Small molecule based and solution processed highly efficient red electrophosphorescent organic light emitting devices

The authors report the very high luminous efficiency in solution processed red electrophosphorescent organic light emitting devices using small molecular host and guest materials. The maximum luminous efficiency reached 12.7 cd/A, corresponding to external quantum efficiency of 15.1%, with its emission peak wavelength of 620 nm and the Commission Internationale de l'Eclairage coordinates of (0.65,0.33). Along with these excellent performances of the solution processed device, which were comparable to those of the vacuum deposited counterpart device with similar structure and materials, the comparative study on both devices suggests the merits of the solution process adopting robust small molecular materials only. (c) 2007 American Institute of Physics.