Active Polymer Center for Pattern Integration, Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, South Korea.
ChemSusChem. 2012 Nov;5(11):2173-80. doi: 10.1002/cssc.201200349. Epub 2012 Sep 3.
A solid-state polymerizable monomer, 2,5-dibromo-3,4-propylenedioxythiophene (DBProDOT), was synthesized at 25 °C to produce a conducting polymer, poly(3,4-propylenedioxythiophene) (PProDOT). Crystallographic studies revealed a short interplane distance between DBProDOT molecules, which was responsible for polymerization at low temperature with a lower activation energy and higher exothermic reaction than 2,5-dibromo-3,4-ethylenedioxythiophene (DBEDOT) or its derivatives. Upon solid-state polymerization (SSP) of DBProDOT at 25 °C, PProDOT was obtained in a self-doped state with tribromide ions and an electrical conductivity of 0.05 S cm⁻¹, which is considerably higher than that of chemically-polymerized PProDOT (2×10⁻⁶ S cm⁻¹). Solid-state ¹³C NMR spectroscopy and DFT calculations revealed polarons in PProDOT and a strong perturbation of carbon nuclei in thiophenes as a result of paramagnetic broadening. DBProDOT molecules deeply penetrated and polymerized to fill nanocrystalline TiO₂ pores with PProDOT, which functioned as a hole-transporting material (HTM) for I₂-free solid-state dye-sensitized solar cells (ssDSSCs). With the introduction of an organized mesoporous TiO₂ (OM-TiO₂) layer, the energy conversion efficiency reached 3.5 % at 100 mW cm⁻², which was quite stable up to at least 1500 h. The cell performance and stability was attributed to the high stability of PProDOT, with the high conductivity and improved interfacial contact of the electrode/HTM resulting in reduced interfacial resistance and enhanced electron lifetime.
一种固态聚合单体 2,5-二溴-3,4-丙二氧基噻吩（DBProDOT）在 25°C 下合成，生成一种导电聚合物聚（3,4-丙二氧基噻吩）（PProDOT）。晶体学研究揭示了 DBProDOT 分子之间的短层间距离，这使得在低温下聚合成为可能，所需的活化能较低，放热反应比 2,5-二溴-3,4-乙二氧基噻吩（DBEDOT）或其衍生物更高。在 25°C 下进行固态聚合（SSP）时，DBProDOT 得到了自掺杂状态的 PProDOT，带有三溴化物离子和 0.05 S cm⁻¹ 的电导率，明显高于化学聚合的 PProDOT（2×10⁻⁶ S cm⁻¹）。固态 ¹³C NMR 光谱和 DFT 计算表明，在 PProDOT 中存在极化子，并且由于顺磁展宽，噻吩中的碳核受到强烈的干扰。DBProDOT 分子深入渗透并聚合，用 PProDOT 填充纳米晶 TiO₂ 孔，作为无 I₂ 固态染料敏化太阳能电池（ssDSSC）的空穴传输材料（HTM）。引入有序介孔 TiO₂（OM-TiO₂）层后，在 100 mW cm⁻² 下能量转换效率达到 3.5%，至少稳定 1500 小时。电池性能和稳定性归因于 PProDOT 的高稳定性，其高导电性和改善的电极/HTM 界面接触导致界面电阻降低和电子寿命延长。
