Fabrication and analysis of dye-sensitized solar cell using natural dye extracted from dragon fruit

Dragon fruit dye has been prepared and used in the fabrication of DSSC as sensitizer. The properties of dragon fruit dye have been investigated by UV-Vis and FTIR technique. The absorption spectrum shows a peak value of 535 nm. Chemically dragon fruit dye shows present of intermolecular H-bond, conjugate C=O stretching and esters acetates C-O-C stretching vibration, which is due to the component of anthocyanin. On the other hand, the resistivity of TiO2 film on ITO glass before it is used for the fabrication of DSSC is also investigated. The TiO2 sheet resistivity increase from 1 layer = 22.1 Ω cm to 2 layers = 369.6 Ω cm. Finally, the efficiency of assemble DSSC was evaluated and simulated using a custom made technique. The result shows fill factor, Pmax and efficiency during the present of halogen lamp are 0.30, 13 μW, 0.22%, respectively. We have successfully showed that the DSSC using dragon fruit as a dye sensitizer is useful for the preparation of environmental friendly and low-cost DSSC

Structural and Electrical Properties of TiO2 Thin Film Derived from Sol-gel Method using Titanium (IV) Butoxide

Fabrication of titanium dioxide (TiO2) thin film on microscope glass using sol-gel method has been studied intensively. The starting materials were titanium (IV) butoxide, ethanol, acetic acid, triton x-100, hydrochloric acid and deionized water. The materials were mixed together to form the sols. Then, the heat and ageing treatment was applied to form stable sols. The sols were then spin coated on the glass substrate to form the homogenous and transparent TiO2 thin film. The TiO2 thin film was coated at several layers using specific conditions. To evaluate the performance of thin film, the crystallinity of the thin film was determined by using the x-ray diffractometer  (XRD). The change on the surface morphology was observed using atomic force microscope (AFM). The electrical property of the thin film was determined by doing the current-voltage (I-V) analysis on the thin film. It has been successfully shown that the anatase crystalline phase was observed when the TiO2 thin film was heated at 500°C. The roughness and the crystalline phase of TiO2 thin film changed drastically with the growth conditions. Finally, the effect of film preparation to the film resistivity also showed a critical aspect where we should take into account during the preparation of TiO2 thin film

Indium tin oxide thin films: an ideal transparent and conductive oxides contact for solar cells application

Transparent and conducting oxides (TCOs) materials usually demonstrates simultaneously an exceptional properties such as high optical transmittance and good electrical conductivity[1]. TCOs materials have attracted a lot of interest, since after the first report of transparent and conductive cadmium oxide films in 1907 [2]. The increasing demands and advancement of optical and optoelectronic devices such as portable and flexible electronics, displays, solar cells, multi-functional windows and not long ago the transistors are some of the reasons for the huge interest [2,3]. Furthermore, the integration of different materials like metals, semiconductors, ceramics, plastics molecular and polymer organics into these devices have called for the provision of an improve TCO materials with required functional morphology, high performance and new processibility [5]

Study on morphological properties of polyvinyl alcohol/poly(lactic acid) wound dressing membrane as drug delivery carrier in wound healing treatment

Wound dressing have experienced continuous improvement and changes since ancient time. Electrospinning of polymeric nanofibers have captured the interest of researchers due to its simplicity and cost effective technique that able to produce wound dressing membrane that meet the requirement as ideal wound dressing and drug delivery carrier. In this work, polyvinyl alcohol (PVA) and poly (lactic acid) (PLA) were chosen polymer to produce wound dressing membrane through electrospinning and coating method. PVA was electrospun and then coated with PLA. Preliminary study had been conducted between 1, 4 and 8% concentration for the selection of optimum PLA coating concentration. PLA has been proposed for the use of coating materials at 4%, the coated nanofiber membrane started to exhibit high Ultimate Tensile Strength at 1022.5 ± 9.28 MPa, highest degree of swelling (1850 ± 3.7 %) and optimum water contact angle (60.9 ± 11.46 ̊). The aim of this study was to investigate the morphological properties of PVA/PLA wound dressing membrane. Based on the results from Atomic Force Microscope, PVA nanofiber coated with 4% PLA exhibit the highest value of Rq which is 0.47 ± 0.19 μm compared to neat PVA nanofibers membrane. Field Emission Scanning Electron Microscope (FE-SEM) image revealed that PVA nanofiber coated with 4% PLA shows porous fiber-like morphology and well incorporated with each other without any gap formed between them. This report clearly suggestive of the fact that synthetic biodegradable polymers such as PLA can be exploited for the synergistic combination with PVA nanofiber for wound dressing application

