| 초록 |
We synthesized four SMAs (i.e., A1, A2, A3, and A4) with different halogenations at two different positions of inner side-chains and IC end-groups. It was found that appropriate halogenations on both the inner side-chains and IC end-groups of the SMA impact the pristine and blend morphologies; 1) SMAs featuring IC-F end-groups exhibit more enhanced molecular ordering and thin-film crystallinity than SMAs having IC-Cl end-groups, indicating the importance of the selection of a suitable halogen atom in IC end-groups. 2) The chlorination on the inner side-chains of SMA can promote its intermixing with PD and induce a favorable face-on packing orientation of the SMA, thus reducing the energetic disorder at the D/A interface and enhancing the PCE. As a result, the OSC based on A4 SMA featuring both IC-F end-groups and Ph-Cl side-chains achieved the highest PCE of 17.19%, enabled by the high crystallinity, improved charge mobility, and suppressed non-radiative Vloss. |
