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The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus emerged in late 2019 leading to the COVID-19 disease pandemic that triggered socioeconomic turmoil worldwide. A precise, prompt, and affordable diagnostic assay is essential for the detection of SARS-CoV-2 as well as its variants. Antibody against SARS-CoV-2 spike (S) protein was reported as a suitable strategy for therapy and diagnosis of COVID-19. We, therefore, developed a quick and precise phase-sensitive surface plasmon resonance (PS-SPR) biosensor integrated with a novel generated anti-S monoclonal antibody (S-mAb). Our results indicated that the newly generated S-mAb could detect the original SARS-CoV-2 strain along with its variants. In addition, a SARS-CoV-2 pseudovirus, which could be processed in BSL-2 facility was generated for evaluation of sensitivity and specificity of the assays including PS-SPR, homemade target-captured ELISA, spike rapid antigen test (SRAT), and quantitative reverse transcription polymerase chain reaction (qRT-PCR). Experimentally, PS-SPR exerted high sensitivity to detect SARS-CoV-2 pseudovirus at 589 copies/ml, with 7-fold and 70-fold increase in sensitivity when compared with the two conventional immunoassays, including homemade target-captured ELISA (4 × 10

The SPR phenomenon results in an abrupt change in the optical phase such that one can measure the phase shift of the reflected light as a sensing parameter. Moreover, many studies have demonstrated that the phase changes more acutely than the intensity, leading to a higher sensitivity to the refractive index change. However, currently, the optical phase cannot be measured directly because of its high frequency; therefore, investigators usually have to use complicated techniques for the extraction of phase information. In this study, we propose a simple and effective strategy for measuring the SPR phase shift based on phase-shift interferometry. In this system, the polarization-dependent interference signals are recorded simultaneously by a pixelated polarization camera in a single snapshot. Subsequently, the phase information can be effortlessly acquired by a phase extraction algorithm. Experimentally, the proposed phase-sensitive SPR sensor was successfully applied for the detection of small molecules of glyphosate, which is the most frequently used herbicide worldwide. Additionally, the sensor exhibited a detection limit of 15 ng/mL (0.015 ppm). Regarding its simplicity and effectiveness, we believe that our phase-sensitive SPR system presents a prospective method for acquiring phase signals.

In this investigation, the effect of deposition time (5, 60, or 300 s) on a double-sided antireflection (AR) coating done by layer-by-layer deposition of polyelectrolyte was determined. The different structures and transmittance of an AR coating induced by electric-field-assisted layer-by-layer deposition (ELBLD) (with voltage of 0.5, 5, 50, or 500 V) and normal deposition (with voltage of 0 V) were compared. The electric field was perpendicular to the glass surface. After 5.5 bilayers of PAH/PAA were fabricated, the film was exposed to an acidic treatment of HCl solution (pH 2.4) for 65 s, followed by a brief rinse (~15 s) in deionized water, blown dry with air, and heat treated at 220°C for 2 h. Regardless of whether the electric field was applied, the average transmittance of visible light of the AR coating was more than 96% except for the reduced transmittance because of the excessive deposition of polyelectrolyte at an applied voltage of 500 V and a deposition time of 300 s. Average transmittance of 97.68 ± 0.31% was obtained at normal deposition of 5.5 bilayers with deposition time of 60 s. The polyelectrolytes had a propensity to form larger particles or accumulate into bundles under ELBLD, which was detrimental to the transmittance of an AR coating. Therefore, at the same deposition time, transmittance values of ELBLD samples were slightly lower than those of normal deposition. In other words, in the overall performance, the AR films of normal deposition are superior to those of ELBLD. The blowing pressure applied to dry the coating had significant impact on the quality of the film.

