Electrochemical synthesis of conjugated copolymer poly(3-hexylthiophene-co-dithenopyrrole): Stepwise approach to enhance electro-optical properties
Authors:   National Key Laboratory of Polymer and Composite Materials, Ho Chi Minh City University of Technology, Vietnam National University - Ho Chi Minh City, 268 Ly Thuong Kiet Street, Ward 14, District 10, Ho Chi Minh City, Vietnam, Le Nguyen Thao Phuong , Thi Nguyen Cam Hong ,   National Key Laboratory of Polymer and Composite Materials, Ho Chi Minh City University of Technology, Vietnam National University - Ho Chi Minh City, 268 Ly Thuong Kiet Street, Ward 14, District 10, Ho Chi Minh City, Vietnam, Luu Tam Hoang ,   Faculty of Materials Technology, Ho Chi Minh City University of Technology, Vietnam National University - Ho Chi Minh City, 268 Ly Thuong Kiet Street, Ward 14, District 10, Ho Chi Minh City, Vietnam, Truong Thuy Thu ,   National Key Laboratory of Polymer and Composite Materials, Ho Chi Minh City University of Technology, Vietnam National University - Ho Chi Minh City, 268 Ly Thuong Kiet Street, Ward 14, District 10, Ho Chi Minh City, Vietnam, Doan Bao Kim ,   National Key Laboratory of Polymer and Composite Materials, Ho Chi Minh City University of Technology, Vietnam National University - Ho Chi Minh City, 268 Ly Thuong Kiet Street, Ward 14, District 10, Ho Chi Minh City, Vietnam, Nguyen Thiet Quoc ,   Institute of Applied Materials Science, Vietnam Academy of Science and Technology, 1B TL29 Street, Thanh Loc Ward, District 12, Ho Chi Minh City, Vietnam, Nguyen Ha Tran ,   National Key Laboratory of Polymer and Composite Materials, Ho Chi Minh City University of Technology, Vietnam National University - Ho Chi Minh City, 268 Ly Thuong Kiet Street, Ward 14, District 10, Ho Chi Minh City, Vietnam,   Faculty of Materials Technology, Ho Chi Minh City University of Technology, Vietnam National University - Ho Chi Minh City, 268 Ly Thuong Kiet Street, Ward 14, District 10, Ho Chi Minh City, Vietnam
Published: December 2023

Electrochemical polymerisation of 3-hexylthiophene (3HT) and electrochemical copolymerisation of 3HT and N-benzoyl dithienopyrrole (BDP) were performed to prepare polymer and copolymer films using a linear sweep voltammetry potentiostatic technique with a voltage range from 1.7-1.8 V and a scan rate of 0.1 mV/s. Cyclic voltammetry (CV) curves, Fourier-transform infrared (FTIR) spectra, scanning electron microscope (SEM) images, and UV-Vis absorption spectra of the polymer and copolymer were recorded for analysis and comparison of the electropolymerisation process and properties of the resultant films. The SEM photographs of the copolymer base on 3HT and BDP exhibited a rigid structure with large spherical aggregates with an average size around 200 nm. The copolymer of 3HT and BDP exhibited the band gaps of 2.25 eV which was determined via electrochemical measurement that is higher than of band gaps of homopolymer poly(3-hexylthiophene) (P3HT). The copolymer’s energy bandgap HOMO-LUMO was enhanced compared to polymer P3HT. Moreover, the increased conjugation length significantly improved the morphology structure as well as the electrochemical stability of the conjugated copolymer.