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Large elongated single crystals (2.91 mm × 97 μm) of 1,6-dibromopyrene were successfully obtained from solution using the slow evaporation method. Their carrier mobility was obtained via current–voltage characteristics of bottom-gate bottom-contact-type field-effect transistors. In these devices, the longitudinal direction of each crystal was parallel or perpendicular to the conductive channel. The highest mobility was 6.0 × 10−4 cm2 V−1 s−1 and 2.2 × 10−3 cm2 V−1 s−1 in the linear and saturation region, respectively, when the electric current flowed across the crystal’s longitudinal direction. The emission strength ratio and mobility ratio between the two longitudinal directions (parallel and perpendicular to the conductive channel, respectively) were 3.1 and 2.2. X-ray diffraction measurements suggested that both the emission strength and mobility are larger in the transverse intermolecular contact direction than in the stacking direction. The mobilities in the linear region were tentatively corrected by subtracting the contributions of charge injection barriers and were estimated to be 2.1–2.9 times larger than the uncorrected ones. The results of this study suggest that bromine substitution is one of the effective methods to modify the optical properties and improve the solution processability of organic semiconductor materials while maintaining the carrier mobility.

The photophysical properties of 2,5-bis(4’-cyanobipheny-4-yl)thiophene (BP1T-CN) molecule as a function of solvent polarity are intensively studied by means of steady-state spectra and femtosecond ...

Microcavity systems with organic luminescent materials have a hot prospect for room-temperature cavity-polariton devices. The polariton dispersion relation of organic microcavities is significantly different from that of inorganic microcavities due to the strong localization of Frenkel excitons. Also photoexcited particles will undergo a different cooling mechanism until they reach the polariton ground state. In the characterization of efficient polariton condensates, therefore, the polariton cooling dynamics as well as the kinetics of the polariton eigenstate should be measured. Here we present experimental studies on ultrafast dynamics of cavity polaritons in an organic single-crystal microcavity under nonresonant pumping. In time-resolved photoluminescence measurements we observed, for the first time, an ultrafast dynamics of stimulated cooling of the organic cavity polariton. Transient transmission measurement enabled us to investigate the detailed renormalization dynamics of the polariton eigenstate....

We demonstrated direct fabrication of a diffraction grating onto organic oligomer crystals by focused ion beam (FIB) lithography followed by argon/oxygen plasma etching. Surface analysis suggested that FIB irradiation broke the oligomer molecules near the crystal surface to form a carbonized layer resulting in emission quenching. The plasma etching removed the damaged layer near the crystal surface and successfully recovered the emission. This technique was applied to fabricate the diffraction grating onto organic oligomer crystals and provided diffracted peaks in their fluorescence spectra without significant emission quenching.

We improved carrier injection of organic field-effect transistors (OFETs) by utilizing organic/inorganic hybrid electrodes. One of thiophene/phenylene co-oligomers (TPCOs) was employed as a...

We investigated solar cells in which various thiophene/phenylene co-oligomers (TPCOs) were used as the major photoelectric-conversion component and obtained enhanced performance. These simple planar heterojunction solar cells consisted of TPCO as the p-type semiconductor and fullerenes as the n-type semiconductor. The variation in the highest occupied molecular orbital levels of the TPCOs caused systematic modulation of the open-circuit voltage ( V OC ) without incurring a large change in the short-circuit current. We obtained a maximum power-conversion efficiency (PCE) of 3.0%, with V OC reaching 1.0 V. This PCE exceeds that obtained for a device containing zinc phthalocyanine, a conventional p-type photoelectric-conversion material.

A metal-lustrous self-standing film, named "porphyrin foil", was formed from a glass-forming polymeric porphyrin. The amorphous glass nature of the porphyrin foil played a key role in spontaneously producing a smooth surface. Its sharp contrast in intense absorption and specular reflection of light at each wavelength provided a brilliant metallic lustre.