We present a sprayed composite thin film, comprising Cu−In-Zn−S (CIZS) particles embedded in ZnO matrix for photoelectrochemical hydrogen production from water splitting. CIZS, a photoactive semiconductor was used as a photon absorber, whereas ZnO channels as the pathway for charge transfer. It was found that the distribution of the CIZS particles had a direct impact on the photoelectrochemical (PEC) activity. A more homogeneous dispersion of smaller CIZS particles (0.56 μm) within ZnO matrix exhibited a higher photocurrent density, and 3.27 μmol/ cm2 hydrogen evolution for 5 h. Electrochemical impedance spectroscopy (EIS) was employed to analyze the charge transfer mechanism of this composite thin film. In addition, ZnO coating on top of CIZS particles also served as the adhesion and protection layers. All the PEC experiments were performed in 0.5 M K2SO4 electrolyte. No sacrificial reagents were used. The composite electrode was stable under illumination: 75.67 % of photo-activity remained after 1 h illumination at a bias of 0.2 V vs. SCE. This study demonstrates a simple and low-cost spray preparation of composite thin film consisting of particles embedded in any semiconductor matrix.

The effect of reactive gases—oxygen and hydrogen—on the tunable work function of Al-doped ZnO (AZO) films was studied. An increase in the work function with an increase in the oxygen flow rate was mainly interpreted as reflecting a decrease in the carrier concentration, which was attributed to the filling of oxygen vacancies. However, a decrease in the carrier concentration would result in the resistivity increasing sharply. This article presents a new concept for improving the performance of organic light-emitting diodes (OLEDs) through easy and effective hole injection from a multilayer AZO anode to the organic layer. A bilayer AZO film prepared using a tunable work function technique was used to modify the surface of AZO anodes and to ensure that the anodes had low resistivity. The AZO anode stacked with high-work-function AZO films, similar to hole transport buffer layers, had a low turn-on voltage of 2.89 V, and its luminance efficiency and power efficiency were 5.01% and 6.1% greater than those of tin-doped indium oxide anodes used in OLEDs.

This study focuses on the SiOx:C thin films on polyethyleneterephtalate (PET) produced by radio-frequency (RF) magnetron sputtering with hexamethyldisiloxane (HMDSO). Silicon atoms are inserted into SiOx:C thin films using a silicon target to improve the gas barrier property. Since inserting Si atoms into SiOx:C thin films can reduce the number of pores and increase the density of the film. This process has two benefits. First, it can be easily combined with sputtering processes to produce a multilayer film; and second, it can be performed at low pressures (~ 10 − 1 Pa) to improve the quality of the plasma polymer film. A more linear-like structure and a less cage-like structure is associated with higher density of SiOx:C thin films. The average transmittance of the films thus obtained exceeds 91% in the wavelengths of visible region, and the lowest water vapor transmission rate achieves 0.076 g/m 2 /day. It is about one fourth of the optimum WVTR value (0.3 g/m 2 /day) of a single layer of SiOx:C thin film fabricated with HMDSO at present.

This study aims to discuss the sheet resistance of ultrathin indium tin oxide (ITO) transparent conductive films during the postannealing treatment. The thickness of the ultrathin ITO films is 20 nm. They are prepared on B270 glass substrates at room temperature by a direct-current pulsed magnetron sputtering system. Ultrathin ITO films with high sheet resistance are commonly used for touch panel applications. As the annealing temperature is increased, the structure of the ultrathin ITO film changes from amorphous to polycrystalline. The crystalline of ultrathin ITO films becomes stronger with an increase of annealing temperature, which further leads to the effect of enhanced Hall mobility. A postannealing treatment in an atmosphere can enhance the optical transmittance owing to the filling of oxygen vacancies, but the sheet resistance rises sharply. However, a higher annealing temperature, above 250°C, results in a decrease in the sheet resistance of ultrathin ITO films, because more Sn ions become an effective dopant. An optimum sheet resistance of 336 Ω/sqr was obtained for ultrathin ITO films at 400°C with an average optical transmittance of 86.8% for touch sensor applications.

