| 1. |
- Ans, Muhammad, et al.
(författare)
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Designing of non-fullerene 3D star-shaped acceptors for organic solar cells
- 2019
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Ingår i: Journal of Molecular Modeling. - : Springer. - 1610-2940 .- 0948-5023. ; 25:5
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Tidskriftsartikel (refereegranskat)abstract
- The design and fabrication of solar cells have recently witnessed the exploration of non-fullerene-based acceptor molecules for higher efficiency. In this study, the optical and electronic properties of four new three-dimensional (3D) star-shaped acceptor molecules (M1, M2, M3, and M4) are evaluated for use as acceptor molecules in organic solar cells. These molecules contain a triphenylamine donor core with diketopyrrolopyrrole acceptor arms linked via a thiophene bridge unit. Molecules M1–M4 are characterized by different end-capped acceptor moieties, including 2-(5-methylene-6-oxo-5,6-dihydrocyclopenta-b-thiophen-4-ylidene)malononitrile (M1), 2-(2-methylene-3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (M2), 2-(5-methyl-2-methylene-3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (M3), and 3-methyl-5-methylnene-thioxothiazolidin-4-one (M4). The properties of the newly designed molecules were compared with a well-known reference compound R, which was recently reported as an excellent acceptor molecule for organic solar cells. Molecules M1–M4 exhibit suitable frontier molecular orbital patterns for charge mobility. M2 shows maximum absorption (λmax) at 846.8 nm in dichloromethane solvent, which is ideal for the design of transparent solar cells. A strong electron withdrawing end-capped acceptor causes a red shift in absorption spectra. All molecules are excellent for hole mobility due to a lower value of λh compared to the reference R.
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| 2. |
- Javed, Iqbal, et al.
(författare)
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Quinacridone-Based Small Acceptor Molecule for Obtaining High Open Circuit Voltage in Solution Processed Organic Solar Cells
- 2015
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Ingår i: Journal of the Chemical Society of Pakistan. - : Chemical Society of Pakistan. - 0253-5106. ; 37:3, s. 418-425
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Tidskriftsartikel (refereegranskat)abstract
- Dioctylquinacridone di(cyanoimine) CN-DOQA was synthesized according to previously reported method. CN-DOQA having suitable HOMO-LUMO energy levels due to -CN groups as electron withdrawing groups was used in organic solar cells as an acceptor in a blend with poly (3-hexyl thiophene) (P3HT) as donor. The photovoltaic devices have shown reasonable high open circuit voltage (Voc) although solar cells have not been fully optimized. Photovoltaic study was supported by thermogravimetric analysis (TGA), dynamic scanning calorimetry (DSC) of CN-DOQA and morphological study of the blend films by atomic force microscopy (AFM).
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| 3. |
- Javed, Muhammad Sufyan, et al.
(författare)
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The energy crisis in Pakistan : A possible solution via biomass-based waste
- 2016
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Ingår i: Journal of Renewable and Sustainable Energy. - : American Institute of Physics (AIP). - 1941-7012. ; 8:4
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Tidskriftsartikel (refereegranskat)abstract
- Developing countries like Pakistan need a continuous supply of clean and cheap energy. It is a very common fear in today's world that the fossil fuels will be depleted soon and the cost of energy is increasing day-by-day. Renewable energy sources and technologies have the potential to provide solutions to long-standing energy problems faced by developing countries. Currently, Pakistan is experiencing a critical energy crisis and renewable energy resources can be the best alternatives for quickly terminating the need for fossil fuels. The renewable energy sources such as solar energy, wind energy, and biomass energy combined with fuel cell technology can be used to overcome the energy shortage in Pakistan. Biomass is a promising renewable energy source and is gaining more interest because it produces a similar type of fuel like crude oil and natural gas. Energy from biomass only depends upon the availability of raw materials; therefore, biomass can play an important role to fulfill the energy requirements of the modern age. The use of energy has increased greatly since the last century and almost all human activities have become more dependent on energy. Biomass, being a potential and indigenous candidate, could be a good solution to meet the energy needs of Pakistan. In this review paper, the detailed current energy requirements and solutions from available energy resources and the scope, potential, and implementation of biomass conversion to energy in Pakistan are explored with a special focus on the major province of Punjab and the advantages of biomass for energy purposes.
