The organic light-emitting diodes have been considered for applications in backlights of liquid-crystal displays

ultrathin plat full-color display

efficient illuminators and electro-pumped organic solid laser

etc.The process responsible for electroluminescence requires the injection of electrons from one electrode and holes from the other

the electron-hole pairs form excitons in emitting layer

and then the light generate through the radiative recombination of the excitons.In the past near upon twenty years

great progress has been made in electroluminescent devices and materials.Up to now

the three primary colors of red

green and blue

which are required for full-color displays

have been achieved.Among these

the green emission is the most perfect and the corresponding device almost reaches to commercial criterion.However

the blue and red emissions are more challenging

and there are many activities to be focused on efficient blue and red light-emitting materials.This paper reviews our recent works on blue organic light-emitting diodes

including blue materials

such as the metal chelate complex

(2

3-methyl-8-hydroxy-quinoline) lithium(LiMMq)

and derivates of polyfluorene

dendritic polyfluorene(PDFA)

and blue electroluminescent devices based on exciplex emission formed at the interface between9

9-Dibutyl-N

N

N'

N'-tetraphenyl-9H-fluorene-2

7-diamine(DTFD) and 2

2-[1

2-phenylenebis(oxy)] bis(N

N'-diphenyl-acetamide)(PBD).The performances of the blue emitting materials and the devices have been studied by photoluminescent

electroluminrescent spectra and characteristic of current-brightness-bias voltage etc.The life-time and color-purity of blue organic light-emitting diodes are required to be further improved for the commercial production.