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Four new monomers for directional stepwise synthesis of oligophenylenevinylenes (OPVs) (4-{2-[4-(5,5-dimethyl[1,3]dioxan-2-yl)-2,5-dipropoxyphenyl]vinyl}benzyl)phosphonic acid diethyl ester, (5-{2-[4-(5,5-dimethyl[1,3]dioxan-2-y])-2,5-dipropylphenyl]vinyl}thiophene-2-ylmethyl)phosphonic acid diethyl ester, (5-{2-[4-{5,5-dimethyl[1,3]dioxan-2-yl)-2,5-diprepoxyphenyl]vinyl}thiophene-2-ylmethyl)phosphonic add diethyl ester, and (7-{2-[4-(5,5-limethyl[1,3] dioxan-2-yl)z2,5-dipropylphenyl]-vinyl}benzo[1,2,5]thiadiazol-4-ylmethyl)phosphonic acid diethyl ester have been prepared. Trimeric OPVs were then synthesized and tested as active materials in photovoltaic cells. Conversion efficiencies in the range of 0.5–1% were obtained in blends with the soluble C60 derivative PCBM. A terpyridine end-functionalized trimer and a heterotrimer with a mixed composition of monomers were also prepared. [ABSTRACT FROM AUTHOR]

A new stepwise directional synthetic route to single-oligomer p-phenylenevinylenes (OPVs) has been developed. The first step in the reaction sequence is the condensation of a functionalized benzaldehyde with a novel monomer having a methyl phosphonate ester group in one end and an acetal-protected aldehyde at the other end of a stilbene core. Oligomerization then proceeds stepwise by alternating reaction of the previous aldehyde-terminated OPV fragment with the monomer and deprotection of the acetal. Thus, a series of OPVs with 3, 5, 7, 9, and 11 phenylene vinylene units has been prepared that has an electron-donating methoxy group at one end and an electron-accepting aldehyde group at the other end. Some examples where a dimethylamino group replaced the methoxy group were also prepared. The oligomer with seven phenylene vinylene units was then further derivatized at the aldehyde position to create a series of OPVs with a range of substituents from strongly electron-accepting nitrophenyl to electron-donating methoxyphenyl. Photovoltaic cells were assembled with the synthesized OPVs as the photoactive layer. Illumination under simulated sunlight (AM1.5) gave short circuit currents (Isc) in the range 0.015-0.5 mA cm-2 and typical open circuit voltages (Voc) of 0.4-0.8 V. The maximum efficiency obtained was ∼0.1%. [ABSTRACT FROM AUTHOR]

A multidomain compound with applications in the area of organic solar cells has been prepared. This all-in-one molecule compound integrates all the functionalities needed for solar cell action from light harvesting, carrier generation, and separation, to transport and contact to external electrodes. A convergent synthetic strategy with some 60 steps involving preparation of regioregular oligothiophenes, a zinc porphyrin, a bisterpyridine ruthenium(II) complex, a hetero oligo phenylenevinylene and functional end groups is described. Preliminary investigations of photovoltaic devices based on the target molecule gave values of 0.18 V, 0.0044 mA cm-2, 29% and 0.000081% for the open circuit voltage (Voc), short circuit current (Isc), fill factor (FF), and efficiency (η). These poor values are compared to those obtained with an oligo-3-hexylthiophene which gave values of 0.7 V, 0.046 mA cm-2, 24.6%, and 0.0081% for the open circuit voltage (Voc), short circuit current (Isc), fill factor (FF) and efficiency (η). This latter compound was also studied in a bulk heterojunction device with PCBM (1:1 blend) which gave values of 0.43 V, 0.45 mA cm-2, 33.5%, and 0.063%. [ABSTRACT FROM AUTHOR]