Surface Pinholes Research Articles

Toward preparation of large scale and uniform mesoporous BiVO4 thin films with enhanced photostability for solar water splitting

The preparation methods of photocatalyst thin films play a critical role in increasing their efficiency. Ease of fabrication, the ability to commercialize, production on a large scale, reproducibility, and preparing the layers with stable performance are some of the most important criteria for a synthesis method to prepare a high-performance phot-electrode. A straightforward, cost-effective and reproducible hot spin coating (HSC) method was introduced in this work, to achieve these goals for BiVO4 thin films. The most important HSC parameters, namely substrate revolution speed (ωs), substrate temperature (Ts), and combustion time (Ct), were investigated systematically. The BiVO4 thin films prepared via the HSC method under the optimized parameters of ωs = 1200 rpm, Ts = 200 °C, and Ct = 15 s exhibited a uniform mesoporous surface texture (average pore diameter of 13.4 nm) and high adhesion (5B) to the substrate. Interestingly, the HSC method was capable of preparing super-hydrophilic BiVO4 layers on a large scale (tested up to 8 × 8 cm2) without any surface pinholes. The practical application of the obtained layers was examined inside a photoelectrochemical (PEC) cell. The optimized BiVO4 electrode generated a remarkable and robust photo-current density of ∼500 μA/cm2 without any change after 30 days. The preparation of BiVO4 thin films with such interesting properties via the facile HSC method makes it a promising technique to prepare highly efficient photo-anodes for practical use on a large scale.

GaAs hetero-epitaxial layers grown by MOVPE on exactly-oriented and off-cut (1 1 1)Si: Lattice tilt, mosaicity and defects content

Integration of III-V devices with Si-photonics and fabrication of monolithic III-V/Si tandem solar cells require the heteroepitaxy of III-V compounds on Si. We report on the lattice tilt, mosaicity and defects content of relaxed GaAs grown by MOVPE on exactly-oriented and 4°-offcut (111)Si. Thin GaAs single-layers grown at 400 °C and annealed at 700 °C show ∼ 3 × 108 cm−2 density of surface pinholes. Double-layer samples were obtained by GaAs overgrowth at 700 °C. GaAs epilayers are tilted by (0.05–0.14)° with respect to Si. Rotational twins were observed in X-ray diffraction (XRD) pole figures: the most abundant ones originate from 60°-rotation of GaAs around the 1¯1¯1¯ growth direction and are identified as micro-twins along the GaAs/Si hetero-interface. Twins obtained by rotations around the 1¯1¯1, 11¯1¯, and 1¯11¯ directions or by combined rotations around the growth direction and one of the former, were also observed. The GaAs mosaicity and block size were studied through high-resolution XRD intensity mapping: for single-layer samples crystal blocks are ascribed to 3–5 nm thin micro-twins, whose size does not change upon annealing. In double-layer samples thicker (32–35 nm) micro-twins occur. GaAs samples grown on offcut (111)Si show less rotational twins but a reduced mosaic block size with respect to exactly-oriented Si.

Nugget zone characterization of friction stir welded hypereutectic Al-Si alloy

Despite excellent properties of aluminium silicon (Al-Si) alloys in several aircraft and automotive applications, its usage is limited because near net shape casting of Al-Si alloys may cause several defects like surface pinholes and grooves. Fabrication of components and then welding them via fusion-based welding processes imposes issues like porosity and slag inclusions which may severely degrades its properties. Thus in present study, friction stir welding (FSW) was employed for welding of hypereutectic Al-Si cast alloy. The nugget zone (NZ) of welded alloy and its as-cast counterparts were characterized for their performance in terms of mechanical and tribological behaviour. The results depicted fragmentation of α-Al dendrites, refinement and redistribution of acicular Si particles as a result of stirring with high strain rate, and improvement in mechanical properties such as ultimate tensile strength, yield strength, ductility, hardness and wear resistance as compared to as-cast alloy. It is also shown that disparate wear mechanisms occured in friction stir welded (FSWed) and as-cast alloys. A sizeable amount of adhesion with plastic deformation and delamination pits were observed for as-cast alloy, while the dominant mechanism in FSWed alloy was peeling with little adhesion.

