Samiksha Sikarwar

Carbon Nanotube: Synthesis and Application in Solar Cell

Carbon nanotubes and fullerenes have a cylindrical and hollow spherical molecular structure with outstanding mechanical and electronic properties. Their versatility is outstanding and envisioned by the wide application range from field emission displays to impregnated metal composites, battery storage media, and nano-electronic devices. The combination of simple materials, diverse behavior, and ease of fabrication make these materials a cornerstone topic in current research. They have very wide applications in electronic devices and identifying the potential applications which is due to low bias transport at several nanometers. Since valance and conduction bands are symmetric, so they have a direct band gap and due to this it can be used in optical emission. CNTs can be synthesized via three techniques such as arc discharge, laser ablation and chemical vapor deposition, but the CVD process is mainly used for the synthesis because the CNT yield in such case will be more than 98xa0% pure. 100xa0% pure MWCNTs having multiple chirality results the enhanced optical property and better employment as light harvesting material. The dye sensitized solar cells are fabricated using CNT composites and functionalized nanotubes. The synthesis of CNT and its application in solar cell are presented in this short review.

Growth and characterization of sol–gel processed rectangular shaped nanostructured ferric oxide thin film followed by humidity and gas sensing

In the present work nanostructured ferric oxide has been synthesized using sol–gel method. Thin films of ferric oxide were fabricated via spin coating process. The surface of the thin film was scanned by scanning electron microscope that exhibited the surface morphology of ferric oxide nanostructures. The material was also characterized by XRD, Acoustic particle sizer and FTIR. All the particles distributed on the surface have some spaces among them known as pores. These pores serve as adsorption sites for moisture and other gases. EDX confirmed the elements forming the ferric oxide in pure form. The particle size of the ferric oxide was estimated as ~12.2xa0nm. The pore size of the film was ~50xa0nm i.e., nature is mesoporous. Annealing effect on the surface morphology was also observed. Humidity sensing, electrical as well as optical of the prepared film was carried out. The results showed the suitability of material for the development of humidity sensors. Variations in resistance with the exposure of LPG were recorded and found that resistance of film increases with the increasing exposure time and concentration of gas. The maximum sensing response of the sensor was recorded as 3.26 for 1000xa0ppm at room temperature. The response and recovery times of the sensor were found to be ~12 and 9xa0min, respectively.

Preparation of zinc (II) nitrate poly acryl amide (PAAm) and its optoelectronic application for humidity sensing

The present paper reports the investigation of transmitted power through the nanostructured zinc (II) nitrate polyacrylamide deposited substrate to investigate the adsorption/desorption ofxa0humidity at room temperature. For this purpose, the precursor of Zn(NO3)2·(AAm)4·2H2O was prepared and used for the deposition of films on borosilicate flat substrates. The film was then investigated using SEM, XRD and UV–Vis absorption techniques. Scanning Electron Microscope showed the macroporous nature of the film with multiple pores in situ. XRD revealed the nature of monomer and polymer. Energy band-gap of the film was estimated as 3.865xa0eV by UV–Vis spectrophotometer. SAED confirmed the crystalline nature of the material. From Zeta nanosizer, the minimum range of particles was found as 5–20xa0nm. The film was employed as transmission based opto-electronic humidity sensor. Maximum sensitivity was found as 1.831xa0µW/%RH. Response and recovery times of the sensor were found as 250 and 37xa0s respectively. Experiments were repeated time to time and found that the sensor was ~u200996% stable after a long run. Thus the investigated opto-electronic sensor being polymeric is flexible in nature.

Synthesis and investigation of cubical shaped barium titanate and its application as opto-electronic humidity sensor

In the current scenario, nanoscience and nanotechnology are playing a vital role in the upliftment of the quality of human life. The quantum confinement effect that arises at the nano-dimensional particles, changes the properties of the material in a drastic way. The present paper reports the successful synthesis of BaTiO3 using rotary evaporator and fabrication of sensing elements by deposition of films on flat borosilicate glass substrates using 2-methoxy ethanol and homogeneous precursor in the ratio of 1:4, 2:4, 3:4 and 4:4. These films were then annealed at 650xa0°C and characterized through various techniques. Morphological investigation as obtained from SEM reported the cubical clusters and the dimensionality of these clusters, decreases with increase in the concentration of 2-methoxy ethanol. An optical investigation done through UV–Vis spectrum showed the absorbance in the UV range and Tauc plot estimated the optical band gaps of 3.842, 3.854, 3.864 and 3.872xa0eV for the respective films. Structural information as obtained from XRD of the film having 2-methoxy ethanol and homogeneous precursor in the ratio of 4:4 gave minimum crystallite size of ~u200918xa0nm. Further, these films were employed as opto-electronic humidity sensor where the maximum sensitivity of the sensing elements was found as 2.15, 2.79, 3.28 and 3.67xa0µW/%RH respectively. Thus as the concentration of 2-methoxy ethanol in the solution increases, the properties of the material increases and hence the humidity sensing potency also increases.

Synthesis and characterization of nanostructured MnO2–CoO and its relevance as an opto-electronic humidity sensing device

Metal carboxylates are widely used in science and technology and have been the subject of intense studies due to the practical importance of their products. The present paper reports the synthesis of MnO2–CoO using metal carboxylates as precursors and the effect of humidity on the transmitted power through its thin film at room temperature. The refractive index of the material was found to be 1.445930 and the peak obtained from the photoluminescence spectra lies in the visible region. TEM reported a minimum grain size of ∼5.7 nm and SAED confirmed the crystalline nature of the material, which was further confirmed by XRD. Fluorescence characteristics also confirmed the low dimensionality of the material. The film was then investigated using SEM which exhibited the porous morphology. Through UV-Vis spectroscopy, it was found that the absorption of the film takes place in the UV region and the optical band-gap was observed to be 3.849 eV from the Tauc plot. The film was employed as a transmission based opto-electronic humidity sensor. Average sensitivity was found to be ∼2.225 μW/% RH with response and recovery times of 47 s and 59 s respectively. Experiments were repeated and the reproducibility of result was found to be ∼89%.