fig1
![Unraveling the main chain effects of fused thiophene conjugated polymers in electrochromism](https://image.oaes.cc/b3ae5c60-3d68-4623-a906-5b19a85a5869/4408.fig.1.jpg)
Figure 1. Optimized molecular geometries and frontier molecular orbital distributions of T, TT and DTT using density functional theory by Gaussian 09 at the B3LYP/6-31G(d,p) level. LUMO: Lowest unoccupied molecular orbital; HOMO: highest occupied molecular orbital; T: thiophene; TT: thieno[3,2-b]thiophene; DTT: dithieno[3,2-b:2’,3’-d]thiophene.