Improved efficiency for lead-free CsCu2I3 halide microplatelets by suppressing surface pinholes via surface functionalization

Lead-free copper(I)-based halides have attracted tremendous attentions in producing optoelectronic devices due to their outstanding optical properties and low-cost synthesis. However, the low efficiency of copper(I)-based halides in the long-wavelength visible emissions (typically yellow- or red-light emissions) has hindered the use of such non-toxic halides in full-color displays and solid-state lighting applications. In this work, lead-free, air-stable and yellow-light emissive CsCu2I3 microplatelets (MPs) with well-defined smooth surface were synthesized by a one-pot anti-solvent solution method at room temperature via surface functionalization with different long-chain surfactants. The results suggested that oleic acid (OA) was the most favorable surfactant for the CsCu2I3 MPs with the best performance. Photoluminescence quantum efficiency of the yellow-emissive CsCu2I3 MPs (centered at 580 nm) was dramatically enhanced fourfold by coordinating OA ligands during the synthesis to eliminate the surface pinholes of the CsCu2I3 MPs. Notably, the CsCu2I3 MPs showed ultra-high stability towards exposure of ambient air over 50 days. These findings may open new directions to synthetize high-efficiency copper(I)-based halides that generate long-wavelength visible emissions for lead-free nontoxic full-color optoelectronic devices.

A Study on the Recreated Experiment and Casting Method of Ancient Iron Seated Buddha by Spilt Casting Method

The study aimed to investigate the split casting method based on the recreation of the iron-seated Buddha (ISB) statue (number 1971) in the Chuncheon Museum. The statue was designed using three-dimensional scan data and reduced to half-size. Using the existing research results, the ISB statue was created by mold production and split casting. The mold was prepared by mixing sand and clay at a ratio of 3:4 and 1:3 on the outside and inside, respectively, and then casting was done. Various casting defects were observed in the ISB casting and similar shapes were seen. The casting defects included veining or finning, misrun, open or external shrinkage, surface or subsurface blowholes, surface pinholes, and shift. The microstructures were identified as branch-shaped dendrite and pearlite organizations, and black graphite was observed between the cementite organizations. The study findings may be relevant in exploring traditional casting and manufacturing techniques of ISB and may aid in the production of the original form of ISB.

Low-temperature-deposited SnO2 films for efficient planar CH3NH3PbI3 photovoltaics

Low-temperature-synthesized electron transport layers (ETLs) are in demand for the industrialization and flexibility of perovskite solar cells (PeSCs). SnO2 ETLs are prepared via chemical bath deposition at low temperature. Uniform SnO2 ETLs with high crystallinity and transmittance are obtained from a 0.3 M SnCl4 solution through a 100 °C heat treatment. They effectively transport electrons and weaken recombination loss in SnO2-based photovoltaics. SnO2-based PeSCs exhibit a power conversion efficiency (PCE) of 16.92% with a short-circuit current density (JSC) of 21.48 mA cm−2 and a fill factor (FF) of 73.62%. Secondary bath modification is proposed to mend the surface pinholes of SnO2 ETLs and boost the photoelectric properties of SnO2-based devices. The photovoltaic performance of the devices based on modified SnO2 (2-SnO2) films exhibits an impressive increase compared with unembellished ones due to less pinholes and suppressed surface defects. The open circuit voltage (VOC) and FF of 2-SnO2-based photovoltaics are enhanced to 1.10 V and 76.71%, respectively, resulting in PCE to 18.04%. Simultaneously, the dark current and hysteresis of 2-SnO2-based PeSCs are reduced because the secondary bath refines the surface nanoparticles of ETLs, passivates defects and reduces charge recombination at ETL/perovskite interfaces. Accordingly, 2-SnO2-based photovoltaics with a large area (~ 1 cm2) achieves 12.91% efficiency.

Molecular Imprinting of Bisphenol A on Silica Skeleton and Gold Pinhole Surfaces in 2D Colloidal Inverse Opal through Thermal Graft Copolymerization.

