A cyano-based electron-accepting building block to design n-type conjugated polymers with absorption wavelength of >1000 nm

There are much fewer n-type conjugated polymers than p-type counterparts because of the lack of strong electron-accepting building blocks. We report a novel strong electron-accepting unit based on a dicyanomethylene unit. The resulting polymers exhibit LUMO energy levels of as low as -4.04 eV and narrow optical gaps with an onset absorption wavelength of 1050 nm. Moreover, the polymers exhibit near-infrared light absorption with good photostability because of their low-lying LUMO/HOMO energy levels.

Core and double bond functionalisation of cyclopentadithiophene-phosphaalkenes

Opto-electronic tuning by functionalisation of phosphorus heterofulvenoid cores. Oxidation, metal coordination at phosphorus, and substitution with donor and acceptor units at the carbon framework.

BODIPY dyads and triads: synthesis, optical, electrochemical and transistor properties

A series of D–A dyads and D–A–D triads molecular systems based on triphenylamine and 9-ethyl-carbarzole as donor (D) and BODIPY as acceptor (A) has been designed and synthesized. The optoelectronic properties including optical, electrochemical, and charge carrier mobility of these molecules have been investigated. We found that the D–A–D triads exhibited broader absorption, raising the HOMO energy levels and increase hole carrier mobilities. Analysis surface morphology revealed that BODIPY containing carbazole demonstrated smooth film and no macro phase aggregation was observed upon thermal annealing.

Synthesis and Characterization of Cyclopentadithiophene Heterofulvenes: Design Tools for Light-Activated Processes

The development of new materials for solar-to-energy conversion should consider stability, ease of fabrication, and beneficial photophysical properties. In this context, a set of novel π-conjugated building blocks, with phospha- and arsaalkenes possessing a unique dithienyl annulated heterofulvenoid core, have been prepared as air- and moisture-stable sensitizers. These compounds unify electron-donor and -acceptor moieties, making them potential candidates for light-harvesting applications. Optical characterization of these systems was performed by steady-state and time-resolved absorption spectroscopy, supported by time-dependent DFT calculations. Tuning of the optical properties of these systems can be achieved by varying the pnictogen element at the bridgehead position, giving a bathochromic shift of ≈40 nm and coordinating the phosphaalkene towards gold Au^I centers. The latter results in a ≈2000-fold extension of the ≈10 ps lifetime of uncoordinated systems well into the ns regime.

Highly efficient and facile alkylation of 4H-cyclopenta-[2,1-b:3,4-b′]dithiophene in water

A facile and highly economical methodology for the dialkylation of 4H-cyclopenta-[2,1-b:3,4-b′]dithiophene is reported.