Quantum Espresso Package Research Articles

First principles investigation of elastic, electronic and thermoelectric properties of lead-free Cs–X–I (X = Pb, Gd, Nd, Y) perovskites

Abstract Perovskites have become the center of recent research for their possible application in perovskite solar cells, owing to their desirable optical and electronic properties, flexibility, tunability, and low–cost fabrication. Most of the perovskites are however made of lead, which is a highly poisonous element. It is therefore necessary to seek alternative perovskites for this application that are less toxic. This study investigated the elastic, electronic, and thermoelectric properties of Cs–X–I (X = Pb, Gd, Nd, and Y) as possible replacements to the leaded CsPbI3 due to their less toxic nature. The density functional theory was utilized in the computations, with quantum espresso and BoltzTrap packages. The results showed that all the materials were structurally stable. The computed mechanical properties also showed that all the other materials had better elastic constants compared to those of CsPbI3. CsPbI3 was observed to exhibit the lowest band gap, unlike the others. Moreover, the other materials possessed higher elastic constants, electrical conductivities, and lowest thermal conductivities, which are highly needed in the perovskite solar cells. However, an experimental treatment needs to be done on the studied structures in order to confirm the properties obtained in this work.

CALCULATION OF ELECTRONIC PROPERTIES OF LiBX3 (B = Pb AND Sn; X = Br, Cl AND I) CUBIC PHASE BY DENSITY FUNCTIONAL THEORY

Perovskite solar cells utilize perovskite as the active material to convert sunlight into electrical energy. Perovskite is a compound with a crystal structure of ABX₃, where A and B are cations, and X is an anion, usually a halide. Research continues to find perovskites with high efficiency. This efficiency is related to the electronic structure, which can be analyzed using Density Functional Theory (DFT). In this study, the electronic structure of cubic phase LiBX₃ perovskites (B = Pb and Sn; X = Br, Cl, and I) is investigated using Quantum ESPRESSO software. Various parameters such as cut-off energy, k-points, and lattice constants were modified to obtain optimal values. From the optimization results, the band gap, DOS, and PDOS values for the six perovskites were obtained. The resulting band gap energy (Eg) are LiPbBr₃ at 1,71 eV, LiPbCl₃ at 1,87 eV, LiPbI₃ at 1,43 eV, LiSnBr₃ at 0,51 eV, LiSnCl₃ at 0,65 eV, and LiSnI₃ at 0,28 eV. These results show that the band gap energy values increase with the change in atomic radius from Sn to Pb and decrease with the change in atomic radius from Cl, Br to I. The electronic structure calculations of LiBX₃ (B = Pb and Sn; X = Br, Cl, and I) show semiconductor properties that have the potential to be used as light-absorbing materials in perovskite solar cells. This study states that LiBX₃ has great potential in solar cell applications and offers a deep understanding of the relationship between crystal structure and its electronic properties.

Deciphering the Conformations of Glutathione Oxidized Peptide: A Comparative NMR Study in Solution and Solid-State Environments.

Glutathione (GSH) and its oxidized dimer (GSSG) play an important role in living systems as an antioxidant, balancing the presence of reactive oxygen species (ROS). The central thiol (-S-S-) bond in GSSG can undergo free rotation, providing multiple conformations with respect to the S-S bridge. The six titratable sites of GSSG, which are influenced by pH variations, affect these conformations in solution, whereas in solids, additionally crystal packing effects come into play. In view of differing reports about the structure of GSSG in literature, we have here conducted an extensive reexamination of its conformations using NMR, and contrasting results have been obtained for solution and solid state. In solution, the existence of more than one antiparallel orientation of the monomer unit with different hydrogen bonding schemes has been indicated by NOE and amide temperature coefficient results. On the other hand, in the solid-state, a 1H-1H double-quantum (DQ) to 13C single-quantum (SQ) correlation study has confirmed a parallel orientation, consistent with the reported X-ray crystal structure. Experimentally assigned solid-state NMR resonances have been validated using GIPAW calculations incorporated in the Quantum ESPRESSO package.

