Dadansoddiad o berfformiad lampau electroymoleuol printiedig ar is-haen ddi-draidd (Understanding performance deficiencies in printed thick film EL lamps on paper)

In order to examine new potential markets for printed electronics, a research study was undertaken to understand the performance of opaque substrate electroluminescent (EL) lamps. Opaque EL lamps are made possible by a PEDOT:PSS top electrode which replaces the ITO used in the conventional lamps. Screen-printed lamps were manufactured on four substrates (one plastic and three paper) and their performance was measured through brightness measurement. Generally, opaque substrate lamps were 50% less bright than a comparable ITO lamp. Further reductions in brightness were observed with the lighter and rougher papers. Additional layers of PEDOT:PSS increased sheet conductivity but reduced lamp brightness due to a reduction in layer transparency. As lamp size increased, the resistive nature of the PEDOT:PSS caused a significant reduction in lamp output, with a brightness of 25% of a comparable ITO lamp with an illuminated area of 5000 mm². The relatively poor performance of the opaque lamps is derived not only from the reduced conductivity and transparency of the PEDOT:PSS compared to ITO, but is also caused by the topological nature of the phosphor particles which result in some phosphor material lying outside the electric field created between the two electrodes.