The carrier collection efficiency (ηc) and energy conversion efficiency (ηe) of polymer photovoltaic cells were improved by blending of the semiconducting polymer with C60 or its functionalized derivatives. Composite films of poly(2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylene vinylene) (MEH-PPV) and fullerenes exhibit ηc of about 29 percent of electrons per photon and ηe of about 2.9 percent, efficiencies that are better by more than two orders of magnitude than those that have been achieved with devices made with pure MEH-PPV. The efficient charge separation results from photoinduced electron transfer from the MEH-PPV (as donor) to C60 (as acceptor); the high collection efficiency results from a bicontinuous network of internal donor-acceptor heterojunctions.

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Polymer photovoltaic cells : enhanced efficiencies via a network of internal donor-acceptor heterojunctions

This Review summarizes recent progress in the development of polymer solar cells. It covers the scientific origins and basic properties of polymer solar cell technology, material requirements and device operation mechanisms, while also providing a synopsis of major achievements in the field over the past few years. Potential future developments and the applications of this technology are also briefly discussed.

Polymer solar cells

-phenylenevinylene)s L4. Fluorene-Based Conjugated Polymers L4.1. Fluorene-Based Copolymers ContainingElectron-Rich MoietiesM4.2. Fluorene-Based Copolymers ContainingElectron-Deﬁcient MoietiesN4.3. Fluorene-Based Copolymers ContainingPhosphorescent ComplexesQ5. Carbazole-Based Conjugated Polymers R5.1. Poly(2,7-carbazole)-Based Polymers R5.2. Indolo[3,2-

https://ir.nctu.edu.tw:443/bitstream/11536/6508/1/000271856900020.pdf

Synthesis of Conjugated Polymers for Organic Solar Cell Applications

Protein and polymer analyses up to m/z 100 000 by laser ionization time-of-flight mass spectrometry

Fabrication and processing of polymer solar cells: A review of printing and coating techniques

We describe the synthesis and complete characterization of soluble derivatives of C-60 for applications to physics and biology. The goal of the strategy was to have a ''modular'' approach in order to be able to easily vary a functional group attached indirectly to the cluster. The functionality could be hydrophilic (e.g., histamide) or hydrophobic (e.g., cholestanoxy). The former was prepared for biological studies and the latter for photophysical studies toward improvement of photoinduced electron transfer efficiencies in the fabrication of photodetectors and photodiodes. An important intermediate, a carboxylic acid, was found to be recalcitrant to characterization by the usual mass spectroscopic and elemental analysis techniques. This problem was solved by the use of MALDIMS. The carboxylic acid was easily converted to the key intermediate acid chloride, which in turn was convertible to a large variety of derivatives. Both isomeric forms ([5,6], fulleroid and [6,6], methanofullerene) of the C-61 clusters were prepared. The fulleroid formation could have given rise to a 50:50 mixture of phenyl-over-former pentagon phenyl-over-former hexagon isomers but, remarkably, afforded a 95:5 mixture of these isomers, respectively. The fulleroid and methano-fullerene gave different cyclic voltammograms, with the former being reduced at 34 mV more positive potential than the latter.

Preparation and Characterization of Fulleroid and Methanofullerene Derivatives

A diamido diacid diphenyl fulleroid derivative was designed specifically to inhibit an HIV enzyme. The detailed synthesis and mass spectrometric analysis of the water-soluble, biologically active methanofullerene are described. The compound was prepared in three steps from C[sub 60] via a suitably diphenyldiazomethane. High-resolution mass spectrometric analysis was possible only under mild matrix-assisted laser desorption/ionization Fourier transform mass spectrometry conditions. Direct infrared or ultraviolet laser desorption resulted exclusively in observation of C[sub 60] ions, in either positive or negative mode. 13 refs., 3 figs.

Synthesis of a fullerene derivative for the inhibition of HIV enzymes

Double Exponential Dendrimer Growth

Phenylacetylene Dendrimers by the Divergent, Convergent, and Double-Stage Convergent Methods

At moderate temperatures in flowing gas, pentacene undergoes a disproportionation reaction to produce 6,13-dihydropentacene (DHP) and a series of polycondensed aromatic hydrocarbons, including the previously unknown peripentacene (PP). The process requires activation by heating to 320 degrees C and is possibly catalyzed by impurities such as DHP, 6,13-pentacenequinone (PQ), Al, or Fe found in the starting materials. These impurities also result in a decrease in the intrinsic field-effect mobility (FEM) of pentacene crystals. Subsequent purifications remove such impurities, thus inhibiting the formation of the disproportionation products and increasing the FEM of pentacene (2.2 cm(2)/Vs). These results clarify the importance of purification of semiconductive materials for measurements of intrinsic mobility and optimal device performance.

Charles L. Wilkins

Papers

Preparation and Characterization of Fulleroid and Methanofullerene Derivatives

Synthesis of a fullerene derivative for the inhibition of HIV enzymes

Double Exponential Dendrimer Growth

Phenylacetylene Dendrimers by the Divergent, Convergent, and Double-Stage Convergent Methods

Pentacene Disproportionation during Sublimation for Field-Effect Transistors