Influence of SiO2/TiO2 Nanocomposite on the Optoelectronic Properties of PFO/MEH-PPV-Based OLED Devices

Abstract

The influence of SiO2/TiO2 nanocomposites on the performance of organic light-emitting diodes (OLEDs) based on poly(9,9′-di-n-octylfluorenyl-2,7-diyl) (PFO) and various amounts of poly(2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene-vinylene) (MEH-PPV) was investigated. Prior to the fabrication of the OLEDs on indium-tin oxide (ITO) substrates, the hybrids of PFO/MEH-PPV, in the presence and absence of the SiO2/TiO2 nanocomposites, were prepared via the solution blending technique. Improvement of the performances of the devices in the presence of the SiO2/TiO2 nanocomposites was detected. The existence of the SiO2/TiO2 nanocomposites led to better charge carrier injection and, thus, a significant reduction in the turn-on voltage of the devices. The enhancement of MEH-PPV electroluminescence peaks in the hybrids in the presence of SiO2/TiO2 nanocomposites is not only a result of the Förster resonance energy transfer, but also of hole-electron recombination, which is of greater significance. Moreover, the existence of the SiO2/TiO2 nanocomposites led to a shift of the CIE chromaticity coordinates of the devices.

Improving Photophysical Properties of White Emitting Ternary Conjugated Polymer Blend Thin Film via Additions of TiO2 Nanoparticles

“…Figure 9 illustrates the effect of the TiO 2 nanoparticles on the J-V characteristics of the ternary blend devices. Consistent with previous studies, the additions of TiO 2 nanoparticles increased the current density and decreased the turn-on voltage [ 20 , 38 ]. The increment in current density as the direct consequence of the decrement in the resistance signified the presence of a greater number of charge carriers in the nanocomposite layer [ 39 ].…”

“…One of the important data that can be extracted from Figure 4 is that the emission intensities of the acceptors can be enhanced if the donor’s emission quenching can be reversed. The reversal quenching trend in emission of donor has been observed in different binary blend thin films [ 8 , 19 , 20 ]. In these works, the general emission of the binary blend thin film was remarkably improved.…”

“…Earlier efforts to overcome this drawback in the binary blends proved that the addition of metal oxide nanoparticles, particularly TiO 2 effectively inhibited the emission quenching. More interestingly, the presence of the nanoparticles at an appropriate amount stimulated the creation of excitons specifically in the donor and thus improved the overall emissions intensities of the blend [ 8 , 19 , 20 ]. The electron trapping effect has been proposed as the underlying explanation for the observed improvement.…”

Effect of Donor-Acceptor Concentration Ratios on Non-Radiative Energy Transfer in Zero-Dimensional Cs4PbBr6 Perovskite/MEH-PPV Nanocomposite Thin Films

“…The incorporation of conjugated polymers as a matrix layer in optoelectronic devices based on perovskites can play a significant role in enhancing the morphology of the films resulting in superior device performance [14,15]. Moreover, through-space or dipole-dipole energy transfer plays a significant role in the donor/acceptor hybrids that have been used to produce optoelectronic devices with high performance efficiency [16][17][18][19].…”

High-Performance White Organic Light-Emitting Diodes Using Distributed Bragg Reflector by Atomic Layer Deposition

“…In OLED microcavities, the active layers of OLEDs are composed by the optimal medium between two mirrors [13]. The most common OLED microcavity architectures contain (i) two similar metal mirrors with different thicknesses, where one mirror is only partially reflective, while the other mirror is almost thoroughly reflective and (ii) one mirror serves as a dense dielectric distributed Bragg reflector (DBR), generally consisting of a periodic stack of SiO 2 /TiO 2 or SiO 2 /SiN as well as other mirror materials with a low work function metal [14,15].…”