2-Methyl-butyric acid ester

Phenyl C60 butyric acid methyl ester (PCBM) derivative... 

Butyric acid, methyl ester 10 FALSE FALSE FALSE FALSE... 

One of the most promising uses of C60 involves its potential application, when mixed with 7r-conjligated polymers, in polymer solar cells. Most often the so-called bulk heterojunction configuration is used, in which the active layer consists of a blend of electron-donating materials, for example, p-type conjugated polymers, and an electron-accepting material (n-type), such as (6,6)-phenyl-Cgi -butyric acid methyl ester (PCBM, Scheme 9.6).38... 

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). 

In order to learn about the true quantum efficiency of photogeneration one therefore has to study the photoinduced charge generation mechanism at faster time scales. Pump probe spectroscopy utilising a few optical-cycle laser pulses (5-6 fs) in the visible spectral range with broadband frequency conversion techniques [89] now makes it possible to study extremely fast optically-initiated events with unprecedented time resolution. Such a setup was used to time-resolve the kinetics of the charge transfer process from a polymer chain to a fullerene moiety in thin films of poly[2-methoxy, 5-(3, 7 -dimethyl-octyloxy)]-p-phenylene vinylene (MDMO-PPV) and [6,6]-phenyl C6i butyric acid methyl ester (PCBM). Solutions prepared from 1 wt% solutions of toluene on thin quartz substrates were studied. 

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... 

PCBM [6,6]-Phenyl-C6i butyric acid methyl ester... 

Figure 7.1 Chemical stractures of some common organic photovoltaic materials poly(2-methoxy-5-(3,7-dimethyloctyloxy)-l,4 phenylenevinylene) (MDMO-PPV), poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl Cei-butyric acid methyl ester (PCBM).

Pacios R., Chatten A. J., Kawano K., Durrant J. R., Bradley D. D. C. and Nelson J. (2006), Effects of photo-oxidation on the performance of poly 2-methoxy-5-(3, 7 -dimethyloctyloxy)-l,4-phenylenevinylene 6,6-phenyl Cei-butyric acid methyl ester solar cells , Adv. Eunct. Mat. 16, 2117-2126. 

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... 

Huang J, Li G, Yang Y (2005) Influence of composition and heat-treatment on the charge transport properties of poly(3-hexylthiophene) and [6,6]-phenyl C i-butyric acid methyl ester blends. Appl Phys Lett 87 112105... 

Another method of improving these solar cells is to dope the material with a fullerene derivative such as [6]-phenyl-C6]-butyric acid methyl ester (PCBM) 46,... 

The devices suffer from a relatively high threshold voltage > 25 V due to electron trapping, which might be related to the relatively low electron afhnity of fluoroalkyl substituted thiophene molecules [59]. -Type field-effect conduction has also been reported in methanofullerene phenyl Cg,-butyric acid methyl ester (PCBM) [60] and... 

BUTYRIC ACID, METHYL ESTER (623-42-7) Forms explosive mixture with air (flash point 57°F/14°C cc). Incompatible with strong acids, nitrates, oxidizers. 

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