This study successfully fabricated BPA-imprinted poly(4-vinylpyridine-co-ethylene glycol dimethacrylate) (poly(4-VP-co-EGDMA)) quartz crystal microbalance (MIP-QCM) sensors on a silica skeleton surface and gold pinholes of silica inverse opal through surface-initiated atom transfer radical polymerization (SI-ATRP). The sensing features of the two MIP films on the structured silica surface and nano-scale local gold surface were investigated by measuring the resonant frequency change (∆f) in QCM sensors. The ∆f values for the p-MIP (MIP on gold pinholes) and s-MIP films (MIP on silica skeleton surface) were obtained with the ∆f value of −199 ± 4.9 Hz and −376 ± 19.1 Hz, respectively, whereas for p-/s-NIP films, the ∆f values were observed to be −115 ± 19.2 Hz and −174 ± 5.8 Hz by the influence of non-specific adsorption on the surface of the films. Additionally, the imprinting factor (IF) appeared to be 1.72 for p-MIP film and 2.15 for s-MIP film, and the limits of quantitation (LOQ) and detection (LOD) were 54.924 and 18.125 nM (p-MIP film) and 38.419 and 12.678 nM (s-MIP film), respectively. Using the Freundlich isotherm model, the binding affinity of the BPA-imprinted films was evaluated. This was measured in an aqueous solution of BPA whose concentration ranged between 45 and 225 nM. It was found that the p-MIP film (m = 0.39) was relatively more heterogeneous than the s-MIP film (m = 0.33), both of which were obtained from the slope of the linear regressions. Finally, the selectivity of the MIP-QCM sensors for BPA detection was determined by measuring the effect of other analogous chemicals, such as bisphenol F (BPF), bisphenol AP (BPAP), and bisphenol B (BPB), in aqueous solutions. The selectivity coefficients (k*) of the two MIP films had ~1.9 for the p-MIP and ~2.3 for the s-MIP films, respectively. The results reveal that, with respect to signal amplification of the QCM sensors, the s-MIP film has better sensing features and faster detection responses than the p-MIP film.

Influence of seed layers on optical properties of aluminum in the UV range

The potential of titanium and copper seed layers to enhance the optical properties of aluminum films for ultra-violet (UV) applications is analyzed. The seed layers significantly influence the initial layer growth of aluminum films. For the titanium-seeded aluminum, a surface roughness of 0.34 nm was observed. UV spectral reflectance measurements showed an average higher reflectivity of 4.8% for wavelengths from 120 nm to 200 nm for the aluminum film grown on the titanium seed layer. Furthermore, the titanium-seeded aluminum coatings were stable at an elevated temperature of 225°C and showed no increase in surface roughness or pinholes.

Deformation Behavior of Pure Copper Castings with As-Cast Surfaces for Electrical Parts

Herein, the tensile deformation behavior of pure copper castings with as-cast surfaces was investigated. It was found that small and sufficiently large uniform elongation types corresponded, respectively, to the presence or absence of a Cu-Cu2O eutectic phase in the microstructure. Fissure defects were observed near the as-cast surfaces when the eutectic phase was present, probably leading to stress concentration. On the other hand, surface pinholes were observed when the eutectic phase was absent, and these were not prevented by directional solidification. Although the as-cast specimens (non-directionally solidified) exhibited a slightly reduced uniform elongation compared to the machined specimens in the absence of the eutectic phase, the directionally solidified as-cast samples exhibited a uniform elongation that was similar to that of the machined specimens. In addition, micropore arrays were formed along the grain boundaries inside the castings when the eutectic phase was absent, whereas almost no micropores were observed inside the directionally solidified as-cast specimens because the solidification process involved a faster cooling rate and/or higher temperature gradient. These results do not only suggest the existence of surface pinholes but also indicate that microporosity can reduce the cross-sectional area of the specimens, thus, affecting their uniform elongation.

Studies on the influence of etching solution on the properties of Cu2ZnSn(S,Se4) thin film solar cells

Cu2ZnSn(S,Se)4 (CZTSSe) thin film solar cells (TFSCs) have emerged as the most promising low-cost alternatives to well-established CuInGaS2 and CuInS2-based TFSCs technologies. The surface composition of the absorber layer and the interface quality between the absorber and buffer layers play a key role in the performance of CZTSSe TFSCs. In this study, we investigated the influence of different etchants namely potassium cyanide (KCN), hydrochloric acid (HCl) and ammonia on different properties such as structural, morphological, and compositional as well as the solar cell performance of CZTSSe TFSCs. The results revealed no significant changes in the film structural properties before and after etching with any of the tested etchants. However, the slight changes in the composition and microstructure were observed after etching treatment. The microstructure was improved after KCN treatment with larger grain size compared to absorber layer without etching, whereas the slightly distorted microstructure with several surface pinholes was observed after HCl and ammonia treatment. Surprisingly, HCl and ammonia treatments degraded the open circuit voltage and fill factor values and thereby decreasing the power conversion efficiency (PCE) of the CZTSSe TFSCs. On the other hand, KCN treatment slightly improved the PCE of CZTSSe TFSCs. The decreased PCE after HCl and ammonia treatments could be mainly attributed to the deteriorated absorber quality as well as poor formation of poor juction between the absorber layer and the CdS buffer layer.

