Bright neodymium complexes for efficient near infra-red organic light emitting diodes

This paper reports the synthesis, structures, photophysics and optoelectronics of three NIR-emitting ternary neodymium tris beta-diketonate complexes, [Nd(hfpd)(3)(L)(n=1-2)(H2O)(x=0-2)](H2O)(y=0-1)(hfpd = anionic form of 1,1,1,5,5,5-hexafluoropentane-2,4-dione; L = diphenyl sulfoxide (dpso),n= 1,x= 2,y= 1 (1); L = dibenzyl sulfoxide (dbso),n= 1,x= 1,y= 0 (2); L = triphenyl phosphine oxide (tppo),n= 2,x= 0,y= 0 (3)). The complexes were used as active components in emitting layers to fabricate NIR-OLEDs with multilayered structures: ITO/MoO3(2 nm)/beta-NPB (30 nm)/TcTa:[Nd-complex] (20 nm)/TPBi:[Nd-complex] (10 nm)/TPBi (10 nm)/Alq(3)(40 nm)/LiF (0.1 nm)/Al (100 nm). The performance of the present devices is on a par with the best Nd complex based devices reported so far.