Oligomers excited

Figure 4-8. 1NDO/SCI simulation of the wavcfunclion y/(x,xi, = 16, chain I) of the lowest charge transfer-excited stale in a cofacial dimer formed by two five-ring PPV oligomers separated by 4A. Ili/(x,x/, - 16, chain 1) represents the probability amplitude in finding an electron on a given site xt. assuming the hole is centered on site 16 of chain I. The site labeling is the same as that reported on top of Figure 4-7.

Starting from the assumption that the geometry relaxation after excitation is of primary importance with respect to the luminescence response, we decided to employ a solid polymer matrix to suppress conformational changes of the oligomers. For the measurements, dilute blends with polysulfone as the transparent host matrix were prepared. In Figure 16-13, the PL decay curves for the two cyano compounds in both chloroform and polysulfone are presented, as are the PL spectra of Ooct-OPV5-CN in chloroform and polysulfone [69J. 

Figure 4-3. Absolute values of the INDO/SCI-calculalcd electron wavcfunctions v/(a, jt, = 34) calculated for the eleven-ring PPV oligomer as a function of carbon site (hole fixed on site 34) for the excited stales corresponding to (a) die first absorption peak (3.0 cV) (b) the second absorption peak (3.8 eV) (c) the third absorption peak (5.6 eV) (d) lire fourth absorption peak (6.3 eV) and (e) lire fifth absorption peak (7.0 cV). The energies given between parentheses refer to the theoretical values.

Rawashdeh-Omary, M.A., Omary, M.A., Patterson, H.H. and Fackler, J.P. Jr (2001) Excited-state interactions for [Au(CN)2 ]n and [Ag(CN)2 ]n oligomers in solution. Formation of luminescent gold-gold bonded excimers and exciplexes./oumol of the American Chemical Society, 123, 11237-11247. 

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