar water splitting
Journal of Alloys and Compounds, 2018Co-Authors: Min Woo Kim, Bhavana Joshi, Edmund Samuel, Karam Kim, Yong Il Kim, Tae Gun Kim, Mark T Swihart, Suk Goo YoonAbstract:Abstract We demonstrate fabrication of films of highly textured bismuth oxide (Bi2O3) pillars via electrostatic Spray Deposition and test the performance of these films as photoanodes in photoelectrochemical water splitting. The β-Bi2O3 and α-Bi2O3 phases were identified and distinguished using X-ray diffraction, Raman spectroscopy, and transmission electron microscopy. The β-Bi2O3 pillars of optimized thickness exhibited a photocurrent density of 0.97 mA⋅cm−2 at 0.5 V vs Ag/AgCl. The tetragonal β-Bi2O3 pillars had enhanced visible light absorbance compared to α-Bi2O3 as well as other metal oxides like ZnO and TiO2. Tauc plot analysis of film absorbance showed a decrease in the bandgap of the β-Bi2O3 phase to 2.5 eV. In Na2SO3 electrolyte, a hole scavenger, the onset voltage for the β-Bi2O3 phase was shifted to a more negative value (−0.4 V), which increased photocurrent density. The electron concentration reached its highest value of 9.1 × 1020 cm−3 for the film with the highest photocurrent density.
-
electrostatic Spray Deposition of transparent tungsten oxide thin film photoanodes for solar water splitting
Catalysis Today, 2016Co-Authors: Hyun Yoon, Min Woo Kim, Mukund G Mali, Salem S Aldeyab, Suk Goo YoonAbstract:Abstract Photocatalytic water splitting has been explored extensively as a promising way to capture and store solar energy. In this study, stable WO 3 thin-film photoelectrodes for water splitting applications were prepared with the simple, inexpensive, and scalable technique of electrostatic Spray Deposition. The physicochemical, structural, optical, and morphological properties of the WO 3 films were studied with X-ray diffraction, Raman spectroscopy, UV–visible spectroscopy, and scanning electron microscopy. The thickness of the films prepared was varied from 50 to 400 nm in order to establish a relationship between film thickness and water splitting performance. The photocurrent of the WO 3 thin films, measured in a 0.5 M Na 2 SO 4 electrolyte solution against a standard Ag/AgCl reference electrode, increased with increasing film thickness. The film electroSprayed for 10 min exhibited a photocurrent density of 0.04 mA/cm 2 . The photocurrent density was increased by 10-fold to 0.40 mA/cm 2 when the electroSpraying time was increased to 60 min. Of all the films tested in this study, the film electroSprayed for 60 min, which had a thickness of 400 nm, showed the best photoelectrochemical cell activity.
-
enhanced photocatalytic performance of graphene zno nanoplatelet composite thin films prepared by electrostatic Spray Deposition
Ceramics International, 2014Co-Authors: Bhavana Joshi, Hyun Yoon, Jae Young Choi, Suk Goo YoonAbstract:Abstract Graphene–ZnO (G–ZnO) composite thin films were produced using the electrostatic Spray Deposition technique (ESD). The effects of the concentration of graphene and annealing temperature on the structural and photocatalytic properties of the G–ZnO films were studied by X-ray diffraction, scanning electron microscopy, atomic force microscopy, Raman spectroscopy, and UV–visible spectroscopy. We demonstrated that the G–ZnO films exhibit enhanced activities towards the photodegradation of methylene blue dye. A G–ZnO film with 0.1 wt% graphene that was annealed at 300 °C showed the highest photo-degradation activity. We found that the incorporation of graphene reduced electron–hole recombination in the ZnO film.
Tetsuo Tsutsui - One of the best experts on this subject based on the ideXlab platform.
