Koji Utsugi

Disordered carbon anode for lithium-ion battery I. An interfacial reversible redox action and anomalous topology changes

The authors investigated mechanisms for an interfacial reversible surface redox action and a solid electrolyte interphase (SEI) formation based on LiF with surface topology changes for a disordered carbon electrode in LiPF 6 /propylene carbonate -based electrolyte. The electrochemical reaction mechanism that delivers a large capacity was found to occur differently in two potential regions, region A (1.4 to 0.4 V) and B (0.4 to 0.0 V). During the reversible process in region A, a lithium alkoxide (C-OLi) is formed on the carbonyl edge planes as solvated lithium complex of the C-O - Li + (solv.) n (n = 1, 2, or 3). The formation of the lithium alkoxide traps solvents on the edge surfaces preventing further intrusion into stacked graphene sheets, that in turn suppresses a exfoliation and stabilized repeated redox cycles. In region A, a Li 2 CO 3 and a LiF are formed as an SEI film by the reduction of solvents and LiPF 6 making a smooth surface. region B involves three parallel processes, viz., a lithium intercalation into graphene layers, a lithium metal cluster deposition at nanosized voids or pores, and a formation of LiF by disproportionation of the C-OLi formed at region A. Since the LiF is produced rapidly by a proposed repeated cycle, the electrode surface generates a rough anomalous topology.

Organic electroluminescent devices with molecularly doped polymers and anode interface phthalocyanine layer

We studied the properties of organic electroluminescent devices using molecularly doped polymers as a hole transport layer and having a metal-free phthalocyanine (H2Pc) layer between anode and hole transport layer. A vacuum-deposited H2Pc metastable layer was converted to a more stable microcrystalline layer by dichloromethane solvent treatment. The devices exhibited good current–voltage and luminance properties. Because the activation energy of carrier transport for the devices with H2Pc was almost the same as that for the devices without it, it is considered that the H2Pc layer in this device is electrically inert. This means that improved contact efficiency may be obtained at the anode interface due to the introduction of the H2Pc layer.

P‐30: Fine Patterning of Lateral Three Color Emitters for Organic EL Devices Using a Metal Mask Sliding in Vacuum Vapor Deposition

In order to form high-resolusion pixels for a small organic elctroluminescent (EL) device having a three-color independent emission system using a low molecular evaporation method, a metal mask sliding control system with a pulse control motor was made for the initial trials. This system has a substrate holding table which has the functions of rotation angle adjustment, adjustment of the XY direction movements, adjustment of the Z direction movements and an XY stage for a metal mask sliding which is based on the leaf spring structure. The patterning of the RGB thin films was done by precisely controlling the position of the XY stage for a metal mask sliding using a DC servomotor. An organic EL device, which has the sub-pixel pitch of 33 μm × 100 μm, aperture ratio of 70% and 254 ppi (pixel/inch), has been manufactured using this system.