Carrier transport in flexible organic bistable devices of ZnO nanoparticles embedded in an insulating poly(methyl methacrylate) polymer layer

Abstract

The bistable effects of ZnO nanoparticles embedded in an insulating poly(methyl methacrylate) (PMMA) polymer single layer by using flexible polyethylene terephthalate (PET) substrates were investigated. Transmission electron microscopy (TEM) images revealed that ZnO nanoparticles were formed inside the PMMA polymer layer. Current-voltage (I-V) measurement on the Al/ZnO nanoparticles embedded in an insulating PMMA polymer layer/ITO/PET structures at 300 K showed a nonvolatile electrical bistability behavior with a flat-band voltage shift due to the existence of the ZnO nanoparticles, indicative of trapping, storing, and emission of charges in the electronic states of the ZnO nanoparticles. The carrier transport mechanism of the bistable behavior for the fabricated organic bistable device (OBD) structures is described on the basis of the I-V results by analyzing the effect of space charge.

Carrier transport mechanisms of hybrid ZnO nanorod-polymer LEDs

“…As the voltage increases further to higher than 8 V, the I-V curve shows the SCLC, behavior and this type of carrier transport can be understood by considering the large energy barrier of 2.19 eV at the interface between PVK (2.0 eV) and ZnO NRs (4.19 eV). This result is analogous to the previously-reported one for a organic bistable device with a ZnO NP-PMMA polymer hybrid layer [30]. In the latter case, the observed SCLC characteristics in the voltage range of 1.7 V ∼ 3.8 V can be attributed to another large energy barrier of 2.3 eV between PVK (2.0 eV) and Al (4.3 eV).…”

Charge transport mechanisms and memory effects in amorphous TaN x thin films

“…The I-Vs in Figure 5a are fitted well by a power law I ∝ V m , with m = 2.7 to 5.5, indicating that the predominant charge carrier transport mechanism is the space-charge-limited current [47-50]. Due to the band bending of the quasi-conduction band near the metal-dielectric interfaces, a space charge layer is formed near the surface of the dielectric where electrons are depleted.…”

“…This is attributed to the presence of tantalum nanoparticles, as those identified in Figure 3d, which provide additional free charge carriers after a proper value of the applied field, changing the conductive behavior from almost parabolic, m = 1.8, to almost ohmic, m = 1.3 to 1.5, Figure 5c [49,50]. The threshold value of the applied field is much lower compared to the a-TaN x deposited on Au, considering the lower threshold bias voltage and the thickness of the film.…”

Organic Bistable Switching Memory Devices with MeH-PPV and Graphene Oxide Composite

“…As shown in the energy level band diagram (Fig. 2(c)) [11,12], the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of MeH-PPV occur at 5.4 and 3.2 eV, respectively. In the active layer of MeH-PPV:GO, the energy difference between the work function of Al and LUMO of MeH-PPV (1.1 eV) is higher than the energy difference between the work function of ITO and HOMO of MeH-PPV (0.6 eV ).…”