Exciplex-Sensitized Triplet–Triplet Annihilation in Heterojunction Organic Thin-Film

Lin, Bo‐Yen; Easley, Connor J.; Chen, Chia‐Hsun; Tseng, Po-Chen; Lee, Ming-Zer; Sher, Pin-Hao; Wang, Juen-Kai; Chiu, Tien‐Lung; Lin, Chi‐Feng; Bardeen, Christopher J.; Lee, Jiun-Haw

doi:10.1021/acsami.6b16397

Cited by 40 publications

(47 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the EL spectra of TTAUC‐OLED consist respectively of fluorescence and delayed fluorescence of Alq 3 and ADN. To improve the color purity of blue emission for OLED display application, one may add a high‐efficiency dopant into the ADN host to improve the blue emission, or change to a higher efficiency TTA material . By using an organic material with a high ISC rate and a nonradiative triplet, emission from sensitizer can be suppressed to achieve high color purity in a blue TTAUC‐OLED.…”

Section: Eqe Performances Of Devices Blue and Green Emission Were Sementioning

confidence: 96%

“…Electrons and holes recombine in the Alq 3 layer, generating 25% singlets and 75% triplets with energies of 2.7 and 2.0 eV, respectively . The Alq 3 triplets can sensitize the ADN triplets ( E T = 1.7 eV) to enable the TTA process, which generates blue photons …”

Section: Eqe Performances Of Devices Blue and Green Emission Were Sementioning

confidence: 99%

“…To improve the TTAUC efficiencies, a TDSB layer was inserted between the Alq 3 and ADN layers. This layer should have a triplet energy close to Alq 3 to facilitate TET from Alq 3 to ADN, and a singlet energy higher than ADN to block singlet energy transfer from ADN back to Alq 3 . A 10 nm thick layer of 1‐(2,5‐dimethyl‐4‐(1‐pyrenyl)phenyl)pyrene (DMPPP) with singlet and triplet energies at 3.2 and 2.1 eV, respectively, was used for the TDSB layer, as shown in Figure a.…”

Section: Eqe Performances Of Devices Blue and Green Emission Were Sementioning

confidence: 99%

See 2 more Smart Citations

Efficient Triplet–Triplet Annihilation Upconversion in an Electroluminescence Device with a Fluorescent Sensitizer and a Triplet‐Diffusion Singlet‐Blocking Layer

et al. 2018

Self Cite

View full text Add to dashboard Cite

energy transfer (TET) populates the triplet state of the TTA emitter. When two triplet excitons encounter each other, the TTA process puts the emitter into its singlet excited state to emit fluorescence. One criterion for the sensitizer is efficient ISC to convert the singlet to the triplet, and sensitizers like phosphors, thermally activated delay fluorescence emitters, inorganic quantum dots, and perovskites have been used. [5][6][7] Charge transfer states between electron donor and acceptor materials can also act as sensitizers, resulting in efficient sub-bandgap emission (i.e., the driving voltage is ≈1/2 of the emitted photon energy) for organic light-emitting diode (OLED) applications. [8] For electrical excitation, 75% of the electron-hole pairs recombine as triplets without any ISC. By harnessing these triplet excitons to generate luminescence, TTAUC provides a path to higher efficiency devices.In this Communication, we show that a new device architecture can significantly improve TTAUC blue emission efficiencies, which is one of the important issues for OLED development. [9] The basic idea is to separate the triplet sensitization and upconversion layers while still allowing triplet energy migration. To demonstrate this concept, tris-(8-hydroxyquinoline)aluminum (Alq 3 ) was used as the sensitizer. This molecule has been used as an electron-transporting layer (ETL) and emitting layer material in one of the first OLED Solid-state triplet-triplet annihilation upconversion (TTAUC) blue emission in an electroluminescence device (i.e., an organic light-emitting diode (OLED)) is demonstrated. A conventional green fluorophore, tris-(8-hydroxyquinoline)aluminum (Alq 3 ), is employed as the sensitizer that generates 75% triplet under electrical pumping for the blue triplet-triplet annihilation emitter, 9,10-bis(2′-naphthyl) anthracene (ADN), with the heterojunction bilayer structure. The operation lifetime is elongated both for ADN blue (4.1x) and Alq 3 green (34.8%) emission due to efficient use of excitons and separation of recombination and emission zone. To reduce the singlet quenching (SQ) of blue TTAUC signal by the Alq 3 sensitizer with lower bandgap, 1-(2,5-dimethyl-4-(1-pyrenyl)phenyl)pyrene (DMPPP) is inserted between the Alq 3 and ADN as a triplet-diffusion-and-singlet-blocking layer. DMPPP exhibits triplet energy close to Alq 3 and higher than ADN, as well as higher singlet energy than both Alq 3 and ADN. It allows triplet diffusion from Alq 3 to ADN, but blocks the SQ of the blue TTAUC signal by Alq 3 . 86.1% intrinsic efficiency of TTAUC is demonstrated in this trilayer (Alq 3 /DMPPP/ADN) OLED. Organic Light-Emitting DiodesThe ORCID identification number(s) for the author(s) of this article can be found under https://doi.

