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Perovskite solar cell with carbon nanotube (CNT) is the most current research interest in the field of photonics and renewable energy. Recently many researchers are trying to incorporate several types of CNTs in different layers of solar cell to enhance the efficiency. In this work the effect of CNT chirality for incorporating semiconductive CNT in active layer of perovskite solar cell is simulated to comprehend the optimization dependencies to attain better cell performance parameters. Also the efficiency of solar cell is increased for incorporating CNT in the active layer of solar cell. Single chiral semi-conductive single wall CNTs with diameter range from 0.28 nm to 1.04 nm as well as a cell structure is considered which consists of $\mathrm {C}\mathrm {H}_{3}\mathrm {N}\mathrm {H}_{3}\mathrm {P}\mathrm {b}\mathrm {I}_{3}$ active layer and Spiro-MeOTAD hole transport layer. Open circuit voltage, short circuit current density and absorption coefficient are determined for CNT chirality variation. To calculate fill factor and power conversion efficiency equivalent circuit parameters are extracted. Maximum open circuit voltage and fill factor are determined as 1.33 V and 0.79 for (4,3) chirality respectively. Also short circuit current density up to 25.44 mA/cm2 and efficiency to 21.84% can be maximized for (6,4) CNT chirality. Finally it is perceived that by changing CNT chirality efficiency can be increased by a range of about 74.7%.

In this work, density functional theory is used to study the effect of finite length on electronic property of different types of Single Walled Carbon Nanotubes (CNT). The change in band gap due to short length effect in case of metallic (5,2) CNT and semiconducting (4,5) CNT is discussed here. Ordinarily electrons are restricted along the circumference of carbon nanotubes. But in this investigation a supplementary restraint of electrons has been applied along the axis of tube by making the tube lengths short. Due to this short length effect, band gap value of both types of CNT reduces as length of the tube increases. But this change is not tedious. Rather it exhibits observable oscillations in short length. These oscillations have been interpreted with reference to the bonding characteristics of frontier orbitals. This investigation providing novel acumen into the large band gap opening of chiral CNTs could be valuable in advancing future applications of CNTs in optical, electronic devices.

Multiwall Carbon Nanotube (MWCNT) thin films were electrodeposited on Indium Tin Oxide (ITO) substrate. The effects of 0.1 % solutions of MWCNT incorporation in methanol with and without 1 mg red phosphorus doping were investigated. The electrodeposited MWCNT films were characterized by current density in methanol solution, SEM and UV-VIS-IR spectroscopy. During deposition in methanol solution a moderate current density in liquid phase was found. By incorporation of MWCNT in methanol the current density increases. The current density also increases by doping red phosphorus in methanol with and without MWCNT. In SEM micrographs, changes were observed in the electrodeposited films compared to pure ITO substrates. Red phosphorus doping make changes in SEM. From the UV - VIS-IR measurement it was observed that absorption increases using methanol in UV - VIS range but decreases in IR region from that of pure ITO. After doping red phosphorus in methanol absorption decreases all through UV-VIS-IR from that of pure ITO. By phosphorus doping with MWCNT, absorption decreases slightly from the films of undoped MWCNT. So the optoelectronic properties of the electrodeposited films are tunable by MWCNT incorporation on ITO substrates.

Equivalent circuit parameters are very important to simulate the performance of perovskite solar cell to achieve the finest working condition. Being the present research interest extraction of these parameters for perovskite solar cell are limitedly reported. So in this work, device parameters of previously reported carbon nanotube incorporated perovskite solar cell are extracted using Newton-Raphson method. Cell structure and the effect of incorporating carbon nanotube in different layer of perovskite solar cell are studied based on these parameters.

By introducing a sub-wavelength square nanohole in a semitransparent thin silver film, the penetration depth and the propagation length of the evanescent field can be reduced remarkably, confining the excitation field to a very small region. The excitation volume in the proposed structure is reduced to only 1.8% of the analyte volume excited in the conventional fluorescence spectroscopy structure based on surface plasmon coupled emission (SPCE) technique. Additionally, the proposed structure does not require hemispherical glass substrate for the wavevector match, since normally incident light beam can excite the surface plasmon mode at the aperture walls, rendering the device size to micrometer scale. Moreover, for the optimized dimensions of the nanohole, the peak excitation field is found to be ~3.3 times stronger than the peak evanescent field obtainable in the conventional arrangements. With reduced device size, increased resolution and enhanced field strength, the proposed structure will find applications in chip array implementation of florescence microscopy, and variants of SPCE based single molecule detection (SMD).

