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Review on Cu2SnS3, Cu3SnS4, and Cu4SnS4 thin films and their photovoltaic performance
Vasudeva Reddy Minnam Reddy,Mohan Reddy Pallavolu,Phaneendra Reddy Guddeti,Sreedevi Gedi,Kishore Kumar Yarragudi Bathal Reddy,Babu Pejjai,김우경,Thulasi Ramakrishna Reddy Kotte,박진호 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.76 No.-
The rapid progress on the Cu–Sn–S (Cu2SnS3, Cu3SnS4, and Cu4SnS4) solar cells has opened a new avenueto generate the electrical energy at ultra-low-cost. Therefore, the progress in the deposition of Cu2SnS3,Cu3SnS4, and Cu4SnS4 thinfilms by various chemical and physical methods is reviewed comprehensively. This article briefly describes (i) the phase diagrams of Cu–Sn–S, (ii) the bulk properties of Cu2SnS3,Cu3SnS4, and Cu4SnS4, (iii) the effect of deposition conditions on the phase formation, (iv) the physicalproperties of Cu2SnS3, Cu3SnS4, and Cu4SnS4 thinfilms, and (v) the photovoltaic performance of Cu2SnS3,Cu3SnS4, and Cu4SnS4 solar cells.
Reddy, Andra Naresh Kumar,Sagar, Dasari Karuna The Korea Institute of Information and Commucation 2014 Journal of information and communication convergen Vol.12 No.2
The simultaneous suppression of sidelobes and the sharpening of the central peak in the process of diffraction pattern detection based on asymmetric apodization have been investigated. Asymmetric apodization is applied to a semicircular array of two-dimensional (2D) aperture functions, which is a series of 'coded-phase arrays of semicircular rings randomly distributed over the central circular region of a pupil function' and is similar to that used in the field of diffractive optics. The point spread function (PSF) of an imaging system with asymmetric apodization of the discrete type has been found to possess a good side with suppressed sidelobes, whereas its bad side contains enhanced sidelobes. Further, the diffracted field characteristics are obtained in the presence of these aperture functions. Asymmetric apodization is helpful in improving the performance of the optical gratings or 2D arrays used in real-time imaging techniques.
Reddy, Y. Ashok Kumar,Kang, In-Ku,Shin, Young Bong,Lee, Hee Chul Elsevier 2017 CERAMICS INTERNATIONAL Vol.43 No.12
<P><B>Abstract</B></P> <P>The aim of this paper is to investigate the effects of oxygen atmosphere annealing on the bolometric properties of Nb: TiO<SUB>2−x</SUB> samples for infrared detectors. We conducted the structural and composition analyses of as-deposited and annealed samples. The structural properties demonstrate an improvement in the film crystallinity and the composition analysis confirms the compensation of oxygen vacancies though post-deposition annealing in an oxygen atmosphere. A test device was fabricated to find the bolometric properties of the resistivity, temperature coefficient of resistance (TCR), 1/f noise parameter, bolometric parameter (β) and thermal stability. The logarithmic decrement of the resistivity with the temperature confirms that both the as-deposited and annealed test device samples show typical semiconducting behavior. Meanwhile, the annealed samples show lower TCR values while they have high resistivity due to their small changes in resistance with the temperature. The sample annealed for 20min has good thermal stability and is similar in terms of the 1/f noise and β values to the as-deposited samples. The obtained results suggest that the post-deposition annealing of TNO samples in an oxygen atmosphere will lead to much stronger thermal stability compared to that of an as-deposited sample.</P>
Kumar, N.Suresh,Basavaraja, H.K.,Kumar, C.M.Kishor,Reddy, N.Mal,Datta, R.K. Korean Society of Sericultural Science 2002 International Journal of Industrial Entomology Vol.5 No.2
Earlier breeding experiments undertaken at Central Sericultural Research and Training Institute, Mysore, India since a decade had resulted in the development of many productive and qualitatively superior bivoltine hybrids. However, the hot climatic conditions of tropics prevailing particularly in summer are not conducive to rear these high yielding bivoltine hybrids. This has necessitated breeding of compatible bivoltine hybrids for year-round rearing. Accordingly, the Japanese hybrid, B2Ol ${\times}$ BCS12 which was found to be tolerant to high temperature was used as breeding resource material. Following hybridization and selection rearing of silkworms was taken up in SERICATRON (Environmental chamber with precise and automatic control facilities for uniform maintenance of temperature and humidity) at high temperature of $36{\times}1^{\circ}C$ and 85${\times}$5% RH in fifth instar and the control batches at $25{\times}1^{\circ}C$ and 65{\times}$5% RH. Directional selection was resorted to the batches reared at 36$\pm$1$^{\circ}C$ till F$_{5}$ keeping pupation rate as important selection criteria. From $F_{2}% onwards the experiment was modified in such a way as to conduct normal rearing every alternate generation to regain the lost vitality due to continuous exposure to high temperature and high humidity stress. At $F_{2}$ , Oval and dumb-bell cocoons were separated out and designated as CSR18 and CSR19, respectively. By utilizing these lines at $F_{12}$, the hybrid CSR18$\times$CSR19 was prepared and studied for the thermotolerance by subjecting to stress condition at high temperature of 36$\pm$1$^{\circ}C$ and 85$\pm$5% RH in fifth instar and the control batches at $25{\times}1^{\circ}C$ and 65${\times}$5% RH. The better performance of CSR18${\times}$CSR19 (survival > 88%) at $36{\times}1^{\circ}C$ clearly indicates the general superiority of CSR18${\times}$CSR19 with regard to high temperature tolerance over the productive hybrids and CSR18$\times$CSR19 can perform well in varied agro-climatic conditions of the tropics with optimum qualitative and quantitative characteristics.s.
