FINETECH JAPAN 2023/14th FILMTECH JAPAN/12th PLASTIC JAPAN/10th Metal Japan/3rd Sustainable Material Japan
Materials of device emerged as a central player in some exhibitions

October 4-6, FINETECH JAPAN 2023/14th FILMTECH JAPAN/12th PLASTIC JAPAN/10th Metal Japan/3rd Sustainable Material Japan were held in Makuhari Messe. Main topics about material in these exhibitions are picked up.

JX Metals appealed an electrolytic copper foil with high etching factor

Pic.1 Comparison of subtract etching circuit

As regards material for FPC, JX Metals Corporation appealed an electrolytic copper foil with high etching factor (EF). EF means slope of side plane of Cu pattern after wet-etching. If EF is high, cross-section shape of Cu pattern becomes to be vertical; on the other hand, EF is low, it becomes to be trapezoid. As a result, if electrolytic copper foil with high FE is used, it can be patterned by etching Cu foil only because of unnecessity of plated Cu film；as a result, it's possible to manufacture FPC by low cost. Furthermore, it's easy to form fine pattern such as L&S=20/20μm order. Picture 1 shows comparison of the conventional Cu foil and this Cu foil. As picture, this new foil is used, Cu pattern can be patterned sharply.

Of course, Cu foil can be etched by the conventional CuCl2 etchant and same etching condition. The company will supply sample in the near future, and also, will mass-produce at 2026.

Organic series solar cell is encapsulated by H2O gas barrier film

With respect to organic series solar cell such as perovskite solar cell and organic film solar cell, Kuraray introduced new gas barrier film "KURARISTER CW series" for flexible device.

Pic.2 Organic film solar cell using gas barrier film

It's composed of gas barrier layer/PET film/gas barrier layer. In case of using encapsulation film, it's laminated on manufactured device. Its transmittance is 91.4% at film thickness=25μm and 92.5% at 75μm. And also, H2O permeability is 10^-3g/m²/day (WVTR). In short, practical gas barrier property is obtained for perovskite solar cell and organic film solar cell.

Picture 2 shows a pilot-produced organic film solar cell module. Solar device was produced on a rubber sheet, and then, was encapsulated by KURARISTER CW. As you can image easily, its sample is suitable for bag because of light weight and semi-rigid.

Metal plate + film is used as a substrate of flexible OLED

Pic.3 Flexible OLED using laminate steel plate

On the other hand, JFE group proposed a laminate integration film, which was composed of metal sheet and plastic film, as a substrate of flexible OLEDs. High gas barrier property and insulation property were ensured by metal sheet, on the other hand, flexibility was ensured by plastic film. Typical thickness is 0.2 �o. Its flexibility is sufficient for bendable use.

Yamagata University has pilot-produced a OLED using this sheet, and also, estimated lifetime property at 60℃/90%RH. After 500 h, dark spot did not occur, and luminance state was not almost changed. In fact, H2O permeability could not be observed. In short, H2O and O2 gas do not penetrate into OLED device.

Ultra-thin metallic oxide film is adopted as ETL of organic series solar cell

Fig 1 Deposition image of electron transport layer and SEM image

Furthermore, JFE group proposed metallic oxide film was deposited as electron transport material by electrolytic plating method. For example, M(OH)x precursor is deposited by electrolytic plating method, and then, annealed at 80℃. As a result, it's changed to MOx film at a few dozen nm thickness. Compared to the existing method, it can be deposited at low temperature, and also, be denser. In fact, IPCE (incident photon-to-current efficiency) of sample device was increased at 20 % than that of the conventional device.

In the booth, a roll shape film was exhibited. It's possible to correspond to the Roll to Roll process. By the way, the company will supply technology license to solar cell makers in the future.

Dexerials appealed new ACF for mount of MICRO-LED chip by laser transfer method

Pic.5 Green emission MICRO-LED

Pic.4 Transparent conductive film with coated electron transport layer

As regards MICRO-LED, Dexerials appealed a new ACF (anisotropic conductive film)for mount of MICRO-LED chip by laser transfer method. In this process, ACF is laminated on all surface of glass substrate, and then, LED chip on a sapphire substrate is directly mounted on pixel area in glass substrate at each color by the laser transfer method.

In this time, Shin-Etsu Chemical pilot-produced a Green emission MICRO-LED, which was composed of 2500 array (20×40μm dot, 40μm dot pitch). As picture 5, green emission has been succeeded to be emitted on the whole. By the way, the company is supplying this ACF as a sample for the present moment.