In this paper, we have investigated the non-ballistic properties of Silicon Nanowire Field Effect Transistor (SiNW-FET) which has significant potential in future nanoelectronic applications. Our first goal is to study the effects of non-ballistic properties like elastic scattering and strain effect. The study reveals that elastic scattering decreases the drain current whereas tensile strain tends to increase it. Secondly, effects of change in drain voltage and temperature on SiNW-FET's non-ballistic I-V characteristics have been studied in this paper. It has been observed that the degree of ballisticity decreases with the increase of temperature for lower drain bias but increases with temperature for higher drain voltage. Finally, we have studied the ballisticity for Carbon Nanotube Field Effect Transistor (CNT-FET). It has been shown that SiNW-FET exhibits better performance than CNT-FET for the combined non-ballistic effects as the degree of ballisticity is higher for the former.

Zigzag carbon nanotubes possess special structural symmetry and some unique characteristics among three categories of single wall carbon nanotubes (SWCNTs). In this work, a quick method to calculate the first five optical transition energies of semiconducting zigzag and nearly zigzag SWCNTs is presented. Using the proposed method, the transition energy of any semiconducting zigzag and nearly zigzag SWCNT can be predicted directly just by knowing its first chiral index. The predicted results are compared with recent experimental data and found to be accurate over a wide diameter range. The proposed method can help finding the relation between geometric structure and optical properties of zigzag SWCNTs. It is also helpful for the applications of SWCNTs where information of optical transitions of a semiconducting zigzag nanotubes is needed.

This paper presents optimization of various parameters of carbon nanotube field effect transistor (CNFET) based op amp in sub-10 nm node for high frequency operation. Parameters such as, channel length, gate oxide thickness, gate dielectric constant, spacer doping, spacer dielectric constant and pitch, are optimized. For high frequency operation of op amp, optimum values of CNFET parameters are found to be 10 nm channel length, 10 dielectric constant of gate oxide, 3 nm gate oxide thickness, 5 nm pitch, zero source/drain doping concentration, 4 dielectric constant of spacer oxide. Performance of CNFET op amp incorporating these optimum values is investigated and compared with previous work. Obtained results reveals significant differences among previously designed Si CMOS op amp, 32 nm CNFET and the sub-10-nm CNFET op amp investigated here.

In this paper the delay occurring in SWCNT bundle interconnect is analysed based on process related parameters and it is also compared to copper wire. The circuit parameters are calculated to develop an equivalent RLC model for both SWCNT and copper considering the practical constraints. This model is used to calculate the delay for local, intermediate and global interconnects by varying the bundle density and contact resistance. The relative effect of circuit parameters is analysed for different technology nodes. This paper also points out the most important parameter affecting the performance. Similarly, the equivalent circuit model for copper interconnect is developed and the delay is determined. The comparison of copper and CNT interconnect shows that the delay for CNT can be up to 2 times more than copper in local length. The delay of CNT interconnects in 16nm, 22nm and 45nm is less than copper in intermediate range. For global interconnects, the SWCNT delay is 0.3–0.5 times less than the delay of copper wire.

Bangladesh, a subtropical country located not very far from the equator, has certain geographical advantages in solar energy generation. But, as the solar energy generation is not as robust as other forms of energy, the solar systems must be optimally installed to reap every physical benefits possible. One very important factor in this matter is the tilt angle of the solar panel. This paper focuses on finding the optimum tilt angle for a solar panel in a particular region. The paper finds the optimum tilt angles for various divisions of Bangladesh using two methods: one optimum tilt angle for a whole year, and two tilt angles for two halves of a year. The paper demonstrates the benefit of using two seasonal tilt angles instead of using just one tilt angle throughout the year. The paper additionally checks the extent of benefit that might occur from using more complex systems involving more tilt angles.

Multiwall Carbon Nanotube (MWCNT) films were spincoated on Silicon (Si) substrate. The effect of 0.1% and 0.2% solutions of MWCNT incorporation with methanol were investigated. The spincoated MWCNT films were characterized by SEM and UV-VIS-IR spectroscopy. In SEM micrographs, changes were observed in the spincoated films compared to pure Si substrates. Existence of carbon nanowire was also observed in SEM micrograph. From the UV-VIS-IR measurement it was observed that the absorption of light has been increased by the increase of MWCNT. So the optoelectronic properties of the electrodeposited films are tunable by spincoating using MWCNT on Si substrates.

With the advancement of silicon technology having culminated to a point where the scaling limitations of silicon transistors have manifested themselves as being unavoidable, experimentation with Graphene Nanoribbon and Carbon Nanotube field effect transistors has become of the utmost importance. In this paper the effect of gate oxide thickness on the performances of ballistic Schottky barrier Graphene Nanoribbon field effect transistor (GNRFET) and ballistic Schottky barrier Carbon Nanotube field effect transistor (CNTFET) is studied. A comparative analysis is also done on the two kinds of FETs based on the effect of gate oxide thickness. It has been observed that lowering the gate oxide thickness increases the on-state drain current in both the FETs but the effect is larger in CNTFETs. In this paper a graph is plotted calculating the on-off current ratios of the two transistors, further differentiating their performances with various gate oxide thicknesses.

