Phenyl-C61-butyric acid methyl ester

In a bulk-heterojunction photovoltaic cell with methanofullerene [6,6]-phenyl C61-butyric acid methyl ester (PCBM) as an electron acceptor, alternating copolymer 19 (Fig. 9), derived from 2,7-fluorene and 2,5-dithienylsilole, can show impressive performance as the electron donor.31 In a device configuration of ITO/PEDOT/active layer/Ba/Al, the dark current density—bias curve shows a small leakage current, suggesting a continuous, pinhole-free active layer in the device. Under illumination of an AM 1.5 solar simulator at 100 mW/cm2, a high short-circuit current of 5.4 mA/cm2, an open-circuit voltage of 0.7 V, and a fill factor of 31.5% are achieved. The calculated energy conversion efficiency is 2.01%. 

Nowadays the best performing organic photovoltaic cell is represented by a bulk heterojunction (BHJ) solar cell based on the polymer poly(3-hexylthiophene) (P3HT) and the fullerene derivative [6, 6]-phenyl-C61-butyric acid methyl ester (PCBM), with reproducible efficiencies approaching 5% [262,263], However, a serious drawback for the preparation of efficient organic photovoltaic cells is represented by the low optical absorbance in the red/near-infrared region of the lightharvesting component(s), as well as their low extinction coefflcient(s). 

Mihailetchi [134] investigated the open circuit voltage of the bulk heterojunction organic solar cells based on methanol-fullerene [6,6]-phenyl C61-butyric acid methyl ester (PCBM) as electron acceptor and poly[2-methoxy-5(3 ,7 -dimethyloctyloxy)-p-phenylene vinylene] (OC1C10-PPV) as an electron donor. It is known that a single layer device follows the MIM model [166] and the open circuit voltage V0c is equal to the difference in the work functions of the metal electrodes [134], If charges accumulate in the... 

Pacios R, Nelson J, Bradley DDC, Brabec CJ (2003) Composition dependence of electron and hole transport in polyfluorene [6,6]-phenyl C61-butyric acid methyl ester blend films. Appl Phys Lett 83 4764... 

Polymer solar-cell devices based on a blend of poly(3-hexylthiophene) and [6,6]-phenyl-C61-butyric acid methyl ester, and incorporating doped PANI-NTs as an interfacial layer, have been fabricated [511,512]. The power-conversion efficiency of an annealed device incorporating the PANI-NTs layer showed an increase of 26% relative to that of the annealed device lacking the PANI-NTs interfacial layer. The high conductivity, controlled tubular nanoscale morphologies, and mobility of the annealed PANI-NTs layer led to efficient extraction of photogenerated holes to the buffer layer and suppression of exciton recombination, thereby improving the photovoltaic performance. 

FIGURE 8.1 Chemical structure of (a) polystyrene (PS), (b) poly(methyl methacrylate) (PMMA), (c) 8-hydroxyqui-noline (8HQ), (d) 1-dodecanethiol (DT), (e) 2-naphthalenethiol (2NT), (f) polyaniline (PANI), (g) tetrathiafiilvalene (TTF), and (h) methanofullerene [6,6]-phenyl C61-butyric acid methyl ester (PCBM). 

Domain sizes and compositional heterogeneities in poly-3-hexyl-thiophene phenyl C61-butyric acid methyl ester bulk heterojunction thin films are studied by spin diffusion Solid-state Si, Al, C,... 

Regioregular PHT, a p-type conjugated polymer, blended with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), as n-type material, is an active material for photovoltaic devices (40). The deposition methods and the induced morphology strongly influence the functionality of the active material and in turn the final charge generation performances of a photoactive layer. 

PCBM [6,6]-phenyl-C61-butyric acid methyl ester... 

Attempts have been made to deposit TIPS-pentacene from solution as the functional layer in a pentacene/C60 bilayer photovoltaic device. Careful optimization of deposition conditions, optimal concentration of mobile ion dopants, thermal postfabrication annealing, and the addition of an exciton-blocking layer yielded a device with a moderate white-light PCE of 0.52% [41]. Since TIPS-pentacene derivatives rapidly undergo a Diels-Alder reaction with fiillerene, the assembly of potentially more efficient bulk-heterojunction photovoltaic devices from TIPS-pentacene and fiillerene derivatives were not possible [42]. The energy levels of the TIPS-pentacene-PCBM adduct (PCBM is [6,6]-phenyl C61-butyric acid methyl ester) ineffectively supports the photoinduced charge transfer. 

Nieuwendaal, R.C. et al. (2010) Measuring the extent of phase separation in poly-3-hexylfhiophene/phenyl-C61-butyric acid methyl ester photovoltaic blends with 1H spin diffusion NMR spectroscopy. Chem. Mater., 22 (9), 2930-2936. 

In these and other applications where fullerenes are blended with homo- or copolymers, it is necessary to be able to control the interaction between the polymeric matrix and the fullerene molecules to optimize device performance. However, the solubility of fullerenes with polymers is still very poorly understood, motivating fundamental studies such as those contained in this research. Specifically in this work, we study polymer-fullerene interactions in blends with PCBM ([6,6]-phenyl C61 butyric acid methyl ester), which is widely used in organic electronics as an electron acceptor. 

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