The correlation between molecular orientation and optoelectrical properties is most critical to the future design of molecular materials. We made highly-anisotropic microcrystalline array structures with an organic semiconductor, a methoxy-substituted thiophene/phenylene co-oligomer (TPCO), by depositing it on friction-transferred poly(tetrafluoroethylene) (PTFE) layers fabricated on substrates with several heat treatments. Polarising microscope observation, polarised emission and absorption spectra measurements indicated that the TPCO molecules aligned along the drawing direction of PTFE. Using these films, we fabricated two types of field-effect transistors (FETs) and compared them with those using non-heated TPCO films which provide aligned pleats structures. Ones had the channel length direction parallel to the drawing direction of PTFE and the others had the channel length direction perpendicular to that drawing direction. As for the microcrystalline array films, the mobility ratio of the former FET to that of the latter device was about 27 in the saturation region, while the emission polarisation ratio was 4.5. The heat treatment promoted the crystal growth to enhance the mobility while retaining the high anisotropy. The results demonstrate that the heat treatments of the TPCO films on the friction-transferred layers were useful for controlling crystallinity and orientation of the molecules.

We introduced a crystal of an oligomer material for p-type emission layer into an organic light-emitting diode (OLED), and compared it with the device composed of thin films. To fabricate the devices, we laminated the oligomer crystal or deposited the oligomer thin film on a substrate covered with patterned indium tin oxide electrodes. We completed the devices by depositing an n-type material, an electron injection layer, and an Al electrode. For the current-voltage characteristics, both of the crystal and thin-film devices indicated rectification properties. At a certain current density, estimated applied electric fields for the crystal device was almost a quarter of that for the thin-film device. Both devices showed the current-injected emission. Comparison of the current-injected emission spectra to photoluminescence spectra revealed that the oligomer layers dominated emissions from the devices. The rough estimation of the input power for the current-injected emissions showed the crystal device required the lower input power than the thin-film device. These results suggest an advantage of the crystal device for current injection and light emission.

Distributed feedback (DFB) lasing is achieved with CH3NH3PbBr3 perovskite embedded in channel-type waveguides. By using a focused ion beam, DFB gratings are engraved within the bottom surface of channel-type waveguides etched on a SiO2/Si wafer. The oriented CH3NH3PbBr3 crystallized inside the waveguide with the DFB gratings shows second-order DFB lasing mode in lateral and normal directions above a threshold excitation density of 47 μJ cm−2 which is one order of magnitude lower than that in the non-DFB laser. The splitting DFB peaks are well reproduced by finite-differential time-domain calculation. The peaks change to a power-broadened amplified spontaneous emission as the excitation fluence is increased far above the threshold.

A series of reorganization energies of multi-halogen-substituted pyrenes were calculated by the density functional theory method [B3LYP/6-31++G(d,p)]. The reorganization energies decreased in the order of substituted halogen species, that is, fluorine, chlorine, and bromine. Among the bromine-substituted pyrenes, 1,3,6,8-tetrabromopyrene showed the lowest electron reorganization energy. Its charge transfer integrals were calculated on the basis of the known crystal structure and found to be larger in the stacking direction than those in the molecular plane direction. The estimated electron mobility in the stacking direction was 1.8 × 10−4 cm2 V−1 s−1. This value is about 20 times larger than that of previously reported hydroxypyrene.

We have formed one-dimensional (1D) diffraction gratings on a photoresist polymer (SU-8) by interference exposure using a Lloyd mirror. A single crystal of thiophene/phenylene co-oligomers (TPCOs) grown in a vapor phase was placed on the 1D diffraction grating. Excitation of the single crystal by an ultraviolet light of a mercury lamp produced spectrally-narrowed fluorescence. On the basis of the grating periods and emission peak locations, we evaluated effective refractive indices and diffraction orders. The relevant information enables us to design and fabricate the 1D diffraction gratings that cause the spectrally-narrowed emission lines to superimpose inherently occurring high-intensity fluorescence peaks.