Graphene Nanoribbon (GNR) and Carbon Nanotube (CNT) are currently being considered as two of the most promising options to replace silicon technology. Silicon technology is faced with scaling limits and other material issues which hinder the development of transistor technology. In this paper, the effect of relative dielectric constant on the performances of ballistic schottky barrier Graphene Nanoribbon field-effect transistor (GNRFET) and Carbon Nanotube field-effect transistor (CNTFET) is studied and a comparative analysis between the two transistors is provided. It has been observed that using a gate material with higher relative dielectric constant leads to a higher on-state drain current for both the transistors. However, CNTFET has higher on-state drain current compared to GNRFET. Also in this literature, the on and off-state current ratios of both the transistors are calculated and plotted to further differentiate between the performances of GNRFET and CNTFET.

Multiwall Carbon Nanotube (MWCNT) films were deposited on Silicon (Si) substrate. The effect of 0.1% and 0.2% solutions of MWCNT incorporation with methanol were investigated. pH of various solutions before and after deposition has been analyzed. pH of the solutions was increased after deposition. Change in the variation of current density as a function of applied potential was observed. Current density was increased as the percentage of MWCNT was increased. The electrodeposited MWCNT films were characterized by SEM, UV-VIS-IR and Raman spectroscopy. In SEM micrographs, changes were observed in the electrodeposited films compared to pure Si substrates. Raman measurement proved the amorphous nature of MWCNT in these thin films. From the UV-VIS-IR measurement it was observed that the absorption of light has been increased by the increase of MWCNT. So the optoelectronic properties of the electrodeposited films are tunable by electrodeposition using MWCNT on Si substrates.

The main objective of this paper is to make a detailed modelling of a single solar cell incorporating basic operating equations and include the dependence of cell temperature on irradiance as a combined effect in the model. For this purpose at first the change of open circuit voltage and short circuit current at varying operating conditions like irradiance and temperature is theoretically explored. After that, a simulink model is made using MATLAB to simulate the separate and combined effect of irradiance and temperature on single solar cell and the output curves are analyzed to compare the model with used module's datasheet. Then fall of open circuit voltage with irradiance due to temperature effect is illustrated and explained in detail.

The main objective of this paper is the modeling and analysis of inorganic homo-junction and inorganic-organic hybrid solar cells. For this, an independent model is developed that is capable of simulating the I–V characteristics of any homo-junction solar cell. The efficiency from the model is 14.897% at standard conditions and from PC1D, a commercial software the efficiency is 14.37% under the same conditions. Also hybrid series and hybrid parallel solar cells are modeled. The efficiency of the single inorganic cell is increased from 15% to 19.5% by the hybrid parallel connection.

The overall performance of solar cell varies with varying Irradiance and Temperature with the change in the time of the day the power received from the Sun by the PV panel changes. Not only this both irradiance and temperature affect solar cell efficiency as well as corresponding Fill factor also changes. This paper gives an idea about how the solar cell performance changes with the change in irradiance in reality and the result is shown by conducting a number of experiments. In this paper authors also try to show that parasitic resistance of the solar cell be a function of irradiance that was not considered in any PV model. All effects are observed from 105 W/m 2 to 602 W/m 2 in this experiment.

Carbon nanotube is being considered as a prospective alternative for the existing Silicon technology in present days. The advancement of Silicon technology, at present, has slowed down considerably because of its various material issues and scaling limitations and so, carbon nanotubes have gained the attention of researchers around the world over. In this literature, the effect of change of dielectric constant of the gate material on the performance of carbon nanotube field effect transistor (CNTFET) with non-ballistic conduction is extensively investigated. It is found in this study that with the value of dielectric constant of the gate material greatly improves the current output of CNTFET considering Non-Ballistic conduction. In addition to this, the obtained results are compared with previously reported CNTFET with ballistic conduction data for a better perception of the non-ballistic conduction with effects. Also, the on and off state current ratios have been calculated and plotted in this work to further contrast the ballistic and non-ballistic conduction of CNTFET.

Carbon nanotube is being considered as a prospective alternative for the existing Silicon technology in present days. The advancement of Silicon technology, at present, has slowed down considerably because of its various material issues and scaling limitations and so, carbon nanotubes have gained the attention of researchers around the world over. In this literature, the effect of gate oxide thickness on the performance of carbon nanotube field effect transistor (CNTFET) with non-ballistic conduction is extensively investigated. It is found in this study that with the increase of the gate oxide thickness, the current output of CNTFET considering non-ballistic conduction deteriorates by a significant amount. In addition to this, the results obtained from this experiment are compared with previously reported CNTFET with ballistic conduction data for a better perception of the non-ballistic conduction effects. Also, the on and off state current ratios have been calculated and plotted in this work to further contrast the ballistic and non-ballistic conduction of CNTFET.

