Résumé:
The work presented inthe context of this thesis concerns the analysis of charge density of
organic photovoltaic compound with chemical formula C27H18AlN3O3 (Alq3) from a
spectrum of high-resolution X-ray diffraction on Powder (polycystal) of this compound,this
determination requires first a good quality recording of diffraction pattern of the materials
studied, followed by appropriate treatment of these intensities. We used the formalism of
Blessing for reducing these intensities taking into account the different experimental errors
that may have affected the measures, to get to the end the best structure factors that were used
in the analysis of the electron density. This work consists mainly of four parts: The first part
devoted to the descriptive study of the Alq3 and its structure and the industrial applications,
Part II presents the basics of the theory of X-ray diffraction on powders and data processing
and the study of the nature of X-rays and the interaction of radiation with matter (Bragg law)
and decomposition of the diagram then the refinement of structure and profile. the third part
presents the experimental device and the steps we have begun to record and cover the
spectrum of X-ray diffraction for solving and refinement of crystal structure, and the
determination of the crystal structure which involves two steps: the resolution and the
structure refinement and structural analysis of the molecule. During the resolution and the
structure refinement, program was used [ITO] among the programs [TREOR] and [DICVOL].
the resolution of the structure leads to coordinate positions xj, yj, zj, but the most interesting
for us chemists is the arrangement of atoms with each other, for this purpose, we describe the
structure of these bond lengths and valence angles and torsion angles, the last part reserved
for analysis of electronic charge density on the different plans of molecule at the level of each
compound, using the program (Mopro) with many methodes and their impact on the chemical
properties of this compound.
