Garcia-Basabe Yunier, Ceolin Denis, Zarbin Aldo J G, Roman Lucimara S, Rocco Maria Luiza M
Instituto de Química, Universidade Federal do Rio de Janeiro 21941-909 Rio de Janeiro RJ Brazil.
Instituto Latino Americano de Ciências da Vida e da Natureza, Universidade Federal da Integração Latino-Americana, UNILA 85866-900 Foz do Iguaçu PR Brazil
RSC Adv. 2018 Jul 24;8(46):26416-26422. doi: 10.1039/c8ra04629h. eCollection 2018 Jul 19.
The interfacial electronic structure and charge transfer dynamics of poly-3-hexylthiophene (P3HT) and multi-walled carbon nanotube (Fe-MWCNT) nanocomposites were investigated by near-edge X-ray absorption fine structure (NEXAFS) and resonant Auger (RAS) spectroscopies around the sulfur K-edge. Nanocomposites with 5 wt% (P3HT/Fe-MWCNT-5%) and 10 wt% (P3HT/Fe-MWCNT-10%) of Fe-MWCNT species were prepared and compared with pristine P3HT film. The quantitative NEXAFS analysis shows a strong π-π interchain interaction of the pristine P3HT polymer film, which is reduced by the presence of the Fe-MWCNT. S-KLL RAS spectra were measured at photon energies corresponding to the main electronic transitions appearing in the S-K edge NEXAFS spectrum. Ultrafast charge transfer times were estimated from the RAS spectra using the core-hole clock approach with the S 1s core-hole lifetime as an internal clock. The π-π interchain charge transfer time increases from 4.7 fs on pristine P3HT polymer to 6.5 fs on the P3HT/Fe-MWCNT-5% nanocomposite. The electronic coupling between P3HT and Fe-MWCNT species occurs mainly through the P3HT π* molecular orbital. The increase of Fe-MWCNT concentration from 5 to 10 wt% reduces the charge transfer rate at the resonance maximum due probably to Fe-MWCNT aggregation, reducing the P3HT and Fe-MWCNT electronic coupling.
通过硫 K 边附近的近边 X 射线吸收精细结构（NEXAFS）和共振俄歇（RAS）光谱，研究了聚-3-己基噻吩（P3HT）与多壁碳纳米管（Fe-MWCNT）纳米复合材料的界面电子结构和电荷转移动力学。制备了含有 5 重量%（P3HT/Fe-MWCNT-5%）和 10 重量%（P3HT/Fe-MWCNT-10%）Fe-MWCNT 物种的纳米复合材料，并与原始 P3HT 薄膜进行比较。定量 NEXAFS 分析表明，原始 P3HT 聚合物薄膜存在强烈的π-π链间相互作用，而 Fe-MWCNT 的存在使其减弱。在与 S-K 边 NEXAFS 光谱中出现的主要电子跃迁相对应的光子能量下测量了 S-KLL RAS 光谱。使用以 S 1s 芯孔寿命作为内部时钟的芯孔时钟方法，从 RAS 光谱估计超快电荷转移时间。π-π链间电荷转移时间从原始 P3HT 聚合物上的 4.7 飞秒增加到 P3HT/Fe-MWCNT-5%纳米复合材料上的 6.5 飞秒。P3HT 与 Fe-MWCNT 物种之间的电子耦合主要通过 P3HT π*分子轨道发生。Fe-MWCNT 浓度从 5 重量%增加到 10 重量%，可能由于 Fe-MWCNT 聚集，降低了共振最大值处的电荷转移速率，从而减少了 P3HT 与 Fe-MWCNT 的电子耦合。
