Candidate For Solar Cell Applications Research Articles

In-situ surface reconstruction of CsPbl3 perovskite for efficient and stable solar cells

All-inorganic perovskite is a promising candidate for solar cell applications. However, a significant challenge lies in its poor phase stability to environmental moisture. To address this problem, we develop a strategy for in-situ reconstruction of the CsPbI3 surface using siloxane surfactants such as 3-aminopropyltriethoxysilane (APTES) and 3-aminopropyltrimethoxysilane (APTMS), which both demonstrate multifunctional roles in surface engineering. The siloxanes undergo air-induced hydrolysis, leading to the formation of Si-O-Si networks. Additionally, the –NH2 convert to –NH3+, enabling interaction with the I− ions on the surface of CsPbI3. This facilitates the formation of a self-assembled siloxane cross-linked ligand layer, which offers extra function for providing water and oxygen shielding, consequently stabilizing the surface of CsPbI3. Furthermore, the siloxane surfactants can passivate uncoordinated Pb2+ ions, resulting in a reduction of non-radiative recombination at the interface, thereby significantly augmenting device performance and stability. Following research comparisons, APTES with longer alkyl chains displays superior performance. As a result, with the APTES passivation, the PCE is increased from 19.01 % to 21.42 %, which is one of the highest PCE devices in pure CsPbI3 PSCs reported so far. Meanwhile, the devices treated with APTES show superior moisture stability over those without APTES, especially in the absence of encapsulation.

Unveiling the influence of end-capped acceptors modification on photovoltaic properties of non-fullerene fused ring compounds: a DFT/TD-DFT study.

Herein, unique A-D-A configuration-based molecules (NBD1-NBD7) were designed from the reference compound (NBR) by utilizing the end-capped acceptor modification approach. Various electron-withdrawing units -F, -Cl, -CN, -NO2, -CF3, -HSO3, and -COOCH3, were incorporated into terminals of reference compound to designed NBD1-NBD7, respectively. A theoretical investigation employing the density functional theory (DFT) and time-dependent DFT (TD-DFT) was performed at B3LYP/6-311G(d,p) level. To reveal diverse opto-electronic and photovoltaic properties, the frontier molecular orbitals (FMOs), absorption maxima (λ max), density of states (DOS), exciton binding energy (E b), open-circuit voltage (V oc) and transition density matrix (TDM) analyses were executed at the same functional. Moreover, the global reactivity parameters (GRPs) were calculated using the HOMO-LUMO energy gaps from the FMOs. Significant results were obtained for the designed molecules (NBD1-NBD7) as compared to NBR. They showed lesser energy band gaps (2.024-2.157 eV) as compared to the NBR reference (2.147 eV). The tailored molecules also demonstrated bathochromic shifts in the chloroform (671.087-717.164 nm) and gas phases (623.251-653.404 nm) as compared to NBR compound (674.189 and 626.178 nm, respectively). From the photovoltaic perspectives, they showed promising results (2.024-2.157 V). Furthermore, the existence of intramolecular charge transfer (ICT) in the designed compounds was depicted via their DOS and TDM graphical plots. Among all the investigated molecules, NBD4 was disclosed as the excellent candidate for solar cell applications owing to its favorable properties such as the least band gap (2.024 eV), red-shifted λ max in the chloroform (717.164 nm) and gas (653.404 nm) phases as well as the minimal E b (0.126 eV). This is due to the presence of highly electronegative -NO2 unit at the terminal of electron withdrawing acceptor moiety, which leads to increased conjugation and enhanced the intramolecular charge transfer (ICT) rate. The obtained insights suggested that the designed molecules could be considered as promising materials for potential applications in the realm of OSCs.

