Phthalocyanines are among the most promising of efficient molecules for commercial application in dye sensitized solar cells due to their extremely intense red absorbance and excellent photochemical stability.

A C60-SiPc-C60 triad showing no aggregation is synthesized and characterized. Photoexcitation of the triad results in formation of the charge-separated state by photoinduced electron transfer from the singlet excited state of the SiPc moiety to the C60 moiety. The charge-separated state has a lifetime of 5 ns in benzonitrile at 298 K.

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Introducing porous material into optical cavities is a critical step toward the utilization of quantum-electrodynamical (QED) effects for advanced technologies, e.g. in the context of sensing. We demonstrate that crystalline,...

A method to determine the glass transition temperature (Tg) of photorefractive (PR) polymer composites, based on photoconductivity measurements, is proposed. The composite Tg is identified as the temperature at which a clear change in slope in the Arrhenius plot representation of the photoconductivity is obtained. We demonstrate that for PR polymers, this method is more appropriate than the one generally used, based on differential scanning calorimetry (DSC). For PR composites based on the hole transporting polymer poly(N-vinylcarbazole), the Tg value determined from photoconductivity data is around 30°C higher than that obtained by DSC.

The binding of the snake-like trinitrodicyanomethylenefluorene-C60 derivative (TNDCF-C60) to the dynamic receptor, tetrathiafulvalene calix[4]pyrrole (TTF-calix[4]pyrrole), may be controlled via the use of a chloride anion as an external trigger. Whereas, in the absence of a chloride anion, the TNDCF “tail” of the trinitrodicyanomethylenefluorene-C60 substrate binds to the TTF−calix[4]pyrrole in a 2:1 (substrate/receptor) stoichiometry in CH2Cl2 solution, addition of a chloride anion (yellow) leads the TNDCF tail to be displaced in favor of a bound C60 “head”, a process that leads to the formation of a complex with overall 1:2:2 substrate/receptor/chloride anion stoichiometry. These chemical switching events are reflected in easy-to-visualize color changes, as well as in the production of two different kinds of charge-separated states following selective femtosecond photoexcitation.

The first perylenediimide (PDI) covalently linked to an azafullerene (C59N) is described. PDI-C59N and PDI-C60 dyads where PDI acts as an electron-donor moiety have been synthesized by connection of the balls to the PDI 1-bay position. Photoexcitation of the PDI unit in both systems results in formation of the charge-separated state by photoinduced electron transfer from the singlet excited state of the PDI moiety to the C59N or to the C60 moiety. The charge-separated state has a lifetime of 400 ps in the case of PDI-C59N and 120 ps for the PDI-C60 dyad in benzonitrile at 298 K. This result has significant implications for the design of organic solar cells based on covalent donor-acceptor systems using C59N as an electron acceptor, indicating that longer-lived charge-separated states can be attained using C59N systems instead of C60 systems.

Sequential photoinduced energy transfer followed by electron transfer and the formation of charge-separated states, which are primary events of natural photosynthesis, have been demonstrated in a newly synthesized multichromophoric covalently linked triad, PDI-SiPc-C . The triad comprises a perylenediimide (PDI), which primarily fulfils antenna and electron-acceptor functionalities, silicon phthalocyanine (SiPc) as an electron donor, and fulleropyrrolidine (C ) as a second electron acceptor. The multi-step convergent synthetic procedure developed here produced good yields of the triad and control dyads, PDI-SiPc and SiPc-C . The structures and geometries of the newly synthesized donor-acceptor systems have been established from spectral, computational, and electrochemical studies with reference to appropriate control compounds. Ultrafast energy transfer from PDI* to SiPc in the case of PDI-SiPc and PDI-SiPc-C was witnessed. An energy-level diagram established from spectral and electrochemical data suggested the formation of two types of charge-separated states, that is, PDI-SiPc -C and PDI -SiPc -C from the SiPc* in the triad, with generation of the latter being energetically more favorable. However, photochemical studies involving femtosecond transient spectroscopy revealed the formation of PDI-SiPc -C as a major charge-separated product. This observation may be rationalized in terms of the closer spatial proximity to SiPc of C compared to PDI in the triad. The charge-separated state persisted for a few nanoseconds prior to populating the SiPc* state during charge recombination.