Highly efficient orange–red electroluminescence from a single layer MEH-PPV-POSS:CdS0.75Se0.25 hybrid PLED

Abstract

In this study, poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] end capped with polyhedral oligomeric silsesquioxanes (MEH-PPV-POSS): cadmium sulfide selenide quantum dots (CdS0.75Se0.25 QDs) nanocomposites based OLEDs were fabricated. By the addition of CdS0.75Se0.25QDs into the polymer active layer, a considerable enhancement was observed in terms of hole and electron injection in devices. Additionally, the presence of QDs reduced the interchain interaction of polymer that resulted in narrower electroluminescence (EL) spectrum. The device structure of ITO/PEDOT: PSS/MEH-PPV-POSS: 25 wt% CdS0.75Se0.25/Ca (40 nm)/Al demonstrated the best performance with a brightness of 8672 cd/m 2 at 10 V, current efficiency of 2.5 cd/A at 8 V, and an EQE of 0.55% at 150 mA/cm2

Developing a facile method for highly luminescent colloidal CdSxSe1−x ternary nanoalloys

“…In addition, the nanoalloy CdS 0.75 Se 0.25 coated with TOPO was blended with MEH-PPV to fabricate a hybrid PLED device. 34 In the cited work, the nanoalloys enhanced electron injection and played a role as a hole blocker in separate devices. We furthermore showed control of spontaneous emission originating from nanocrystals embedded in electrospun nanobers.…”

Efficiency enhancement in a single emission layer yellow organic light emitting device: Contribution of CIS/ZnS quantum dot

“…Ionization potential (I p ) and electron affinity (E a ) represents the oxidation and reduction potentials of a semiconductor and widely used in calculating the valance and conduction energy levels, respectively [13,14,29]. This route is followed for the determination of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels of organic semiconductors as well [30][31][32].…”

“…This situation is attributed to lower charge injections from the electrodes to the active layer and supported with the decreases in current densities. These kinds of observations have been described through either aggregation of QDs or phase segregation of them in the composite [13,14,38,39] and both results in EL from the polymer.…”

“…Although this down conversion approach allows reaching high efficiencies and being announced as having the potential of increasing stabilities, the latter mainly depends on the stability of blue LED substrate and oxygen and water permittivity of the used encapsulate polymer. However, solution processability, color stability, high PL quantum yield and electron mobility of QDs are also advantages for their utilization in the emitting layer of red (R), green (G), blue (B) or white light emitting PLEDs [11][12][13][14].…”