Electro-optic and thermoelectric reponse of SiP and SiAs for solar and thermal applications

Based on first-principles calculations, we investigated the electro-optic and thermoelectric properties of SiX (X = P, As). We find that the SiP (−0.17 eV/atom) is more favorable than SiAs (−0.12 eV/atom) due to higher formation energies. The dynamical stability is calculated from the phonon spectra, and the non-negative frequencies confirms the stable nature of SiX. Our calculated electronic band gap shows the semiconductor nature of the SiP, and SiAs with the band gap values of 2.33 eV, and 2.04 eV, respectively. Interestingly, the SiP possesses a direct band gap, which could be promising for optoelectronic devices. Additionally, we performed calculations by replacing P/As with Se atom, and observed that the semiconducting nature is alter to metallic one. The sharp peaks in the optical spectra confirms the electron transition from valance band to conduction band. The SiX (X = P, As) compound strongly absorbed light of energy 4.0 eV, which suggests it a potential candidate for solar cell applications. Furthermore, the compound exhibited the strong absorption of whole sun spectrum (ultra-violet to infra-red wave length), makes it capable for the applications in optical devices. Additionally, we have computed the thermoelectric properties using Boltztrap code. We have estimated the zT value 0.67 and 0.76 for SiP and SiAs, respectively. Both the SiAs and SiP exhibits a high zT, which could be applicable in the thermoelectric devices. Based on our calculated results, we anticipate that our studied materials could be an encouraging candidate for optical devices and thermoelectric devices.

Optical properties enhancement via WSSe/silicene solar cell junctions

A Janus–silicene heterojunction as a potential candidate for solar cell applications.

Band gap engineering in lead free halide cubic perovskites GaGeX3 (X = Cl, Br, and I) based on first-principles calculations.

Lead-free inorganic Ge-based perovskites GaGeX3 (X = Cl, Br, and I) are promising candidates for solar cell applications due to their structural, mechanical, electrical, and optical properties. In this work, we performed density functional theory (DFT) calculations using the CASTEP module to investigate these properties in detail. We found that the lattice parameters and cell volumes increase with the size of the halogen atoms, and that all the compounds are stable and ductile. GaGeBr3 has the highest ductility, machinability, and lowest hardness, while GaGeCl3 has the highest anisotropy. The band gap values, calculated using the GGA-PBE and HSE06 functionals, show a direct band gap at the R-R point, ranging from 0.779 eV and 1.632 eV for GaGeCl3 to 0.330 eV and 1.140 eV for GaGeI3. The optical properties, such as absorption coefficient, conductivity, reflectivity, refractive index, extinction coefficient, and dielectric function, are also computed and discussed. We observed that the optical properties improve with the redshift of the band gap as Cl is replaced by Br and I. GaGeI3 has the highest dielectric constant, indicating the lowest recombination rate of electron-hole pairs. Our results suggest that GaGeX3 (X = Cl, Br, and I) can be used as effective and non-toxic materials for multijunction solar cells and other semiconductor devices.

Phase Separation of Br-Doped CsPbI3: A Combined Cluster Expansion, Monte Carlo, and DFT Study.

Cluster expansion, which is a method that describes the concentration-dependent thermodynamic properties of materials while maintaining density functional theory accuracy, was used to predict new (CsPbIxBr1-x) structures. The cluster-expansion method generated 42 new stable (CsPb)xIyBrz (where x = 1 to 3 and y and z = 1 to 8) structures and these were ranked as meta-stable structures based on their enthalpies of formation. Monte Carlo calculations showed that CsPbI0.5Br0.5 composition separates into different phases at 300 K, but changes to a homogeneous phase at 700 K, suggesting that a different phase of CsPbI3 may exist at higher temperatures. Among the 42 predicted structures, randomly selected structures around iodide-rich, 50:50, and bromine-rich sites were studied further by determining their electronic, optical, mechanical, and thermodynamic properties using first-principle density functional theory. The materials possess similar properties as cubic Br-doped CsPbI3 perovskites. The mechanical properties of these compounds revealed that they are ductile in nature and mechanically stable. This work suggests that the introduction of impurities into CsPbI3 perovskite materials, as well as compositional engineering, can alter the electronic and optical properties, making them potential candidates for solar cell applications.

