•Lead-free perovskite solar cell based on RbGeI3.•All inorganic perovskite solar cell.•Non-toxic renewable energy.
The toxic lead component of perovskite solar cells poses a hindrance to their ...commercialization. The state-of-art organic HTM, Spiro-OMeTAD has a high synthetic cost because of its complex synthesis procedure. In the present work, an all inorganic, lead free n-i-p planar RbGeI3-based PSC was demonstrated through SCAPS-1D simulation. The effect of various HTL and ETL materials, their thickness, thickness of perovskite layer, ETL doping concentration, HTL doping concentration, doping concentration of the absorber, defect density of perovskite layer, defect density of ETL/absorber and absorber/HTL interface, various back contacts, series resistance, shunt resistance and temperature on the performance of perovskite solar cell (PSC) has been analysed. The optimized device exhibited a power conversion efficiency (PCE) of 10.11%, fill factor (FF) of 63.68% and quantum efficiency (QE) of 90.3% in the visible range. This study demonstrates the potential of RbGeI3 as a perovskite material to achieve toxicity free renewable energy.
In search of novel, non-toxic and high performance materials for the use in quantum dot solar cells (QDSCs), we have investigated the effect of adatoms (nitrogen, boron and phosphorus) on carboxyl ...edge-functionalized graphene quantum dot (COOH-GQD) through the state-of-the-art first principles calculation based on density functional theory. The HOMO, LUMO and energy gaps are analysed in order to check the modulation in electronic properties by the foreign atom through hybrid functional B3LYP with 6-31G basis set. Binding mechanism, molecular electrostatic potential (MESP), and charge transfer are investigated to study the electron injection and charge separation in doped/undoped COOH-GQD. Optical properties show broad spectrum in the visible range favorable to harvest solar light. To envisage the application of adatom doped COOH-GQD in QDSC, the solar cell parameters such as open circuit voltage (Voc), Fill factor (FF), short circuit current density (Jsc) and efficiency (η) are presented. The efficiency of COOH-GQD increases by 22–30% after the substitutional doping of nitrogen, boron and phosphorus. Maximum efficiency is achieved in case of phosphorus doping due to its more electron donating nature which will inject more electrons in TiO2 surface. Our findings show that these new sensitizers based on GQD are promising candidates for QDSCs applications.
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•Adatoms improves electronic, optical and photovoltaic properties of COOH-GQD.•The efficiency of COOH-GQD increases by 22–30% after the substitutional doping.•The efficiency of P-COOH-GQD is maximum due to the high electron injection in TiO2.
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•Sensing behaviour of highly anisotropic borophene is investigated.•Borophene interaction with toxic gases: phosgene and carbon monoxide.•Structural and electronic properties of ...pristine and gas adsorbed borophene.•Change in the work function of borophene over adsorption.
Recently predicted and grown new single element two dimensional (2D) material borophene gathered tremendous research interest due to its structural, electronic and other properties. Using first principles based dispersion corrected density functional calculations, we have studied interaction of two toxic gases phosgene (COCl2) and carbon monoxide (CO) with borophene to understand the role of borophene as biosensor and carriers in drug delivery. The sensing behaviour of borophene towards COCl2 and CO has been studied by calculating the binding energy and electronic density of states (DOS). The change in the band structure, DOS, charge density and work function (WF) upon adsorption of gas molecules further confirms the sensing properties of borophene towards these molecules. The binding energy for COCl2 and CO molecules on borophene is −0.306 eV and −0.15 eV respectively which indicates that the COCl2 is adsorbed more favourably than CO over borophene. The WF is enhanced by 0.193 eV and 0.051 eV after the adsorption of COCl2 and CO over borophene. Short recovery time of 148 ns and 37 ns for COCl2 and CO has been predicted. These findings show that the borophene can be used as nanosensor to detect COCl2 and CO.
Perovskite solar cells (PSC) are the third‐generation solar cells, which have a low production cost and have achieved similar laboratory scale efficiencies as the first‐generation silicon solar ...cells. In the present work, we performed density functional theory calculations on the organic material, poly3‐(5‐carboxypentyl) thiophene‐2,5‐diyl regioregular (P3CPenT). The ground state and excited state properties of P3CPenT are calculated. The HOMO‐LUMO levels and electronic bandgap obtained from the calculations are compared with the experimental values for validation of the theory. A high electron reorganization energy and low hole reorganization energy ensures that P3CPenT aids the flow of holes and hinders the flow of electrons. The optical bandgap and low exciton binding energy indicates its potential as a hole transport layer (HTL). The ease of fabrication of P3CPenT is established by showing that the oligomer is soluble in dimethyl sulfoxide (DMSO), which is the most commonly utilized solvent for the fabrication of PSCs. The hydrophobic nature of P3CPenT as established by the present work shows that it is stable with moisture and would thus protect the underlying MAPbI3 perovskite layer from decomposing and hence improve its lifetime and stability. Fill factor (FF) of 78.07% and a power conversion efficiency (PCE) of 14.88% has been obtained for PSC with P3CPenT HTL.