Multi-scale structure, pasting and digestibility of adlay (Coixlachryma-jobi L.) seed starch

The hierarchical structure, pasting and digestibility of adlay seed starch (ASS) were investigated compared with maize starch (MS) and potato starch (PS). ASS exhibited round or polyglonal morphology with apparent pores/channels on the surface. It had a lower amylose content, a looser and more heterogeneous C-type crystalline structure, a higher crystallinity, and a thinner crystalline lamellae. Accordingly, ASS showed a higher slowly digestible starch content combined with less resistant starch fractions, and a decreased pasting temperature, a weakened tendency to retrogradation and an increased pasting stability compared with those of MS and PS. The ASS structure-functionality relationship indicated that the amylose content, double helical orders, crystalline lamellar structure, and surface pinholes should be responsible for ASS specific functionalities including pasting behaviors and in vitro digestibility. ASS showed potential applications in health-promoting foods which required low rearrangement during storage and sustainable energy-providing starch fractions.

Heat pretreatment improves the enzymatic hydrolysis of granular corn starch at high concentration

Abstract Heat pretreatment was investigated as a way to improve the α-amylase-catalyzed hydrolysis of granular corn starch at high concentration (45%, w/w). Native and preheated starches were hydrolyzed in the granular state for 1 h at 40 °C using a commercially available α-amylase. The initial dextrose equivalent (DE) value of the native granular starch (8.0%) increased significantly (to 12.6%) after pretreatment at 60 °C for 15 min. Microscopic analysis of the starch granules indicated that heat pretreatment increased the number and size of the pores and pinholes on the granule surface, which facilitated the adsorption and subsequent penetration of enzyme molecules. Furthermore, the amylose present in amorphous regions leached rapidly when corn starch was incubated at 60 °C, suggesting weaker interactions within the granules. The DE value of the hydrolysate showed a linear dependence on the amount of amylose that leached during the course of heat pretreatment (R 2 = 0.9771). Mobilization of amylose chains within the granule, caused by the heat pretreatment, may have allowed the enzyme to make greater use of amylose, which is its primary substrate during starch granule hydrolysis. In addition, a 35% reduction in the K m value showed that heat pretreatment increased the affinity of α-amylase for the starch granules. This can be attributed to the mobilization of amylose chains within the granule and expansion of the surface pinholes. These effects demonstrate that proper heat pretreatment of granular starch before amylolysis has great potential in industry.

A Review of Permanent Magnet Stirring During Metal Solidification

Rather than using conventional electromagnetic stirring (EMS) with three-phase alternating current, permanent magnet stirring (PMS), based on the use of sintered NdFeB material which has excellent magnetic characteristics, can be employed to generate a magnetic field for the stirring of liquid metal during solidification. Recent experience with steel casting indicates that PMS requires less than 20 pct of the total energy compared with EMS. Despite the excellent magnetic density properties and low power consumption, this relatively new technology has received comparatively little attention by the metal casting community. This paper reviews simulation modeling, experimental studies, and industrial trials of PMS conducted during recent years. With the development of magnetic simulation software, the magnetic field and associated flow patterns generated by PMS have been evaluated. Based on the results obtained from laboratory experiments, the effects of PMS on metal solidification structures and typical defects such as surface pinholes and center cavities are summarized. The significance of findings obtained from trials of PMS within the metals processing sector, including the continuous casting of steel, are discussed with the aim of providing an overview of the relevant parameters that are of importance for further development and industrial application of this innovative technology.

