| 1. |
- Maity, Jyoti Prakash, et al.
(författare)
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Furfural removal from water by bioremediation process by indigenous Pseudomonas putida (OSBH3) and Pseudomonas aeruginosa (OSBH4) using novel suphala media : An optimization for field application
- 2023
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Ingår i: GROUNDWATER FOR SUSTAINABLE DEVELOPMENT. - : Elsevier BV. - 2352-801X. ; 20, s. 100895-
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Tidskriftsartikel (refereegranskat)abstract
- The release of furfural as effluent from industries has been considered a major pollution source since it adversely affects health and the environment. In a proper nutrient condition, the indigenous microbial removal process is always considered efficient, economical, and eco-friendly. Thus, the main objective is to employ the effective indigenous bacteria to remove the furfural from wastewater. In the present study, the indigenous isolates OSBH3 (strain number) and OSBH4 (strain number) were isolated from furfural-containing-oily-sludge and were iden-tified by 16S-rRNA technique with >99% nucleotide similarity as Pseudomonas putida (P. putida) (Acc. No. GU329915) and Pseudomonas aeruginosa (P. aeruginosa) (Acc. No. GU329916) respectively. In a batch experi-ment, the furfural degradation was observed higher in the presence of the most efficient isolate P. putida (compare to P. aeruginosa) at different nutrient conditions including Suphala (Nitrogen-Phosphorous-fertilizer), glucose, and carbohydrate-free synthetic media (CFM). Generally, the furfural degradation rate was lower in CFM than the other substrates (Nitrogen-Phosphorous-fertilizer/glucose), in the presence of P. putida or P. aeruginosa. The furfural degradation efficiency was observed higher in presence of P. putida, compare to P. aeruginosa. Experimentally, the total (100%) degradation of furfural (500 mg/L) was noticed by P. Putida within 12h incubation time in presence of 1 mg/L Suphala. Even among different factors (based on 'Taguchi L9 orthogonal array study'), the suphala (Nitrogen-Phosphorous-fertilizer) was influential in degrading the furfural at level 2, where the effects of pH and glucose were noticed at level 2 and level 2, respectively. The experimental findings supported the orthogonal array study positively. The bacterial (P. putida) growth rate and furfural degradation were promoted at the condition of 1 mg/L suphala, 2 mg/L glucose (pH 7.2), where the furfural was used by P. putida as the sole-carbon-source for growth. Thus, the indigenous P. putida (OSBH3; Acc. No. GU329915) (in presence of modified nitrogen-phosphorous-fertilizer media), can be applicable for furfural (Toxic) remediation from industrial effluent water by the eco-friendly process.
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| 2. |
- Almeida, Roseley, et al.
(författare)
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Theoretical Evidence behind Bifunctional Catalytic Activity in Pristine and Functionalized Al2C Monolayers
- 2018
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Ingår i: ChemPhysChem. - : Wiley-VCH Verlagsgesellschaft. - 1439-4235 .- 1439-7641. ; 19:1, s. 148-152
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Tidskriftsartikel (refereegranskat)abstract
- First principles electronic structure calculations based on the density functional theory (DFT) framework are performed to investigate hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) on two-dimensional Al2C monolayers. In addition to the pristine Al2C monolayer, monolayers doped with Nitrogen (N), Phosphorous (P), Boron (B), and Sulphur (S) are also investigated. After determining the individual adsorption energy of hydrogen and oxygen on the different functionalized Al2C monolayers, the adsorption free energies are predicted for each of the functionalized monolayers in order to assess their suitability for HER or OER. The density of states and optical absorption spectra calculations along with the work function of the functionalized Al2C monolayers enable us to gain a profound understanding of the electronic structure for the individual system and their relation to the water splitting mechanism.
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| 3. |
- Anversa, Jonas, et al.
(författare)
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High pressure driven superconducting critical temperature tuning in Sb2Se3 topological insulator
- 2016
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 108:21
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Tidskriftsartikel (refereegranskat)abstract
- In this letter, we are reporting the change of superconducting critical temperature in Sb2Se3 topological insulator under the influence of an external hydrostatic pressure based on first principles electronic structure calculations coupled with Migdal-Eliashberg model. Experimentally, it was shown previously that Sb2Se3 was undergoing through a transition to a superconducting phase when subjected to a compressive pressure. Our results show that the critical temperature increases up to 6.15K under the pressure unto 40GPa and, subsequently, drops down until 70 GPa. Throughout this pressure range, the system is preserving the initial Pnma symmetry without any structural transformation. Our results suggest that the possible relevant mechanism behind the superconductivity in Sb2Se3 is primarily the electron-phonon coupling.