A DFT study of the effect of hydrostatic pressure on the structure and electronic properties of sarcosine crystal

ContextWe perform density functional theory calculations to study the dependence of the structural and electronic properties of the amino acid sarcosine crystal structure on hydrostatic pressure application. The results are analyzed and compared with the available experimental data. Our findings indicate that the crystal structure and properties of sarcosine calculated using the Grimme dispersion-corrected PBE functional (PBE-D3) best agree with the available experimental results under hydrostatic pressure of up to 3.7 GPa. Critical structural rearrangements, such as unit cell compression, head-to-tail compression, and molecular rotations, are investigated and elucidated in the context of experimental findings. Band gap energy tuning and density of state shifts indicative of band dispersion are presented concerning the structural changes arising from the elevated pressure. The calculated properties indicate that sarcosine holds great promise for application in electronic devices that involve pressure-induced structural changes.MethodsThree widely used generalized gradient approximation functionals—PBE, PBEsol, and revPBE—are employed with Grimme’s D3 dispersion correction. The non-local van der Waals density functional vdW-DF is also evaluated. The calculations are performed using the projector-augmented wave method in the Quantum Espresso software suite. The geometry optimization results are visualized using VMD. The Multiwfn and NCIPlot programs are used for wavefunction and intermolecular interaction analyses.

Density functional theory study of cobalt sulfide as a counter electrode material for dye-sensitized solar cells

Abstract Dye-sensitized solar cells (DSSCs) are viewed as potential substitutes for traditional silicon-based solar cells due to their affordability, impressive performance in low-light conditions, eco-friendly energy production, and adaptability in solar product integration. The use of noble metals such as platinum as counter electrodes in DSSCs was initially limited by their high cost; however, cobalt sulfide has been recognized as a viable alternative due to its abundance, non-toxic properties, and cost-effectiveness. In this work, the crystal structure, electronic, optical characteristics and electrocatalytic activity of the tetragonal phases of cobalt sulfide are investigated through density functional theory with a quantum espresso package. The results obtained for the lattice parameter are a = b = 3.53 Å and c = 4.80 Å. The generalized gradient approximation and hybrid exchange correlation function yield bandgaps of 1.63 and 1.69 eV, respectively, which are consistent with the reported experimental values. An analysis of the density of states and the projected density was carried out to validate the accuracy of the calculated band gaps. Additionally, significant information was obtained from the optical properties through the calculation of the dielectric function. The findings reveal real and imaginary static dielectric constants of 11.85 and 0.13, respectively. Furthermore, the measured absorption and conductivity spectra exhibit promising attributes in the UV–visible range and good electrical conductivity. Moreover, the electrocatalytic activity was studied to analyze the adsorption energy of CoS and the electrolyte. Generally, the calculated electronic and optical properties of CoS crystals indicate their potential application as counter electrodes in dye-sensitized solar cells.

Stability analysis of SnO2 surfaces using First-Principles computational methods

Abstract This study focuses on investigating the structural and electronic properties of the most stable faces of SnO2 using the Quantum Espresso software. Structural properties were found applying the generalized gradient approximation (GGA-PBE) with ultrasoft pseudopotentials and plane wave basis sets. Methodology involved determining the cutoff of the set of plane waves, selecting appropriate k-points to represent the first Brillouin zone, and optimized the lattice parameters (a and c). Models were generated for each studied surface, with the most optimal being the one with the lowest energy. These results are based on the periodicity of infinite sets of surfaces, increasing the gaps of the vacuum layers. As a result of the calculations, a discrepancy of less than 1% was observed in the lattice parameters compared to previous publications. Furthermore, it was found that the (110) is the most stable surface, in agreement with results published using VASP.