We fabricated organic light-emitting transistors (OLETs) characterized by an Ag layer deposited on a one-dimensional (1D) or two-dimensional (2D) diffraction grating that acts as a combined gate insulator with SiO2. The Ag layer was entirely covered with an organic crystal. Upon photoexcitation that crystal showed narrow linewidth emissions (NLEs) parallel to the substrate plane. The narrowed lines were either redshifted or blueshifted with rotation of the crystal around a normal to its surface with respect to the grating wave vector. Strong emissions (∼104–106 cd m−2) accompanied by current-injected NLEs were observed from the 1D and 2D grating OLETs.

An organic laser device is constructed as distributed feedback (DFB) type using an anisotropic single crystal of an organic semiconductor oligomer BP3T. The DFB structure is formed on top of the crystal via an interference exposure technique of a positive type photoresist. In the DFB structure, both the phase matching condition and waveguide condition must be fulfilled. Under these conditions, the effective refractive indices can be precisely predicted for a BP3T crystal, and they vary depending upon the crystal thickness. As a result, the device produces a single-mode laser oscillation at an intended wavelength (typically ∼569 nm). The present study enables us to design a down-to-earth laser device based on an anisotropic organic semiconductor crystal toward practical use.An organic laser device is constructed as distributed feedback (DFB) type using an anisotropic single crystal of an organic semiconductor oligomer BP3T. The DFB structure is formed on top of the crystal via an interference exposure technique of a positive type photoresist. In the DFB structure, both the phase matching condition and waveguide condition must be fulfilled. Under these conditions, the effective refractive indices can be precisely predicted for a BP3T crystal, and they vary depending upon the crystal thickness. As a result, the device produces a single-mode laser oscillation at an intended wavelength (typically ∼569 nm). The present study enables us to design a down-to-earth laser device based on an anisotropic organic semiconductor crystal toward practical use.

Organic single-crystalline semiconductors with long-range periodic order have attracted much attention for potential applications in electronic and optoelectronic devices due to their high carrier mobility, highly thermal stability, and low impurity content. Molecular doping has been proposed as a valuable strategy for improving the performance of organic semiconductors and semiconductor-based devices. However, a fundamental understanding of the inherent doping mechanism is still a key challenge impeding its practical application. In this study, solid evidence for the "perfect" substitutional doping mechanism of the stacking mode between the guest and host molecules in organic single-crystalline semiconductors using polarized photoluminescence spectrum measurements and first-principles calculations is provided. The molecular host-guest doping is further exploited for efficient color-tunable and even white organic single-crystal-based light-emitting devices by controlling the doping concentration. The clarification of the molecular doping mechanism in organic single-crystalline semiconductor host-guest system paves the way for their practical application in high-performance electronic and optoelectronic devices.

Doping effects in thiophene/phenylene co-oligomers (TPCOs) have been studied by means of extreme-UV (EUV) excited photoelectron spectroscopy (EUPS) and electro-luminescence experiments. Doped poly-crystalline films were fabricated by p-type doping with MoO3 to inherent p-type TPCO, BP1T (2,5-bis(4-biphenylyl)thiophene), and by n-type doping with Cs2CO3 to n-type AC5-CF3 (1,4-bis{5-[4-(trifluoromethyl)phenyl]thiophen-2-yl}benzene), respectively. Doping concentrations were 2% in both cases. The work function of BP1T was shifted from 4.0 to 4.3 eV and that of AC5-CF3 was shifted from 4.8 to 3.9 eV. The energy shifts are reasonable directions for p- and n-type doping. We also confirmed higher current injection with the doping films.

We synthesized a novel small-molecule organic semiconductor, which is soluble in organic solvents at room temperature under normal pressure. We demonstrated that its high-quality crystalline films can be directly grown on substrates using various solution techniques such as solution casting, slow evaporation, and edge casting. We applied crystals to FETs with a bottom- or top-contact configuration, revealing that the carrier mobility ranged from ~10−4 to ~10−2 cm2 V−1 s−1.

