554
T. Onodera and H. Oikawa
Fig. 32.2 Raman spectra of
a Cu-TCNQ bulk crystal
(Cu:TCNQ=1:1) and
b nanocrystal
(Cu:TCNQ=1.3:1) with 34 ±
12 nm in size, and calculated
spectra of c TCNQ anion
and d TCNQ dianion by
DFT calculation Ref. [17]
crystal (Cu:TCNQ=1:1), respectively [19]. In addition, new bands were observed
in nanocrystals. These new bands were assigned to TCNQ dianion [20], which
roughly agreed with DFT (density functional theory, EDF2/6-31G*, Spartan’10 software) calculation as shown in Fig. 32.2d. Furthermore, chemical state of Cu in
Cu-TCNQ nanocrystals was also investigated using scanning transmission electron
microscopy—electron energy loss spectroscopy (STEM-EELS: FEI, Titan
3 Double
Corrector Super-X). Figure 32.3 indicates STEM-EELS spectra of Cu in Cu-TCNQ
nanocrystals and bulk crystals. The EELS spectrum of Cu in Cu-TCNQ nanocrystals corresponds to Cu-L 3 edge and agreed with that in bulk crystals, which means
Fig. 32.3 STEM-EELS
spectra of a Cu-TCNQ
nanocrystals
(Cu:TCNQ=1.3:1) and
b bulk crystal
(Cu:TCNQ=1:1)