標題: Di(4-methylphenyl)methano-C-60 Bis-Adduct for Efficient and Stable Organic Photovoltaics with Enhanced Open-Circuit Voltage
作者: Cheng, Yen-Ju
Liao, Ming-Hung
Chang, Chih-Yu
Kao, Wei-Shun
Wu, Cheng-En
Hsu, Chain-Shu
應用化學系
Department of Applied Chemistry
關鍵字: C-60 bis-adduct;open-circuit voltage;morphological stability;organic photovoltaics
公開日期: 13-九月-2011
摘要: A new class of fullerene bis-adducts di(4-methyl-phenyl)methano-C-60 bis-adduct (DMPCBA), di(4-fluorophenyl)methano-C-60 bis-adduct (DFPCBA), and diphenylmethano-C-60 bis-adduct (DPCBA) were rationally designed and easily synthesized. Compared to the lowest unoccupied molecular orbital (LUMO) energy level of PC61BM (-3.95 eV), the double functionalization effectively raises the LUMO energy levels of these fullerene materials to ca. -3.85 eV, regardless of the substituent groups (CH3-, F-, and H-) at the para-position of the phenyl rings. This phenomenon suggests that the plane of the phenyl groups is preferentially parallel to the fullerene surface, leading to poor orbital interactions with C-60 and negligible electronic effect. Importantly, such geometry sterically protects and shields the core C-60 structure from severe intermolecular aggregation, rendering it intrinsically soluble, morphologically amorphous, and thermally stable. The device based on the P3HT:DMPCBA blend exhibited an open-circuit voltage (V-oc) of 0.87 V, a short-circuit current density (J(sc)) of 9.05 mA/cm(2), and a fill factor (FF) of 65.5%, leading to a high power conversion efficiency (PCE) of 5.2%, which is superior to that of the P3HT:PC61BM-based device. Most significantly, the amorphous nature of DMPCBA effectively suppresses the thermal-driven aggregation and thus stabilizes the morphology of the P3HT:DMPCBA blend. Consequently, the device retained 80% of its original PCE value against thermal heating at 160 degrees C over 20 h.
URI: http://dx.doi.org/10.1021/cm201784w
http://hdl.handle.net/11536/150365
ISSN: 0897-4756
DOI: 10.1021/cm201784w
期刊: CHEMISTRY OF MATERIALS
Volume: 23
起始頁: 4056
結束頁: 4062
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