White-light scanning interferometry (WLSI) is often used to study the surface profiles and properties of thin films because the strength of the technique lies in its ability to provide fast and high resolution measurements. An innovative attempt is made in this paper to apply WLSI as a time-domain spectroscopic system for localized surface plasmon resonance (LSPR) sensing. A WLSI-based spectrometer is constructed with a breadboard of WLSI in combination with a spectral centroid algorithm for noise reduction and performance improvement. Experimentally, the WLSI-based spectrometer exhibits a limit of detection (LOD) of 1.2 × 10−3 refractive index units (RIU), which is better than that obtained with a conventional UV-Vis spectrometer, by resolving the LSPR peak shift. Finally, the bio-applicability of the proposed spectrometer was investigated using the rs242557 tau gene, an Alzheimer’s and Parkinson’s disease biomarker. The LOD was calculated as 15 pM. These results demonstrate that the proposed WLSI-based spectrometer could become a sensitive time-domain spectroscopic biosensing platform.

High absorptivity and low emissivity are characteristics needed in an ideal solar selective absorber. In high-temperature applications, such as a solar concentration power system in which the solar surface works under a long-term high temperature (about 400 to 800 &deg, C), the absorber material has to maintain high absorption in the visible region, high reflectance in the infrared region, and excellent thermal stability at high temperature. In this research, the design of a molybdenum-based (Mo-based) solar selective absorber was analyzed by the admittance locus method, and the films were deposited by magnetron sputtering. The ratio of the extinction coefficient to the refractive index of the Mo layer was close to 1, so that the Mo-based solar selective absorber had a broad absorption band, high absorption, and good solar selectivity. Its average reflectance in the visible region was less than 0.4%. The experimental absorption was 97.1% (simulated absorption was 98%) and the emissivity was from 13% to 20% (simulated emissivity was 8% to 26%) as the temperature increased from 400 to 800 &deg, C.

The article investigated the dependence of the sensitivities of the Fourier amplitude and nonlinear phase spectra on the thin-film properties. A method has been applied to measure organic thin-film thickness profile and refractive index.

Optical monitoring plays an important role in film deposition. In this study, an optical monitoring method which can work out the refractive index of material in real-time improves the quality of narrow-band pass filter effectively.

Plasma-assisted thermal chemical vapor deposition (CVD) was carried out to synthesize high-quality graphene film at a low temperature of 600°C. Monolayer graphene films were thus synthesized on Cu foil using various ratios of hydrogen and methane in a gaseous mixture. The in situ plasma emission spectrum was measured to elucidate the mechanism of graphene growth in a plasma-assisted thermal CVD system. According to this process, a distance must be maintained between the plasma initial stage and the deposition stage to allow the plasma to diffuse to the substrate. Raman spectra revealed that a higher hydrogen concentration promoted the synthesis of a high-quality graphene film. The results demonstrate that plasma-assisted thermal CVD is a low-cost and effective way to synthesis high-quality graphene films at low temperature for graphene-based applications.

The work function can be adjusted by the different oxygen and hydrogen flow rate. This is a very promising technology which could be matched with electrode to increase the conductivity and transparency in these devices.

A magnetron sputtering system with plasma polymerized organic monomer was developed. The barrier films, the best WVTR value of 7.6*10-2 g/m2/day, was deposited by magnetron sputtering coupled with HMDSO/O2 plasma polymerization.

We have designed and fabricated the low-polarizing X-plate to increase the luminous throughput for LED projector. We calculate reflectivity characteristic of X-plate as a function of the wavelength at different angles of incidence from air of unpolarized light. A new way to design filter to control the title effect of thin film filters. The wavelength shift of the new design for reflected red filter and reflected blue filter at the angle of 45° ± 8° is 16 nm and 14 nm, respectively.

Low resistivity and high transmittance of Al-doped ZnO (AZO) and Ga-doped ZnO (GZO) transparent conductive thin films have been achieved by use of pulsed dc magnetron sputtering in a hydrogen environment at room temperature. The addition of hydrogen to the sputtering gas can reduce the resistivity of the films and improve their electrical properties compared to those prepared without H2, because the hydrogen acts a shallow donor. The average transmittance was over 85% in the visible region, and the lowest resistivity of the AZO and GZO films was 4.01×10(-4) (Ω-cm) and 4.39×10(-4) (Ω-cm), respectively.