Ab-initio investigation of the structural, mechanical, electronic, thermodynamic and optical properties of V2FeNiGe2 and Hf2FeNiSb2 double half-Heusler compounds

In the present work, using ab-initio density-functional theory methods based on the Quantum ESPRESSO package, we have investigated the structural, elastic, electronic and optical properties of 18–electron V2FeNiGe2 and Hf2FeNiSb2 double half-Heusler alloys. The calculated elastic properties suggest a ductile behavior with metallic bonding for V2FeNiGe2 and a brittle behavior with covalent bonding for Hf2FeNiSb2. The thermodynamic properties (Debye temperature, melting temperature) are also predicted and discussed for the studied alloys. The alloys are found to be semiconducting with indirect band gaps of 0.53eV for V2FeNiGe2 and 0.47eV for Hf2FeNiSb2. We also computed and analyzed their optical properties (dielectric function, optical conductivity, refractive index, absorption index and reflectance) and our calculations suggest that both materials have high absorption coefficient and optical conductivity in the UV as well as visible region. The results make them potential candidates for the manufacture of opto-electronic devices.

Ab-initio investigation of stability and electronic properties of new yttrium-based solid solution of double transition metal YMXTx (M= Ti and zr; X= C and N; Tx= H, O, and F) MXenes

In this study, an extensive examination was carried out to explore the stability, and physical characteristics of a novel solid solution comprising two transition metals, namely YMXTx (M = Ti and Zr; X = C and N; Tx = H, O, and F) MXenes. The Quantum-Espresso computational package which is based on density functional theory (DFT) and pseudopotential techniques has been employed for performing calculations. The results obtained from the investigation of the structural, dynamic, and mechanical stability revealed that the YTiX and YZrX MXenes exhibited remarkable stability. These findings strongly suggest the feasibility and potential success of experimental synthesis of these materials. Furthermore, the result of cohesive energy indicated that Nitride-based MXenes (Y(Ti/Zr)N) are more stable than Carbide-based MXenes (Y(Ti/Zr)C). By performing comprehensive calculations of the total density of states and band structures, using various approximations such as LDA, GGA, and GGA + HSE06, the investigation revealed a metallic behavior in YMX MXenes. Additionally, the analysis of the TDOS revealed the presence of a pseudogap close to the Fermi level. This observation provides further evidence for the structural stability of the investigated mentioned MXenes. After undergoing saturation with different functional groups, it was observed that the YTiNH2 and YTiNF2 MXenes displayed semiconducting behavior, whereas YZrNO2 is classified as a non-conductive material, and the remaining monolayers exhibit metallic properties. Analyses of charge density and electron localization functions confirmed the metallic behavior of the studied MXenes. Modifying the electronic band gap of 2D MXenes, while also preserving structural stability, could lead to enhancing the application of these materials in optoelectronic devices.

CH3NH3SnI3${\mathrm{CH}}_{\mathrm{3}}{\mathrm{NH}}_{\mathrm{3}}{\mathrm{SnI}}_{\mathrm{3}}$: Superior Light Absorption and Optimized Device Architecture with 31.93% Efficiency

AbstractThis research investigates and optimizes the perovskite solar cells. Initially, optoelectronic parameters of perovskite absorber materials, including , , and , are estimated using Density Functional Theory (DFT) principles implemented in the Quantum Espresso software. The absorption of light energy is examined, detailing electron transitions between the highest p energy states of halogens (I, Br, and Cl) in the VB and the lowest 5p energy states of tin in the CB. shows superior optical characteristics, surpassing and , and demonstrating more effective absorption within the visible spectrum than . Subsequently, a numerical analysis is conducted for a P–I–N configuration Fluorine doped Tin Oxide (FTO)////Anode using SCAPS‐1D software. The optimization process focuses on absorber thickness, defect density, acceptor density, and the work function (WF) of the anode materials. Simulation findings recommend a defect density () of for optimal performance, coupled with an absorber thickness of 1 µm. Examining the transformation from to through oxidation reveals that reducing the concentration of acceptors in the absorber layer (NA) significantly enhances device performance. Superior performance is achieved by a high WF anode material. This study not only contributes to advancing our understanding of lead‐free perovskite optoelectronics but also provides valuable insights for the development of highly efficient and stable solar cells.

