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We investigate the effect of a high hole mobility triarylamine-based conjugated polymer on a bulk hetero-junction organic solar cell. We employed a polymer blend consisting of poly(3-hexylthiophene) (P3HT), [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), and poly(N-(4 -(9,9-dioctyl-fluoren-2-yl)phenyl)-N,N′,N′-triphenyl-l,4-phenylenediamine) (PFLAM) as active materials. The hole mobility of PFLAM is ∼10−3 cm2 V−1 s−1, which is similar to the electron mobility of PCBM. Addition of PFLAM improves the hole mobility of the photovoltaic cell augmenting the charge balance of the system. The overall efficiency gain for such a device is 34%.

A solution-processable functional polyimide (PYTPA-PI), containing triphenylamine-substituted diphenylpyridine moieties (PYTPA, electron donors) and phthalimide moieties (PI, electron acceptors), was synthesized. The copolymer exhibits a high glass transition temperature of 342 °C. A switching device, based on a solution-cast thin film of PYTPA-PI sandwiched between an indium-tin oxide (ITO) bottom electrode and an Al top electrode, exhibits two accessible conductivity states and can be switched from the low-conductivity (OFF) state to the high-conductivity (ON) state, with an ON/OFF current ratio of more than 103, at the threshold voltage of about 2.7 V. The ON state is volatile and relaxes readily to the OFF state. However, it can be electrically sustained by a refreshing voltage pulse of 2 V. The ON state can also be reset to the initial OFF state by a reverse bias of −0.9 V. The ability to write, erase, read, and refresh the electrical states fulfills the functionality of a dynamic random access memor...

A conjugated copolymer of 9,9-didodecylfluorene and 4-triphenylamino-2,6-bis(phenyl)pyridine (F12TPN), containing both electron donor and acceptor moieties, was synthesized via Suzuki coupling polymerization. Polymer memory devices, based on thin films of F12TPN and its carbon nanotube composites, were fabricated. The current density-voltage characteristics of the indium tin oxide (ITO)/F12TPN/Al sandwich structure could be switched from a low conductivity (off) state to a high conductivity (on) state, when operated under negative bias with ITO as the anode. The switch-on voltage of the as-fabricated device was around −2.3V. The on/off state current ratio was about 10. The on/off state current ratio could be enhanced to 105 and the switch-on voltage reduced to about −1.7V by doping the F12TPN layer with about 1wt% of carbon nanotubes. Once the memory devices had been switched on, they could not be erased (switched off) with a reverse bias (positive bias). Thus the memory effect was characteristics of that of a write-once read-many-times memory. The memory mechanism was deduced from molecular simulation and modeling of the nature of currents in both states.