White Organic Light‐Emitting Diodes Using Exciplex Emission with Multiple Emitting Layers

Abstract

In this paper, multiple‐exciplexed white organic light‐emitting diodes (WOLEDs) with blue and yellow–green emitting layers (EMLs) to improve charge balance and efficiency roll‐off through exciton confinement are investigated. Several types of WOLEDs are fabricated a number of including exciplex generated by only host materials without fluorescent or phosphorescent dopant. Moreover, various multiple exciplex can control electrical behavior of holes and electrons in whole EML. The performance improvement by the insertion of multi‐EMLs is realized throughout enhancement of exciton confinement and the reduced exciton quenching in EML. Efficiency roll‐off was 40% improved comparing to WOLED without multi‐EMLs and also color rendering index was achieved higher than 70 at 1000 cd m−2 in WOLED with multi‐EMLs.

Oxygen Vacancies Mediated Co‐Sputtered Ti‐Doped BiVO4 Thin Films‐Based Transparent Photovoltaic Device

“…On the other hand, the doping scheme influences the minority carrier lifetime to improve the photovoltaic performance. [ 69 ] The photovoltaic performance enhancement by the Ti‐doped BiVO 4 TPV device can be clarified by the increased minority carrier lifetime. In this context, minority carrier lifetime was estimated using the transient photovoltage spectra measurements.…”

Recent Advances of Interface Exciplex in Organic Light-Emitting Diodes

“…As for reaching high-performance OLEDs based on exciplex, effective exciplex systems are essential [58][59][60]. Meanwhile, bulk exciplex has been attested to be a useful emitter and host for dyes that relies on an efficient and balanced charge transportation that can be achieved by employing donor and acceptor materials with high charge mobilities [61][62][63][64][65][66], whereas multi-doping technology and precise control of doping concentration aggravate manufacturing complexity [67][68][69][70][71].…”

The influence of the doping concentration and reverse intersystem crossing on the efficiency of tricomponent organic light-emitting diodes with the thermally activated delayed fluorescence exciplex emitter

“…5 Although 100% IQE can be realized in OLEDs based on phosphorescent materials (PhOLEDs) because they can simultaneously capture excitons in both singlet and triplet excitons, the high costs and unclear toxicities of precious-metal materials always limit their further development. [6][7][8][9] In recent years, non-conventional uorescent materials such as the thermally activated delayed uorescence (TADF) material and exciplex forming co-hosts have attracted tremendous attention and effort from both academia and industry. 9,10 Among them, low-energy triplet excitons can obtain energy to up-convert to the emissive singlet level through the endothermic reverse intersystem crossing (RISC) process.…”