Density functional theory (DFT) calculations on the organic material, poly3‐(5‐carboxypentyl)thiophene‐2,5‐diylregioregular (P3CPenT) undertaken in order to show it's applicability as hole transport layer (HTL) in perovskite solar cell (PSC). Fill factor (FF) of 78.07% and power conversion efficiency (PCE) of 14.88% obtained through SCAPS simulation.
Proton-exchange membranes (PEMs) consisting of sulfonated poly(ether sulfone) (SPES) with enhanced electrochemical properties have been successfully prepared by incorporating different amount of ...sulfonated graphene oxide (SGO). Composite membranes are tested for proton conductivity (30–90 °C) and methanol crossover resistance to expose their potential for direct methanol fuel cell (DMFC) application. Incorporation of SGO considerably increases the ion-exchange capacity (IEC), water retention and proton conductivity and reduces the methanol permeability. Membranes have been characterized by FTIR, XRD, DSC, SEM, TEM, and AFM techniques. Intermolecular interactions between the components in composite membranes are established by FTIR. The distribution of SGO throughout the membrane matrix has been examined using SEM and TEM and found to be uniform. The maximum proton conductivity has been found in 5% SGO composite with higher methanol crossover resistance.
The energy band gap of graphene, h-boron nitride, stanene, silicene, germanene, and phosphorene nanoribbons is investigated theoretically with two approaches. In the first approach, a set of ...equations to calculate the energy band gap of nanoribbons is deduced using the expression of Fermi velocity. The size dependency of the energy band gap so obtained confirms previous expressions. The second approach, however, determines resistivity by directly connecting quantity to the energy band gap using an electron-acoustical phonon scattering mechanism. For the calculation of the energy band gap and resistivity, the armchair configuration of nanoribbons is considered. It is observed that the transverse magnetic field influences the energy band gap and resistivity. The magnitude of the band gap is negative up to a certain value of the field and turns positive at a sufficiently higher field. The negative band gap can be interpreted as metallic behavior of the materials. The results of the work are useful in the determination of the energy band gap of nanoribbons for their nanoelectronic and optoelectronic applications as well as tuning the band gap using the applied magnetic field.
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•The possibility of using 2D CoOOH as a sensor for H2O2 and NH3 is investigated.•H2O2 is adsorbed more strongly over 2D CoOOH than NH3.•The Electronic band gap of 2D CoOOH increases ...after interaction with H2O2 and NH3.•NH3 increases the work function of 2D CoOOH by 2% and H2O2 decreases by 10%.•Higher selectivity of 2D CoOOH observed for H2O2 and NH3 than CO, CO2, NO and NO2.
To the chain of development of 2D materials, recently synthesized ultrathin cobalt oxy-hydroxide (CoOOH) nano sheets gain potential interest due to its structural, electronic and other properties. We have studied the interaction mechanism of two toxic gases hydrogen peroxide (H2O2) and ammonia (NH3) adsorbed over 2D CoOOH to understand the role of 2D CoOOH as a toxic gas sensor. We employ first principles based dispersion corrected density functional calculations to study the sensing behavior of 2D CoOOH towards H2O2 and NH3 by calculating adsorption energy, electronic band structure, density of states (DOS) and work function. The electronic band structure, DOS and work function of 2D CoOOH are modulated after adsorption of H2O2 and NH3 molecules. Adsorption of gas molecules confirms the sensing behavior of 2D CoOOH towards these molecules and depicts its use in a sensing device. The full phonon dispersion curves and phonondensity of states reveal the dynamical stability of 2D CoOOH. The calculated adsorption energy of H2O2 and NH3 molecules is −0.532 and −0.460 eV respectively which indicates the strong physisorption of these gases over 2D CoOOH. The ultrafast recovery time of 1239 and 1203 ns respectively were found for H2O2 and NH3 on 2D CoOOH. The work function which is 6.29 eV found for 2D CoOOH, decreases to 5.63 eV for H2O2 as it follows the reduction process on 2D CoOOH, and increases to 6.44 eV for NH3 molecules as it acts as oxidation gas on CoOOH. Our study reveals that the 2D CoOOH can be a better sensor for the H2O2 and NH3 gases than some traditional two-dimensional materials.
