Materials Department, University of California Santa Barbara, Santa Barbara, California 93106, United States.
J Am Chem Soc. 2012 Sep 26;134(38):15869-79. doi: 10.1021/ja305875u. Epub 2012 Sep 13.
The improvement of the power conversion efficiency (PCE) of polymer bulk heterojunction (BHJ) solar cells has generally been achieved through synthetic design to control frontier molecular orbital energies and molecular ordering of the electron-donating polymer. An alternate approach to control the PCE of a BHJ is to tune the miscibility of the fullerene and a semiconducting polymer by varying the structure of the fullerene. The miscibility of a series of 1,4-fullerene adducts in the semiconducting polymer, poly(3-hexylselenophene), P3HS, was measured by dynamic secondary ion mass spectrometry using a model bilayer structure. The microstructure of the bilayer was investigated using high-angle annular dark-field scanning transmission microscopy and linked to the polymer-fullerene miscibility. Finally, P3HS:fullerene BHJ solar cells were fabricated from each fullerene derivative, enabling the correlation of the active layer microstructure to the charge collection efficiency and resulting PCE of each system. The volume fraction of polymer-rich, fullerene-rich, and polymer-fullerene mixed domains can be tuned using the miscibility leading to improvement in the charge collection efficiency and PCE in P3HS:fullerene BHJ solar cells. These results suggest a rational approach to the design of fullerenes for improved BHJ solar cells.
通过合成设计来控制给电子聚合物的前沿分子轨道能量和分子有序性，通常可以提高聚合物体异质结（BHJ）太阳能电池的功率转换效率（PCE）。控制 BHJ 的 PCE 的另一种方法是通过改变富勒烯的结构来调节富勒烯和半导体聚合物的混溶性。使用模型双层结构，通过动态二次离子质谱法测量了一系列 1,4-富勒烯加合物在半导体聚合物聚（3-己基硒吩）P3HS 中的混溶性。使用高角度环形暗场扫描透射显微镜研究了双层的微结构，并将其与聚合物-富勒烯的混溶性联系起来。最后，从每个富勒烯衍生物制备了 P3HS:富勒烯 BHJ 太阳能电池，从而可以将活性层微结构与每个系统的电荷收集效率和最终的 PCE 相关联。使用导致电荷收集效率和 P3HS:富勒烯 BHJ 太阳能电池的 PCE 提高的混溶性，可以调节富勒烯丰富、聚合物丰富和聚合物-富勒烯混合域的体积分数。这些结果表明了一种设计用于改善 BHJ 太阳能电池的富勒烯的合理方法。
