Hicham Bouda

Owing to the growing demand for environmentally friendly technologies across a wide range of fields, including energy, environment and medicine, photocatalytic materials have gained a lot of interest in recent years. First-principles calculations were used in order to examine a variety of physical characteristics such as electronic density of states, structural, optical, and photocatalytic properties of pristine and rare-earth (RE = La, Pr, Eu) doped SrTiO₃. The reported electronic band gap of pristine SrTiO₃ is E_g = 3.03 eV, which is reasonably consistent with prior theoretical and experimental studies. On the other hand, related to Sr_(1−x)RE_xTiO₃, the obtained energy band gaps are 2.75 eV, 2.80 eV, and 2.90 eV associated with Eu-SrTiO₃, Pr-SrTiO₃, and La-SrTiO₃ respectively. The narrowing of the electronic band gap of the studied systems is due to the incorporation of RE-doped SrTiO₃, which greatly enhanced the visible light absorption spectra and photocatalytic properties. Thus, it can be concluded that adding RE elements to this kind of materials, is a suitable choice for optoelectronic and photocatalytic applications.

Thermoelectric compounds have the potential to produce electricity from waste heat, these materials are environmentally-friendly, which can play a key role on sustainable energy solution. This paper reports an investigation of electronic, optical and thermoelectric properties of two Half Heusler compounds TiNiSn and TiPtSn by employing density functional theory (DFT). Both compounds i.e. TiNiSn and TiPtSn exhibit an overestimated band gap with respective values 0.40 and 0.95 eV obtained by Tran Blaha modified Becke–Johnson functional (TB-mBJ) approximation, while, we found 0.113 and 0.84 eV within GGA + U (U = 6.13 eV) approximation, which are around other theoretical and experimental results. A detailed investigation of the obtained optical properties particularly, dielectric function, absorption, refractive index, and reflectivity of these compounds are given and discussed. Additionally, the transport properties of these compounds have been examined within Boltzmann statistics through BoltzTrap code, as well as certain thermoelectric parameters such as electrical conductivity, Seebeck coefficient and figure of merits are also determined. The obtained results reveal that the studied compounds are quite promising materials for thermoelectric applications.