Design and Etching of Bandpass FSS in Hard‑Coated Energy‑Saving Glass to Improve Transmission of Useful RF/MW Signals

An efective etching method is proposed to create frequency-selective Surface (FSS) on energy-saving glass (ESG) for the improvement of RF/MW signals ranging from 0.5 GHz to 5 GHz. ESG is commonly used in buildings to reduce energy consumption, but the coating on it blocks frequencies from 0.5 GHz to 5 GHz, causing problems in communication systems. The unit cell of the proposed FSS design was modeled and simulated in CST Microwave Studio, and the results were verifed through experimental work. The results showed that the proposed design provided full transmission for the entire microwave band from 0.5 GHz to 5 GHz, including GSM, 3G, 4G, and personal communication signals. The proposed method involves etching the FSS pattern on ESG with a cutting width of 1 mm by using a glass cutter tool. The design is angle- and polarization-insensitive, as it provided angular stability from 0° to 45° oblique incidence for both transverse electric (TE) and transverse magnetic (TM) modes. Moreover, only 9.03% of the ESG coating was removed, which is acceptable in terms of heat loss compared to recent research. On average, there is an improvement of about 18 dB in attenuation for the entire band as compared to full coating. This method outperforms previous etching techniques, as full transmission is achieved for the entire band and not just for some specifc bands. Moreover, a complete sample of the ESG was etched and used in measurements instead of a small portion of the ESG as used by other researchers. The measured results are in good agreement with simulations. A stable frequency response under oblique incidence was achieved for both the TE and TM polarization

Study on Morphological Properties of Polyvinyl Alcohol/Poly(lactic acid) Wound Dressing Membrane as Drug Delivery Carrier in Wound Healing Treatment

Wound dressing have experienced continuous improvement and changes since ancient time. Electrospinning of polymeric nanofibers have captured the interest of researchers due to its simplicity and cost effective technique that able to produce wound dressing membrane that meet the requirement as ideal wound dressing and drug delivery carrier. In this work, polyvinyl alcohol (PVA) and poly (lactic acid) (PLA) were chosen polymer to produce wound dressing membrane through electrospinning and coating method. PVA was electrospun and then coated with PLA. The aim of this study was to investigate the morphological properties of PVA/PLA wound dressing membrane. Based on the results from Atomic Force Microscope, PVA nanofiber coated with 4% PLA exhibit the highest value of Rq which is 0.47 ± 0.19 μm compared to neat PVA nanofibers membrane. Field Emission Scanning Electron Microscope (FE-SEM) image revealed that PVA nanofiber coated with 4% PLA shows porous fiber-like morphology and well incorporated with each other without any gap formed between them. This report clearly suggestive of the fact that synthetic biodegradable polymers such as PLA can be exploited for the synergistic combination with PVA nanofiber for wound dressing application

The effect of deposition time on the properties of titanium dioxide thin film prepared using CVD

