给体分子的三氟甲基取代基的结构调控及其聚合物太阳能电池

Thin film Polymer Solar Cells had been widely concerned due to the remarkable advantages in flexible wearable solar cell devices. Although the fluorated polymers were the only donor materials which PCEs were archived over 10% in PSCs, there were also disadvantages limited the commercial applications such as unsuitable HOMO energy levels, difficult for purifying, poor crystallization, inferior solubility, and especially the unsatisfactory hole mobilities. So the futher optimizations were needed to enhance their photo-voltaic performance..Trifluoromethyl group, which has the smallest size and the lowest steric hindrance of perfluorinated alkyls, has satisfactory electron withdrawing ability between fluorine and long ranged perfluoroalkyl groups. As been reported in literature, trifluoromethyl-substituted moleculars appeared good properties such as lower HOMO energy levels, better satblity, higher solubility, and stronger π-stacking. These suggested the great potentials for optimizing the morphology and energy levels as well as enhancing the solubility and photo-stability of the trifluoromethyl-substituted polymers of donor materials. Moreover, we can learn about the influence among the structure, morphology and photo-voltaic performance of the moleculars with the help of studying the properties such as energy level, morphology and interpenetrating polymer network of target polymers and the effect of the changes of these properties on photovoltaic performance induced by trifluoromethyl Substituent in PSCs.

聚合物薄膜太阳能电池因在柔性可穿戴太阳能电池器件上的优势而受到人们的广泛关注。其中含氟聚合物是目前仅有的能源转化效率超过10%的给体材料。但这类聚合物也存在HOMO能级较高，纯化困难，结晶性较差等不足，尤其是载流子迁移率不高限制了其商业化应用，因此还有进一步优化的空间。.三氟甲基作为一个最小的全氟基团，它的吸电性介于氟原子与全氟长烷基之间，位阻也远小于一般的全氟烷基，在文献报道中三氟甲基诱导下分子往往具有能级低，稳定性好，具有良好的溶解性和分子堆叠能力等特点。因此该取代基在对高效聚合物活性层材料的形貌调控和能级优化上具有相当的潜力,同时也能极大改善聚合物溶解性和光化学稳定性。通过研究三氟甲基诱导下聚合物其能级和空间结构的变化与混合薄膜尺寸和互穿网络结构的改变，及其对光伏性能的影响，有助于了解此时分子结构、形貌和光伏性能的相互影响因素，为进一步优化聚合物结构，制备高效太阳能电池提供理论依据。

聚合物薄膜太阳能电池因在柔性可穿戴太阳能电池器件上的优势而受到人们的广泛关注。但这类器件较低载流子迁移率也限制了其商业化应用，因此还有进一步优化的空间。三氟甲基的吸电性介于氟原子与全氟长烷基之间，位阻也远小于一般的全氟烷基，在文献报道中三氟甲基诱导下分子往往具有能级低，稳定性好，具有良好的溶解性和分子堆叠能力等特点。因此该取代基在对高效聚合物活性层材料的形貌调控和能级优化上具有相当的潜力,同时也能极大改善聚合物溶解性和光化学稳定性。通过研究三氟甲基诱导下聚合物其能级和空间结构的变化与混合薄膜尺寸和互穿网络结构的改变，及其对光伏性能的影响，有助于了解此时分子结构、形貌和光伏性能的相互影响因素，为进一步优化聚合物结构，制备高效太阳能电池提供理论依据。为此，本项目通过在给、受体上引入氟原子或三氟甲基基团，分别制备了含三氟甲基官能团的聚合物给体材料PBDT-TT-CF3以及含氟非富勒烯受体材料ITIF和含三氟甲基受体ITICF3，并将其运用到三组分有机太阳能电池中。发现加入适量含三氟甲基第三组分，可以有效提高器件短路电流，基于给体PBDT-TT-CF3的三组分器件，其载流子迁移率有一个数量级的提升，器件效率更是在较高膜厚下从二元的4.3%大幅度提高到了7.5%；而基于受体ITICF3的三元器件，其短路电流也从15.73 mA/cm2提高到17.59 mA/cm2。此外，通过对比，还发现含氟受体ITIF在提高短路电流的同时还能提高器件开路电压和填充因子，使得器件效率从二元的9.2%提高至三元的10.5%。由此可见，三氟甲基应用于三组分光伏器件中，更有利于提高器件电流和有效厚度。有理由相信该结果对利用最新的高效太阳能电池制备更高效率的三组分光伏器件也具备一定的指导意义。