We propose a novel technique of dimensional engineering to realize low dimensional topological insulator from a trivial three dimensional parent. This is achieved by confining the bulk system to one ...dimension along a particular crystal direction, thus enhancing the quantum confinement effects in the system. We investigate this mechanism in the Half-Heusler compound LiMgAs with face-centered cubic (FCC) structure. At ambient conditions the bulk FCC structure exhibits a semi-conducting nature. But, under the influence of high volume expansive pressure (VEP) the system undergoes a topological phase transition (TPT) from semi-conducting to semi-metallic forming a Dirac cone. At a critical VEP we observe that, spin-orbit coupling (SOC) effects introduce a gap of Formula: see text 1.5 meV in the Dirac cone at high symmetry point Formula: see text in the Brillouin zone. This phase of bulk LiMgAs exhibits a trivial nature characterized by the Formula: see text invariants as (0,000). By further performing dimensional engineering, we cleave 111 plane from the bulk FCC structure and confine the system in one dimension. This low-dimensional phase of LiMgAs has structure similar to the two dimensional Formula: see text system. Under a relatively lower compressive strain, the low-dimensional system undergoes a TPT and exhibits a non-trivial topological nature characterized by the SOC gap of Formula: see text 55 meV and Formula: see text invariant Formula: see text = 1. Although both, the low-dimensional and bulk phase exhibit edge and surface states, the low-dimensional phase is far more superior and exceptional as compared to the bulk parent in terms of the velocity of Fermions (Formula: see text) across the surface states. Such a system has promising applications in nano-electronics.
Fullerene-based biosensors have received great attention due to their unique electronic properties that allow them to transduce electrical signals by accepting electrons from amino acids. Babies with ...MSUD (maple syrup urine disease) are unable to break down amino acids such as l-leucine, and excess levels of the l-leucine are harmful. Therefore, sensing of l-leucine is foremost required. We aim to investigate the interaction tendencies of size-variable fullerenes (C X ; X = 24, 36, 50, and 70) toward l-leucine (LEU) using density functional theory (DFT-D3) and classical molecular dynamics (MD) simulation. The C24 fullerene shows the highest affinity of the LEU biomolecule in the gas phase. Smaller fullerenes (C24 and C36) show stronger interactions with leucine due to their higher curvature in water environments. Moreover, recovery times in the ranges of 1010 and 104 s make it a viable candidate for the isolation application of LEU from the biological system. Further, the interaction between LEU and fullerenes is in line with the natural bond order (NBO) analysis, Mulliken charge analysis, quantum theory atom in molecule (QTAIM) analysis, and reduced density gradient (RDG) analysis. At 310 K, employing the explicit water model in classical MD simulations, fullerenes C24 and C36 demonstrate notably elevated binding free energies (−24.946 kJ/mol) in relation to LEU, showcasing their potential as sensors for l-leucine. Here, we demonstrate that the smaller fullerene exhibits a higher potential for l-leucine sensors than the larger fullerene.
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Alkaline anion exchange membrane (AAEM) is the key component for alkaline exchange membrane fuel cells (AEMFCs). AAEMs with good ionic conductivity, excellent thermo-mechanical and ...alkaline stability were synthesized by chloromethylation and quaternization followed by alkalization of polyetherimide. Chloromethylation of polyetherimide, a key step in the synthesis of anion exchange membranes based on polyetherimide, frequently involves cancer-causing chemicals. Here, an approach towards the use of non-carcinogenic reagent has been implemented for the synthesis of AAEMs. Physiochemical properties of prepared membranes are tuned by varying tertiary amines. Derivatives during the membrane synthesis are characterized by proton NMR spectroscopy. FTIR spectroscopy confirms the successful quaternization of polyetherimide, and dense nature of membranes is cross-checked by SEM imaging. Synthesized anion exchange membranes show ionic conductivity in order of 2.68–3.22 × 10−2 S/cm complemented by ion exchange capacity of 1.58–2.07 meq/g. Under strong alkaline conditions 1 M KOH at 60 °C and 5 M KOH at room temperature, membranes are stable without losing their integrity. Based on preliminary studies, it is anticipated that functionalized polyetherimide may be a suitable candidate as an anion exchange membrane in fuel cell applications.
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