Synthesis of new alternating conjugated copolymers consisting of tetrazine/carbazole or tetrazine/fluorene derivatives along with thiophene spacers for photovoltaic applications

► Tetrazine-carbazole (PCTz) and tetrazine-fluorene polymers were synthesized. ► The bandgap and HOMO level of PCTz were 2.23 and −5.32 eV, respectively. ► PCTz had a very high absorption coefficient. ► The open-circuit voltage of PCTz solar cells was very high. ► Under the same conditions, the power conversion efficiency was 2.13%.