Full-thickness defects of the entire nasal ala, including the rim, can be challenging to reconstruct. A forehead flap may provide a more imperceptible and natural-appearing reconstructed nasal ala. Previously, many authors have insisted adding cartilaginous infrastructural support for an entire, full-thickness defect to keep the postoperative alar structure symmetrical. They finally use a forehead flap after thinning of the distal covering portion subcutaneously, possibly for a Caucasian-type nasal ala. However, Asian skin has a thicker and more compact dermis than that of Caucasian skin, and the Asian ala is rounder and thicker. There may be another approach for an Asian-type nasal ala. The authors propose the possibility of nasal alar reconstruction for an entire, full-thickness defect in Asians using a forehead flap without structural support. Six patients with entire full-thickness nasal alar defects treated with full-thickness forehead flaps above the periosteum without structural support were reviewed. Five patients demonstrated esthetically good to excellent outcomes in color, texture, and symmetry. Their nasal linings were reconstructed using mucoperiosteal flaps or mucosal grafts. One patient treated with a nasal lining using a local flap showed a fair result esthetically. Asians forehead above the periosteum has adequate thickness and supportability to reconstruct the entire full-thickness nasal ala in Asians. No cartilage support is necessary.

The incidence of postoperative wound dehiscence following inguinal lymph node dissection (ILND) is higher than that in other anatomic regions. To prevent wound dehiscence, intraoperative interventions, such as trimming off the ischemic part of the flap before wound closure based on indocyanine-green (ICG) fluorescence angiography, have been introduced in our institute. This report describes a retrospective clinical study of 17 cases, and the objective of the study was to evaluate the clinical efficacy of intraoperative intervention using ICG fluorescence angiography. A total of 17 patients who underwent ILND for skin cancer between 2009 and 2013 at our institute were reviewed retrospectively, and the significance of variables, including intervention using ICG fluorescence angiography, was evaluated using Fisher’s exact test. There were nine cases of wound dehiscence, and two of these cases required a secondary skin graft. Only one case of wound dehiscence developed in the eight patients who underwent intervention based on ICG fluorescence angiography. This procedure was a significant factor influencing the risk of wound dehiscence (p = 0.003) in our study. Although this was a small case series, intraoperative intervention based on ICG fluorescence angiography was effective for preventing postoperative wound dehiscence after ILND.

We applied thiophene/phenylene co-oligomers (TPCOs) to a major component of organic solar cells. We made sandwich-type devices combining a p-type TPCO with fullerene (C60) or an n-type TPCO. As an option we made a device that combined a mixed layer of p-type and n-type TPCOs with the C60 layer. All devices indicated rectification properties in the dark and generated electric powers under the white light illumination. The device comprising methoxy-substituted biphenyl-capped bithiophene and C60 achieved the best power conversion efficiency of 1.20% with a short-circuit current of 4.28 mA/cm2 and fill factor of 0.46. The results demonstrate that the TPCO materials are useful as the major component of the organic solar cells.

Because of long-range order and high chemical purity, organic crystals have exhibit unique properties and attracted a lot of interest for application in solid-state lasers. As optical gain materials, they exhibit high stimulated emission cross section and broad tunable wavelength emission as similar to their amorphous counterpart; moreover, high purity and high order give them superior properties such as low scattering trap densities, high thermal stability, as well as highly polarized emission. As electronic materials, they are potentially able to support high current densities, thus making it possible to realize current driven lasers. This paper mainly describes recent research progress in organic semiconductor laser crystals. The building molecules, crystal growth methods, as well as their stimulated emission characteristics related with crystal structures are introduced; in addition, the current state-of-the-art in the field of crystal laser devices is reviewed. Furthermore, recent advances of crystal lasers at the nanoscale and single crystal light-emitting transistors (LETs) are presented. Finally, an outlook and personal view is provided on the further developments of laser crystals and their applications.