Effect of Boron Substitution on Magnetic and Electronic Properties of Single-Layered Graphene Studied by Density Functional Theory Method

Abstract Graphene is a two-dimensional material that has special characteristics. The electronic properties of graphene show zero band gap conditions. The magnetic properties of graphene can be created by modifying the electronic properties through atomic substitution. In this research, we study the magnetic and electronic properties of single-layer graphene substituted with boron (B) atoms, because it has almost the same atomic radius as carbon (C) atoms, resulting in only small lattice deformation. The spin-polarized density functional theory (DFT) method implemented in the Quantum Espresso package was selected to perform the calculations. The simulated models are a 4×4×1 supercell of pristine graphene structure consisting of 32 C atoms and boron-substituted graphene with a variety number of atoms (B = 1 and 2 atoms). The results of band gap energy obtained after the structure was optimized are 0.19 and 0.21 eV (spin-down and spin-up) for G-B and 0.36 and 0.37 eV (spin-down and spin-up) for G-2B. Boron substitution in graphene opens the bandgap and shifts the Fermi energy level. It also influences the magnetic moment of the graphene layer, estimated at 0.22 and 0.06 μB/cell for G-B and G-2B, respectively. This research shows that modifying graphene by substituting boron makes the graphene material semiconductive and weakly magnetic.

Study of structural and mechanical properties of the C2CaNa half-Heusler alloy using density functional theory approach

The mechanical properties of the half-Heusler alloy C2CaNa using density functional theory approach as installed in Quantum Espresso software was examined. We observed that C2CaNa will be easily compressed due to the small value of its bulk modulus. The values of the lattice constant a0, elastic constants (C11, C12, C14), Young’s modulus E, Piosson’s ratio ν, Shear modulus G, Zener anitropy A, pressure derivative B′, and band-gap Eg were obtained. Also the Voigt approximation, Reuss approximation and the Voigt–Reuss–Hill average of the approximation were gotten. Calculated values of G/B ratio is 0.581; this shows that C2CaNa has low resistance opposed to shear deformation. The B/G ratio evaluated for C2CaNa is 1.72. This implies that C2CaNa is “brittle” in nature at ambient condition. Our calculated elastic constants (C11, C12, and C44) for C2CaNa satisfied the following mechanical stability conditions for cubic structure: C11 – C12 > 0, C44 > 0, and C11 + 2C12 > 0. The value of C12 is an indication that C2CaNa is mechanically stable. This examination gives important experiences into the primary dependability and mechanical way of behavior of this material, this will empower advance material plan and application.

Vacancy-ordered CsRbGeCl6 and CsRbGeBr6 perovskites as new promising non-toxic materials for photovoltaic applications: A DFT investigation

In this study, we have proposed novel vacancy-ordered double perovskites, CsRbGeCl6 and CsRbGeBr6, and conducted computational analyses to investigate their mechanical, optoelectronic and thermoelectric properties, for the first time. All calculations are performed using the Density Functional Theory (DFT) as implemented in the Quantum Espresso package. The two materials exhibit considerable chemical and mechanical stability, with CsRbGeCl6 additionally exhibiting thermodynamic stability. Using the PBE (SCAN) functional, the calculated band gap energies for CsRbGeCl6 and CsRbGeBr6 perovskites are 2.17 eV (2.57 eV) and 0.88 eV (1.23 eV), respectively. Consequently, the perovskites, particularly CsRbGeBr6, possess the optimal band gap energy for photovoltaic applications. Their excellent electronic properties are further supported by their remarkable optical properties spanning from visible to ultraviolet region, characterized by high absorption coefficients (up to 106 cm−1) and minimal reflectivity (below 23 %). Moreover, the analysis of their thermoelectric properties revealed that they exhibit the required characteristics as thermoelectric materials.