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| 4. |
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| 5. |
- Araujo, Rafael B., et al.
(författare)
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Na2M2(SO4)(3) (M = Fe, Mn, Co and Ni) : towards high-voltage sodium battery applications
- 2016
-
Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 18:14, s. 9658-9665
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Tidskriftsartikel (refereegranskat)abstract
- Sodium-ion-based batteries have evolved as excellent alternatives to their lithium-ion-based counterparts due to the abundance, uniform geographical distribution and low price of Na resources. In the pursuit of sodium chemistry, recently the alluaudite framework Na2M2(SO4)(3) has been unveiled as a high-voltage sodium insertion system. In this context, the framework of density functional theory has been applied to systematically investigate the crystal structure evolution, density of states and charge transfer with sodium ions insertion, and the corresponding average redox potential, for Na2M2(SO4)(3) (M = Fe, Mn, Co and Ni). It is shown that full removal of sodium atoms from the Fe-based device is not a favorable process due to the 8% volume shrinkage. The imaginary frequencies obtained in the phonon dispersion also reflect this instability and the possible phase transition. This high volume change has not been observed in the cases of the Co- and Ni-based compounds. This is because the redox reaction assumes a different mechanism for each of the compounds investigated. For the polyanion with Fe, the removal of sodium ions induces a charge reorganization at the Fe centers. For the Mn case, the redox process induces a charge reorganization of the Mn centers with a small participation of the oxygen atoms. The Co and Ni compounds present a distinct trend with the redox reaction occurring with a strong participation of the oxygen sublattice, resulting in a very small volume change upon desodiation. Moreover, the average deintercalation potential for each of the compounds has been computed. The implications of our findings have been discussed both from the scientific perspective and in terms of technological aspects.
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| 6. |
- Araujo, Rafael B., et al.
(författare)
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Predicting electrochemical properties and ionic diffusion in Na2+2xMn2-x(SO4)(3) : crafting a promising high voltage cathode material
- 2016
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry. - 2050-7488 .- 2050-7496. ; 4:2, s. 451-457
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Tidskriftsartikel (refereegranskat)abstract
- Sodium ion batteries have emerged as a good alternative to lithium based systems due to their low cost of production. In this scenario, the search for higher voltage, sodium cathodes results in a new promising alluaudite structure Na2+2xMn2-x(SO4)(3). The structural, electronic and Na diffusion properties along with defects have been reported in this investigation within the framework of density functional theory. A band gap of 3.61 eV has been computed and the average deintercalation potential is determined to be 4.11 V vs. Na/Na+. A low concentration of anti-site defects is predicted due to their high formation energy. The biggest issue for the ionic diffusion in the Na2+2xMn2-x(SO4)(3) crystal structure is revealed to be the effect of Mn vacancies increasing the activation energy of Na+ ions that hop along the [001] equilibrium positions. This effect leads to activation energies of almost the same high values for the ionic hop through the [010] direction characterizing a 2D like ionic diffusion mechanism in this system.
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| 7. |
- Araujo, Rafael B., et al.
(författare)
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Unveiling the charge migration mechanism in Na2O2 : implications for sodium-air batteries
- 2015
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 17:12, s. 8203-8209
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Tidskriftsartikel (refereegranskat)abstract
- Metal-air batteries have become promising candidates for modern energy storage due to their high theoretical energy density in comparison to other storage devices. The lower overpotential of Na compared with Li makes Na-air batteries more efficient in terms of battery lifetime. Additionally, the abundance of Na over Li is another advantage for Na batteries compared to Li batteries. Na2O2 is one of the main products of sodium-air battery reactions. The efficiency of air cells is always related to the charge transport mechanisms in the formed product. To unveil these diffusion mechanisms in one of the main products of the cell reaction Na-O-2 we systematically investigate the mobility of charge carriers as well as the electronic structural properties of sodium peroxide. The framework of the density functional theory based on hybrid functional approach is used to study the mobility of charge carriers and intrinsic defects in Na2O2. Our calculations reveal that the formation of small electron and hole polarons is preferentially occurring over the delocalized state in the crystal structure of Na2O2. The migration of these small polarons displays activation energies of about 0.92 eV and 0.32 eV for the electron and hole polarons respectively, while the analysis of the charged sodium vacancy mobility reveals an activation energy of about 0.5 eV. These results suggest that the charge transport in sodium peroxide would mainly occur through the diffusion of hole polarons.
