In summary, a series of new unsymmetrical push–pull A–D–A
small molecules based on different 5,15-dialkylated porphyrin
cores were designed and synthesized, which show good solubility
in common organic solvents, a broad absorption in the visible
and NIR regions, a relatively high hole mobility and good filmforming
properties of solution-processed BHJ OSCs. Based on the
blend film of CS-I/PC71BM spin-coated from a mixture of 3%
pyridine in chlorobenzene, a high PCE of 6.49% was achieved.
These primary results indicate that the A–D–A small molecules
based on meso-alkyl directly substituted porphyrin core are a new
class of donor candidates for highly efficient BHJ OSCs.