On the performance of polymer-inorganic perovskite oxide composite light-emitting diodes: The effect of perovskite SrTiO additives

This study reports the performances of a single structured light-emitting diode (LED) devices based on polymer material poly(9,9-di- n -hexylfluorenyl-2,7-diyl) (PHF) mixed with various concentrations of perovskite oxide strontium titanate (SrTiO 3 ) particles deposited as a composite PHF: SrTiO 3 emitting layer. The performances of the single structured organic LED indium tin oxide (ITO)/PHF/aluminum (Al) device and the composite LED ITO/PHF: SrTiO 3 /Al devices were compared in terms of turn-on voltage and luminance intensity. By incorporating perovskite SrTiO 3 particles into PHF emitting layer, the turn-on voltage of the device is significantly reduced from 11.25 V to 1.80 V and the luminance intensity increased from 57.7 cd/m 2 to 609 cd/m 2 . The improvement of turn-on voltage and the electroluminescence spectrum of the composite devices were found to be dependent on the weight ratios of SrTiO 3 content in the PHF emitting layer.