In the last few years

organic electroluminescent devices (OLEDs) have been the subject of increasing interest due to their potential impact on lighting industry and back lighting application. In order to optimize the device structure and explore the marketable OLEDs

researchers are synthesizing high performance emitting materials with desirable properties. So far

many new materials with RGB (red

green

blue) emission have been developed to meet this requirement. However

in contrast to green-light-emitting materials

blue-light-emitting materials still need to be further improved in performance. In this paper

two blue-light-emitting materials

Ca(Ⅱ) complex of aromatic N

O-chelate ligand

namely Ca(BTZ)

2

and Ca(BTZ)

2

phen [BTZ:2-(2-hydroxyphenyl)benzothiazolate

phen:1

10-phenanthroline]

were synthesized and charac-terized by FT IR and UV-Vis absorption spectra. Their energy band

photoluminescent property

and film-forming ability were investigated by UV-Vis absorption spectra

cyclic voltammetry

atomic force microscope

and photoluminescent spectra. The results show that the UV-Vis absorption bands of Ca(BTZ)

2

are located at about 290

330 and 422 nm

while

UV-Vis absorption bands of Ca(BTZ)

2

phen are located at 292

330 and 428 nm. The 290 nm or 292 nm bands

which are S

0

→S

1

transition

are attributed to the local π→π

*

transition of the deprotonated ligands. The broad bands of 330 nm can be assigned to a phenoxido-to-thiazolyl π→π

*

transition. The bands of 422 nm or 428 nm

which correspond to the transition of HOMO to LUMO

are mainly caused by the charge transition from electron donor O to electron acceptor N. The optical gap

the energy of the highest occupied orbital (

E

HOMO

)

and the energy of the lowest unoccupied orbital (

E

LUMO

) of Ca(BTZ)

2

are 2.79

5.74 and 2.95 eV

respectively. The values of optical gaps

E

HOMO

and

E

LUMO

of Ca(BTZ)

2

phen are 2.77

5.8 and 3.03 eV

respectively. The increased degree of conjugation by introducing phen reduced the value of optical gap of Ca(BTZ)

2

phen. Ca(BTZ)

2

powder emited blue fluorescence with peak wavelength at 458 nm and 500 nm. PL spectrum maximum peak wavelengths of Ca(BTZ)

2

phen were located at 465 nm and 514 nm. Ca(BTZ)

2

phen formed compact film by vacuum vapor deposition. Ca(BTZ)

2

and Ca(BTZ)

2

phen were found to be potentially excellent broad-band blue photoluminescent materials.