Comparative Properties Investigations of Organic Doped Hybrid-Perovskite Solar Cells

The intermediate-dimensional hybrid mixed-organic perovskite active layers PEA2(CH3NH3) n −1(PbI2) n and Dodec2(CH3NH3) n −1(PbI2) n with various n values were successfully fabricated. Their characteristics were compared to find out a promising candidate for solar cell applications. The appropriate layer thickness of the films was tuned by a variation of n values based on stoichiometry. The physical appearance, crystal structure, surface morphology, chemical bonding, optical properties, stability to the heat and humidity, and power conversion efficiency of all films were examined thoroughly to determine their potential. For low n values of both film types, they showed the quasi-2D characteristic improving the film stability and conversion efficiency. The absorption edge of both types of materials shifted to a higher energy side and the electronic band gap increased with the decrease of n values. The mixed phase and MAPbI3 perovskite diffraction peaks were still observable even after time has passed for 72 h. Under the 60% humidity condition, the PEA-doped MAPbI3 films decomposed slower than the Dodec-doped MAPbI3 films.

Bandgap tuning, mechanical and thermoelectric properties of Cs2CuScX6 (X = Cl, Br, I) halide ion substitution for optoelectronic devices using density functional theory

As a result of their exceptional optoelectronic properties, the growing need for renewable and sustainable energy has heightened interest in perovskites. Using DFT, mechanical, electronic, optical, and thermoelectric properties of double perovskites (DPs) Cs2CuScX6 (X = Cl, Br, I) were analyzed to gain a comprehensive understanding of these materials. To ensure structural and thermal stability, permissible values for the tolerance factor (tG) and energy of formation (ΔHf) have been determined. The bandgap values of Cl, Br, and I-based compositions are recorded as 1.9 eV, 1.80 eV, and 1.70 eV, respectively. According to their bandgap, Cs2CuScBr6 and Cs2CuScI6 DPs determine the suitability of the materials for use in ideal photovoltaic devices. Further, optical properties are investigated in the energy range 0–10 eV, indicating visible and ultraviolet absorption. The investigated compound Cs2CuScI6 exhibited the highest visible spectrum absorption, making it an ideal candidate for solar cell applications. Moreover, the BoltzTrap code have been used for thermoelectric behaviour for temperature shows that all double perovskites have high Seebeck coefficients and low thermal conductivities.

Ab initio insight into the structural, vibrational, electronic, optical, magnetic, and thermal properties of lead-free perovskite Cs3Sb2Cl9 for solar cell application

In recent years, semiconducting lead (Pb) free perovskite materials have become more attractive materials due to their less toxicity. In this study, we have investigated structural, electronic, optical, magnetic, and thermal properties of Pb-free Cs3Sb2Cl9 perovskite material using density functional theory. We have calculated the Energy-Volume (E-V) curve to evaluate the structural stability. The estimated lattice parameters for the studied material are a = b = 7.818 Å and c = 9.436 Å. Electronic properties suggest that Cs3Sb2Cl9 is a semiconductor material with a suitable energy band gap (Eg = 3.214 eV) for solar cell applications. Optical properties like high absorption, high optical conductivity, and peak reflectivity value in the visible region suggest that Cs3Sb2Cl9 is the most promising material for photovoltaic applications. Furthermore, the dynamic vibrational stability has been investigated as a calculated phonon energy dispersion curve, which shows that Cs3Sb2Cl9 is a dynamically stable compound. The spin-polarized calculations show that the material as a whole and even at the elemental bands level has zero resultant magnetic moments. We have also calculated thermodynamic properties, including enthalpy, free energy, and entropy. Therefore, the calculated results suggest that Cs3Sb2Cl9 is a potential candidate for solar cell applications.