Autologous bone grafts remain the gold standard for the treatment of congenital craniofacial disorders; however, there are potential problems including donor site morbidity and limitations to the amount of bone that can be harvested. Recent studies suggest that granulocyte colony-stimulating factor (G-CSF) promotes fracture healing or osteogenesis. The purpose of the present study was to investigate whether topically applied G-CSF can stimulate the osteoconductive properties of beta-tricalcium phosphate (β-TCP) in a rat calvarial defect model. A total of 27 calvarial defects 5 mm in diameter were randomly divided into nine groups, which were treated with various combinations of aβ-TCP disc and G-CSF in solution form or controlled release system using gelatin hydrogel. Histologic and histomorphometric analyses were performed at eight weeks postoperatively. The controlled release of low-dose (1 μg and 5 μg) G-CSF significantly enhanced new bone formation when combined with aβ-TCP disc. Moreover, administration of 5 μg G-CSF using a controlled release system significantly promoted the biodegradable properties ofβ-TCP. In conclusion, the controlled release of 5 μg G-CSF significantly enhanced the osteoconductive and biodegradable properties ofβ-TCP. The combination of G-CSF slow-release andβ-TCP is a novel and promising approach for treating pediatric craniofacial bone defects.

We have grown crystals in which two kinds of thiophene/phenylene co-oligomers (TPCOs) are hybridized. Biphenyl-capped thiophene (BP1T) and biphenyl-capped terthiophene (BP3T) were chosen from among the TPCOs. The hybrid crystals were grown in both the vapor phase and the liquid phase. These hybrid crystals showed the emission colors intermediate between the two components. Correspondingly maximum peak positions of the emissions from the hybrid crystals were located halfway between those from single-component crystals of BP1T and BP3T. We made hybrid thin films by co-deposition of the two TPCOs in vacuum. The thin films exhibited both emission colors and emission peak positions similar to those of the hybrid crystals. The X-ray diffraction measurements indicate that the crystallographic structure of the hybrid crystals resembles that of the BP1T crystal. Also we made field-effect transistors using the hybrid crystals and measured their hole mobilities. We briefly discuss the implications of the X-ray diffraction and electrical data.

We have grown the crystals of two thiophene/phenylene co-oligomers (TPCOs) composed of in-line five and seven alternating thiophene and benzene rings. These TPCOs are characterized by thiophenes located at both molecular terminals. The grown crystals had several pairs of parallel crystal faces that function as optical resonators. These produced interference fringes in their emission and reflectance spectra. We measured the emission spectra in both weak broadband excitation and intense laser excitation regimes. From these spectra we determined the phase refractive index dispersion and the anisotropic group refractive indices. We made field-effect transistor devices using the above TPCO crystals and carried out their electrical measurements. These optical and charge transport properties are compared with those of crystals of other alternating TPCOs with phenylenes located at both molecular terminals.

We have been successful in growing well-defined polygon crystals of fullerene and pentacene in liquid and vapor phases, respectively. These crystals were grown directly or laminated on substrates, allowing us to carry out their detailed structural characterization. We estimated the crystal structure of fullerene crystals by comparing the results of microscope and X-ray diffraction (XRD) observations with the crystal structure of a solvate. We carried out spectroscopic and XRD measurements on the pentacene crystals. Combining density functional theory calculations with the polarizing microscope observation, we related the principal axes of refractive index to the crystal geometry of pentacene.