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| 8. |
- Banerjee, Amitava, et al.
(författare)
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Bromination-induced stability enhancement with a multivalley optical response signature in guanidinium [C(NH2)(3)](+)-based hybrid perovskite solar cells
- 2017
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Ingår i: Journal of Materials Chemistry A. - : ROYAL SOC CHEMISTRY. - 2050-7488 .- 2050-7496. ; 5:35, s. 18561-18568
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Tidskriftsartikel (refereegranskat)abstract
- Guanidinium lead iodide (GAPbI(3)) has been synthesized experimentally, but stability remains an issue, which can be modulated by the insertion of bromine (Br) into the system. We have performed a systematic theoretical investigation to see how bromination can tune the stability of GAPbI(3). The optical properties were also determined, and we have found formation enthalpy-based stability in the perovskite systems, which are active in the visible and IR region even after bromine insertion and additionally more active in the IR range with the transition from GAPbI(3) to GAPbBr(3). The spin orbit coupling effect is considered throughout the band structure calculations. The ensemble of the primary and secondary gaps in the half and fully brominated hybrid perovskites leads to the phenomenon of a multipeak response in the optical spectra, which can be subsequently attributed as multivalley optical response behaviour. This multivalley optical behaviour enables the brominated guanidinium-based hybrid perovskites to exhibit broad light harvesting abilities, and this can be perceived as an idea for natural multi-junction solar cells.
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| 9. |
- Banerjee, Amitava
(författare)
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Materials Modelling for Energy Harvesting : From Conversion to Application through Storage
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this Ph.D. thesis, ab initio density functional theory along with molecular dynamics and global optimization methods are used to unveil and understand the structures and properties of energy relevant materials. In this connection, the following applications are considered: i. electrocatalyst for solar fuel production through water splitting, ii. hybrid perovskite solar cell for generation of electrical energy and iii. Battery materials to store the electrical energy. The water splitting mechanism in terms of hydrogen evolution and oxygen evolution reactions (HER and OER) on the catalytic surfaces has been envisaged based on the free energy diagram, named reaction coordinate, of the reaction intermediates. The Ti-functionalized two-dimensional (2D) borophene monolayer has been emerged as a promising material for HER and OER mechanisms as compared to the pristine borophene sheet. Further investigation in the series of this noble metal free monolayer catalyst is 2D Al2C monolayer both in form of pristine and functionalized with nitrogen (N), phosphorous (P), boron (B), and sulphur (S). It has been observed that only B substituted Al2C shows very close to thermoneutral, that could be the most promising candidate for HER on functionalized Al2C monolayer. The adsorption of O* intermediate is stronger in S-substituted Al2C, whereas it is less strongly adsorbed on N-substituted Al2C. The subsequent consideration is being the case of n-type doping (W) along with Ti codoped in BiVO4 to enhance the efficiency of BiVO4 photoanode for water splitting. The determined adsorption energy and corresponding Gibbs free energies depict that the Ti site is energetically more favorable for water splitting. Moreover, the Ti site possesses a lower overpotential in the W–Ti codoped sample as compared to the mono-W doped sample. We have also explored the effect of mixed cation and mixed anion substitution in the hybrid perovskite in terms of structural stability, electronic properties and optical response of hybrid perovskite crystal structures. It has been found that the insertion of bromine (Br) into the system could modulate the stability of the Guanidinium lead iodide (GAPbI3) hybrid perovskite. Moreover, the band gap of the mixed hybrid perovskite is increased with the inclusion of smaller Br anion while replacing partially the larger iodine (I) anion. Finally the electrochemical storage mechanism for Sodium (Na) and lithium (Li) ion insertion has been envisaged in inorganic electrode (eldfellite, NaFe(SO4)2) as well as in more sustainable organic electrode (di-lithium terephthalate, Li2TP). The full desodiation capability of the eldfellite enhances the capacity while the activation energies (higher than 1 eV) for the Na+ ion diffusion for the charged state lower the ionic insertion rate. The key factor as the variation of Li-O coordination in the terephthalate, for the disproportionation redox reaction in Li2TP is also identified.