-
polymer field effect transistors of f8t2 prepared by evaporative Spray Deposition using ultradilute solution technique
Journal of Photopolymer Science and Technology, 2008Co-Authors: Koji Sagane, Masato Shakutsui, Tetsuo Tsutsui, Takahiko FujitaAbstract:The evaporative Spray Deposition using ultradilute solution (ESDUS) technique enables layer-by-layer and pixel-by-pixel Deposition of polymer semiconductors. In this study we prepared thin films of dioctylfluorene-co-bithiophene) alternating copolymer, F8T2, by ESDUS and by a conventional spin-coat. These films were made into fabricated field effect transistors to investigate carrier transportation properties. Since the organic films were formed by Deposition of aerosol particles in ESDUS, the carrier transportation properties in ESDUS films had been expected lower than those in spin-coat films, which are formed through spread polymer solution. However, the device performance was almost identical, indicating that the polymer deposited as particles undergoes rearrangement process on the substrate.
-
improvement in polymer light emitting diode performance using polymer heterojunction structure prepared by evaporative Spray Deposition from ultradilute solution
Japanese Journal of Applied Physics, 2006Co-Authors: Masato Shakutsui, Katsuhiko Fujita, Tetsuo TsutsuiAbstract:We successfully demonstrated a significant improvement in polymer light-emitting diode performance by employing a polymer bilayer structure prepared by evaporative Spray Deposition from ultradilute solution (ESDUS). The bilayer structure consisted of two π-conjugated polymers, where the top layer was deposited from tetrahydrofuran (THF) solution by ESDUS onto the preceding bottom layer composed of the other THF-soluble polymer. The external quantum efficiency (EQE) of the bilayer device is improved markedly in comparison with that of a corresponding single-layer device prepared by conventional spin-coating. Moreover, the EQE of the bilayer device tends to be constant throughout a wide current region, whereas that of single-layer devices increases gradually with current density. These observations indicate that carriers are effectively blocked at the polymer/polymer interface of the bilayer device.
-
small area Deposition of light emission polymer by evaporative Spray Deposition from ultradilute solution technique
Japanese Journal of Applied Physics, 2005Co-Authors: Takamasa Ishikawa, Katsuhiko Fujita, Tetsuo TsutsuiAbstract:The evaporative Spray Deposition from ultradilute solution (ESDUS) technique has enabled the preparation of organic devices from highly diluted solutions of polymer semiconductors. Here, we report another feature of this technique, the pixel-size Deposition of a π-conjugated polymer. Small-area coating was carried out using a simple shadow mask with pixel-size holes. A blue-emission polymer, PFHB, was deposited through the mask. The resultant film had a pixel pattern of 10 µm separation. Moreover, a green-emission polymer, CN-PDHFV, was subsequently deposited over the first patterned layer. The pixel pattern was maintained clear without getting blurred even using the same solvent, tetrahydrofuran, for each polymer Deposition. An electroluminescent (EL) device consisting of a patterned partial double layer showed a green emission from a single layer area.
-
preparation of organic bulk heterojunction photovoltaic cells by evaporative Spray Deposition from ultradilute solution
Applied Physics Letters, 2004Co-Authors: Takamasa Ishikawa, Katsuhiko Fujita, Makiko Nakamura, Tetsuo TsutsuiAbstract:An organic bulk heterojunction photovoltaic cell (OPC) having a thin layer consisting of a functionalized fullerene and a poly-p-phenylenevinylene (PPV) derivative was prepared from a highly diluted tetrahydrofuran solution at the concentration below 1 ppm by the evaporative Spray Deposition from ultradilute solution (ESDUS) technique. The power conversion efficiency of the OPC prepared from 1:1 mixture solution of fullerene/PPV derivative at the concentration of 1 ppm was 0.69%, which was almost comparable to that prepared by the conventional spin coating technique from 0.5 wt % chlorobenzene solution of the mixture. Although the bulk heterojunction OPCs are known to show relatively high power conversion efficiency, they have two major problems for development of higher device performance. One is a solubility problem of used materials and the other is a strong dependence of the device performance on the preparation solvent. The former has been a stumbling block to improve the performance by examining var...