In combination with optical cavities, organic semiconductor crystals are powerful candidates for current-injected organic laser devices. For such cavities diffraction gratings are applicable. In common with external diffraction gratings made of dielectrics and oxides, built-in ones are effective for producing narrow linewidth emissions. However, direct fabrication of the diffraction gratings on the surfaces of the organic crystals is still challenging. In the present studies, we directly engraved one-dimensional (1D) diffraction gratings on the flat surfaces of organic semiconductor crystals by using focused ion beam (FIB) lithography, and shaped a distributed feedback resonator (DFB) structure. We chose as the organic semiconductor material 5,5'''''-diphenyl-2,2':5',2'':5'',2''':5''',2'''':5'''',2'''''-sexithiophene (P6T) from among thiophene/phenylene co-oligomers. We grew plate-like crystals of P6T in a vapor phase. The P6T crystals showed emissions with a maximum intensity around 630 nm. We laminated them on Si wafer substrates covered with 300-nm-thick silicon dioxide and 160-nm-thick Al-doped ZnO (AZO) layers. The AZO layer was used to prevent the crystals from being charged during the FIB lithography. We precisely controlled FIB process conditions and obtained the gratings having the equally-spaced 200 (400) grooves with the periods of 240 (200) nm. When we observed the emissions perpendicular to the grating grooves as well as parallel to the crystal surface under ultraviolet light from a mercury lamp, these crystals with the 1D diffraction gratings indicated narrowed emission peaks at 745 (670) nm. From the grating period and the emission peak position, we estimated an order of diffraction and an effective refractive index. We related the effective refractive index with a phase refractive index of the crystal and decided the optimum grating period to be 190 nm to produce the narrowed peak at 630 nm. We fabricated the diffraction grating having the optimum grating period on the P6T crystal by engraving 400 grooves, and succeeded in observing strong single peak at 629 nm. Using the present method, we can design the diffraction grating periods for the optical devices of organic oligomer crystals that show the narrow linewidth emissions.

We have fabricated light-emitting field-effect transistors (LEFETs) using p-type organic crystals directly grown onto a two-dimensional polymer diffraction grating made of a triangular lattice of circular air holes. An n-type organic thin film was inserted between the crystal and the metal electrode. Distinct current-injected spectrally narrow linewidth emissions (NLEs) were observed under application of alternating-current voltages to the gate contact. The NLE peaks were related to the combined refractive index of the p-type crystal and the grating. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

We observed current-injected spectrally narrowed emissions (SNEs) from a light-emitting field-effect transistor (LEFET) characterized by both layered organic semiconductor crystals and a two-dimensional (2D) diffraction grating. The grating fabricated using nanoimprint lithography had circular air holes forming a triangular lattice. We laminated the p- and n-type crystals in this order on the grating and deposited heterogeneous metal drain and source electrodes. The several SNE peaks were definitively observed when we applied square-wave alternating-current voltages to the gate contact.

Summary Background There is no consensus on the most appropriate treatment for patients with large to giant congenital melanocytic naevi (CMN) because of the risk of melanoma development. Surgical excision followed by skin grafting or expanded skin coverage may cause unfavourable scarring. There is a balance to be achieved between minimizing the disfiguring appearance and the risk of malignant change. The pulsed dye laser (PDL) is commonly used for vascular lesions and is highly absorbed by melanin and haemoglobin. Its pulse duration is longer than that of Q-switched ruby lasers (QsRL), which can have nonspecific photothermolytic effects on surrounding nonpigmented naevus cells. Objectives To investigate the effectiveness of combined treatment with the PDL and QsRL for large to giant CMN. Methods Six patients with large to giant CMN were enrolled in this study. Treatment consisted of one pass of PDL treatment followed by one pass of QsRL treatment. Multiple rounds of treatment were applied to all patients. Results All patients responded to this combined regimen, and the lesional colour was effectively reduced. The mean number of rounds of laser treatment required to achieve skin lightening was 7·7. No patients suffered severe hypertrophic scarring. No cases of recurrence or malignant transformation were observed. The histological results from the patient who underwent the most laser therapy in this study showed a remarkable reduction in the number of melanocytic naevus cells after treatment. Conclusions This technique may enable the removal of most of the pigmented lesion and melanocytic naevus cells with minimal scarring.