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| 10. |
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| 11. |
- Banerjee, Amitava, et al.
(författare)
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Rashba Triggered Electronic and Optical Properties Tuning in Mixed Cation-Mixed Halide Hybrid Perovskites
- 2019
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Ingår i: ACS Applied Energy Materials. - : AMER CHEMICAL SOC. - 2574-0962. ; 2:10, s. 6990-6997
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Tidskriftsartikel (refereegranskat)abstract
- The inherent spin-orbit coupling (SOC) effect in non-centrosymmetric crystal structure has laid the foundation of Rashba splitting phenomena. This Rashba splitting directly governs the charge carrier recombination, which eventually controls the carrier lifetime and diffusion length and therefore the solar cell efficiency for such hybrid perovskite materials. In this work, we have performed a rigorous structural search prediction of the mixed cation-mixed halide hybrid perovskites FA(0.83)MA(0.17)Pb(I0.83Br0.17)(3) and FA(0.875)MA(0.125 )Pb(I0.875Br (0.125))(3), which are the two nearest neighbor structures of record efficiency (22.1%) holder FA(0.85)MA(0.15)Pb(I0.85Br0.15)(3) in the structural composition phase space. We have found the prediction routes for a structural search such as the mixed perovskite structure govern the Rashba splitting energy value, depending on whether it has been predicted from FPI (FAPbI(3)) or MPB (MAPbBr(3)) as parent structure, which are leading to the mixed phase FA(0.83)MA(0.17)Pb(I0.83Br0.17)(3) and FA(0.875)MA(0.125)Pb(I0.875Br0.125)(3) respectively. The strong dependency of the splitting energy on the structural phase evolution along with the stoichiometry and space group is also observed, where in the mixed phase, 0.045 difference in concentration could lead to a remarkable difference in the splitting energy, which is more pronounced in the valence band as compared to the conduction band. We have also determined the Goldschmidt tolerance factor to envisage structural stability of the newly predicted crystal structures based on the corresponding chemical route in the composition phase space.
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| 12. |
- Banerjee, Amitava, et al.
(författare)
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Reaction Coordinate Mapping of Hydrogen Evolution Mechanism on Mg3N2Monolayer
- 2020
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Ingår i: International Journal of Hydrogen Energy. - : Elsevier BV. - 0360-3199 .- 1879-3487.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- In this work, we have envisaged the hydrogen evolution reaction (HER) mechanism on Mg3N2 monolayer based on electronic structure calculations within the framework of density functional theory (DFT) formalism. The semiconducting nature of Mg3N2 monolayer motivates us to investigate the HER mechanism on this sheet. We have constructed the reaction coordinate associated with HER mechanism after determining the hydrogen adsorption energy on Mg3N2 monolayer, while investigating all possible adsorption sites. After obtaining the adsorption energy, we subsequently obtain the adsorption free energy while adding zero point energy difference (Delta ZPE) and entropic contribution (T Delta S). We have not only confined our investigations to a single hydrogen, but have thoroughly observed the adsorption phenomena for increasing number of hydrogen atoms on the surface. We have determined the projected density of states (DOS) in order to find the elemental contribution in the valence band and conduction band regime for all the considered cases. We have also compared the work function value among all the cases, which quantifies the amount of energy required for taking an electron out of the surface. The charge transfer mechanism is also being investigated in order to correlate with the HER mechanism with amount of charge transfer. This is the first attempt on this material to the best of our knowledge, where theoretical investigation has been done to mapping the reaction coordinate of HER mechanism with the associated charge transfer process and the work function values, not only for single hydrogen adsorption, but also for increasing number of adsorbed hydrogen.
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| 13. |
- Banerjee, Amitava, et al.