Nb doped TiO 2 (TNO) is a promising transparent conducting oxide suitable for many applications such as in solar cells, OLEDs, LEDs, FPDs, touch panels, etc. TNO thin film was deposited on an unheated glass substrate by pulsed direct current (DC) magnetron co-sputtering. After annealing in a vacuum ( -6 Torr) at 370° for 10 minutes, the film crystallized into a polycrystalline anatase TiO 2 structure, the resistivity decreased to 4.5×10 -4 Ω-cm and the average transmittance increased to above 70% in the visible light region. The influence of annealing on the TNO amorphous-to-anatase phase transition, decrease in the resistivity and increase in the average transmittance will be discussed.

Low resistivity and high transmittance of Al-doped ZnO and Ga-doped ZnO transparent conductive thin films have been achieved by a pulsed DC magnetron sputtering in various hydrogen ambient at low temperature.

The well-known indium-tin-oxide is not suitable for solar cell, because of the chemical reduction, even without any hydrogen dilution. The inexpensive and non-toxic of transparent conducting Aluminum and Gallium doped ZnO (AZO and GZO) thin films have been investigated for the substitutes for the indium-tin-oxide thin films. AZO performs high transmittance at visible region, however, higher resistance than GZO. In this study, AZO and GZO composed film (GAZO) will be fabricated using DC magnetron co-sputtering deposition system to achieve lower resistance than AZO and higher transmittance than GZO. The optical and electric properties of different thickness of GAZO such as transmittance, reflection, carrier concentration, Hall mobility, and resistivity will be measured and analyzed.

A method to measure thin-film thickness, refractive index, and dispersion constants based on white-light interferometry is described. The thin-film property is retrieved from the Fourier amplitude of the white-light correlogram. The sources of errors in Fourier amplitude, which include the accuracy of wave number, light source variation in time, and illumination nonuniformity, are investigated. With all these errors reduced, the film thicknesses and refractive indices of four samples measured by white-light interferometry are within 1% of the ellipsometry results.

This article has shown that the co-sputtering method and post-annealing treatment have successfully fabricated the transparent conductive distributed Bragg reflectors (TCDBR). The transparent conducting film, anatase Nb-doped TiO2 (TNO), which has a high refractive index can be combined with Al-doped ZnO (AZO) low refractive index transparent conducting films to make a TCDBR capable of transferring the current from electrode to semiconductor while still maintaining the advantage for the micro resonant cavity. The eight-period stack of AZO/TNO achieves a reflectivity of up to 90% centered at 550 nm and a resistivity of 1.88×10-3 Ω cm.

Low resistivity Nb-doped TiO2 transparent conducting oxide (TNO) thin films have been achieved by a pulsed dc magnetron co-sputtering at room temperature and the annealing treatment. Pulsed dc power provides the stabilization of reactive sputtering. The dc power of Nb target is controlled to find the optimum Nb content in TNO films. The carrier concentration is linearly proportional to Nb content in TNO films. The lowest resistivity was measured as 4.55×10-4 Ω cm at 24 W dc power of Nb and the average absorbance in the visible light region was smaller than 8% for different dc powers. The results of contact angle revealed that TNO films still keep the surface hydrophilicity and have the characteristic of photo-catalyst.

An approximate growth model was employed to predict the time required to grow a graphene film by chemical vapor deposition (CVD). Monolayer graphene films were synthesized on Cu foil at various hydrogen flow rates from 10 to 50 sccm. The sheet resistance of the graphene film was 310Ω/□ and the optical transmittance was 97.7%. The Raman intensity ratio of the G-peak to the 2D peak of the graphene film was as high as ~4 when the hydrogen flow rate was 30 sccm. The fitting curve obtained by the deviation equation of growth model closely matches the data. We believe that under the same conditions and with the same setup, the presented growth model can help manufacturers and academics to predict graphene growth time more accurately.