Investigating the Structural, Electronic and Magnetic Properties of Single Vanadium Atom Doped Germanene Monolayer using Density Functional Theory (DFT)

In this study, density functional theory (DFT) within generalized gradient approximation (GGA) as implemented in Quantum ESPRESSO package has been employed. The structural, electronic, and magnetic properties of single Vanadium atom (V)-doped germanene monolayer have been investigated. The doping is carried out in 2x2x1 supercell with 32 atoms which gives around 3.12% doping concentration. The results revealed that single V atom doped Germanene monolayer induced both ferromagnetic and antiferromagnetic behavior with total magnetic moment of about 0.77 μB and 1.95 μB respectively. Also the behavior of the pristine germanene remains unaffected by the single V doping. The stability of the doped system are investigated by calculating cohesive and binding energies. These results are in good agreement with many reported results in case of both graphene and silicene. It’s also suggested that, the single V-doped germanene monolayer can support the quantum anomalous Hall effect, which has significant potential for spintronic applications.Keyword: Density Functional Theory (DFT), Generalized Gradient Approximation (GGA), Structural, Electronic and Magnetic Properties, Doping, Germanene Monolayer

Novel vacancy-ordered RbKGeCl6 and RbKGeBr6 double perovskites for optoelectronic and thermoelectric applications: an ab-initio DFT study

The present study examines the key characteristics of new vacancy-ordered halide double perovskites, RbKGeCl6 and RbKGeBr6, encompassing the elastic, structural, mechanical, optoelectronic, and thermoelectric properties. The Density Functional Theory (DFT) was employed to perform the calculation of the properties, facilitating the evaluation of their potential applications in optoelectronic and thermoelectric devices. The DFT calculation was conducted using the Quantum Espresso package alongside the thermo_pw tool and the BoltzTraP codes. The results revealed that the two proposed compounds possess both chemical and mechanical stability with optimized lattice constants recorded at 10.14 Å and 10.72 Å for RbKGeCl6 and RbKGeBr6, respectively. The evaluation of the elastic properties of the materials suggested reasonably high mechanical moduli of the materials. Based on the calculated electronic properties, the materials are classified as direct gap semiconductors, with energy gap values of 2.11 eV for RbKGeCl6 and 0.80 eV for RbKGeBr6 using the GGA-PBE functional. Furthermore, the use of the SCAN approximation yields more reliable energy gap of 2.51 eV and 1.08 eV for the respective compounds. The materials exhibited a high absorption coefficient and a significantly low reflectivity within the visible-ultraviolet energy spectrum. These findings strongly suggest the promising properties of the materials under study for optoelectronic applications. Furthermore, the calculated thermoelectric properties of the materials, particularly the figure of merit, revealed the materials’ potential use as thermoelectric materials. The calculated figure of merit values of RbKGeCl6 and RbKGeBr6 were found to range from 0.73 to 0.75, respectively, between 300 K and 800 K. Despite being lower, these values are comparable to those of some well-established materials including SiGe alloys (0.95), Bi2Te3 (≈0.90), and PbTe (≈0.80).

Functions of tensile and compressive strain on electronic and optical properties of B-doped monolayer arsenene.