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| 4. |
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| 5. |
- Raza, Rizwan, et al.
(författare)
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Ce-0.8(SmZr)(0.2)O-2-carbonate nanocomposite electrolyte for solid oxide fuel cell
- 2014
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Ingår i: International Journal of Energy Research. - : Hindawi Limited. - 0363-907X .- 1099-114X. ; 38:4, s. 524-529
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Tidskriftsartikel (refereegranskat)abstract
- A nanocomposite Zr/Sm-codoped ceria electrolyte coated with K2CO3/Na2CO3 was synthesized by a coprecipitation method. The electrochemical study of the two-phase nanocomposite electrolytes with carbonate coated on the doped ceria shows high oxygen ion mobility at low temperatures (300-600 degrees C). The interface between the two constituent phases was studied by electrochemical impedance spectroscopy. Ionic conductivities were also measured with electrochemical impedance spectroscopy. The morphology and structure of composite electrolyte were characterized using field-emission scanning electron microscopy and X-ray diffraction. The fuel cell power density is 700 mW cm(-2), and an open-circuit voltage of 1.00 V is achieved at low temperatures (400-550 degrees C). This codoped approach with a second phase provides a good indication regarding overcoming the challenges of solid oxide fuel cell technology.
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| 6. |
- Thomas, HS, et al.
(författare)
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- 2019
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swepub:Mat__t
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| 7. |
- Adnan, Muhammad, et al.
(författare)
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Fine Tuning the Optoelectronic Properties of Triphenylamine Based Donor Molecules for Organic Solar Cells
- 2017
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Ingår i: Zeitschrift fur physikalische Chemie (Munchen. 1991). - : Walter de Gruyter GmbH. - 0942-9352 .- 2196-7156. ; 231:6, s. 1127-1139
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Tidskriftsartikel (refereegranskat)abstract
- Geometrical parameters, electronic structures and photophysical properties of three new triphenylamine (TPA) and diphenylamine (DPA) based electron donor materials M1-M3 (for organic solar cells) have been investigated through density functional theory (DFT) methods at the B3LYP/6-31G(d) level of the theory. TPA and DPA are used as donor moieties due to their electron donating ability while benzothiazole, cyanide and cyanomethylacetate (CMA) moieties have been taken as acceptor moieties. The time dependent-DFT (TD-DFT) method has been employed [TD-B3LYP/6-31G (d)] for the computation of excited state properties in the gas phase and in solvent (chloroform). The polarization continuum model is applied for calculations in the solvent phase. The designed molecules exhibited broad absorption in the visible and near infra-red region of spectrum with respect to a reference molecule "R" of a similar class of compounds. Based on reorganization energies calculations, these materials could act as excellent hole transport materials.
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| 8. |
- Ahmed, A., et al.
(författare)
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Highly efficient composite electrolyte for natural gas fed fuel cell
- 2016
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Ingår i: International journal of hydrogen energy. - : Elsevier. - 0360-3199 .- 1879-3487. ; 41:16, s. 6972-6979
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Tidskriftsartikel (refereegranskat)abstract
- Solid oxide fuel cells (SOFCs) have the ability to operate with different variants of hydro carbon fuel such as biogas, natural gas, methane, ethane, syngas, methanol, ethanol, hydrogen and any other hydrogen rich gas. Utilization of these fuels in SOFC, especially the natural gas, would significantly reduce operating cost and would enhance the viability for commercialization of FC technology. In this paper, the performance of two indigenously manufactured nanocomposite electrolytes; barium and samarium doped ceria (BSDC-carbonate); and lanthanum and samarium doped ceria (co-precipitation method LSDC-carbonate) using natural gas as fuel is discussed. The nanocomposite electrolytes were synthesized using co-precipitation and wet chemical methods (here after referred to as nano electrolytes). The structure and morphology of the nano electrolytes were examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The fuel cell performance (OCV) was tested at temperature (300-600 °C). The ionic conductivity of the nano electrolytes were measured by two probe DC method. The detailed composition analysis of nano electrolytes was performed with the help of Raman Spectroscopy. Electrochemical study has shown an ionic conductivity of 0.16 Scm-1 at 600 °C for BSDC-carbonate in hydrogen atmosphere, which is higher than conventional electrolytes SDC and GDC under same conditions. In this article reasonably good ionic conductivity of BSDC-carbonate, at 600 °C, has also been achieved in air atmosphere which is comparatively greater than the conventional SDC and GDC electrolytes.
