Efficiency roll-off suppression in organic light-emitting diodes using size-tunable bimetallic bowtie nanoantennas at high current densities

Abstract

Size-tunable bimetallic bowtie nanoantennas have been utilized to suppress the efficiency roll-off characteristics in organic light-emitting diodes (OLEDs) using both the numerical and experimental approaches. The resonant range can be widened by the strong dual-atomic couplings in bimetallic bowtie nanoantennas. Compared with the green OLED with conventional bowtie nanoantennas at a high current density of 800 mA/cm2, the measured efficiency roll-off ratio of the OLED with size-modulated bowtie nanoantennas is decreased from 53.2% to 41.8%, and the measured current efficiency is enhanced by 29.9%. When the size-modulated bowtie nanoantennas are utilized in blue phosphorescent OLEDs, the experimental roll-off ratio is suppressed from 43.6% to 25.9% at 250 mA/cm2, and the measured current efficiency is also enhanced significantly. It is proposed that the efficiency roll-off suppression is mainly related to the enhanced localized surface plasmon effect, which leads to a shorter radiative lifetime.

Intersystem Crossing and Triplet Fusion in Singlet-Fission-Dominated Rubrene-Based OLEDs Under High Bias Current

“…Thus, it is commonly used in organic light emitting diodes (OLEDs), ,, organic photovoltaic cells (OPVs), and organic field-effect transistors (OFETs) . However, the widespread commercialization of OLEDs is hampered by efficiency roll-off (i.e., OLEDs exhibit low efficiency at high current densities ( j ) and high brightness). − As charge carrier injection and transport of high j in certain OLEDs (e.g., organic laser diodes) is a principle requirement, , a deeper understanding of the excited-state processes that occur within rubrene-based OLEDs driven at high j is necessary for extending their use to a variety of applications.…”

Investigation of the localized surface plasmon resonance of Ag@SiO2 core-shell nanocubes and its application in high-performance blue organic light-emitting diodes

“…It is well known that an appropriate distance between metal NPs and exitons is crucial for the efficient energy transfer and radiation enhancement of excitons [8,9]. So we firstly fabricated a group of devices with a ultra-thin yellow EML (bis(4-phenyl-thieno[3,2-c]pyridinato-C2,N) (acetylacetonato)iridium(III), PO-01, 1 nm) inserting at the different places in the blue EML to test the exciton recombination zone and figure out the distance between the Ag@SiO 2 NCs and the excitons in our blue OLED.…”

“…Second, the energy transfer between the LSPR field of metal NPs and the radiation field of excitons should be efficient. In OLEDs, a proper distance between NPs and excitons is usually the most important factor for the efficient energy transfer [8,9]. In previous studies, metal NPs were usually adopted in carrier transport layer or the carrier transport layer/electrode interface to keep a certain distance from excitons [2,10].…”

Reducing the Efficiency Roll-Off in Organic Light-Emitting Diodes at High Currents under External Magnetic Fields

“…8,9 Several research groups have proposed various approaches to suppress the exciton-polaron annihilation. [10][11][12][13][14] Nevertheless, these approaches may be rather inefficient, technically complicated, or costly to implement into practical applications. Therefore, development of effective, straightforward, inexpensive, and easy-to-implement techniques for reducing the exciton-polaron annihilation is of particular importance.…”