Optical properties of substituted phthalocyanine rare-earth metal complexes

Abstract

Comparative study of optical properties of alkylthio-group-substituted phthalocyanine rare-earth metal sandwich complexes (͓(C n S͒ 8 Pc͔ 2 M,MϭEu,Lu,Tb) is presented. Photoluminescence and photoconductivity of ͓(C n S͒ 8 Pc͔ 2 M complex is very weak. Two photoluminescence bands were observed at around 400-650 and 720-800 nm in chloroform solution corresponding to the Soret and Q bands in the absorption spectra, respectively. However, the emission from Eu 3ϩ ion ͑as well as Tb 3ϩ ) was not found compared with other Eu complexes because the 5d levels of the Eu 3ϩ ion lie higher than the triplet level of the ligand. The significant enhancement of the photoconductivity of ͓(C 16 S͒ 8 Pc͔ 2 M after C 60 doping is reported. The photoconductivity is positive at the low electric field in the ohmic regime while it becomes negative at the high electric field upon photoexcitation with strongly absorbed light. The negative photoconductivity is attributed to space-charge effects. The mechanism of photoluminescence and photoconductivity are discussed by taking the electronic energy schemes of phthalocyanine ligands and lanthanide ion and C 60 into consideration.

Tuning the magneto-optical response of TbPc2 single molecule magnets by the choice of the substrate

“…They represent ligand-related pp* optical transitions from the HOMO (highest occupied molecular orbital) to the LUMO+1 and from HOMOÀ1 to LUMO (lowest unoccupied molecular orbital). 28 The magneto-optical activity in the Q-band range is significantly stronger than that in the B-band or Soret-band range (around 3.8 eV), similar to the planar phthalocyanines but in contrast to porphyrins. 29 This indicates that the ligand symmetry considerations that govern the selection rules of the (magneto-)optical transitions in planar phthalocyanines remain valid also in the double-decker molecules.…”

Anomalously Large Spectral Shifts near the Quantum Tunnelling Limit in Plasmonic Rulers with Subatomic Resolution

“…As previously described, conductance, refractive index/polarizability, and charge transfer all influence the plasmon coupling behaviour. 2,72 BPc derivatives are strong visible light absorbers 49,73,74 and in such tightly-confined plasmonic NPoM systems, strong coupling has already been observed for dyes. 72 While the UV-Vis absorption spectra of the BPc* complexes studied here exhibit a noticeable spectral shift from Sm to Lu (Figure 2c), the range ∆ α ≈ 12 nm (∆ ≈ 30 meV) is only 40% of the observed energy shift in ̅ C and occurs in the opposite direction.…”

Liquid crystalline and charge transport properties of double-decker cerium phthalocyanine complexes

“…10 The additional peak at 313 nm has been previously ascribed to the N-band. 18 Interestingly, the absorption band at 499 nm is rather weak as compared to that of other substituted lanthanide doubledecker phthalocyanines. 10,18 However, the intensity of this band can also be enhanced or reduced by addition of iodine or lithium aluminium hydride, respectively (Fig.…”