The structurals stability, electronic structure, density of states (DOS), and optical properties of B-doped arsenene under biaxial tensile and compressive strains were investigated using density functional theory (DFT) calculations. The doping system was found to exhibit good stability. The introduction of B atom transformed the originally indirect band gap of arsenene into a direct band gap. Under compressive strain, the band gap remained direct, gradually decreasing in value. In contrast, under tensile strain, the direct band gap occurred a transition into an indirect band gap, of which value initially increasing and then decreasing with an increasing strain. The static dielectric constant was increased under both compressive and tensile strains, but compressive strain had a stronger effect. Compressive strain led to an increase in the imaginary peak of the dielectric function, while tensile strain resulted in a decrease. Moreover, as compressive strain increased, the absorption and loss function peak initially blue-shifted and then red-shifted, while tensile strain caused a gradual red-shift of the absorption peak. All DFT calculations were performed using Quantum Espresso software; the structures were optimized using generalized gradient approximation (GGA-PBE), and electronic structure and optical properties are performed using Heyd-Sceria-Ernzerhof (HSE06). The cut-off energy was set as 70 Ry, the Monkhorst-Pack grid was set to 10 × 10 × 1, the atomic convergence criterion was set as 1.0 × 10-6 Ry, and the convergence criterion of interatomic force was set as 1.0 × 10-4 Ry/Bohr.

Computational analysis of MOF-functionalized polymeric membranes for wastewater treatment and applications

Contaminants in drinking water can cause several health issues. In this study, solution cast technology was used to create polycaprolactone (PCL) or graphene nanocomposite membranes with diameters ranging from 2 to 6 m. The industry of water purification has benefited greatly from the use of membrane separation processes. The membranes are also made of biocompatible, non-toxic, and environmentally friendly materials. We utilized PCL polymer solution that was dissolved in chloroform to create membranes, and we added graphene to the PCL polymer solution. Quantum espresso software was used to determine the band structure, DOS, and Fermi-energy. The results of this study’s inducible tests suggested that solution-cast PCL and polycaprolactone or graphene membranes might be a good choice for removing waste from water. According to the biological sensing component (enzymes, antibodies, entire cells, aptamers, tissues, molecularly imprinted polymers (MIPs) and DNA) or transducers (optical, electrochemical, piezoelectric, and thermal), biosensors are analytical devices. The transducer produces a signal corresponding to the concentration of the analyte when the target analyte interacts with the biological sensing component. A signal processor is used to boost the signal and display it. The industrial utilizations of Metal-Organic Frameworks (MOFs) have been a growing area of interest in recent years. Researchers are exploring the use of MOFs in various industrial applications such as gas storage, catalysis, drug delivery, and sensing.

β12-Borophene/Graphene Heterostructure as a High-Performance Anode Material for Li-Ion Batteries.

In the world of two-dimensional (2D) materials, various Borophene allotropes have gained significant attention for their remarkable specific capacity. However, the instability of monolayers has challenged experimental investigations of innovative approaches. Due to this limitation, in this work, graphene was investigated as a sublayer with the aim of providing stability to the β12-borophene monolayer. This study delves into the potential of a novel β12-borophene/graphene (β12-B/G) van der Waals (vdW) heterostructure using Quantum Espresso software based on vdW-corrected density functional theory. Our investigation includes exploring thermal and dynamical stability, adsorption energy, open circuit voltage, specific capacity, and diffusion barrier energy properties. Impressively, the calculated specific capacity reached 907 mAh/g, outperforming other 2D materials and heterostructures. The combination of a graphene layer not only ensures dynamical stability but also provides the adsorption energy of lithiumon the β12-borophene layer, simultaneously decreasing the diffusion barrier energy in comparison with the β12-borophene monolayer. The calculated open circuit voltage falls in the range 0.08-1.09 V, rendering it suitable for an overall average commercial voltage. For the borophene layer, the computed diffusion barrier energies are approximately 0.52 and 0.78 eV. Collectively, these findings underscore the potential of theβ12-B/G heterostructure as an advanced anode material for lithium-ion batteries.