In this study, adsorption characteristics of arsenic on commercially produced multiwall carbon nanotube (MWCNT) have been assessed in laboratory experiments. Batch adsorption tests were carried out under different conditions (e.g. varying dispersion time, varying amount of materials) in order to evaluate the suitability of Multiwall Carbon nanotube particles for Arsenite or As(III) removal. Tests were conducted using batch adsorption technique or mixing method. It was found that during the experiment pH was within 7.1–7.3 range. Firstly the dispersion time was varied using MWCNT and it was observed that percentage adsorption was increased with dispersion time. Maximum adsorption was found about 38.37% for 120 minutes dispersion. Secondly the amount of materials (MWCNT) was varied using 542 ppb As(III) contaminated water. Maximum adsorption for MWCNT was about 34.22% using 1g/l concentration. The result reveals that MWCNT can remove arsenic to safe limit for the lower level of arsenic contaminated water.

The chirality (n, m) of single walled carbon nanotubes (SWNTs) in the samples produced by alcohol catalytic CVD method on quartz substrate and by HiPco (High-pressure CO technique) process has been determined using the optical absorption spectra of the samples and the composition in the two samples has been compared. It has been found that, the average diameter for the sample on quartz substrate is around 1.1nm and around 0.95nm for HiPco SWNTs. The relative abundance of nanotubes with respect to band gap energy in the samples has also been showed.

Carbon thin films were deposited on Aluminium(Al), Copper(Cu) and Silicon(Si) substrates by electrolysis of methanol. The effect of camphor (C 10 H 16 O) a natural source, incorporation with methanol is investigated. Camphor with varying amount was mixed in methanol solvent to prepare the electrolytes. Al, Cu and Si substrates were mounted on the negative electrode. Remarkable change in the variation of current density as a function of applied potential was observed with the camphor content. Thin films deposited on Al, Cu and Si substrates for different percentage of camphor are compared. It is found that for all the substrates the current density decreases initially with camphor from that of only methanol solution and increases thereafter. However, there is a limit for camphor to add in methanol solution for increasing current density. The optimum percentage of camphor to get maximum current density was observed to vary with substrate. For both Al and Cu substrates current density was highest for the 2% camphor in methanol solution but for Si substrates current density was highest for 6% camphor in methanol solution. Among the three substrates Si shows highest current densities for all level of voltages. Electron Dispersion Spectroscopy (EDS) analysis of three electrodeposited films were compared. Maximum carbon percentage was found for the electrodeposited films on Si substrates. The films were characterized by Fourier Transform of Infrared (FTIR) spectroscopy. Existence of hydrogenated amorphous carbon (a-C: H) bond were found for the films deposited on Al, Cu and Si substrates. The FTIR spectroscopy also indicates presence of both sp2 and sp3 C-H stretch for the films deposited on Si substrate. But there is no clear indication of the presence of sp2/sp3 C-H stretch for the film deposited on Cu and Al.

This paper describes an effect of articulatory Δ and ΔΔ parameters on automatic speech recognition (ASR). Articulatory features (AFs) or distinctive phonetic features (DPFs)-based system shows its superiority in performances over acoustic features based ASR. These performances can be further improved by incorporating articulatory dynamic parameters into it. In this paper, we have proposed such a phoneme recognition system that comprises two stages: (i) DPFs extraction using a multilayer neural network (MLN) from acoustic features, local features (LFs) and (ii) incorporation of dynamic parameters (Δ and ΔΔ) into a hidden Markov model (HMM) based classifier for more accurate performances. From the experiments on Japanese Newspaper Article Sentences (JNAS), it is observed that the proposed method provides a higher phoneme correct rate and phoneme accuracy over the method that does not incorporate dynamic articulatory parameters. Moreover, it reduces mixture components in HMM for obtaining a higher performance.

In this paper, we have prepared a medium size Bangla speech corpus and compare performances of different acoustic features for Bangla word recognition. Most of the Bangla automatic speech recognition (ASR) system uses a small number of speakers, but 40 speakers selected from a wide area of Bangladesh, where Bangla is used as a native language, are involved here. In the experiments, mel-frequency cepstral coefficients (MFCCs) are inputted to the triphone hidden Markov model (HMM) based classifiers for obtaining word recognition performance. From the experiments, it is shown that MFCC-based method of 39 dimensions provides a higher word correct rate (WCR) and word accuracy (WA) than the other methods investigated. Moreover, a higher WCR and WA is obtained by the MFCC39-based method with fewer mixture components in the HMM.