Zinc Porphyrin–Ethynylaniline Conjugates as Novel Hole-Transporting Materials for Perovskite Solar Cells with Power Conversion Efficiency of 16.6%

New zinc porphyrins Y2 and Y2A2 have been utilized in perovskite solar cells specifically as hole-transporting materials (HTMs) rather than photosensitizers. The combination of MAPbI3 as photosensitizer and porphyrins as HTMs is a potential alternative to well-known MAPbI3/Spiro-OMeTAD hybrids owing to high performance and versatility toward molecular engineering of porphyrin families. A high efficiency of 16.60% is achieved by n-butyl tethered Y2 HTM (VOC = 0.99 V; JSC = 22.82 mA cm–2) which is comparable to that of Spiro-OMeTAD of 18.03% (VOC = 1.06 V; JSC = 22.79 mA cm–2). Both materials possess similar highest occupied molecular orbital level and the same order of magnitude of hole mobility at 10–4 cm2 V–1 s–1. The slightly poorer performance of 10.55% (VOC = 1.01 V; JSC = 17.80 mA cm–2) is obtained for n-dodecyl tethered Y2A2 HTM. This is believed to stem from more surface pinholes when deposited on perovskite leading to an order of magnitude slower mobility.

Silicon particle pinhole defects in aluminium\u2013silicon alloys

It was recently shown that silicon particles in heat-treated Al–Si casting alloys can contain flaws such as surface pinholes and grooves, which cause varying degrees of reduction in the in situ particle fracture strength and hence influence the mechanical properties of this class of alloys. In this work, we show that the formation of one class of such strength-limiting flaws in solidified and coarsened Si particles, namely surface pinholes, is caused by alloy impurities such as Fe and Ti in both binary eutectic Al–Si alloys and also in casting alloy A356. This is evidenced by using Focused Ion Beam serial sectioning tomography coupled with Energy-Dispersive X-Ray Spectroscopy, and confirmed by the observation that a high-purity Al–Si alloy presents a significantly lower proportion of pinholes along the surface of the silicon phase than does an alloy of commercial purity. A similar correlation between alloy purity and the formation of another, more severe strength-limiting particle defect, namely grooved interfaces, was on the other hand not found.

Solution Processing and Conversion of Transparent Metal Oxide Optical Coatings By Solid State Diffusion

Many modern technologies are based on materials that are deposited on special underlying materials. Optical coatings can prevent tarnishing, give anti-reflection benefits, and in some cases filter out harmful UV rays. In consumer devices, many modern optoelectronic devices that make up a vast majority of electronic products such as active displays, touch screens etc. are based thin film transistors and transparent materials, as are parts of solar cells, smart windows, antireflection coatings for a range of devices and applications, anti-fingerprint and antifogging glass, among many other modern uses of see-through materials and coatings with well-defined characteristics in visible light. While the science and technology of controlling materials into a whole host of electronics and photonic or optical devices has advanced considerably in the last decade, industry still requires all this to be done without using critical raw materials, expensive coating methods that are often very slow, and to do so at much lower temperatures for coating on to curved or flexible displays or materials – all without sacrificing quality that current methods provide. Here, we report a facile solution processed technique for the formation of a transparent thin film through an inter-diffusion process involving substrate dopant species at a range of low annealing temperatures compatible with processing conditions required by many state-of-the-art devices. The inter-diffusion process facilitates the movement of Si, Na and O species from the substrate into the as-deposited vanadium oxide thin film forming a composite fully transparent V0.0352O0.547Si0.4078Na0.01. Thin film X-ray diffraction and Raman scattering spectroscopy show the crystalline component of the structure to be α-NaVO3 within a glassy matrix. This optical coating exhibits high broadband transparency, exceeding 90-97% absolute transmission across the UV-to-NIR spectral range, while having low roughness and free of surface defects and pinholes. The production of transparent films for advanced optoelectronic devices, optical coatings, and low- or high-k oxides is important for planar or complex shaped optics or surfaces. It provides opportunities for doping metal oxides to new ternary, quaternary or other mixed metal oxides on glass, encapsulants or other substrates that facilitate diffusional movement of dopant species. References (1) C. Glynn, D. Creedon, H. Geaney, T. Collins, E. Armstrong, M. A. Morris and C. O'Dwyer, Sci. Rep., 5, 11574 (2015). (2) C. Glynn, D. Aureau, G. Collins, S. O'Hanlon, A. Etcheberry and C. O'Dwyer, Nanoscale, 7, 20227 (2015). (3) S. O'Hanlon, C. Glynn and C. O'Dwyer, ECS J. Solid State Sci. Technol., 5, R3100 (2016). (4) K. K. Banger, Y. Yamashita, K. Mori, R. L. Peterson, T. Leedham, J. Rickard and H. Sirringhaus, Nat. Mater., 2011, 10, 45-50. (5) K. Ellmer, Nat. Photon, 2012, 6, 809-817. (6) C. G. Granqvist, Thin Solid Films, 2014, 564, 1-38. (7) H. Dotan, O. Kfir, E. Sharlin, O. Blank, M. Gross, I. Dumchin, G. Ankonina and A. Rothschild, Nat. Mater., 2013, 12, 158-164. Figure 1

