Fabrication of highly efficient hybrid device structure based white light emitting diodes

Abstract

In this study, white light is generated from the combination of BaMgAl10O17:Mn2+ (BAM) green phosphor and colloidal red CdSe/ZnS quantum dots (QDs) via two different solid and hybrid type geometries. Problem of aggregation in solid type device is discussed in details and motivates us to move towards the fabrication of hybrid type device structure. The photoluminescence (PL) characterization was used to record the excitation and emission spectra of BAM and QDs materials. The size of CdSe/ZnS QDs was confirmed by transmission electron microscopy technique. The CdSe/ZnS QDs owned high quantum yield (>50%) and contributed to fabrication of high luminous efficiency of white light emitting diodes (WLEDs). The hybrid-type WLED showed 98% lm/W with outstanding color gamut values with a National Television System Committee (NTSC) value of 138% and Rec.2020 value of 105%. Moreover, the hybrid type device structure shows only 5% attenuation in luminous efficiency after 500 h of storage which maintains a great optical property.