Reddy, Y Ashok Kumar,Kang, In-Ku,Shin, Young Bong,Lee, Hee Chul IOP 2018 Journal of Physics. D, Applied Physics Vol.51 No.2
<P>In order to reduce the sun-burn effect in a sample of the bolometric material Nb:TiO<SUB>2−<I>x</I> </SUB>, oxygen annealing was carried out. This effect can be examined by comparing thermal stability test results between the as-deposited and oxygen-atmosphere-annealed samples under high-temperature exposure conditions. Structural studies confirm the presence of amorphous and rutile phases in the as-deposited and annealed samples, respectively. Composition studies reveal the offset of oxygen vacancies in the Nb:TiO<SUB>2−<I>x</I> </SUB> samples through oxygen-atmosphere annealing. The oxygen atoms were diffused and seemed to occupy the vacant sites in the annealed samples. As a result, the annealed samples show better thermal stability performance than the as-deposited samples. The universal bolometric parameter (<I>β</I>) values were slightly decreased in the oxygen-annealed Nb:TiO<SUB>2−<I>x</I> </SUB> samples. Although bolometric performance was slightly decreased in the oxygen-annealed samples, high thermal stability would be the most essential factor in the case of special applications, such as the military and space industries. Finally, these results will be very useful for reducing the sun-burn effect in infrared detectors.</P>
Kumar Reddy Cheepati,Nageswara Rao Maddala,Surya Kalavathi Munagala 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.2
The exponential growth of non-linear loads results the generation of harmonics in electrical distribution system. Major Harmonic generation efects due to non-linear loads are energy loss, nuisance tripping, equipment failure/mal-operation, and transformer saturation, overheating of neutral conductors and/or capacitors, interference with communication circuits, excess reactive power burden and lowering the true power factor. Improving the current quality is the prime responsibility of the consumers whereas utility is accountable for minimizing the supply voltage distortions. Shunt active flters (SAFs) were being used for many years to mitigate the current harmonics typically up to 25th order. Mainly, time and frequency domain reference current extraction control techniques were being used for SAF. Time-domain reference current extraction techniques were proved efcient than frequency-domain techniques due to their faster response. Time-domain reference current extraction techniques such as real and reactive (p-q) and synchronous reference frame (SRF) are having their own merits and demerits. The p-q control does not perform well under distorted and unbalanced supply voltage conditions whereas SRF control is limited to balanced loads. In this paper a novel reference current extraction control strategy is proposed i.e. inverse matrix averaging pq-SRF (IMApq-SRF) control. IMApq-SRF control extract the features of both conventional p-q and SRF control, based on inverse matrix average. The mathematical modeling of the proposed IMApq-SRF control is tested with MATLAB Simulink environment and it validates that the proposed IMApq-SRF control gives the superior performance as compared with conventional p-q and SRF techniques under balanced, unbalanced and distorted supply voltage and dynamic loading conditions.
Kumar, D. Praveen,Park, Hanbit,Kim, Eun Hwa,Hong, Sangyeob,Gopannagari, Madhusudana,Reddy, D. Amaranatha,Kim, Tae Kyu Elsevier 2018 Applied catalysis. B, Environmental Vol.224 No.-
<P><B>Abstract</B></P> <P>The hollow materials have played a significant role in cutting-edge innovations for energy conversion due to their peculiar properties and their wide range of potential applications. These materials show great promise for the development of cleaner power sources to address growing environmental concerns at a time of increasing global demand for energy. Noble metal-free MOF-derived onion slice-type hollow structured Co<SUB>4</SUB>S<SUB>3</SUB> was developed and embedded with CdS nanoparticles for photocatalytic hydrogen production. The incorporation of Co<SUB>4</SUB>S<SUB>3</SUB> with the CdS particles effectively accelerated charge separation and transfer in photocatalytic reactions due to the low density, hollow interior, and shell permeability of the onion-type composite. The optimized Co<SUB>4</SUB>S<SUB>3</SUB>/CdS photocatalyst led to an enhanced rate of H<SUB>2</SUB> production of 12,360μmolh<SUP>−1</SUP> g<SUP>−1</SUP> under simulated solar light irradiation; this value is 26-fold greater than that of the pristine CdS nanoparticles. The Co<SUB>4</SUB>S<SUB>3</SUB>/CdS composite exhibited remarkably stable photocatalytic performance for up to 65h and could be reused in five successive cycles. Furthermore, to the best of our knowledge, this is the highest H<SUB>2</SUB> production rate achieved with cobalt sulfide-based CdS nanoparticle photocatalysts in the photocatalysis of water under simulated solar light irradiation. Owing to its low cost and high efficiency, this photocatalytic system should hold great potential for the development of highly efficient photocatalytic materials for use in various fields.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Noble metal-free MOF-derived onion slice-type hollow structured Co<SUB>4</SUB>S<SUB>3</SUB> was developed. </LI> <LI> The Co<SUB>4</SUB>S<SUB>3</SUB> with the CdS particles effectively accelerated charge separation. </LI> <LI> The low density, hollow interior, shell permeability of Co<SUB>4</SUB>S<SUB>3</SUB> improves the transfer property. </LI> <LI> The optimized Co<SUB>4</SUB>S<SUB>3</SUB>/CdS shows high rate of H<SUB>2</SUB> production of 12,360μmolh<SUP>−1</SUP> g<SUP>−1</SUP>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Noble metal-free MOF-derived onion slice-type hollow cobalt sulfide nanostructures: Enhanced activity of CdS for improving photocatalytic hydrogen production by D.P. Kumar et al.</P> <P>[DISPLAY OMISSION]</P>