In this work, the attention was focused on the synthesis of new low-band gap polymers and on the adopted chemical strategy aims on developing the so called push-pull copolymers: formed by a donor (push) and an acceptor (pull) electron unit in the polymer backbone. It was demonstrated that exploited building block approach can lead to copolymers with tunable physical properties. By selecting acceptor (benzothiadiazole or thienopyrrolodione derivatives) and donor (3,6-carbazole, 2,7-carbazole, dialkoxybenzodithiophene) units of different DA strength, it is possible to prepare copolymers through several C-C coupling methods. Detailed physico-chemical studies using complementary spectroscopic, electrochemical, diffraction and thermal techniques enabled the determination of synthesized push-pull copolymers properties, which are crucial for their photovoltaic application. Detailed studies on EPR under illumination and EPR tracing allowed the characterization of various electronic transfers in the presented and particularly designed push-pull copolymers, blended with two types of electron acceptor materials: PCBM and CuInS2 nanocrystals. DFT calculations supported the experimental results. Preliminary tests on synthesized copolymers were carried out taking into account all limiting factors concerning the device fabrication.
