Transparent organic light-emitting diodes with LiF:Al composite cathodes

Abstract

A transparent and electrical conductive layer comprising LiF and Al was designed and obtained. The composite layer was characterized using transparency spectroscopy and sheet resistance measurement. When the ratio of LiF:Al reached 4:4, the sheet resistance and transmittance of the composite layer were measured to be 573 Ω/□ and 55.5% (at 532 nm), respectively. Transparent organic light-emitting diodes (TOLEDs) employing LiF:Al composite layer as cathodes were fabricated and the electroluminescent properties of the TOLEDs were investigated. When the composite cathode had the equal contents of LiF and Al, the TOLED showed acceptable electroluminescent behavior of both top and bottom emission and the total maximum current efficiency (summed from both top and bottom emission) of the TOLED was calculated to be 2.34 cd/A.