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Mahmood Khan I.,Institute of Space Technology | Suleman Chattha M.,Institute of Space Technology | Mateen A.,Institute of Space Technology | Qazi I.,Institute of Space Technology | And 2 more authors.
Optoelectronics and Advanced Materials, Rapid Communications | Year: 2015

The basic drawback of single junction solar cells is their inability to absorb multiple wavelengths of light. Tandem solar cells are designed to extract maximum energy from the light by absorbing multiple wavelengths. A multilayer solar cell was fabricated using multiple coating techniques. The characterization of the cell was carried out to analyze its properties and behavior under different conditions. The effect of layers’ thickness on the light absorption efficiency is discussed in this paper. The thickness of P-type material is varied to examine the effect of layer thickness on the band gap. © 2015, National Institute of Optoelectronics. All rights reserved. Source


Farooq A.,University of Wah | Farooq A.,Ghulam Ishaq Khan Institute of Engineering Sciences and Technology | Karimov K.S.,Ghulam Ishaq Khan Institute of Engineering Sciences and Technology | Karimov K.S.,Physical Technical Institute | And 4 more authors.
Physica B: Condensed Matter | Year: 2015

In this study we present the dependence of electrical properties of copper phthalocyanine (CuPc) and metal free phthalocyanine (H2Pc) bulk heterojunction structure under different illumination levels. To fabricate the device on ITO coated glass substrate the bulk heterojunction thin film of CuPc and H2Pc with thickness varying from 100 nm to 300 nm are deposited by thermal evaporator. Aluminum thin film was deposited by thermal evaporation as a top contact. The optical properties of the fabricated device are investigated using UV-vis spectroscopy. The current-voltage characteristics in dark and under illumination show that the device is sensitive towards visible light. The absorption spectrum describes its photo sensitivity in the range of wavelength from 200 nm to 850 nm. Simulation of current-intensity of light curve is carried out and experimental results are found in good agreement with simulated ones. © 2014 Elsevier B.V. All rights reserved. Source


Maqsood M.,National Institute of Vacuum Science and Technology | Nasir M.N.,University of Engineering & Technology, Taxila
Journal of Physics: Conference Series | Year: 2013

In the near future due to extensive use of energy, limited supply of resources and the pollution in environment from present resources e.g. (wood, coal, fossil fuel) etc, alternative sources of energy and new ways to generate energy which are efficient, cost effective and produce minimum losses are of great concern. Wireless electricity (Power) transmission (WET) has become a focal point as research point of view and nowadays lies at top 10 future hot burning technologies that are under research these days. In this paper, we present the concept of transmitting power wirelessly to reduce transmission and distribution losses. The wired distribution losses are 70-75% efficient. We cannot imagine the world without electric power which is efficient, cost effective and produce minimum losses is of great concern. This paper tells us the benefits of using WET technology specially by using Solar based Power satellites (SBPS) and also focuses that how we make electric system cost effective, optimized and well organized. Moreover, attempts are made to highlight future issues so as to index some emerging solutions. © Published under licence by IOP Publishing Ltd. Source


Hong S.S.,Korea Research Institute of Standards and Science | Lim J.Y.,Korea Research Institute of Standards and Science | Khan W.,National Institute of Vacuum Science and Technology
Journal of the Korean Physical Society | Year: 2014

Pumping systems with large vacuum chambers have numerous applications in the process industry: for example, mixing of various types of gases as in the semiconductor industry, the calibration of vacuum gauges, the measurement of outgassing rates of various materials in the field of space technology, etc. Most often, these systems are used in the medium vacuum range (10-1 Pa-102 Pa) and in the dynamically-generated pressure mode. We have designed and developed a new dynamic flow system at the KRISS (Korea Research Institute of Standards and Science) that can be used for such applications with reliability in the range from 0.1 Pa - 133 Pa. In this report, the design philosophy, operational procedure and experimental data for the generated stable pressure points in the chamber of the system are discussed. The data consist the pressure points generated in the medium vacuum range while pumping the chamber of the system by using two different methods: first by using a dry scroll pump and then by using a combination of a turbomolecular pump backed by the same scroll pump. The relative standard deviations in the pressure points were calculated and were found to be greater than 1.5% for the scroll pump and less than 0.5% for the turbomolecular pump. © 2014 The Korean Physical Society. Source


Maqsood M.,National Institute of Vacuum Science and Technology | Ali J.,Hazara University | Usman A.,National Institute of Vacuum Science and Technology | Farooq M.,Hazara University
Journal of Physics: Conference Series | Year: 2013

Accurate and stable gas flows are very important in different applications like, the performance study of vacuum pumps, gauge calibration, leak detection and advance research in low pressure physics. Primary Orifice Plate Flowmeter (OPF) has been designed and developed indigenously. This flowmeter consists of two orifice plates. Orifice-1 (O1) acts as a flow restriction, while orifice-2 (O2) enables continuous pumping mode. By varying upstream pressure P1, a change in downstream pressure P2 is recorded, and the flow-rate is calculated from the conductance "C" of the orifice O1 and pressure difference by the relation Q = C(P 1 - P2). Main feature of this primary OPF is that it is very simple and compact. A stable and reproducible flow-rate has been achieved in the range of 10-5 to 10-6 mbar.l/s. A variation in Q has been observed with a change in temperature of orifice and orifice diameter. © Published under licence by IOP Publishing Ltd. Source

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