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Provskite solar cells are new devices belonging to the third generation of photovoltaic solar cells. These solar cells are attracting much interest because of their high performance witnessing continuous improvement. In this work, numerical simulations of FTO/NiO/CH3NH3PbI3/(ZnO or TiO2)/Mn perovskite solar cells are performed using AMPS-1D simulator. Two electron transport layers (ETLs) are considered: zinc oxide and titanium oxide. Our perovskite solar cells have brought a wave of innovation to the field of photovoltaics due to their interesting efficiency rivaling established technologies like silicon cells, their simple and low-cost production since that CH3NH3PbI3can be formed using a spin-coating method, making the fabrication process significantly easier and cheaper compared to traditional techniques. Their excellent light absorption, along with their tunable bandgap are also advantageous parameters. This flexibility allows for tailoring the cell to absorb specific parts of the solar spectrum. The influence of the thickness and the doping concentration in the absorber layer and electron transport layer on the photovoltaic parameters (the short circuit current density Jsc,the open circuit voltage Voc,the fill factor FF and the power conversion efficiency (PCE)) is investigated. The best efficiency performance of 28.2% has been obtained for 300 nm thickness of the absorber layer and 260 nm thickness of TiO2as electron transport layer and a doping concentration of 1016cm− 3. The corresponding short-circuit current density is recorded to be 28.81 mA/cm2 whereas the open-circuit voltage is found to be 1.44 V.

A computational study based on the density functional theory calculations is carried out for the band structure and optical spectra of bulk, tri-layer, bi-layer and monolayer CdS system in the hexagonal-wurtzite structure. The aim of this contribution is to see how the electronic and optical properties of CdS change when moving from the bulk form to the monolayer one through tri-layer and bi-layer Cds systems. Our results show that the monolayer form still has a direct (Г-Г) band gap, but with an increased magnitude with respect to that of bulk CdS. The optical properties of the tri-layer, bi-layer and monolayer form are found to be different from those of the bulk form. An anisotropic character has been shown by the optical spectra for light polarized parallel and perpendicular to the x axis of the crystal. Our findings indicate that novel electronic and optical properties may be obtained when passing from bulk to tri-layer, bi-layer and monolayer CdS system.

The present study is concerned with the use of ZnMgO alloys as a potential replacement of the toxic CdS compound for the buffer layer in a ZnO/ZnMgO/CZTS solar cell structure. Simulations on the effect of the thickness of each layer constituting the solar cell have been performed using SCAPS simulator. The optimal values of these thicknesses corresponding to the best conversion efficiency have been determined. The obtained results are found to be 0.02, 0.02, 0.02 and 2 μm for ZnO:Al, ZnO, ZnMgO, and CZTS, respectively and give a conversion yield of 21.86% which compare well with the previous findings quoted in literature. Furthermore, the effect of the band gap energy of CZTS has been addressed. The best performance of our cell corresponds to a CZTS band gap energy in the vicinity of 1.4 eV.

•Energy bandgaps of InSb spherical quantum dots.•Electron effective and heavy hole mass of InSb spherical quantum dots.•Static- and high frequency dielectric constant.•Refractive index.•Transverse effective charge.

•Energy bandgaps of InSb spherical quantum dots.•Electron effective and heavy hole mass of InSb spherical quantum dots.•Phonon longitudinal and transverse optical frequencies.•Frӧhlich coupling constant.•Debye temperature of the LO phonon frequency.

The feasibility of a distributed Bragg reflector (DBR) based on wide band gap II-VI semiconducting alloys is reported. The reflectivity spectra of a Zn0.66Mg0.34Se/Zn0.74Cd0.26Se DBR are calculated within the stratified medium theory using matrix representation. The composition x for each alloy is taken in such a manner to obtain a convenient difference between the respective refractive indices of each constituent material. Both normal and oblique incidence are considered. For both cases the effect of the number of pairs has been studied. We found out that the reflectivity maximum is enhanced as the number of pairs increases. The DBR bandwidth is found to be dependent on the refractive indices difference. The reflectivity spectrum is shifted towards smaller wavelengths, and the Bragg wavelength is diminished as the angle of incidence is augmented.

The optical gain of a strained GaAs1−xNx/GaAs quantum-well laser has been calculated for a nitrogen concentration of 0.03 corresponding to a so-called dilute alloy. The effect of the density of carriers along with that of the quantum well width on the optical gain of the considered laser have been investigated and analyzed. Besides, the emitted wavelength has been also derived as a function of the quantum well width. Numerical results clearly show that by increasing the density of carriers and the quantum well width the optical gain is increased. The emitted wavelength is also enhanced as the quantum well width is augmented. The laser diode being studied here is shown to emit in the infrared-red region of the electromagnetic spectrum.

•The YN structural and elastic properties at normal and pressure are reported.•The phase transition from the NaCl structure to the CsCl structure is addressed.•The linear pressure coefficients of studied elastic moduli are also examined.•The dynamical stability criteria and the phonon dispersion have been considered.•The stability criteria are shown to be satisfied for YN under normal conditions.

•Elastic constants and related properties of rocksalt MgFeO.•Wave velocities at different directions for rocksalt MgFeO.•Various GGA approaches for the exchange-correlation potential.