In this research we have designed electron donors D-π-A type containing two different π fragments to obtain naphthopyrrole (D-NPR-A) and naphthotiophene (D-NTP-A) derivatives, proposed for the use in organic bulk hetero-junction (BHJ) solar cells (OSCs). These derivatives were characterized by DFT and TD-DFT calculations. For all the electron donors the anchorage fragment was 2-methylenemalononitrile, while the chromophore fragment was spanned between diphenylamine, triphenylamine, thiophene. Properties affecting open-circuit photovoltage (VOC) and short-circuit photocurrent (JSC) from D-π-A type derivatives, such as geometric structure, frontier-molecular orbital energies, exciton driving force energy, natural bond orbital analysis, absorption spectra and light harvesting efficiency. Energy from HOMO and LUMO orbitals was discussed. Theoretical calculations from TD-DFT within Coulumb attenuation method CAM-B3LYP were able to predict excited state properties. The electron donors D-π-A type exhibit photoelectric conversion efficiency above 10%, being the naphthopyrrole derivatives (D-NPR-A) along with the [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) the complexes with higher photoelectric properties, these complexes are proposed as photoactive materials in the construction of organic bulk hetero-junction solar cells.

A series of oligomers of 2 to 30 rings of the compound 4H-[1,2,4]-triazole, were computationally studied at level 6-31G(d) in order to evaluate their electro-conductive properties and contribute to design of novel electron carrier polymers (n-type). The band-gap predicted for polymer by extrapolation approach adopted a binomial-fitting scheme of second order, showed good agreement with experimental data. Also, the theoretical calculations show that doping processes improved the conduction in oligomers and polymers (1/n = 0), obtaining band-gap of 0.095 eV for n-type and 0.017eV for p-type respectively. It was found that the C-N, N-N and C-C bond lengths in the oligomers are strongly distorted in the charged state, implying the partial loss of aromaticity on triazole ring, probably caused by the formation of quinoid-like structures.

Se estudiaron computacionalmente una serie de oligómeros de 2 a 30 anillos del compuesto 4H-[1,2,4]-Triazol al nivel B3LYP/6-31G(d), con el fin de evaluar sus propiedades electro conductoras y contribuir con el diseño de nuevos materiales poliméricos transportadores de electrones (dopado n). La brecha de energía prohibida predicha para el polímero mediante extrapolación binomial de segundo orden, mostró buen acuerdo con los reportes experimentales. Asimismo, los cálculos teóricos mostraron que los procesos de dopado mejoraron notablemente la conducción de los diferentes oligómeros y polímeros (1/n = 0), obteniéndose brechas de energía prohibida de 0.095 eV para el dopado n y 0.017 eV para el dopado p respectivamente. Además, se encontró que las distancias de enlace C-N, N-N y C-C, son fuertemente distorsionadas en los oligómeros cargados, implicando con ello la pérdida parcial de la aromaticidad en el anillo triazólico, probablemente por la formación de estructuras quinoides.