Balanced electron and hole injection and transport in OLEDs by using transparent electrodes

Abstract

In this study, electron and hole injection, and transport in semi-transparent organic light-emitting diodes, including dielectric/metal/dielectric (DMD) electrodes, were investigated. The DMD electrode was modified by incorporating a 5 nm-thick Cs:MoOx layer and a 10 nm-thick 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile (HATCN) layer to improve the electron and hole injection in standard and inverse structures, respectively. The inverse structure showed a reasonably good and stable external quantum efficiency due to the well-balanced carrier densities at both low and high voltages which was confirmed by an electrical simulation study. Also, the peak position of the hole and electron recombination rate in the inverse structure was located on the ITO side, which is beneficial for reducing exciton quenching and photon absorption by metallic electrodes.

Progress and Perspective toward Continuous‐Wave Organic Solid‐State Lasers

“…Long‐lived triplets generated via ISC or spin statistics are important for lasing, especially under long‐pulsed excitation. [ 109 ] Triplet accumulation will result in annihilations through multiple channels, as shown in Figure . [ 110–112 ]…”

“…Theoretically, a fast RISC process would be potential to decrease the triplet density and generate the singlets for a lower lasing threshold. [ 109 ] Electrical excitation will be much more complex because of the large number of generated triplets via the spin‐statistic rule, and singlet–polaron annihilation, and triplet–polaron annihilation also would occur during carrier injection, transporting, and recombination.…”

Chemical Defects and Energetic Disorder Impact the Energy‐Level Alignment of Functionalized Hexaazatriphenylene Thin Films

“…In marked contrast, the EA of HATCN (5.41 eV) is significantly larger than that of HATNA (2.76 eV) due to the cyano groups present in the former. In addition to being very suitable candidates to unravel the ELA mechanisms, HATCN and HATNA are also frequently used in electronic applications: HATCN thin films serve as versatile hole-injection electrodes [30][31][32][33] and as charge-transfer material in lithium-ion batteries, [34] while HATNA finds its application in pseudocapacitors, [35] batteries, [36] and hydrogen storage. [37] In the present work, we prepared HATNA and HATCN thin films by stepwise deposition via vacuum-sublimation on indium-tin-oxide (ITO), Au(111), and MoO x substrates, which cover a wide WF range of 4.9 to 6.8 eV.…”