Nji Raden Poespawati

Maskless localized patterning of biomolecules on carbon nanotube microarray functionalized by ultrafine atmospheric pressure plasma jet using biotin-avidin system

Ultrafine plasma jet is a promising technology with great potential for nano- or micro-scale surface modification. In this letter, we demonstrated the use of ultrafine atmospheric pressure plasma jet (APPJ) for patterning bio-immobilization on vertically aligned carbon nanotube (CNT) microarray platform without a physical mask. The biotin-avidin system was utilized to demonstrate localized biomolecule patterning on the biosensor devices. Using ±7.5 kV square-wave pulses, the optimum condition of plasma jet with He/NH3 gas mixture and 2.5 s treatment period has been obtained to functionalize CNTs. The functionalized CNTs were covalently linked to biotin, bovine serum albumin (BSA), and avidin-(fluorescein isothiocyanate) FITC, sequentially. BSA was necessary as a blocking agent to protect the untreated CNTs from avidin adsorption. The localized patterning results have been evaluated from avidin-FITC fluorescence signals analyzed using a fluorescence microscope. The patterning of biomolecules on the CNT mic...

Optimization of ZnO Seed Layer for Growth of Vertically Aligned ZnO Nanorods on Glass Surface

Vertically well aligned zinc oxide (ZnO) nanorods have been developed for the application to photoanode of dye-sensitized solar cells (DSCs). For the growth of the ZnO nanorods, a seed layer is necessary. Spin coating and chemical bath deposition methods are chosen to form the seed layer and the ZnO nanorods, respectively. The effects of speed and cycle number of spin coating are investigated. The most optimized nanorods was found at seed layer with growing conditions of 3000 RPM rotational speed repeated for 3 times. The SEM image shows the longest length at 1.5 – 2 m length while the XRD chart shows considerable peak at (002) crystallinity.

High Coverage ZnO Nanorods on ITO Substrates via Modified Chemical Bath Deposition (CBD) Method at Low Temperature

In the present work, ZnO nanorods array were successfully grown on ITO substrate via chemical bath deposition method (CBD). The seeding solution was prepared at low temperature (0°C) using zinc nitrate tetrahydrate and hexamethylenetetramine. The as-deposited ZnO nanorods were hexagonal wurtzite structure growing vertically on the substrate. Various reaction times from 3 to 5 hours were applied upon the CBD process at 90°C. The results showed that the duration of reaction time has affected the nanorods array properties. With the increase of reaction time from 3 to 5 hours has increased the diameter and crystallite size of nanorods from 325 to 583 nm, and from 22.68 to 34.28 nm. As a result, the band gap energy, Eg of ZnO nanorods decreased from 3.63 to 3.13 eV.

Investigation on physicochemical properties of plasma-activated water for the application of medical device sterilization

Plasma activated water (PAW) is a new approach to bacterial inactivation while ensuring safety and maintaining the properties of the material sterilized. Reported research imply that PAW has been effective for inactivation of bacteria. In this paper, plasma treatment using atmospheric pressure plasma was demonstrated. Physicochemical properties such as pH, temperature, ORP, and nitrite concentration were assessed. The results suggest that plasma treatment causes acidification on water and generate reactive species, creating an environment suitable for killing bacteria. Therefore, plasma activated water is an assuring method for medical devices sterilization.Plasma activated water (PAW) is a new approach to bacterial inactivation while ensuring safety and maintaining the properties of the material sterilized. Reported research imply that PAW has been effective for inactivation of bacteria. In this paper, plasma treatment using atmospheric pressure plasma was demonstrated. Physicochemical properties such as pH, temperature, ORP, and nitrite concentration were assessed. The results suggest that plasma treatment causes acidification on water and generate reactive species, creating an environment suitable for killing bacteria. Therefore, plasma activated water is an assuring method for medical devices sterilization.

