Optical transitions in new trends organic materials

The PTCDA (3,4,9,10-Perylene-tetracarboxylic dianhydride) and the NTCDA (1,4,5,8Naphtalenetetracarboxylic dianhydride) are aromatic, stable, planar and highly symmetric with unusual electrical properties. The PTCDA is a semiconductor organic crystalline of particular interest due to its excellent properties and electronic potential that are used in optoelectronic devices and the NTCDA it is monoclinic and its space group is similar to that of the PTCDA. Recently, alternate layers of PTCDA and NTCDA were growth forming multiple structures of quantum wells showing a new class of materials with new optic lineal properties. Some have assured that their big utilities would be centered in the construction of diodes and of possible guides of waves. We have carried out calculations semi-empirical of the electronic structures and of optic properties of the PTCDA and of the NTCDA that show us that they are structures highly orderly polymeric, semiconductors in a negative load state (charge state= -2).