We have fabricated p–n junctions using a combination of p- and n-type thiophene/phenylene co-oligomer (TPCO) thin films and applied them to organic light-emitting diodes (OLEDs). We made two types of devices using the different p-type TPCOs. Both the devices showed current-injected light emissions and high rectification ratios (~ 10 2 –10 4 ). The one type of the devices produced brighter surface emissions and higher external quantum efficiencies (0.17%) than the other. The results indicated that the p–n junction comprising layered TPCOs showed good functionality.

We present the preparation of giant organic thin single-crystals of 2,5-bis(4-biphenylyl)thiophene (BP1T), a thiophene/phenylene co-oligomer (TPCO). Large-size well-defined hexagon crystals of BP1T were obtained by recrystallization from 1,2,4-trichlorobenzene solution using the constant-volume decreasing-temperature method under various conditions. The largest crystal had a size of 7.6 × 4.4 mm. We describe the detailed growth procedure and characterization of the resulting crystals. The polarizing microscope observation of the crystals confirms that they are present as single-crystals. In virtue of the large size of the crystal we were able to fabricate three field-effect transistor (FET) devices on one single crystal. The devices showed normal p-type FET characteristics. Furthermore, the emission features are examined. Major emission peaks were spectrally narrowed with increasing excitation energies. Several crystals exhibited the narrowed emission lines accompanied by many concentric fringes of various sizes. These observations strongly indicate that the emission is a coherent radiation.

A novel device structure for organic light-emitting field-effect transistors has been developed. The devices comprise bilayer-crystal organic semiconductors of a p-type and an n-type. The pn-junction can readily be formed by successively laminating two crystals on top of a gate insulator. This structure enables the efficient injection and transport of electrons and holes, leading to their effective recombination. As a result, bright emissions are attained. The devices are operated by AC gate voltages. Gate-voltage phase-resolved drain-current and emission-intensity measurements enable us to study the relationship between the emissions and carrier transport. The maximum external quantum efficiency reaches 0.045%.

Background. The triple technique (lymphoscintig- raphy, patent-blue staining, and a gamma probe) constitutes a reliable method for the sentinel lymph node (SLN) biopsy. However, in head and neck melanomas, a shine-through phe- nomenon, which occurs because these SLNs are close to the primary focus, is irreversibly problematic. To get around the shine-through phenomenon, this study uses the fluorescence navigation with indocyanine green (ICG) as well as the triple technique. Methods. ICG is a green dye and can be used as a marker with infrared fluorescence. ICG solution is intradermally injected around the tumor. By using Photodynamic Eye (PDE) intraoperatively, it is possible to observe the injected ICG as SLNs in the fluorescence images. Results. By use of the fluorescence imaging with ICG, clear identification of the SLN of the case became possible. Conclusions. We think the fluorescence navigation with ICG will be a useful option for the SLN biopsy in head and neck melanomas. V C 2011 Wiley Periodicals, Inc. Head Neck 00: 000-000, 2011

Surgical correction of an anophthalmic enophthalmos secondary to inappropriate repair of the eye socket involves several difficult aesthetic issues associated with long-term use of a poorly fitting prosthetic eye. In this paper, we present two cases of anophthalmic enophthalmos. During the treatment of the first patient, unsatisfactory cosmetic problems including lower eyelid retraction, hypoglobus, and severe upper eyelid ptosis were revealed. Accordingly, a three-staged procedure was performed on the second patient, including autologous augmentation of the eye socket, correction of lower eyelid retraction with a cartilage graft, and a frontalis sling procedure to correct upper eyelid ptosis.