This research aimed to investigate effect of deposition time on the structural, morphological properties and optical properties of the titanium dioxide (TiO2) thin film prepared using Chemical Vapour Deposition (CVD). This research involved two processes which are samples preparation process and characterisation process to fulfil the aim. The samples preparation process was done by synthesising TiO2 on indium thin oxide (ITO) substrates heated at 60 ̊C substrate temperature. Titanium butoxide used as the precursor for this chemical reaction was volatilised at 210 ̊C. Oxygen gas was flown at 1 litre per minute as the carrier gas. In order to study the effect of deposition time, the synthesise of the thin films were varied to 15, 30, 45 and 60 minutes. After synthesising process, the samples underwent thermal treatment via annealing process for 1 hour at 500 ̊C. For the characterisation process, Raman Spectroscopy technique was employed to investigate the structural properties of the samples. Apart from that, Field Emission Microscopy (FEM) technique, which was performed via FE-SEM, was employed to investigate the morphologies of the samples. Other than that, UV-Vis spectrometry was employed to analyse the optical properties of the samples. Analysis of data from Raman spectroscopy displayed four Raman Shifts for each sample which confirms that the samples exhibit TiO2 of anatase phases. Whereas, images from FE-SEM displayed reduction of nanoparticle clusters on the samples as the rate of deposition time increases. Meanwhile, UV-Vis analysis displayed transmittance of the samples ranging between 50% to 80% transmittance and each sample exhibits the same optical band gap at 3.25 eV

Study On the Uniformity Aluminum Nitrate Thin Film On 2-Inch Silicon Substrate Prepared by RF Magnetron Sputtering

Aluminum nitrate (AlN) has attracted the researcher's interest due to its unique properties in the semiconductor material and other high-performance devices. This results in numerous techniques to investigate the uniformity of AlN thin film. The deposition in this study is carried out on an AlN on a 2-inch silicon substrate using a magnetron sputtering technique. The RF magnetron sputtering can also produce better film quality and deposit a wide variety of insulators, metals, alloys and composites. In this study, the AlN film was deposited using the RF magnetron sputtering by using three different parameters for the growth of the AlN on the 2-inch Si substrate for uniformity analysis. The uniformity of AlN thin film includes analyses of  the structural, thickness, topology and surface morphology by using the characterization of X-ray diffraction (XRD), atomic force microscopy (AFM), surface profiler and field emission scanning electron microscopy (FE-SEM). Based on the result from three parameters that have been done, parameter one shows the best results. For the crystalline structure results, the peak (100) AlN indicates the highly textured phases similar to a single crystal, and the cross-section result in FE-SEM shows the homogenous thickness

Sharp edges schottky contact electric field simulation

This paper reports investigation on effect of adding sharp edges to Schottky contact. Few studies suggested that sharp edge nanostructures produces high electric field which subsequently improve gas sensing performance on reversed biased mode. Three different shapes: circular-, hexagon- and star-shape were modeled by using COMSOL Multiphysics. The study on effects of different sizes sharp edges Schottky contact also reported. Electric field was observed and it shows that star-shape yields highest summation of electric field 2.79 x 109 V/m and lowest electric field observed at circular-shape 7 x 107 V/m. The results also revealed that distance of sharp edges from substrate edge affects the magnitude of electric field

Nanofabrication Process by Reactive Ion Etching of Polystyrene Nanosphere on Silicon Surface

Nanospheres made of organic polymer have been applied to generate various patterning mask in fabricating functional nanostructures. The patterning and generation of semiconductor nanostructures through nanospheres mask provides a potential alternative to the conventional top-down fabrication techniques. Polystyrene nanosphere was modified using reactive ion etching (RIE) with O2 plasma at various duration of exposure (0, 20, 40 sec) and further extended to produce nanostructure by employing combination of O2 and mixed CHF3/SF6 gases. These edge PS nanospheres are later reduced as nanostructures and characterized using various characterization techniques such as Field Emission Scan Electron Microscopy/Energy Dispersive X-ray Spectroscopy (FESEM)/EDS, Atomic Force Microscopy and Fourier Transformation Infrared Spectroscopy (FTIR). The potential for multi stages etching procedures of O2 and later with SF6/CHF3 plasma etching are found to modify the nanospheres shapes and sizes which are important either as secondary mask for metal evaporation or as direct patterning of carbonaceous materials when exposed to irradiation sources. The nanostructures made using RIE will have applications in low power high performance electronic devices, optoelectronic, photovoltaic, biosensors and lithium ion battery devices