Band-gap optimization for improvement Cu(in, Ga)Se 2 (CIGS) solar cell

Tropical countries, such as Indonesia, need to consider the thread-off between high average solar irradiance throughout the year and the sporadic clouds due to the high rainfall in utilization of solar energy conversion Cu(In, Ga)Se2 (CIGS) with Polyimide substrate is known as one of the materials that produces significant power under low-light and cloudy condition. This 3rd generation solar cell is also promising for thin-film application. Due to Polyimide low thermal stability, a notch problem which significantly affected the current density (Jsc) arose. Single-graded flat-band structure was proven to be an option to solve this situation. In this research, further simulation was run to find the optimum design of this structure.

Comparison of coupling coefficient variation effects on double couplers structured single ring resonator with single and double beams injection

Ring Resonator has become one of the most interesting research topics nowadays since this device has high finesse value at resonance frequency and high sensitivity as well. There have been many scientific publications in the devices characteristic dynamic conditions, structures (single, multi and combination), and their applications as well, such as sensors, filters and others. The performance characteristics of double coupler structured single ring resonator has been discussed so far but the effect of coupling coefficient variation has not been discussed yet. Meanwhile, in previous research we have investigated the effect of coupling coefficient variation on single coupler structured single ring resonator. Now, we explore further the effect of coupling coefficient variation on the power transfer function output of a double couplers structured single ring resonator. Besides, single beam and double beams inputs are utilized to get the transmission powers as the output characteristics from both of drop and through ports of the ring resonator. The simulation results show, for the drop port output, as the higher coupling coefficient is, the peak of the power transfer function output gets higher for both the drop port output of single beam input and double counter directional inputs, but the double counter directional inputs, shows the peak of the power transfer function output much higher compared to its of the single beam input. Meanwhile for through port output, the result with double parallel inputs configuration shows a bit different behavior with its of single beam configuration, where as the result of the double parallel input configuration exhibits peak of the power transfer output almost similar to the simulation result utilizing single ring resonator with single coupler configuration that has already published previously. This simulation works may be useful in the design of resonator performance when transmission power is one of the important parameters to be considered.

A Simple Optimization of Triple-Junction Solar Cell nc-Si:H/a-Si:H/a-SiGe:H Using Computer Modeling and Robust Design

We report for the first time a simple optimization of triple-junction solar cell nc-Si:H/a-Si:H/a-SiGe:H using computer modeling and Robust Design. Firstly we performed a computer modeling of solar cell by wxAMPS software. Subsequently, we investigated the parameters of the solar cell layers and the effect of the solar cell efficiency using Robust Design via Taguchi method, ANOVA and additive model. The results show that the a-Si:H middle absorber cell has the highest contribution of solar cell efficiency at 40.87% and the nc-Si:H n-back layer cell has the second highest contribution of solar cell efficiency at 31.15%. Moreover, the optimum condition for triple-junction solar cell is A2 B1 C2 D2 with solar cell efficiency at 15.73%. These results indicate that Robust Design succeeded predicting the best condition for optimizing triple-junction solar cell nc-Si:H/a-Si:H/a-SiGe:H.

The performance of Si/sub 0.2/Ge/sub 0.8//Si solar cell

Solar cell is optimized to convert solar radiation to electrical current with conversion efficiency as high as possible. Due to their superior performance compared to conventional silicon devices we used the Si/sub x/Ge/sub 1-x/ strained layer for increasing the efficiency of solar cell device. By using simulations tools, i.e. pc1d version 5.6, we investigate and analysis the performance of Si/sub 0.2/Ge/sub 0.8//Si solar cell, especially open circuit voltage, short circuit current, fill factor which will affect the efficiency of the device. We also compare it with conventional silicon solar cell in order to examine their performances and the thickness of both device structures. The Si/sub x/Ge/sub 1-x/ strained layer we applied contents 80% germanium. Results show that by inserting Si/sub 0.2/Ge/sub 0.8/ strained layer in device structure open circuit voltage and short circuit current has been optimal and the thickness of the device compared to conventional silicon solar cell is 1/17 times.