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Invisible Ag-grid transparent electrodes at a line width of the Ag-grid of 5 µm, spacing between the grid lines of 150 µm and a line thickness of 0.6 µm have been prepared on a 50 µm thick flexible polyethylene naphthalate (PEN) film substrate by a conventional gravure offset printing using our newly developed Ag nanoparticle ink. Furthermore, the Ag-grid electrode was laminated with a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) layer. The Ag-grid laminated with PEDOT:PSS (Ag-grid/PEDOT) transparent electrode was applied to a commercial alternating-current powder electroluminescent device (ACPELD) as an ITO replacement. The as-prepared Ag-grid/PEDOT-based ACPELD shows uniform luminescence with a luminance of 292 cd m −2 at 150 V 0-p and 2 kHz. Repeated bending durability of the fabricated ACPELD was evaluated by a cyclic bending test at a bending radius of 1.5 mm up to 20 000 bending cycles. Luminance of the Ag-grid/PEDOT-based ACPELD is stable throughout the bending cycles compared to that of an ITO-based ACPELD. Luminance of the 20 000 cycle-bended Ag-grid/PEDOT-based ACPELD maintains 97% of that of the as-prepared. These results demonstrate that the Ag-grid/PEDOT on PEN-based ACPELDs develop stable luminance characteristics throughout the bending cycles.

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Powder electroluminescent devices (PELDs) have a high potential for commercial application because of flat light emission devices and simple printing process fabrication with low-cost production, without semiconductor processes using vacuum and plasma. In conventional PELDs, indium tin oxide (ITO) has been used as a transparent electrode. However, ITO is unfavourable in flexible electronic devices due to its intrinsic brittleness. The authors evaluated the current and luminance characteristics of PELDs prepared on gravure offset-printed invisible silver-grid (Ag-grid) electrodes that were laminated with and without poly(3,4-ethylenedioxythiophene):poly(styrenesulphonate) (PEDOT:PSS) transparent electrodes. The PELD on the Ag-grid laminated with PEDOT:PSS electrode shows the maximum luminance of ∼250 cd/m 2 at 200 μm spacing, which is five-fold greater than the luminance of PELD without PEDOT:PSS electrode lamination.