Potential applications in optoelectronics had generated a great interest on the study of graphene optical properties. Along with this, graphene has exceptional properties such as high mobility and optical transparency, flexibility, mechanical robustness, etc. Due to these properties, graphene could be used in different devices such as transparent conductors, organic light-emitting diodes, photodetectors, touch screens, saturable absorbers and ultrafast lasers. A transfer-matrix method is used in order to calculate graphene optical properties, such as transmission, and absorption in the infrared region. The quasi-periodic structure consists in intercalated graphene sheets between two consecutives dielectrics. The dielectric materials follow the Thue-Morse sequence (ThMo). The graphene sheets are described by the optical conductivity considering interband and intraband transitions. The structure of the spectra depends strongly on the number of sequence generation, width of the different dielectrics and dielectric permittivity. In our case, the infrared region corresponds to a chemical potential greater than kT. In the calculated spectra, the geometrical properties of the Thue-Morse sequence can be observed. We obtain absorption bands well defined.

Doped hafnium oxide (X-HfO2, X= Eu, Tb, Dy) thin films were deposited by experimental ultrasonic spray pyrolysis process. Doped Hf nano crystal (nc-X-Hf) embebed in the HfO2 matrix were obtained. The process was made at substrate temperature between 300 °C and 550 °C, showing at this higher temperature the monoclinic phase, which improve the dopants incorporation. Computational simulations were made to analyze molecular dynamics in advance to improve physical and chemical properties. Energy relaxation, and charge distribution behaviour demonstrated an atomic re-arranged to form the nano clusters of 5nm to 10 nm diameter. Vibrational modes were calculated. Photoluminescence (PL) spectra were obtained, as dopant function. Atomic Force Microscopy (AFM), X-ray diffraction and High Resolution Transmission Electron Microscopy (HRTEM) characterizations were made. Characteristics bright peaks appear in the Thermoluminescence (TL) spectra, and PL peak emission as well, of the Eu, Tb, Dy dopants in the HfO2 matrix. The results obtained show that nanocrystal structures embebed in a metal oxide matrix of HfO2 could be a prominent material to be used in radiation dosimetry, technological development, and radiological protection.

Many heterogeneous and flat two dimensional (2D) materials with finite band gap have been researched for its suitability in exotic applications. For instance, zinc oxide (ZnO) with honey comb structure has optimum band gap that makes it eligible for opto-electronic applications. Recently, our research group have found that pyrene based tetratopic ligands (PTL) are suitable for functionalizing ZnO nanorods. In this study, neat and defective 2D ZnO layer is functionalized with different pyrene based ligands with various functional groups. First principles calculations are done and the degree of affinity of pyrene ligands towards neat and defective ZnO sheets is compared.