The electron transfer of a well-defined singlecrystalline organic P−N interface of the epitaxial layer of C 60 on the surface of a single-crystalline pentacene (Pen-SC) was observed using time-resolved photoemission electron microscopy (TR-PEEM) with an optical pump and probe mode. The fine energytuning of the probe light and the selected-area detection of the photoelectrons, in addition to the PEEM detection of photoelectrons, allowed the measurement of the dynamics of electrons of rather insulating organic interfaces with a high signal-to-noise ratio, without suffering from the charging of the sample. After determination of the relaxation of the photogenerated electrons in Pen-SC via singlet fission through multiple-exciton states, two distinct electron transfer processes to the LUMO of the C 60 layer were clearly observed by direct detection of the time evolution of the electrons in the LUMO of C 60 .

Highly oriented, multilayer molecular films of picene and dinaphtho[2,3- b :2′,3′- f ]thieno[3,2- b ]thiophene (DNTT) molecules with the long axis parallel to the substrate (parallel configuration, hereafter) were fabricated on their characteristic bulklike monolayer. These molecules form a dense monolayer with a bulklike molecular arrangement on metal surfaces such as Au(111), which allows further stacking of parallel molecules. Indeed, upon adsorption of picene and DNTT on these dense monolayers, growth of straight islands of multilayer without the dendritic layer was observed. Particularly, in the case of picene, one-dimensional islands with lengths over 100 μm were formed and aligned in 3-fold symmetric directions of the substrate, which was not observed in the case of DNTT. X-ray diffraction measurements revealed the presence of [201̅] and [211̅] planes and the absence of the [001] diffractions, indicating that the one-dimensional islands of picene indeed consist of parallel molecules. The formation of huge crystalline islands in the case of picene, in contrast to the case of DNTT, is likely induced by the stronger intermolecular force, as suggested from the calculation of the vibrational energy.

Solid‐state films exhibiting thermally activated delayed fluorescence (TADF) can offer high internal electroluminescence (EL) quantum efficiency, even in a simplified device structure. However, the exciton dynamics in solid‐state TADF films, particularly for the unexpected exciton loss processes such as concentration quenching, have not yet been clarified. The dynamics of photoexcited electrons in the TADF process of a 2,4,5,6‐Tetra (9H‐carbazol‐9‐yl) isophthalonitrile (4CzIPN) solid film are observed via time‐resolved photoelectron emission microscopy (TR‐PEEM) and the results are compared with the conventional time‐resolved photoluminescence (TR‐PL) technique. The initial decay process of the photoexcited electrons probed via TR‐PEEM is thoroughly traced in the TR‐PL signal, while unusual long‐lived electrons are detected only through the use of TR‐PEEM. These results indicate that the excitons of 4CzIPN spontaneously dissociate into free carriers within the exciton lifetime, which seems to be a common process that contributes to the exciton loss in polar organic solids.

We applied photoemission tomography (PT) to a unique one-dimensional row structure of a picene multilayer realized on an anisotropic Ag(110) surface. Taking advantage of the simplified structure of the multilayer film, we successfully deconvoluted the photoelectron momentum maps of three frontier orbitals of picene. Thereafter, the clearly deconvoluted experimental momentum maps were compared to the Fourier transform simulation of the molecular orbitals of picene in detail, enabling not only the evaluation of the electronic structure of the picene in the multilayer but also the determination of the molecular orientation in the multilayer within a few degrees. In addition, the PT results indicated the orientation of the molecules in all layers to be flat-lying. The successful demonstration of PT of the multilayer molecular film marks an important step toward the wide-range utilization of the PT technique.

The electronic structures of (Ga1−yIny)1−xMnxAs have been investigated using the Korringa, Kohn and Rostoker (KKR) method with the coherent potential approximation (CPA). The estimated Curie temperature (TC) of Ga1−xMnxAs is higher than that of (Ga0.5In0.5)1−xMnxAs and In1−xMnxAs when x≲0.10. On the other hand, the estimated TC of Ga1−xMnxAs saturates with an increase of x when x≳0.05, but that of (Ga0.5In0.5)1−xMnxAs and In1−xMnxAs does not saturate even when x>0.10. These results are in good agreement with the previous experimental results. Our calculated results predict that the TC of (Ga0.5In0.5)1−xMnxAs and In1−xMnxAs will be higher than that of Ga1−xMnxAs when x≳0.10.