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A series of efficient light-harvesting systems (FIr3mGx, x = 1−3) based on dendrimer donor (mCP:  N,N‘-dicarbazolyl-3,5-benzene) derivatives coupled with a sky blue phosphorescent acceptor (FIrpic:  iridium(III) bis[(4,6-difluorophenyl)pyridinato-N,C 2‘]-3-hydroxypicolinate derivative) were prepared, and their photophysical properties were investigated. The light-harvesting ability of FIr3mGx (x = 1−3) increases with the number of energy donor mCP units. The acceptor PL intensity of the donor−acceptor conjugate dendrimers (FIr3mGx, x = 1−3) increases over 6 times with the number of mCP units via sensitization from the light-harvesting antenna after excitation at the donor absorption (λex = 310 nm), as compared to that of only an acceptor without a donor (FIrpic) upon excitation at the MLCT region (λex = 380 nm) because of efficient intramolecular singlet−singlet and triplet−triplet energy transfer from the donor to the acceptor and less luminance quenching induced by the bulky dendrimer structure. The singlet−singlet intramolecular energy transfer in FIr3mGx from the dendrimer donor to the acceptor exhibits a high efficiency of greater than 90% via the steady-state PL method and 94% via the transient PL method. Additionally, the triplet−triplet energy transfer efficiency via the transient PL method exhibits an efficiency greater than 99%. This indicates that FIr3mGx exhibits good light-harvesting abilities because the mCP unit is an efficient light absorber and because the core FIrpic functions as a spatial energy concentrator that drains energy from the dendrimer donor.

A neutral tripod system for biotin-avidin assays, which is composed of biotin, FIrpic as an energy acceptor, and mCP as an energy donor, offers remarkable sensitivity over traditional transition metal based protein probes due to the intramolecular energy transfer and increased hydrophobicity associated with the avidin binding site and neutral probe 1.

[reaction: see text] Calix[4]thiacrowns with hetero-L(1) and a homodonor set (L(2)) were synthesized and characterized by X-ray analysis. From the reaction of L(2) with AgPF(6), disilver complex [Ag(2)(L(2))](PF(6))(2) (1) was isolated. By comparing 1,3-alternate conformations of L(2) and 1, we found a considerable decrease of dihedral angles of two opposite aromatic rings upon complexation. This finding can be explained in terms of the "chopsticks process", which illustrates how Ag(+)-arene pi-coordination occurs. Heterobinuclear complexation of L(1) in solution was also observed.

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We have synthesized and characterized four organic dyes (H1-H4) based on a 3,6-disubstituted carbazole donor as sensitizers in dye-sensitized solar cells. These dyes have high molar extinction coefficients and energy levels suitable for electron transfer from an electrolyte to nanocrystalline TiO(2) particles. Under standard air mass 1.5 global (AM 1.5 G) solar irradiation, a device using dye H4 exhibits a short-circuit current density (J(sc)) of 13.7 mA cm(-2), an open-circuit voltage (V(oc)) of 0.68 V, a fill factor (FF) of 0.70, and a calculated efficiency of 6.52%. This performance is comparable to that of a reference cell based on N719 (7.30%) under the same conditions. After 1000 hours of visible-light soaking at 60 °C, the overall efficiency remained at 95% of the initial value.

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