Effect of 2,2-bithiophene additive on the photovoltaic behavior of P3HT/PCBM solar cells

• Main Authors: Hsiang-Wei Chu, 朱祥瑋
• Other Authors: Syang-Peng Rweil
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/ckd58b

碩士 === 國立臺北科技大學 === 有機高分子研究所 === 98 === Polymer solar cells have gained wide interest in the past few years. The most efficient polymer solar cells produced to date are bulk heterojunction (BHJ) photovoltaic devices based on the blend of poly(3-hexylthiophene) (P3HT) and fullerene derivatives, such as [6,6]-penyl-C61-butyric acid methyl ester (PCBM). The power conversion efficiency (PCE) of these devices was greatly improved by thermal annealing or solvent annealing. However, the performance of devices is very sensitive to the annealing conditions. Herein, we demonstrate a simple and rapid fabrication process that involves using 2,2-bithiophene (BT) as an accelerant to induce the P3HT crystallization and control the BHJ morphology. Such devices exhibit similar PCE performance to those of thermally annealed devices. The UV-visible spectrum and x-ray diffraction reveal that P3HT chains in the composite film are packed in an ordered structure. With the optimal BT/P3HT weight ratio of 0.4, the transmission electron microscope (TEM) image of the annealing-free film reveals a nanoscaled phase separation and interpenetrating network morphology like those of thermally annealed conventional film. These evidences demonstrate that this new approach is capable of applying on polymer solar cells with plastic substrate.