| 초록 |
In search of novel blue-light emitting conjugated polymers, a quantum-chemical study of conformations and electronic structures of polyheterocycles fused with vinylenediheteroatoms at the 3- and 4-positions was performed. Conformational potential curves of the polymers were constructed as a function of the helical angle (α) through semiempirical Hartree-Fock band calculations at the Austin model 1 level. Electronic properties of the polymers were obtained through modified extended Huckel band calculations. It is found that poly(3,4-vinylenedioxythiophene) [PVDOT] possesses a quite flat curve ranging from α = 51.4° to 120°. Replacing O atoms with S atoms increases repulsion between the neighboring units, and thereby a deep minimum is found at α = 102.9°. Owing to the hydrogen bonding between O and NH, poly(3,4-vinylenedioxypyrrole) [PVDOP] is predictred to be anti-coplanar. On the other hand, poly(3,4-vinylenediaminofuran) [PVDAF] is estimated to be in a slightly distorted conformation with α = 160°. The HOMO-LUMO gaps of the polymers, except poly(3,4-vinylenedithiathiophene), in the most stable conformations are 2.9~3.5 eV, which meet the electronic requirement for blue-light emitters. |