Effect of permanent magnet stirring on solidification of Sn-Pb alloy

An experimental investigation has been conducted with respect to the influence of permanent magnet stirring (PMS) under different rotation speeds (ω=60, 120 and 150r/min) and center magnetic flux densities (B=757 and 1080Gs) on the solidification of Sn-20wt%Pb alloy. The magnetic field was generated by a pair of arc-shaped NdFeB permanent magnets with a gap that could be adjusted to obtain the required magnetic flux density. The effects of different values of ω and B were investigated by analyzing the driven flow intensity, surface and internal quality, macrostructure, microstructure and tensile properties. It was observed that with increasing ω and B there was significant improvement in the flow intensity of the liquid, surface pinholes, grain refinement and tensile properties. The results obtained have important implications for industrial metal casting processes.

Physico-chemical properties of corn starch modified with cyclodextrin glycosyltransferase

Cyclodextrin glycosyltransferase (CGTase) has been used to produce cyclodextrins (CDs) from starches, but their ability to modify starches has been barely explored. The effect of CGTase on corn starch at sub-gelatinization temperature (50°C) and at different pH conditions, pH 4.0 and pH 6.0, was evaluated. Biochemical features, thermal and structural analysis, oligosaccharides and CDs content were studied. Microscopic analysis of the granules confirmed the enzymatic modification of the starches obtaining structures with irregular surface and small pinholes. The extent of the starch modification was largely dependent on the pHs, being higher at pH 6.0. This was also confirmed by the low viscosity of the resulting pastes during a heating and cooling cycle. Thermal parameters were not affected due to enzymatic treatment. Modified starches were less susceptible to undergo α-amylase hydrolysis. CDs released were higher for samples treated at pH 4.0. Therefore, CGTase modification of corn starches at sub-gelatinization temperature offers an attractive alternative for obtaining porous starches with different properties depending on the pH conditions.

Influence of artificial and casting defects on fatigue strength of moulded components in Ti‐6Al‐4V alloy

AbstractThe influence of defects on the fatigue strength of a cast Ti‐6Al‐4V alloy has been investigated. An experimental programme has been defined with different castings. On a first stage, a flat fatigue specimen has been developed to be representative of the real aircraft component. Then, reference fatigue properties have been determined and reduction of the fatigue strength has been quantified for artificial and natural defects. It is shown that an artificial defect with a chemically milled surface is representative of an in‐service component surface machining: surface pinholes have similar influence on the fatigue behaviour. Furthermore, the experimental results have shown that the geometrical morphology is not the major parameter that governs the fatigue life reduction: the defect type has a major influence. It is also shown that the initiation stage is not negligible in the total fatigue life about 105 cycles. Kitagawa diagrams were built to determine critical defect sizes.

Solution processable broadband transparent mixed metal oxide nanofilm optical coatings via substrate diffusion doping.

Devices composed of transparent materials, particularly those utilizing metal oxides, are of significant interest due to increased demand from industry for higher fidelity transparent thin film transistors, photovoltaics and a myriad of other optoelectronic devices and optics that require more cost-effective and simplified processing techniques for functional oxides and coatings. Here, we report a facile solution processed technique for the formation of a transparent thin film through an inter-diffusion process involving substrate dopant species at a range of low annealing temperatures compatible with processing conditions required by many state-of-the-art devices. The inter-diffusion process facilitates the movement of Si, Na and O species from the substrate into the as-deposited vanadium oxide thin film forming a composite fully transparent V0.0352O0.547Si0.4078Na0.01. Thin film X-ray diffraction and Raman scattering spectroscopy show the crystalline component of the structure to be α-NaVO3 within a glassy matrix. This optical coating exhibits high broadband transparency, exceeding 90-97% absolute transmission across the UV-to-NIR spectral range, while having low roughness and free of surface defects and pinholes. The production of transparent films for advanced optoelectronic devices, optical coatings, and low- or high-k oxides is important for planar or complex shaped optics or surfaces. It provides opportunities for doping metal oxides to ternary, quaternary or other mixed metal oxides on glass, encapsulants or other substrates that facilitate diffusional movement of dopant species.