(författare)
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Scrupulous Probing of Bifunctional Catalytic Activity of Borophene Monolayer : Mapping Reaction Coordinate with Charge Transfer
- 2018
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Ingår i: ACS Applied Energy Materials. - : American Chemical Society (ACS). - 2574-0962. ; 1:8, s. 3571-3576
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Tidskriftsartikel (refereegranskat)abstract
- We have envisaged the hydrogen evolution and oxygen evolution reactions (HER and OER) on two-dimensional (2D) noble metal free borophene monolayer based on first-principles electronic structure calculations. We have investigated the effect of Ti functionalization on borophene monolayer from the perspective of HER and OER activities enhancement. We have probed the activities based on the reaction coordinate, which is conceptually related to the adsorption free energies of the intermediates of HER and OER, as well as from the vibrational frequency analysis with the corresponding charge transfer mechanism between the surface and the adsorbate. Tifunctionalized borophene has emerged as a promising material for HER and OER mechanisms. We believe that our probing method, based on reaction coordinate coupled with vibrational analysis that has been validated by the charge transfer mechanism, would certainly become as a robust prediction route for HER and OER mechanisms in coming days.
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| 14. |
- Banerjee, Hrishit, et al.
(författare)
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Cationic Effect on Pressure Driven Spin-State Transition and Cooperativity in Hybrid Perovskites
- 2016
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Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 28:22, s. 8379-8384
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Tidskriftsartikel (refereegranskat)abstract
- Hybrid or metal organic framework (MOP) perovskites of general composition, ABX(3), are known to show interesting properties that can lead to a variety of technological applications. Our first-principles study shows they are also potential candidates for exhibiting cooperative spin-state transitions upon application of external stimuli. We demonstrate this by considering two specific Fe-based MOF perovskites, namely dimethylammonium iron formate, [CH3NH2CH3][Fe(HCOO)(3)], and hydroxylammonium iron formate, [NH3OH][Fe(HCOO)(3)]. Both the compounds are found to undergo high-spin (S = 2) to low-spin (S = 0) transition at Fe(II) site upon application of moderate strength of hydrostatic pressure, along with large hysteresis. This spin-state transition is signaled by the changes in electronic, magnetic, and optical properties. We find both the transition pressure and the width of the hysteresis to be strongly dependent on the choice of A-site cation, dimethylammonium or hydroxylammonium, implying that tuning of spin-switching properties is achievable by chemical variation of the amine cation in the structure. Our findings open up novel functionalities in this family of materials of recent interest, which can have important usage in sensors and memory devices.
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| 15. |
- Banerjee, Hrishit, et al.
(författare)
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Design and Control of Cooperativity in Spin-Crossover in Metal-Organic Complexes : A Theoretical Overview
- 2017
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Ingår i: INORGANICS. - : MDPI AG. - 2304-6740. ; 5:3
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Forskningsöversikt (refereegranskat)abstract
- Metal organic complexes consisting of transition metal centers linked by organic ligands, may show bistability which enables the system to be observed in two different electronic states depending on external condition. One of the spectacular examples of molecular bistability is the spin-crossover phenomena. Spin-Crossover (SCO) describes the phenomena in which the transition metal ion in the complex under the influence of external stimuli may show a crossover between a low-spin and high-spin state. For applications in memory devices, it is desirable to make the SCO phenomena cooperative, which may happen with associated hysteresis effect. In this respect, compounds with extended solid state structures containing metal ions connected by organic spacer linkers like linear polymers, coordination network solids are preferred candidates over isolated molecules or molecular assemblies. The microscopic understanding, design and control of mechanism driving cooperativity, however, are challenging. In this review we discuss the recent theoretical progress in this direction.
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| 16. |
- Bashir, Amna, et al.
(författare)
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Cu-doped nickel oxide interface layer with nanoscale thickness for efficient and highly stable printable carbon-based perovskite solar cell
- 2019
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Ingår i: Solar Energy. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0038-092X .- 1471-1257. ; 182, s. 225-236
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Tidskriftsartikel (refereegranskat)abstract
- The power conversion efficiency (PCE) of hole conductor free carbon-based perovskite solar cells (PSCs) is restricted by the poor charge extraction and recombination losses at the carbon-perovskite interface. For the first time we successfully demonstrated incorporation of thin layer of copper doped nickel oxide (Cu:NiOx) nanoparticles in carbon-based PSCs, which helps in improving the performance of these solar devices. Cu:NiOx nanoparticles have been synthesized by a facile chemical method, and processed into a paste for screen printing. Extensive X-ray Absorption Spectroscopy (XAS) analysis elucidates the co-ordination of Cu in a NiOx matrix and indicates the presence of around 5.4% Cu in the sample. We fabricated a monolithic perovskite module on a 100 cm(2) glass substrate (active area of 70 cm(2)) with a thin Cu:NiOx layer (80 nm), where the champion device shows an appreciated power conversion efficiency of 12.1% under an AM 1.5G illumination. To the best of our knowledge, this is the highest reported efficiency for such a large area perovskite solar device. I-V scans show that the introduction of Cu:NiOx mesoporous scaffold increases the photocurrent, and yields fill factor (FF) values exceeding 57% due to the better interface and increased hole extraction efficiency. Electrochemical Impedance Spectroscopy (EIS) results reinforce the above results by showing the reduction in recombination resistance (R-rec) of the PSCs that incorporates Cu:NiOx interlayer. The perovskite solar modules with a Cu:NiOx layer are stable for more than 4500 h in an ambient environment (25 degrees C and 65% RH), with PCE degradation of less than 5% of the initial value.
