Effects of the phosphorescent sensitizer on charge dynamics in deep blue phosphor-sensitized-fluorescent organic light-emitting diodes

Lee, Hakjun; Hwang, Kyo Min; Kim, Ki Ju; Song, You Na; Kim, Young Kwan; Kim, Tae‐Kyung

doi:10.1080/15980316.2021.2000514

Cited by 11 publications

(5 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, we applied the PSF system to minimize the roll-off and enable efficient energy transfer . We fabricated PSF OLEDs with t-DABNA as a fluorescent dopant and PtON7- t -Bu as a sensitizer.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Multifunctional Deep-Blue Thermally Activated Delayed Fluorescence Based on an Oxygen-Bridged Boron Acceptor for Highly Efficient Organic Light-Emitting Diodes

Kim,

Kang,

Kim

2024

ACS Appl. Mater. Interfaces

Self Cite

View full text Add to dashboard Cite

Until now, thermally activated delayed fluorescence (TADF) materials based on bridged boron-based acceptors have been primarily developed as dopants. However, in this study, we synthesized and characterized multifunctional deep-blue TADF materials�t-OBO-DMAC and t-OBO-DPAC�using bridged boron-based acceptors in combination with dimethylacridine or diphenylacridine as donors. These materials serve as both dopants and hosts. Theoretical calculations and experimentally measured photophysical properties of t-OBO-DMAC reveal a smaller singlet−triplet energy difference, higher photoluminescence quantum yield, and more efficient reverse intersystem crossing compared to t-OBO-DPAC. When evaluated as TADF emitters, t-OBO-DMAC and t-OBO-DPAC exhibited maximum external quantum efficiency (EQE) of 14.4 and 7.3% with deep-blue color coordinates of (0.14, 0.11) and (0.15, 0.07), respectively. Both materials were further assessed as hosts in various configurations, including host-only, TADF, phosphorescent, and phosphorsensitized fluorescence (PSF)-emitting systems. Notably, t-OBO-DMAC demonstrated a high maximum EQE of 13.9% with deepblue color coordinates of (0.15, 0.07) in a nondoped host-only device. Remarkably, both materials achieved EQEs exceeding 20% in the PSF devices. Our study marks a critical advancement in the field that breaks the conventional boundaries of the dopant and host and demonstrates unprecedented multifunctionalities for advanced organic light-emitting diodes.

show abstract

Section: Resultsmentioning

confidence: 99%

“…In addition, we applied the PSF system to minimize the roll-off and enable efficient energy transfer. 51 We fabricated PSF OLEDs with t-DABNA as a fluorescent dopant and PtON7-t-Bu as a sensitizer. The concentrations of t-DABNA and PtON7-t-Bu were the same as those in the TADF OLEDs and PhOLEDs.…”

Section: Phosphorescent Oledsmentioning

confidence: 99%

Multifunctional Deep-Blue Thermally Activated Delayed Fluorescence Based on an Oxygen-Bridged Boron Acceptor for Highly Efficient Organic Light-Emitting Diodes

Kim,

Kang,

Kim

2024

ACS Appl. Mater. Interfaces

Self Cite

View full text Add to dashboard Cite

show abstract

“…Thus, dopant-induced changes should not be overlooked when analyzing degradation. (1) The causes of degradation are diverse but can be divided into bleaching, quenching, and charge imbalance. Bleaching refers to the loss of emission due to the bond dissociation of molecules and acts as irreversible luminescence loss.…”

Section: Objective and Backgroundmentioning

confidence: 99%

P‐157: Late‐News Poster: Understanding of degradation process by voltage‐sweep loop method in exciplex host‐based phosphorescent organic light‐emitting diodes

Lee,

Kim

2023

Symp Digest of Tech Papers

View full text Add to dashboard Cite

We analyzed the degradation mechanism by deteriorating the exciplex host‐based phosphorescent organic light‐emitting diodes (PhOLEDs) while repeatedly applying voltages in the range of several nA to mA. To identify the most significant degradation factors represented by bleaching, quenching, and charge imbalance, the degradation process was described from various perspectives by the capacitance (C)‐voltage (V) curves (CV), and magneto‐electroluminescence (MEL). Comparing the MEL of the non‐doped and the doped devices, the bleaching of the dopant was confirmed as degradation progressed. Since the highest occupied molecular orbital (HOMO) of the dopant aligns with that of the hole‐transporting layer, the injected holes are easily trapped. As a result, the trap‐induced Shockley‐Read Hall recombination became dominant. Thus, it was identified that the bleaching of the dopant itself acts as the major degradation factor.

show abstract

“…An ideal host should possess the following characteristics: good energy level matching with neighboring functional layers, sufficiently high triplet energy ( E T ) to avoid reverse energy transfer, balanced charge transport to enlarge the recombination zone, and adequate thermal and morphological stabilities to extend the operational lifetime of the device. – Therefore, it is challenging to find effective bipolar hosts that can achieve both high-efficiency and low-efficiency roll-off. Researchers have proposed that incorporating both hole- and electron-transporting units in bipolar host materials can enhance device performance more rapidly than using conventional unipolar hosts. – Scientists have developed multiple classes of bipolar host materials by combining various hole-and electron-transporting moieties. Carbazoles and arylamines have been widely employed as hole-transporting units, – while benzimidazole, oxadiazoles, phenanthroline, phosphine oxide, phosphine sulfide, pyridine, triazine, and triazole have been used as electron-transporting units.…”

Section: Introductionmentioning

confidence: 99%

Highly Efficient Phosphorescent Organic Light-Emitting Diodes Using Benzo[4′,5′]imidazo[2′,1′:2,3]imidazo[4,5,1-jk]carbazole as a Rigid and Effective Electron Acceptor in Bipolar Host

Raikwar

Kim

Sun

et al. 2023

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

A novel bipolar host architecture was investigated to improve the external quantum efficiency (EQE) of green phosphorescent organic light-emitting diodes (PhOLEDs). The host was developed by incorporating carbazole as a hole-transport unit and fused rigid benzo[4′,5′]imidazo[2′,1′:2,3]imidazo[4, 5, 1-jk]carbazole (BzICz) as a new electron transport unit. The primary goal of the BzICz-based host design was to achieve a high triplet energy and bipolar charge transport characteristics. The green PhOLEDs fabricated using the new BzICz and carbazole-based host demonstrated a high EQE of 26.6% due to their high triplet energy and good bipolar charge transporting characteristics.

show abstract

Effects of the phosphorescent sensitizer on charge dynamics in deep blue phosphor-sensitized-fluorescent organic light-emitting diodes

Cited by 11 publications

References 28 publications

Multifunctional Deep-Blue Thermally Activated Delayed Fluorescence Based on an Oxygen-Bridged Boron Acceptor for Highly Efficient Organic Light-Emitting Diodes

Multifunctional Deep-Blue Thermally Activated Delayed Fluorescence Based on an Oxygen-Bridged Boron Acceptor for Highly Efficient Organic Light-Emitting Diodes

P‐157: Late‐News Poster: Understanding of degradation process by voltage‐sweep loop method in exciplex host‐based phosphorescent organic light‐emitting diodes

Highly Efficient Phosphorescent Organic Light-Emitting Diodes Using Benzo[4′,5′]imidazo[2′,1′:2,3]imidazo[4,5,1-jk]carbazole as a Rigid and Effective Electron Acceptor in Bipolar Host

Contact Info

Product

Resources

About