Double-layer organic light-emitting devices (OLEDs) based on a blendsystem of novel small molecule fluorene material 6,6′-(9H-fluoren-9,9-diyl)bis(2,3-bis(9,9-dihexyl-9H-fluoren-2-yl) quinoxaline) (BFLBBFLYQ) and holetransporting material N,N′-biphenyl-N,N′-bis-(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine (TPD) were fabricated. The structure of the double-layer device wasITO/BFLBBFLYQ∶TPD/tris(8-hydroxyquinolinato)aluminum(Alq)/Mg∶Ag. Thephotoluminescence (PL) spectra of BFLBBFLYQ and TPD were located at 447 and 414nm, respectively. The spectral characteristics of the blend system and thedouble-layer device were investigated, which indicated that a new long wavelengthemission peaking at 530 nm was appeared both in PL spectra andelectroluminescence (EL) spectra. The exciplex between BFLBBFLYQ and TPD may playthe role in long wavelength emission in the blend device and the spin-coatedfilm. Based on the absorption spectra of a red fluorescent dye 4-(dicyanomethylene)-2-tert-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran(DCJTB) as probe and the PL spectra of the blend system showing good overlap,energy transfer from the blend system to DCJTB could be expected. Therefore,DCJTB could be selected as a molecular dopant to investigate the influence on ELspectra and the recombination of the devices. It was found that the excitonsrecombine at the interior Alq layer near to the BFLBBFLYQ∶TPD layer.Energy transfer; Recombination(60721001), (863计划)项目(2007AA03Z424), 教育部新世纪优秀人才计划项目(NCET-06-0812)和电子科技大学中青年学术带头人计划项目(060206)资助