PVC polymer/ZnO/NiO/Co3O4 nanocomposites: Toward improved optical properties

AbstractUndoped and doped polyvinyl chloride (PVC) with zinc, nickel and cobalt oxides, ZnO/[(1−x)NiO/xCo3O4], composites were fabricated using co‐precipitation and casting techniques. The different phases present in the nanofiller ZnO/[(1−x)NiO‐xCo3O4] mixed oxides were determined using synchrotron x‐ray diffraction technique. X‐ray diffraction, scanning electron microscopy (SEM) images and energy dispersive spectroscopy (EDS) analysis techniques were used to investigate the structure, composition, and morphology of pure and loaded PVC with nanofiller oxides. In general, compared with pure PVC, the absorbance was greatly enhanced, especially in the UV region, upon loading ZnO/[(1−x)NiO‐xCo3O4], but it changed irregularly with the cobalt oxide (Co3O4) content (x). The direct and indirect optical band gaps of pristine PVC (4.14, 4.12 eV) reduced irregularly to minimum values 3.97 and 3.23 eV respectively for the polymer doped with ZnO/[0.3NiO/0.7Co3O4]. The refractive index was enhanced in the visible and IR regions and attained its highest value for PVC doped with zinc oxide/nickel oxide (ZnO/NiO) only (x = 0.0). NiO and Co3O4 ratios affect the linear and nonlinear optical parameters. The emitted spectra from pure and doped PVC polymers with the composite oxides [ZnO/[(1−x)NiO‐xCo3O4] under different excitation wavelengths were also explored. The FL intensity enhanced for the excitation wavelengths (λexc) = 380 and 434 nm but quenched for λexc = 317 nm. The loaded polymers absorb UVA, UVB, and UVC rays and are good candidates for solar cell applications.

Exploring the structural properties and the optoelectronic features of RbPbX3 (X [formula omitted] Cl, F) perovskite crystals for solar cells solicitations: Showcasing the DFT predictions.

A comprehensive study of the structural, optical, and electronic properties of RbPbX3 (where X is Cl or F) perovskite crystals is reported herein. The calculations of the different physical properties of these two distinguishable RbPbCl3 and RbPbF3 perovskite crystals have been carried within the framework of the Density Functional Theory (DFT) approach for the cubic temperature-dependent phase. The study is motivated by the exploration of innovative perovskites materials for solar cells application due to the marvelous augmentation in power conversion efficiency (PCE) obtained by perovskite crystals (≈ 25% up to date). The investigation were undertaken for determining the perceivable role of the X element in their band gap energy features as well as the band structure proprieties. The simulations were commenced by determining the optimal lattice constants and the lowest total energy of both perovskite crystals. The exploration of the electronic properties of RbPbCl3 and RbPbF3 perovskite crystals have been studied by estimating their variation upon employing spin–orbit-coupling (SOC) and without taking into consideration the SOC interaction by means of LDA-pz and GGA-PBE exchange potentials within the framework of projector augmented wave method (PAW) and the Perdew–Burke–Ernzerh of LDA and (PBE) variant of the generalized gradient approximation (GGA). The integrated suite quantum-ESPRESSO is used for materials modeling, structure calculations, and electronic properties of the studied RbPbCl3 and RbPbF3 perovskite crystals. The thermo_pw driver is employed for the determination of the elastic properties whereas the optical properties were elucidated by aid of Yambo code through solving the many-body perturbation theory (MBPT) approach as introduced in the open-source code. The optical band gap of cubic RbPbCl3 and RbPbCF3 within LDA and PBE, were observed at (2.18, 2.2) eV and (2.4, 2.5) eV respectively. Compared and contrasted with those revealed by the electronic band gap energy of the systems, these obtained values are very consistent with the experimental. The two maximum peaks for the absorption coefficients are found to be within the visible range rending the two perovskite crystals in promising candidate for solar cell applications. Despite some quantitative differences, the material’s enhancement potential is well demonstrated by the absorption coefficient spectrum, refractive index, and conductivity. The study holds promise for solar cell applications and may pave the way for consideration of the RbPbCl3 and RbPbF3 as well as their doped analogs for perovskites-based solar cells as the next generation in the photovoltaic industry.

A DFT investigation of mechanical, optical and thermoelectric properties of double perovskites K2AgAsX6 (X = Cl, Br) halides

