Fig. 1: Basic characteristics of the donor PM6 and six pairs of symmetric and asymmetric acceptors.
From: On the role of asymmetric molecular geometry in high-performance organic solar cells
a Molecular structures of polymer donor PM6 (poly((4,8-bis(5-(2-ethylhexyl)-4-fluoro-thienyl)benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl)-2,5-thiophenediyl(5,7-bis(2-ethylhexyl)-4,8-dioxo-4H,8H-benzo[1,2-c:4,5-c′]dithiophene-1,3-diyl)-2,5-thiophenediyl)) and acceptors (D represents electron-rich unit in blue dashed box, and A represents deficient unit in red dashed box and π represents conjugated bridging unit in the gray circle). b Normalized absorption spectra of twelve acceptors in CHCl3 solution and thin films. c Energy level alignment of PM6 and all acceptors via CV measurement. d 2D GIWAXS images of pristine acceptor films and blend films. e GIWAXS intensity profiles of the corresponding films along the in-plane and out-of-plane directions.