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| 17. |
- Bera, Suman, et al.
(författare)
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Limiting Heterovalent B-Site Doping in CsPbI3 Nanocrystals : Phase and Optical Stability
- 2019
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Ingår i: ACS Energy Letters. - : AMER CHEMICAL SOC. - 2380-8195. ; 4:6, s. 1364-1369
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Tidskriftsartikel (refereegranskat)abstract
- B-site doping with various metal ions in alpha-CsPbI3 has been proven to be a potential approach in bringing phase stability to these nanocrystals. However, while the doping of various homovalent ions in replacing Pb(II) has been extensively studied, heterovalent doping was observed to be limited. To understand the impact of heterovalent doping, Sb(III) was chosen here as an effective dopant for occupying the Pb(II) position in CsPbI3 nanocrystals. Importantly, it was observed that insertion of Sb(III) also stabilized the crystal phase of these red-emitting nanocrystals, but only with limited doping. However, with more intake, the cube shape turned to platelet and therefore also reduced the stability. Details of the insights of formation of these doped nanostructures are investigated, and further, these were implemented for photovoltaic application and comparable efficiency was recorded.
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| 18. |
- Bhattacharya, Prosun, 1962-, et al.
(författare)
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Prevalence of SARS-CoV-2 in Communities Through Wastewater Surveillance—a Potential Approach for Estimation of Disease Burden
- 2021
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Ingår i: Current Pollution Reports. - : Springer Nature. - 2198-6592. ; 7:2, s. 160-166
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Tidskriftsartikel (refereegranskat)abstract
- The episodic outbreak of COVID-19 due to SARS-CoV-2 is severely affecting the economy, and the global count of infected patients is increasing. The actual number of patients had been underestimated due to limited facilities for testing as well as asymptomatic nature of the expression of COVID-19 on individual basis. Tragically, for emerging economies with high population density, the situation has been more complex due to insufficient testing facilities for diagnosis of the disease. However, the recent reports about persistent shedding of viral RNA of SARS-CoV-2 in the human feces have created a possibility to track the prevalence and trends of the disease in communities, known as wastewater-based epidemiology (WBE). In this article, we highlight the current limitations and future prospects for WBE to manage pandemics.
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| 19. |
- Callini, Elsa, et al.
(författare)
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Nanostructured materials for solid-state hydrogen storage : A review of the achievement of COST Action MP1103
- 2016
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Ingår i: International journal of hydrogen energy. - : Elsevier. - 0360-3199 .- 1879-3487. ; 41:32, s. 14404-14428
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Tidskriftsartikel (refereegranskat)abstract
- In the framework of the European Cooperation in Science and Technology (COST) Action MP1103 Nanostructured Materials for Solid-State Hydrogen Storage were synthesized, characterized and modeled. This Action dealt with the state of the art of energy storage and set up a competitive and coordinated network capable to define new and unexplored ways for Solid State Hydrogen Storage by innovative and interdisciplinary research within the European Research Area. An important number of new compounds have been synthesized: metal hydrides, complex hydrides, metal halide ammines and amidoboranes. Tuning the structure from bulk to thin film, nanoparticles and nanoconfined composites improved the hydrogen sorption properties and opened the perspective to new technological applications. Direct imaging of the hydrogenation reactions and in situ measurements under operando conditions have been carried out in these studies. Computational screening methods allowed the prediction of suitable compounds for hydrogen storage and the modeling of the hydrogen sorption reactions on mono-, bi-, and three-dimensional systems. This manuscript presents a review of the main achievements of this Action.
