Modeling of the photophysical and photovoltaic properties of an active layer based on the organic composite poly(2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene-vinylene) (MEH-PPV)-poly(3-hexylthiophene) (P3HT): (6,6)-phenyl C61 butyric acid methyl ester (PCBM)

In this work, two different composite architectures have been investigated. These materials are formed by the block and ramified MEHPPV-P3HT copolymers mixing with the PCBM. Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT) calculation methods have been used to simulate the properties of the photo-physical and photovoltaic material. The results show that adding the PCBM decreases the HOMO-LUMO gap energy to approximately 1.4 eV compared to the basic copolymers. This reduction implies a higher charge transfer between the donor and acceptor materials. Therefore, these composites can be implemented as an active layer in bulk heterojunction organic solar cells. Furthermore, the coupling between the polymers MEH-PPV and P3HT improves their performance order by 5.2%.