Focusing on renewable energy device applications, we explored double perovskites K2AgAsX6 (X = Cl, Br) halides for the first time. We used WIEN2k (all-electron method) and BoltzTrap code to investigate optoelectronic and thermoelectric properties for renewable energy device applications. For structural and elastic calculations, we employed PBEsol generalized gradient approximations and found that both halides in the cubic phase are structurally stable. Further, Pugh's and Poisson's predicted values indicate that both halides are ductile. Furthermore, we also calculate the formation energy to check the thermodynamical stability of both halides. For accurate calculations of optoelectronic properties, we applied Tran-Bhala modified Becke and Johnson potential (TB-mBJ). Electronic band structure calculations indicate both halides are indirect bandgap nature having values of 2.1 eV and 1.6 eV, respectively, and might be potential candidates for solar cell applications. We also discussed the optical parameters within the incident photon energy range of 0–12 eV. We found strong absorption in the visible region for K2AgAsX6 (X = Cl, Br) halides indicating both halides are appropriate solar cell devices. Lastly, we calculate thermoelectric parameters against temperature and chemical potential. A probing figure of merit shows halides is also potential candidates for thermoelectric device applications.

Theoretical description of structural, electronic, elastic, mechanical, and optical response of Ba1−xCdxTiO3 for optoelectronic applications

Barium titanate is well-known oxide-based perovskite with numerous potential applications in optoelectronic and energy storage devices. This manuscript aims to present an ab initio study to correlate effect of changes observed in electronic properties with structural, elastic, mechanical, optical and thermodynamic properties as well as acoustic behavior of Cd decorated barium titanate for optoelectronic applications. Cadmium (Cd) inclusion with varying concentrations (x = 0, 0.11, 0.33, 0.55, 0.77, 1) at Barium site was taken into consideration for a systematic study for the tunable character of material. For DFT study, Cambridge Serial Total Energy Package (CASTEP) under generalized gradient approximation was used. Cd substitution at Ba site has turned out to be effective for fine band gap tuning of barium titanate. The band gap gradually decreases except x = 0.11 and make new end material a conductor. Thus provide a way to design a device for optoelectronic application using a tunable band gap mechanism. To investigate the effect of band gap reduction as well as changes observed in other physical quantities, total and partial densities of states along with elemental density of states were computed. It is evident from the results that Cd surely introduces new states in pristine BaTiO3 (BTO), the main cause of electronic change. The question of stability of material was also addressed using extracted mechanical properties from calculated elastic constants and instituted concentrations separately to satisfyBorn’s stability criteria.Parameters based on Debye temperature and wave velocity calculations were also extracted to investigate thermodynamic and acoustic behavior of system.Optical response was evaluated and presented comparatively. Refractive index and static dielectric function increase to 3.24 and 10.50 respectively with gradual inclusion of Cd concentration. It is evident that the presented materials are not only lead-free for environment-friendly energy storage applications but also a promising candidate for solar cell applications because of ideal band gap range. Moreover, improved optical behavior of these materials is claimed to stand out for optoelectronic applications as well as thermoelectric properties.

Comparative Study on Structural and Optical Properties of Se85Te6Bi9 Nano-Thin Films Synthesized at Disparate Ambient Argon Pressures

In this research work, we have synthesized amorphous Se85Te6Bi9 Chalcogenide Glasses (ChGs) using Melt Quenching Technique. The glassy nature of the synthesized specimen was confirmed by the DSC thermogram plotted at the heating rate of 20 K/min. The nano-thin films of such synthesized samples at two disparate working pressures (1 torr and 3 torr) of ambient argon gas were made using the Physical Vapour Condensation Technique on the ultrasonically cleaned glass substrates. During the synthesis process of nano-thin films substrate temperature (77 K) was kept constant using liquid nitrogen and the thickness of prepared thin films was 40 nm. The morphological analysis of the prepared nanochalcogenide thin films using FESEM confirmed the nanochalcogenide particle size ranges from 20–80 nm. More aggregation and reduction in particle size on the substrates were observed with an increase in working pressure for Se85Te6Bi9 nano-thin films. HRXRD pattern confirmed the amorphous nature of the synthesized nano-thin films. Based on UV-Visible spectroscopy, the optical parameters such as optical absorption coefficients, optical direct band gaps and extinction coefficients were measured for synthesized Se85Te6Bi9 nanochalcogenide thin films. The value of absorption coefficients and extinction coefficients increases with the increase of ambient argon pressure, whereas the value of the optical direct band gap increases with increasing working pressure due to the quantum size effect and dominance of coulombic interactions. The estimated value of optical direct band gaps are 1.37 eV and 1.47 eV at 1 Torr and 3 Torr respectively making our synthesized nano-thin films a preeminent candidate for solar cell applications and other photonic devices.