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| 9. |
- Ali, Qasim, et al.
(författare)
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Drought tolerance potential of Vigna mungo L. lines as deciphered by modulated growth, antioxidant defense, and nutrient acquisition patterns
- 2016
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Ingår i: Revista Brasileira de Botânica. - : Springer. - 0100-8404 .- 1806-9959. ; 39:3, s. 801-812
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Tidskriftsartikel (refereegranskat)abstract
- Water shortage is one of the major environmental constraints that hamper the crop productivity worldwide. The present study was aimed to examine the drought tolerance potential of seven cultivars/lines of Vigna mungo L. depending upon their germination behavior, seedling growth, antioxidative defense mechanism, and nutrient acquisition. An experiment was conducted in the growth chamber using petri-plates and laid out in a completely randomized design (CRD). Hoagland's nutrient solution supplemented with 12 % PEG-8000 (drought treatment) or without PEG-800 (control) was used. Drought stress significantly altered the germination attributes as well as biomass production of all the studied cultivars/lines. Least adversative effects of drought stress were recorded in lines M-01001-1 and M-6036-21, respectively. The studied cultivars/lines exhibited differential response for various biochemical attributes under drought stress. The maximum increase in MDA and SOD activities and protein content was recorded in line M-603621, while the maximum AsA was recorded in line M-01001-1. Drought stress resulted in a significant reduction of plant N, P, K, Ca, and Mg contents, while the plant iron (Fe) contents remained unaffected. Results revealed that cultivars/lines M-01001-1 and M-6036-21 exhibited enhanced performance in terms of nutrient acquisition when stressed by drought. Based upon seed germination behavior, plant biomass production, biochemical attributes and mineral elements, the cultivars/lines M-01001-1 and M-6036-21 were identified as drought tolerant, while M-97 and Arroj-II were identified as drought sensitive.
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| 10. |
- Ans, Muhammad, et al.
(författare)
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Designing Three‐dimensional (3D) Non‐Fullerene Small Molecule Acceptors with Efficient Photovoltaic Parameters
- 2018
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Ingår i: ChemistrySelect. - : WILEY-VCH VERLAG GMBH. - 2365-6549. ; 3:45, s. 12797-12804
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Tidskriftsartikel (refereegranskat)abstract
- Three dimensional (3D) acceptor‐donor‐acceptor (A−D‐A) type small molecules (M1, M2, M3 and M4) are theoretically investigated for optoelectronic properties. The designed molecules contain spirobifluorene as core unit linked with end capped acceptors through four four thieno‐[3,2‐b]Thiophene (TT) units. The end capped acceptors are (3‐methyl‐2‐thioxothiazolidin‐4‐one) (M1), 2‐(2‐ethylidene‐5,6‐difluoro‐3‐oxo‐2,3‐dihydroinden‐1‐ylidene)malononitrile (M2), 2‐(3‐ethyl‐4‐oxothiazolidin‐2‐ylidine)malononitrile (M3) and 2‐(2‐ethylidene‐5,6‐dicyano‐3‐oxo‐2,3‐dihydroinden‐1‐ylidene)malononitrile (M4). The photovoltaic parameters of the designed molecules are compared with the recently reported reference compound R. Among all designed molecules, M4 is a low energy gap material (2.28 eV), broad absorption which is attributed to excellent communication between strong electron withdrawing end capped acceptors through extended conjugation. All newly designed molecules have lower binding energy as compared to reference molecule R which results in higher exciton dissociation in excited state. The reorganization energy calculations indicate good charge transfer ability of the designed molecules. M4 shows the lowest λe (0.0022) value with respect to the reference molecule R (0.034) which signifies its enhanced electronic transport behavior. The calculated open circuit voltages (Voc) ranges from 1.97 to 2.36 eV, 2.11 to 2.49 eV and 1.9 eV to 2.28 eV with respect to three different well known donor materials PTB7‐Th, PBDB−T and P3HT, respectively.
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