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| 20. |
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| 21. |
- Chakraborty, Sudip, et al.
(författare)
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Current computational trends in polyanionic cathode materials for Li and Na batteries
- 2018
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Ingår i: Journal of Physics. - : Institute of Physics (IOP). - 0953-8984 .- 1361-648X. ; 30:28
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Forskningsöversikt (refereegranskat)abstract
- A long-standing effort has been devoted for the development of high energy density cathodes both for Li-and Na-ion batteries (LIBs and SIBs). The scientific communities in battery research primarily divide the Li- and Na-ion cathode materials into two categories: layered oxides and polyanionic compounds. Researchers are trying to improve the energy density of such materials through materials screening by mixing the transition metals or changing the concentration of Li or Na in the polyanionic compounds. Due to the fact that there is more stability in the polyanionic frameworks, batteries based on these materials mostly provide a prolonged cycling life as compared to the layered oxide materials. Nevertheless, the bottleneck for such compounds is the weight penalty from polyanionic groups that results into the lower capacity. The anion engineering could be considered as an essential way out to design such polyanionic compounds to resolve this issue and to fetch improved cathode performance. In this topical review we present a systematic overview of the polyanionic cathode materials used for LIBs and SIBs. We will also present the computational methodologies that have become significantly relevant for battery research. We will make an attempt to provide the theoretical insight with a current development in sulfate (SO4), silicate (SiO4) and phosphate (PO4) based cathode materials for LIBs and SIBs. We will end this topical review with the future outlook, that will consist of the next generation organic electrode materials, mainly based on conjugated carbonyl compounds.
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| 22. |
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| 23. |
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| 24. |
- Chakraborty, Sudip, et al.
(författare)
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Quantum Confinement Effect in Pristine and Oxygen Covered Silicon Nanocrystals with Surface States
- 2011
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Ingår i: Journal of Computational and Theoretical Nanoscience. - : American Scientific Publishers. - 1546-1955 .- 1546-1963. ; 8:9, s. 1739-1743
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Tidskriftsartikel (refereegranskat)abstract
- Absorption spectra for pristine silicon and oxygen capped silicon nanocrystals (ncs) are computed using time dependent local density approximation (TDLDA) in the size regime of 1.0 to 1.5 nm. These clusters show very small highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gaps. This indicates presence of surface states. The partial density of states (PDOS) for these clusters confirms the presence of surface states when compared to the corresponding ncs with hydrogen passivation. The HOMO–LUMO gaps do not show any size dependence. However the optical absorption gaps show the quantum confinement effect (QCE) for both the types of clusters. The oxygen capped silicon ncs are prepared following the wet chemical route. The optical absorption spectrum of experimentally prepared ncs is compared with the computed one. Experimental results support the theoretical argument explaining the QCE in these clusters.
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| 25. |
- Chakraborty, Sudip, et al.
(författare)
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Rational Design : A High-Throughput Computational Screening and Experimental Validation Methodology for Lead-Free and Emergent Hybrid Perovskites
- 2017
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Ingår i: ACS Energy Letters. - : American Chemical Society (ACS). - 2380-8195. ; 2:4, s. 837-845
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Tidskriftsartikel (refereegranskat)abstract
- Perovskite solar cells, with efficiencies of 22.1%, are the only solution-processable technology to outperform multicrystalline silicon and thin-film solar cells. Whereas substantial progress has been made in scalability and stability, toxicity concerns drive the need for lead replacement, intensifying research into the broad palette of elemental substitutions, solid solutions, and multidimensional structures. Perovskites have gone from comprising three to more than eight (CH3NH3, HC(NH2)(2), Cs, Rb, Pb, Sn, I, Br) organic and inorganic constituents, and a variety of new embodiments including layered, double perovskites, and metal-deficient perovskites are being explored. Although most experimentation is guided by intuition and trial-and-error-based Edisonian approaches, rational strategies underpinned by computational screening and targeted experimental validation are emerging. In addressing emergent perovskites, this perspective discusses the rational design methodology leveraging density functional theory-based high-throughput computational screening coupled to downselection strategies to accelerate the discovery of materials and industrialization of perovskite solar cells.
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