show abstract

Section: Eqe Performances Of Devices Blue and Green Emission Were Sementioning

confidence: 96%

Section: Eqe Performances Of Devices Blue and Green Emission Were Sementioning

confidence: 99%

Section: Eqe Performances Of Devices Blue and Green Emission Were Sementioning

confidence: 99%

See 1 more Smart Citation

Efficient Triplet–Triplet Annihilation Upconversion in an Electroluminescence Device with a Fluorescent Sensitizer and a Triplet‐Diffusion Singlet‐Blocking Layer

et al. 2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…Figure 10a shows the luminance decay curves of such a blue OLED under different initial luminance values (5000, 10 000, and 15 000 nits). From Figure 10b , the estimated T 50 at 1000 nits of this blue OLED is ~56 000 h (~6–7 years) 104 , 105 . As new materials and novel device structures continue to advance, the lifetime of OLEDs will be gradually improved.…”

Section: Display Metricsmentioning

confidence: 96%

Liquid crystal display and organic light-emitting diode display: present status and future perspectives

et al. 2017

Self Cite

View full text Add to dashboard Cite

Recently, ‘Liquid crystal display (LCD) vs. organic light-emitting diode (OLED) display: who wins?’ has become a topic of heated debate. In this review, we perform a systematic and comparative study of these two flat panel display technologies. First, we review recent advances in LCDs and OLEDs, including material development, device configuration and system integration. Next we analyze and compare their performances by six key display metrics: response time, contrast ratio, color gamut, lifetime, power efficiency, and panel flexibility. In this section, we focus on two key parameters: motion picture response time (MPRT) and ambient contrast ratio (ACR), which dramatically affect image quality in practical application scenarios. MPRT determines the image blur of a moving picture, and ACR governs the perceived image contrast under ambient lighting conditions. It is intriguing that LCD can achieve comparable or even slightly better MPRT and ACR than OLED, although its response time and contrast ratio are generally perceived to be much inferior to those of OLED. Finally, three future trends are highlighted, including high dynamic range, virtual reality/augmented reality and smart displays with versatile functions.

show abstract

“…Compared to bulk exciplex, in which the constituents are physically blended and doped with guests, an interfacial exciplex host is a simplified bilayer structure doped with guests in either layer or both. Recent results show that an interfacial exciplex host can also be well-applied to OLEDs (Park et al, 2011; Seino et al, 2014; Wang et al, 2015; Zhang et al, 2016; Xu et al, 2017; Lin et al, 2018), with some unique characteristics (Al Attar and Monkman, 2016; Chen et al, 2016; He et al, 2016; Nakanotani et al, 2016; Lin et al, 2017). The key results of reported OLEDs using interfacial exciplex host are summarized in the Supplementary Materials.…”

Section: Interfacial Exciplex As Host In Thermal-evaporated Oledsmentioning

confidence: 99%

Recent Applications of Interfacial Exciplex as Ideal Host of Power-Efficient OLEDs

Zhang

Xie

2019

Front. Chem.

View full text Add to dashboard Cite

Currently, exploring the applications of intermolecular donor-acceptor exciplex couple as host of OLEDs with phosphorescence, thermally activated delayed fluorescence (TADF) or fluorescence emitter as dopant is a hot topic. Compared to other host strategies, interfacial exciplex has the advantage in various aspects, such as barrier-free charge injection, unimpeded charge transport, and the energy-saving direct exciton formation process at the “Well”-like heterojunction interface region. Most importantly, due to a very fast and efficient reverse intersystem-crossing (RISC) process, such a host is capable of regulating singlet/triplet exciton populations in itself as well as in the dopant emitters both under photoluminescent (PL) and electroluminescent (EL) driving conditions. In this mini-review, we briefly summarize and comment on recent applications of this ideal host in OLEDs (including both thermal-evaporation OLEDs and solution-processed OLEDs) with diverse emitters, e.g., fluorescence, phosphorescence, delayed fluorescence, or others. Special attention is given to illustrate the peculiar achievement of high overall EL performance with superiorities of low driving voltages, slow roll-off rate, high power efficiencies and satisfied device lifetime using this host strategy, which is then concluded by personal perspectives on the relevant next-step in this field.

show abstract

Exciplex-Sensitized Triplet–Triplet Annihilation in Heterojunction Organic Thin-Film

Cited by 40 publications

References 41 publications

Efficient Triplet–Triplet Annihilation Upconversion in an Electroluminescence Device with a Fluorescent Sensitizer and a Triplet‐Diffusion Singlet‐Blocking Layer

Efficient Triplet–Triplet Annihilation Upconversion in an Electroluminescence Device with a Fluorescent Sensitizer and a Triplet‐Diffusion Singlet‐Blocking Layer

Liquid crystal display and organic light-emitting diode display: present status and future perspectives

Recent Applications of Interfacial Exciplex as Ideal Host of Power-Efficient OLEDs

Contact Info

Product

Resources

About