We propose a construction of an organic light-emitting field-effect transistor for producing spectrally-narrowed emissions (SNEs) under current injection. The device is characterized by the followings: a diffraction grating fabricated within the channel region, homogeneous source and drain electrodes made of a low work-function metal and a layered structure of organic semiconductor materials. The organic layered structure was composed of a p-type crystal and an n-type thin film. The latter film was deposited so as to cover the grating on the channel. We observed SNEs from the device when it was operated by applying square-wave alternating gate voltages. The observed spectra were peaking as a dominant line around 578 nm with a full width at half maximum less than 4 nm.

The thiophene/phenylene co-oligomers are ranked as a newly occurring class of organic semiconductors. The materials are characterised by that thiophenes and phenylenes are hybridised at the molecular level with their various mutual arrangements. These molecular arrangements produce peculiar morphological features in the solid state and excellent electronic and optical properties. In this review article we outline those characteristics in light of the structure/property relationship with central emphasis upon the crystal structure and its relevance to the leading-edge optoelectronic functionalities. These topics are most suitably approached by device studies including field-effect transistors and light-emitting devices. We describe the device characteristics in close connection with current-injected lasers.

Organic semiconductor crystals exhibit unique optoelectronic characteristics such as high carrier mobility and laser oscillation. Nonetheless, it remains difficult thus far to achieve such potential activities on an optical device configuration mainly because of lack of knowledge of optical parameters such as refractive indices and their dispersion. Here, we demonstrate a simple but powerful design principle of high-performance organic single-crystal light-emitting devices. The method is based upon observation of emission-angle dependent spectra produced from an organic slab single crystal equipped with a one-dimensional diffraction grating. The emission spectra are characterized by sharply resolved lines whose locations are blueshifted or redshifted as a function of the emission angles. Detailed analysis of these emission lines has enabled us to solve equations of electromagnetic wave motion within and outside the slab crystal and to get solutions under appropriate boundary conditions. The design principle also allows us to relate crystal thicknesses and orders of both longitudinal and transverse modes of emission. Thus, we have been able to optimize the geometry of a slab organic crystal in an organic light-emitting device configuration. The relevant knowledge can directly be used for designing an organic laser either optically excited or electrically excited.

Investigation of physics on light-matter interaction and strong coupling formation in organic microcavities is important to characterize the device structure enabling efficient room-temperature polariton condensation. In this study, we evaluate quantitatively the light-matter interaction parameters for three types of organic single-crystal microcavities and discuss the effects of microcavity structures on the strong coupling formation. We found that improvement in cavity quality factor causes a reduction in the photon damping constant, which results in an increase in the Rabi splitting energy. Moreover, when we used a metal thin film as the cavity mirror, it was revealed that the exciton damping became 30 times stronger than that in a dielectric mirror cavity. These experimental findings are very intriguing to achieve low-threshold or electrically pumped organic polariton devices.

Polymer mixtures composed of double networks of a polystyrene derivative (PSAF) and poly(methyl methacrylate) (PMMA) were alternatively synthesized by using ultraviolet (UV) and visible (Vis) light. The PSAF networks were generated by UV irradiation to photodimerize the anthracene (A) moieties labeled on the PSAF chains, whereas PMMA networks were produced by photopolymerization of methyl methacrylate (MMA) monomer and the cross-link reaction using ethylene glycol dimethacrylate (EGDMA) under Vis light irradiation. It was found that phase separation process of these networks can be independently induced and promptly controlled by using UV and Vis light. The characteristic length scale distribution of the resulting co-continuous morphology can be well regulated by the UV and Vis light intensity. In order to confirm and utilize the connectivity of the bicontinuous morphology observed by confocal microscopy, a very small amount, 0.1 wt%, of multi-walled carbon nanotubes (MWCNTs) was introduced into the mixture and the current–voltage (I–V) relationship was subsequently examined. Preliminary data show that MWCNTs are preferentially dispersed in the PSAF-rich continuous domains and the whole mixture became electrically conducting, confirming the connectivity of the observed bi-continuous morphology. The experimental data obtained in this study reveal a promising method to design various scaffolds for conducting soft matter taking advantages of photopolymerization-induced phase separation.