We previously developed a scanning near-field optical microscope (SNOM) for fluorescence microscopy and fluorescence spectroscopy by combining SNOM and atomic force microscope (AFM). In this combined microscope, a bent optical fiber with a sharpened tip end was used for simultaneous SNOM and AFM recording. In the present work, we used slim optical fiber probes with a diameter of 40μm produced by etching in HF solution. Stiffness of previously used optical fiber cantilevers with 125μm for SNOM-AFM was reduced dramatically. The slim optical fiber cantilever could be used for SNOM with tip–sample separation control by contact mode AFM. The contact mode AFM operation allowed simultaneous imaging of AFM, SNOM, and friction force microscopy. We will demonstrate application of such SNOM-contact mode AFM to the study of phase separation in Langmuir–Blodgett films without mechanical damage.

We previously developed scanning near-field fluorescence microscopy (SNFM) by combining SNOM and atomic force microscopy (AFM). We demonstrate that this combination can be used for fluorescence imaging and spectroscopy for a localized nanoarea. A small amount of a cationic cyanine dye with two long alkyl chains (CD) was added to see whether this hydrocarbon (HC) fluorescent dye is preferentially dissolved in the HC island phase in phase-separated mixed monolayers of HC and fluorocarbon (FC) amphiphiles. The SNFM image clearly shows that the modified SNOM–AFM can be used to observe fluorescence and topography images. The image also confirms the preferential dissolution of CD in the HC phase.

To improve the stability and durability of organic EL devices, the mixed HTL layer was fabricated by co-deposition of TPD and Alq(3) and the EL cell with the mixed HTL was compared with that with the conventional pure HTL. When more than 5 wt% of Alq(3) was added in HTL, the increase in surface roughness of ITO / TPD-Alq(3) / Alq(3) by annealing was found by AFM to be reduced dramatically. In addition, the running durability was significantly improved by addition of a small amount of Alq(3) (< 10 wt %), although the EL characteristics of the cells with mixed HTLs were slightly lowered, i.e. IV and L-V curves shifted to the higher voltages.

Photo-electric conversion molecular devices, i.e. molecular photodiodes based upon the charge separation mechanism of the primary process of natural photosynthesis, have been studied in our laboratory. Amphiphilic A-S-D triad molecules can be oriented unidirectionally in monolayers at the air-water interface. The resulting oriented monolayer assemblies are fabricated into thin films on electrode surfaces by the Langmuir-Blodgett (LB) technique. The A-S-D triads for charge separation together with light harvesting antenna molecules can be assembled into sub-micron island domains by making use of phase separation of mixed monolayers of hydrocarbon (HC) and fluorocarbon (FC) amphiphiles. The structure and properties of the domains of HC-FC mixed monolayers were studied by various scanning probe microscopies (SPMs) such as atomic force microscopy, friction force microscopy, scanning surface potential microscopy (SSPM), and scanning near-field optical/atomic force microscopy. Some SPMs can be used not only to characterize the LB films, but also to drive the molecular devices. The photo-induced charge separation in unidirectionally oriented triad molecules embedded in alternate LB films was observed by SSPM.

The existence of liquid-liquid miscibility gap in ferric ferrous oxide-silica system has been reported, however, the phase separation phenomena and the derived morphology of the phase separated glasses are uncertain. In this study, the melt-quenched samples of 5 Fe3O4-95 SiO2 and 15 Fe3O4-85 SiO2 (mol%) were prepared by melting at 2300°C or 2200°C (expected to be above miscibility gap), and subsequently at 1800°C or 1750°C (in immiscible region) by use of infrared image furnace and quenching at the rate of ≈102 K/sec. The glassy materials exhibited phase separation having discrete spherical particles or interconnected structure due to the composition, melting temperature and time. Also, the segregation of Fe component occurred during melting, which was caused by the difference of specific gravity of components in the melt.

In order to clarify the propagation mechanism of dark spots in an organic multilayered electroluminescent device, in situ electroluminescence microscopy as well as photoluminescence (PL) microscopy and Auger electron spectroscopy of the degraded device was carried out. The difference in local PL spectra between the dark spots and the normal surface area was also observed by using scanning near-field optical/atomic force microscopy. The growing mechanism of the dark spots was proposed from these observations.

An organic electroluminescent (EL) device (indium thin oxideN,N′-diphenyl-N,N′-bis(3-methylphenyl)-(1,1′-biphenyl)-4,4′-diamine(TPD)tris(8-hydroxyquinoline)aluminum (Alq3)Al) was prepared to observe the degradation process of the EL device by fluorescence microscopy and atomic force microscopy (AFM). From AFM and fluorescence microscopy observations, we found morphological changes of the Al top electrode surface, e.g. the formation of a dome in the form of a hemisphere. The surface morphology of the Al electrode changed with time, from tiny to growing disks with central sharp peaks, the dome formation, and finally formed crescent shapes due to shrink of the domes. However, under the crescent shape or the dome, there was little change in the organic layer except for the formation of a crevasse. The dome was formed by gas evolution from the crevasse.