Blue electroluminescent diodes utilizing poly(alkylfluorene) have been demonstrated for the first time. A Schottky-type electroluminescent diode of poly(9,9-dihexylfluorene) is driven at ∼10 V and has a peak emission wavelength of 470 nm at room temperature.

A visible-light electroluminescent diode utilizing poly(3-alkylthiophene) has been demonstrated for the first time. The light emission intensity increases superlinearly with increasing injected current. Remarkable enhancement of electroluminescence intensity is obtained for a poly(3-alkylthiophene) diode with longer alkyl side chain length.

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Surface acoustic wave (SAW) properties of z -cut LiNbO 3 waveguides fabricated by proton exchange using octanoic acid are investigated. The phase velocity V p and electromechanical coupling coefficient K 2 of SAWs are significantly decreased by the increase of kd , where k is the wavenumber (2π/λ) and d is the waveguide depth. The insertion loss IL of a SAW is increased by the increase of kd and becomes nearly constant at kd ≥ 0.13. The temperature coefficient of delay TCD of a SAW calculated from the frequency change shows an apparent increase with kd , reaching a maximum at kd = 0.213, then slightly decreasing at higher kd . On the other hand, the effects of annealing on V p and IL are also investigated. The results show that post-annealing can result in a restoration of the decreased V p and an improvement of IL.