Low-cost caesium phosphate as n-dopant for organic light-emitting diodes

Autor: Günter Schmid, Ralf Krause, Jan Hauke Wemken, Thomas Mikolajick
Rok vydání: 2012
Předmět:
Zdroj: Journal of Applied Physics. 111:074502
ISSN: 1089-7550
0021-8979
DOI: 10.1063/1.3699008
Popis: We demonstrate the usage of caesium phosphate (Cs3PO4) as a low-cost n-dopant for conductivity enhancements of the electron transport layer in organic light-emitting diodes (OLEDs). Up to 9 orders of magnitude, reaching 2.3 × 10−5 S/cm with only 10% dopant concentration in 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline single-carrier devices, were achieved. Luminance current voltage and impedance spectroscopy measurements confirmed the increased conductivities of the single carrier devices in green light-emitting diodes. Constant operation voltages of below 4 V were realized independently of the electron transport layer (ETL) thickness, which was varied from 50–150 nm. Dielectric constants were modeled by usage of the least squares method. Measured and calculated capacitances based on the geometric properties and modeled dielectric constants varied by less than 1.3% for doped OLEDs, confirming the highly conductive nature of Cs3PO4-doped ETLs and demonstrating that a highly conductive electron transport la...
Databáze: OpenAIRE