Physical properties of the low-cost CZTS absorber layer deposited by spin-coating: effect of the copper concentration associated with SCAPS-1D simulation.

Five samples of copper zinc tin sulfide (CZTS) thin films were deposited by a spin-coating technique at various copper concentrations ranging from 0.5 M to 2.5 M in steps of 0.5 M, in order to improve their stability, efficiency, performance, and reduce the production costs. The XRD patterns showed the existence of the three main characteristic peaks of CZTS (112), (220), and (312), which indicated the formation of the kesterite structure of CZTS. The gap energy of the thin films was calculated based on the derivation method using the absorbance data, and the values obtained varied from 1.46-1.58 eV for 0.5, 1, 1.5, 2, and 2.5 M copper molarity, respectively. Hall effect measurements were used to determine conductivity, which in turn increased with the concentration of copper in the films. The characterization results showed that the sample C3, which represents the 1.5 M copper concentration, exhibited higher crystallinity and better optical and electrical performance than the others. Finally, a theoretical efficiency of 11.6% was obtained when simulating the solar cell using the CZTS thin film (CZTS/ZnS/S:ZnO) in the SCAPS-1D simulation program using the parameters obtained in this study. Under the adopted synthesis conditions, the theoretical simulation corroborated the experimental findings, thus confirming that the synthesized material is a promising candidate for solar cell applications as an absorber layer.

Donor‐π‐Acceptor N‐Methyl‐4,5‐Diazacarbazole Based Ultra‐High Performance Organic Solar Cells: A Density Functional Theory Study

Herein, a series of D‐π‐A conjugated molecules based on donor N‐methyl‐4,5‐diazacarbazole with a variety of acceptor end caps are quantum chemically proposed with aim of rational design of novel organic materials applicable in organic solar cells (OSCs) by using ab initio density functional theory (DFT) calculations. Herein, the optoelectronic performance of tailored molecules was explored by substituting the bay annulated indigo dye acceptor unit with a variety of molecules including 4‐(5‐methyl‐thiophene‐2‐yl)benzothiadiazole; 1, 2‐(3‐methyl‐5‐methylene‐4‐oxothiazolidin‐2‐ylidene)‐malononitrile; 2, 3‐methyl‐5‐methylene‐2‐thioxothiazolodin‐4‐one; 3, 2‐methylenemalononitrile; 4, 2‐cynaoacryli‐caidmethylester; 5, those are linked through the thiophene bridge. The DFT results encompassed the significant variations of electronic behavior of newly designed molecules (M1‐M5) with respect to the reference molecule, especially in the case of 1, 2, and 3 substitution. The designed molecules exhibit excellent electron transition due to the increasing λ max toward the higher region. The outcomes of this study proposed the designed molecules as a possible choice in designing efficient optoelectronic materials for OSCs. From the future point of view, this finding suggests that the pre‐synthesis of such hypothetical molecules using quantum mechanics is an effective strategy for designing ideal candidates for solar cell applications.

Pressure effect on the halide double perovskite Cs2TlBiCl6; Ab initio study

Motivated by its potential solar cell applications, we investigated the mechanical, electronic, and optical properties of the double halide perovskite Cs2TlBiCl6 in the cubic Fm3‾m phase using first-principles calculations. The obtained lattice parameters of the cubic structure are in good agreement with previous results. The thermodynamic stability of the system from the cohesive energy and the formation energy. Also, from the elastic constants calculations, we confirmed the mechanical stability of this material for cubic symmetry. The calculated B/G ratio and Poisson's ratio show that the Cs2TlBiCl6 system has a ductile nature and strong ionic bonds. The TB-mBJ potential was used to calculate the electronic and optical properties. The Cs2TlBiCl6 system showed a direct band gap that is in the visible region but the absorption is weak in the same region. By applying pressure, we found an increase and shift in the absorption spectrum in the visible region. This finding indicates that the Cs2TlBiCl6 system can be considered as potential candidate for solar cell applications.

