A new quinoxaline-based conjugated donor polymer (PQTBDT), comprising an electron-donating benzodithiophene unit and electron-accepting cyanoquinoxaline was synthesized for bulk heterojunction-type polymer solar cell applications. The effects of morphology and solvent treatment of ZnO interlayer on the photovoltaic properties of PQTBDT-based PSCs were investigated through systemic characterization of morphology, UV–Vis absorption, transmittance, and charge recombination properties. Nano-ripple-structured ZnO electron transport layer enhanced both charge extraction capability and short circuit current density by enlarged interface contact area and light trapping effect, respectively. Additional solvent treatment using ethanolamine further reduced interface charge traps, resulting in higher shunt resistance compared to the devices based on planar ZnO layer. Combination of these two processes for ZnO interlayer optimized performance of PQTBDT-based solar cells with power conversion efficiency up to 6.50%.
This work was supported by a grant from the Priority Research Centers Program ( 2019R1A6A1A11051471 ) funded by the National Research Foundation of Korea (NRF) , and also supported by the NRF funded by the Ministry of Science and ICT ( NRF-2021K1A4A7A03093851 and NRF-2021R1A2C1007304 ). This research was also supported by Basic Science Researches through the NRF under program number ( NRF-2021R1A2C1003755 ).