Density Functional Theory Study on the Reactivity and Stability of Calix[n]arene-paba Complexes: Drug Sensor Application

As drug carriers, calixarenes are often investigated and employed in numerous sectors as host molecules. The use of calixarenes in drug delivery systems is a relatively new notion, despite the fact that countless studies have been conducted on calixarenes and their various applications. It is worthwhile to research the computational investigation of the host-guest interaction between calixarenes and para-aminobenzoic acid (PABA) in terms of their binding energy and band gap. The first principles study of PABA sensing by calix [4] arene (C4) and calix [6] arene (C6) based on density functional theory (DFT) was carried out in this study using Quantum ESPRESSO software. By using the computational method, the binding energy, as well as the band gap of C4, C6, PABA, and the novel complexes, C4-PABA, and C6-PABA, were calculated. Different interaction distances were used in the formation of complexes. Our results demonstrate the reduction of the band gap for both complexes. Furthermore, the calculated binding energy shows the promising stability of the complexes. This demonstrates the sensing ability of calixarenes towards PABA and the potential anti-cancer properties of calixarene-PABA in sunscreens.

Comprehensive performance analysis of perovskite solar cells based on different crystalline structures of MAPbI3

Perovskite solar cells (PSCs) have shown high optical absorption and consequently provide high conversion efficiency with stable performance. In our work, CH3NH3PbI3 (MAPbI3) as an absorber layer is analyzed for different crystalline structures. Cubic, tetragonal, and orthorhombic phases of perovskite material are investigated to check the impact of the crystalline structure on the solar cell performance. Both density of states and band structure are studied using Quantum-ESPRESSO package depending on density functional theory. Then, all relevant parameters were employed in SCAPS software and comprehensive study was done for examining the effect of the crystalline structure of perovskite layer on the solar cell performance. In-depth, analyses were conducted to evaluate key parameters, including open circuit voltage (Voc), short circuit current (Isc), fill factor (FF), and power conversion efficiency (PCE) considering the variations of perovskite layer thickness and bulk defect densities. The obtained results indicate that cells with cubic MAPbI3, which shows a notably higher bandgap of 1.7 eV and an enhanced optical absorption coefficient, especially in the higher wavelength range (around 105 cm−1), show better performance for almost all three scenarios. Cubic MAPbI3 cells achieve relatively higher peak efficiency of 26% when the absorber layer thickness is almost 900 nm. The investigation into absorber bulk defect densities reveals the critical role of defect levels in PSC performance. Adjusting defect levels from 1014 cm−3 to 1018 cm−3 results in deteriorating trends in Voc, Jsc, FF, and PCE. Jsc remains stable until a defect level of 1017 cm−3, highlighting a threshold where defects begin to impact charge carrier generation and separation. Doping effect has been studied, PCE remains stable until a critical doping level of 1016 cm−3 after which it drops significantly which indicates that doping is cautioned against due to its adverse effects on material and carrier transport. This finding holds significant promise for experimental solar cell fabrication, as it suggests that cubic MAPbI3’s superior bandgap and enhanced optical absorption could lead to more efficient and robust photovoltaic devices in real-world applications.

Activation of carbon dioxide on zinc oxide surfaces doped with cerium

AbstractThe adsorption of carbon dioxide on the surfaces of zinc oxide doped with cerium was studied. For this, a theoretical study was carried out using computational simulations based on density functional theory to determine possible improvements in photocatalytic activity. for the capture and dissociation of carbon dioxide. Calculations were performed using density functional theory within the Perdew-Burke-Ernzerhof generalized gradient approximation, also the Hubbard correction together with ultrasmooth atomic pseudopotentials and a basic plane wave implemented in the Quantum-ESPRESSO package. The doping concentration level considered in this work was 6.25%, among the results, the semiconducting character of zinc oxide was evident from the density of states calculations, it was also found that by adding cerium impurities to zinc oxide, the values of the lengths and angles of the bonds vary a little, this may be due to the small difference in covalent radius that the zinc atom has with respect to the cerium atom, consequently, changes occurred in the electronic properties that consist in intermediate states in the energy bandgap located around the Fermi energy. This may suggest that the cerium-doped zinc oxide system can probably absorb visible light, which could lead to possible improvements in the photocatalytic properties of the material. Furthermore, we found that by adding carbon dioxide to the cerium-doped zinc oxide surface, the carbon dioxide is activated and this could suggest the dissociation or reduction of this contaminant.