Corrections of band gaps and optical spectra of N-doped Sb2Se3 from G0W0 and BSE calculations

Nitrogen (N) doped Sb2Se3 semiconductor material shows potential as promising candidate for solar cell application. However, accurate calculations of its basic physical properties have been lacking. In this paper, G0W0 band gap and absorption spectrum of N-doped Sb2Se3 were studied theoretically using G0W0 approximation in combination with Bethe-Salpeter Equation (BSE), which consider the effects of electron-electron (e-e) and electron-hole (e-h) interactions. These methods are chosen and converged carefully in order to yield quantitative results in agreement with experimental data. Our band structure results revealed that apart from a rigid shift of the conduction bands in the G0W0 approach the qualitative features with that obtained within bare DFT are identical. The calculated bandgap values for Sb15N1Se24, Sb14N2Se24, Sb16Se23N1 and Sb16Se22N2 with G0W0 approximation were found to be 1.02, 0.82, 0.92 and 0.81 eV, respectively. These results showed that the bandgap values reduced by substituting N atom at Se and Sb sites in comparison to the undoped Sb2Se3. Reduction of bandgap values by substituting N atoms at Sb and Se sites are in good agreement with previous works. In the BSE calculations, inclusion of e-e and e-h interactions lead to the existence of strong exciton below the G0W0 optical band gap. The value of optical gaps which corresponding to the first peak in the BSE calculations were found to be 0.89, 0.76, 0.86 and 0.76 eV for Sb15N1Se24, Sb14N2Se24, Sb16Se23N1and Sb16Se22N2 respectively. Our theoretical study of N-doped Sb2Se3 suggests that a device fabricated from this materials can be operated on a wide range of the energy scale such as solar cell and broadband photodetector.

Hydrogen Titanate H2TiO3 Nanowires Derived from K2TiO3 as Potential Materials for Solar Cell Applications: A Theoretical Study

AbstractOne‐dimensional systems of titanium dioxide and titanates are interesting for the fundamental study of physical and chemical properties at the nanoscale. In this work we present the electronic structure, mechanical and optical properties of angstrom scale titanate derived nanowires (ASW) by means of density functional theory (DFT) and Density Functional based Tight Binding (DFTB). This one‐dimensional H2TiO3 nanostructure is an interesting real material that could serve for understanding, at a fundamental level, the physical properties of TiO5 concatenated polyhedrons derived from hydrogen titanates. The proposed structural model demonstrates to be locally stable according to phonon analysis, and it can be inferred that the one‐dimension structure is essentially preserved. The mechanical properties put this nanowire as a flexible material, that could be used in flexible substrates maintaining its electronic properties. Also, the capacity of this system to be sensitized with a catechol dye was explored. For this porpoise, the adsorption of the catechol molecule was tested showing that the most stable interaction corresponds to a dissociative chelate configuration. Finally, it was possible to verify the capability of the sensitized system for injecting electrons from the catechol dye to the nanowire under visible light exposure. Thus, we present these extreme one‐dimensional nanostructured materials as candidates for solar cell applications.

Probing direct bandgap of double perovskites Rb2LiTlX6 (X = Cl, Br) and optoelectronic characteristics for Solar cell applications: DFT calculations

A fascinating novelclass of double perovskites materials with interesting optoelectronic and transport features have been discovered. In the current study, optoelectronics and the transport properties of Rb2LiTlX6 (X = Cl, Br) were comprehensively examined. Structure stability was confirmed by calculating tolerance factor value and Born stability criteria. At the Γ-symmetry point, direct band gaps of 2.90 eV and 1.66 eV are observed, ensuring spectral response throughout ultra-violet to visible areas and used as potential candidates for solar cell applications. These are excellent compounds for optoelectronic applications because of their low scattering of light, refractive index range approximately from 1.5 to 2, and wide absorption band in visible areas. Furthermore, thermal properties with the name electrical conductivity, thermal conductivity, Seebeck coefficient, power factor, and figure of merits of double perovskites were studied. The figure of merits (ZT) values of both compounds are 0.43, and 0.51 at room temperature, which confirms that these materials are suitable for use in thermal devices.