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Curing-temperature-dependent spectroscopic studies of the conversion process of the sulfonium chloride prepolymer to the conjugated polymer poly(p-phenylenevinylene͒ reveal an enhancement of the luminescence efficiency when the films are converted under ultrahigh-vacuum conditions. In these experiments, luminescence is excited by electron injection from the tip of a scanning tunneling microscope and the maximum luminescence efficiency is found between 225°C and 260°C. The optimum conversion temperature, the total luminescence yield, and the spectral features of the luminescence depend on the substrate material, heating gradient, and composition and purity of the prepolymer. The curing-temperature dependence of the Franck-Condon intensity distribution has a complex behavior. Maximum luminescence efficiency is characterized by a spectrum where the vϭ0,1 vibronic transition has maximum relative intensity. Images of scanning-tunneling-microscopy-excited luminescence show intensity fluctuations within surface domains as small as a few nanometers in diameter, regions that correlate with the topographic features of the poly͑p-phenylenevinylene͒ surface. ͓S0163-1829͑97͒02028-6͔

It has been shown in a recent analysis of the temperature dependence of the dc conductivity of the quasi-one-dimensional conductor (8uoranthene)2PFs that in spite of the occurrence of the Peierls transition to a charge-density-wave ground state (formally implicating polarons as excitations), the dc conduction is essentially due to electron-hole transport in bands and acoustical phonon scattering of the carriers. The theory allows for the determination of the temperature dependence of the Peierls gap below and the Huctuating pseudogap above the transition temperature. Our dc-conductivity measurements con6rm that a common temperature dependence occurs in organic radical cation salts and in inorganic materials from the groups of the blue bronzes and the transition metal tetrachalcohalogenides. These materials are rather di8'erent especially with respect to the nature of the states forming the conduction band and the filling of the latter. Here we reduce the needed information on the band structure to a minimum connected with optical data and extend the theory to the case of a gap small compared to k&T. The theory is applied to (Fa)2PFs, Kp, spMo03, and (TaSe4)2I as representatives of the above-mentioned groups of materials. From the measured conductivity data the temperature dependence of the Peierls gap below and the pseudogap above the transition temperature are determined as well as several conductivity-related quantities. Similarities and difFerences of the investigated materials are discussed.