Phosphorescent white organic light-emitting devices with color stability and low efficiency decay by using wide band-gap interlayer

Abstract:

High-performance phosphorescent white organic light-emitting devices (PhWOLEDs) with color stability and low efficiency decay are demonstrated by inserting wide band-gap materials between emitting layers. The two devices with N,N′-dicarbazolyl-3,5-benzene (mCP) and p-bis(triphenylsilyl)benzene (UGH2) as the interlayer exhibit both slight Commission Internationale del’Eclairage (CIE) coordinates variations of (± 0.010, ± 0.005) and (± 0.013, ± 0.006) in a wide voltage range, and low decay in current efficiency which shifts from the peak value 35.4 cd·A⁻¹ and 27.4 cd·A⁻¹ to 28.8 cd·A⁻¹ and 23.5 cd·A⁻¹ at 40000 cd·m⁻², respectively. The improvements are attributed to the charge carriers balance and the elimination of energy transfer loss by confining the carrier accumulation at the exciton formation interface through the interlayer.