近年来,有机小分子(OSM)和单壁碳纳米管(SWCNT)的复合材料作为柔性热电(TE)材料引起了人们的广泛关注。这里,我们合成了噻吩并[2',3\':4,5]噻吩并[3,2-b]噻吩并[2,3-d]噻吩(TTA)和2,6-二溴噻吩并[2\',3\':4,5]噻吩并[3,2-b]噻吩并[2,3-d]噻吩(TTA-2Br)并将其与SWCNT复合,获得热电TTA/SWCNT和TTA-2Br/SWCNT复合材料。发现吸电子Br基团的引入降低了TTA-2Br的最高分子轨道能级和带隙(Eg)。因此,OSM/SWCNT复合薄膜的塞贝克系数(S)和功率因数(PF)显著进步。此外,TTA-2Br和SWCNT之间合适的能量势垒有利于能量过滤效果,这进一步提高了40wt%TTA-2Br/SWCNT复合膜的热电性能,具有最佳的热电性能(室温下PF=242.59±9.42μWm-1K-2),良好的热稳定性,机械灵活性。此外,使用40重量%TTA-2Br/SWCNT复合膜和n型SWCNT膜制备的热电发电器(TEG)在20°C的温差下可产生102.8±7.4nW的输出功率。这项工作为制备具有显着增强的热电性能的OSM/SWCNT复合材料提供了新的见解。
Composites of organic small molecules (OSMs) and single-walled carbon nanotubes (SWCNTs) have drawn great attention as flexible thermoelectric (TE) materials in recent years. Here, we synthesized thieno[2\',3\':4,5]thieno[3,2-b]thieno[2,3-d]thiophene (TTA) and 2,6-dibromothieno[2\',3\':4,5]thieno[3,2-b]thieno[2,3-d]thiophene (TTA-2Br) and compounded them with SWCNTs, obtaining thermoelectric TTA/SWCNT and TTA-2Br/SWCNT composites. The introduction of the electron-withdrawing Br group was found to decrease the highest molecular orbital energy level and bandgap (Eg) of TTA-2Br. As a result, the Seebeck coefficient (S) and power factor (PF) of the OSM/SWCNT composite films were significantly improved. Moreover, suitable energy barrier between TTA-2Br and SWCNTs facilitates the energy filtering effect, which further enhances thermoelectric properties of the 40 wt % TTA-2Br/SWCNT composite film with optimum thermoelectric properties (PF = 242.59 ± 9.42 μW m-1 K-2 at room temperature), good thermal stability, and mechanical flexibility. In addition, the thermoelectric generator (TEG) prepared using 40 wt % TTA-2Br/SWCNT composite films and n-type SWCNT films can generate an output power of 102.8 ± 7.4 nW at a temperature difference of 20 °C. This work provides new insights into the preparation of OSM/SWCNT composites with significantly enhanced thermoelectric properties.