Physical properties of cubic BaGeO3 perovskite at various pressure using first-principle calculations for energy renewable devices

Antiferromagnetic Semiconductor BaMnO3 Hexagonal Perovskite with a Direct Bandgap

The unique properties of direct bandgap semiconductors make it important to search for semiconductors exhibiting this phenomenon in perovskite materials. In this study, we employed first-principles calculations to investigate the crystal structures, magnetic configurations, and electronic properties of hexagonal perovskite BaMnO3 in its 4H and 6H phases. The results indicate that both structures exhibit antiferromagnetic characteristics, in which the Mn-O-Mn superexchange plays the dominant role in the 4H phase, although there is a competition between the Mn-Mn direct exchange interaction and the Mn-O-Mn superexchange interaction. In contrast, these two interactions exhibit harmonious coexistence in the 6H phase, and the two antiferromagnetic transitions occurring in the experimental phase should be related to the synergistic effect between them. Despite their different internal arrangements, they exhibit the same charge combination of Ba2+Mn4+O2-3. More importantly, both phases exhibit semiconductor properties with a direct bandgap, making it suitable to serve as an alternative material for photovoltaic and optoelectronic devices. In particular, the band gap of the 4H phase is just the right size to absorb visible light, and the 6H phase should be a potential candidate to absorb light in the ultraviolet region.

Experimental and numerical investigations on feasibility of inorganic KSnCl3 perovskite absorber and SWCNT-HTL for solar cells

Inorganic metal halide perovskite materials have attracted remarkable attention as light harvesters because of their promising optoelectronic merits and photovoltaic features like tunable band gaps, high charge carrier mobilities and greater absorption coefficients. In order to explore new inorganic perovskite materials for use in optoelectronic devices Potassium Tin Chloride (KSnCl₃) has been experimentally synthesized using a supersaturated recrystallization technique at ambient conditions. The resultant nanoparticle (NP) specimens were analyzed for optical and structural properties by characteristic available techniques including scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and UV visible spectroscopy. Experimental investigations about structure reveals that KSnCl₃ crystallizes in orthorhombic phase with particle size of 400-500 nm. SEM showed better crystallization and EDX confirmed the accurate structural composition. UV-Visible analysis indicated a prominent absorption peak at 504 nm, and the band gap is 2.70 eV. Theoretical investigations of KSnCl₃ were also carried out via AB-initio calculations in Wein2k simulation program using modified Becke Johnson (mBJ) and generalized gradient approximations (GGA). Optical properties like extinction coefficient k (ω), complex parts of dielectric constant (ε ₁, ε ₂), reflectivity R (ω), refractive index n (ω), optical conductivity L (ω) and absorption coefficient α (ω) were examined and it was observed that _. theoretical investigations were consistent with experimental findings. Incorporation of KSnCl₃ as an absorber material along with single walled carbon nanotubes as p-type materials in (AZO/IGZO/KSnCl₃/CIGS/SWCNT/Au) solar cell configuration have been investigated by SCAPS-1D simulation package. Open circuit voltage (V_oc) of 0.9914 V, short circuit current density (J_sc) of 47.32067 mA/cm² and a remarkable efficiency of 36.823% with has been predicted. Thermally stable KSnCl₃ may become potential source in manufacturing of photovoltaic and optoelectronic applications on large scale.

Opto-electronic and thermoelectric properties of MgIn2X4 (X = S, Se) spinels via ab-initio calculations

The structural behavior of MgIn₂X₄ (X = S, Se) has been elaborated by FP-LAPW + lo method as included in the Wien2k code. The stability of the phase has been confirmed by negative formation energy (-1.24 eV for MgIn₂S₄ and -0.78 eV for MgIn₂Se₄). The band gap dependent opto-electronic and thermoelectric properties are realized by modified Becke-Johnson exchange potential. The electronic band gap tuned from ultraviolet to visible (3.1 eV and 1.9 eV) by replacing the S with Se that motivated the studied spinels for photovoltaic and solar applications. Moreover, the attenuation of light, dispersion, transparency, reflection and energy loss when light scattered from material are discussed as function of energy. The thermal conductivity to electrical conductivity ratio, potential gradient and thermal efficiency in the range 0.78-0.80 are elaborated. The comparative study of opto-electronic and thermoelectric properties for energy harvesting increases the potential for optoelectronic than thermoelectric applications.