High LUMO energy level C60(OCH3)4 derivatives:Electronic acceptors for photovoltaiccellswithhigheropen-circuitvoltage

E-mail Addresses: [email protected] regioselective C-60(OCH3)(4) derivatives, C-60(OCH3)(4)-PCBM (a methanofullerene derivative of C-60(OCH3)(4), PCBM=[6,6]-phenyl-C-61-butyric acid methyl ester) and C-60(OCH3)(4)-APCBM (an aziridinofullerene derivative of C-60(OCH3)(4)) were synthesized from C60Cl6 and used as acceptor for polymer solar cells. Revealed by cyclic voltammetry, the LUMO energy levels of C-60(OCH3)4-APCBM and C-60(OCH3)(4)-PCBM are 0.2 and 0.3 eV higher than that of PCBM, respectively. For the polymer photovoltaic cells with fullerene (PCBM, C-60(OCH3)(4)-APCBM or C-60(OCH3)(4)-PCBM) acceptor in combination with poly(3-hexylthiophene) (P3HT) donor, the open-circuit voltage is increased from 0.58 V (for PCBM) to 0.63 V (for C-60(OCH3)(4)-APCBm) and 0.72 V (for C-60(OCH3)(4)-PCBM). The higher open-circuit voltages are reasonably attributed to the higher LUMO levels of the C-60(OCH3)(4) derivatives because of four electron-donating methoxy groups attached. The photovoltaic performance of C-60(OCH3)(4)-PCBMbased device is higher than that involving C-60(OCH3)(4)-APCBM, largely due to the structural changeability of C-60(OCH3)(4)-APCBM resulting from the rotatable N-C bond bridge therein. This work demonstrates that fullerene derivatives with higher LUMO level can be functionalized from multiaddition of electron-donating groups, and exemplifies that photovoltaic performances of fullerene-based solar cells are sensitive even to trivial bridge between functional group and fullerene core. (C) 2012 Elsevier B.V. All rights reserved .National Nature Science Foundation of China U1205111 21031004 21021061 J1210014 20923004 National Basic Research 973 Program of China 2011CB93590

Hydroxylation of isophthalic acid in the hydrothermal reaction of Cu-II-isophthalate system - Syntheses and crystal structures of two coordination polymers

The reaction of isoplithalic acid (H(2)ip) and copper nitrate under hydrothermal condition produced an in situ synthesized ligand 2-hydroxy isophthalic acid (or 2,6-dicarboxyl phenol, H(3)ipO) derived from H(2)ip without the presence of N-heterocyclic ligands. The hydroxylation was controlled by the temperature of hydrothermal synthesis. Two coordination polymers,{[Cu-5(OH)(2)(ip)(ipO)(2)]. (H2O)}(n) (1) and [Cu-3(iPO)(2)(H2O)2] (2) were synthesized and characterized by X-ray crystallography, IR spectra and elemental analyses. Complex 1 was assembled with both the original ligand and the in situ synthesized ligand. (c) 2005 Elsevier B.V. All rights reserved