Highly efficient emitters of ultra-deep-blue light made from chrysene chromophores

Shin, Hoon−Kyu; Jung, Hyocheol; Kim, Beomjin; Lee, Jae-Hyun; Moon, Jiwon; Kim, Joonghan; Park, Jong‐Wook

doi:10.1039/c5tc03749b

Cited by 50 publications

(12 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…High PL quantum yield is necessary for the fluorescent emitter because energy transfer is the main emission mechanism of TADF sensitized fluorescent OLEDs. A highly efficient aromatic core structure should be included along with aromatic amine derived auxochromophores …”

Section: Singlet‐exciton‐harvesting Approaches For Fluorescent Oledsmentioning

confidence: 99%

Recent Progress of Singlet‐Exciton‐Harvesting Fluorescent Organic Light‐Emitting Diodes by Energy Transfer Processes

et al. 2019

View full text Add to dashboard Cite

OLEDs and TADF OLEDs are essential. One method to overcome those issues is to harvest singlet excitons by triplet-triplet fusion (TTF) process which converts triplet excitons into singlet excitons. [18][19][20] The TTF approach has been used in the blue fluorescent OLEDs, but the triplet to singlet conversion efficiency is limited, resulting in relatively low EQE compared to the phosphorescent and TADF OLEDs. The other method is to apply singlet-exciton-harvesting technology of fluorescent OLEDs by energy transfer to achieve high EQE and long device lifetime by overcoming the deficiencies of the two technologies. The EQE can be comparable to that of phosphorescent and TADF OLEDs if singlet excitons can be fully harvested, and the device lifetime can be better than that of those devices due to the intrinsic stability of the molecular structures and triplet excitons critical to the device lifetime are excluded in the final light-emission process.Herein, recent progress on the singlet harvesting approach of fluorescent emitters by an energy transfer process from host or sensitizer is discussed. Basic concepts, material requirements, and device architecture for the singlet-exciton-harvesting technology are covered to understand the light-emission process and to develop an ideal emitting layer system for both high EQE and long device lifetime. Additionally, future prospects of singletexciton-harvesting fluorescent OLEDs are proposed. Basic Concept of Singlet-Exciton-Harvesting Fluorescent OLEDsFluorescent emitters can emit light by photoluminescence (PL) or electroluminescence (EL) processes although other processes such as chemiluminescence and mechanoluminescence can induce light emission. [21][22][23][24] In the PL process, fluorescent emitters can exhibit 100% photon conversion efficiency by light excitation if there is no intersystem crossing from the singlet excited state to triplet excited state and no loss during the radiative transition from singlet excited state to ground state. However, an ideal 100% PL efficiency is not realized in the EL process because 75% triplet excitons generated by the electrical carrier injection process are lost by nonradiative pathways. [25][26][27][28][29][30] Only 25% of the singlet excitons contribute to the EL emission process, and the internal quantum efficiency (IQE) of fluorescent OLEDs is limited to 25%. However, the low IQE of fluorescent OLEDs can be improved if triplet exciton The external quantum efficiency (EQE) of organic light-emitting diodes (OLEDs) has been dramatically improved by developing highly efficient organic emitters such as phosphorescent emitters and thermally activated delayed fluorescent (TADF) emitters. However, high-EQE OLED technologies suffer from relatively poor device lifetimes in spite of their high EQEs. In particular, the short lifetimes of blue phosphorescent and TADF OLEDs remain a big hurdle to overcome. Therefore, the high-EQE approach harvesting singlet excitons of fluorescent emitters by energy transfer processes from the host or sensit...

show abstract

Section: Singlet‐exciton‐harvesting Approaches For Fluorescent Oledsmentioning

confidence: 99%

Recent Progress of Singlet‐Exciton‐Harvesting Fluorescent Organic Light‐Emitting Diodes by Energy Transfer Processes

et al. 2019

View full text Add to dashboard Cite

show abstract

“…However, chrysene has found relatively limited interest as a building block in constructing organic semiconductors for organic electronic applications [11] . Disubstitution of the chrysene core at 6,12‐positions with electron‐donating TPA group would enhance both the photoluminescence and hole‐transporting property of the molecule, bringing about a bifunctional chromophore [11c,12] . However, functionalization of the PAH cores with electron‐donating moiety has been found to shift the emission color into the lower energy region resulted in the sky‐blue emission [11c,13] .…”

Section: Introductionmentioning

confidence: 99%

Rational Design of Chrysene‐Based Hybridized Local and Charge‐Transfer Molecules as Efficient Non‐Doped Deep‐Blue Emitters for Simple‐Structured Electroluminescent Devices

Chawanpunyawat

Chasing

Nalaoh

et al. 2021

Chemistry An Asian Journal

View full text Add to dashboard Cite

Herein, we present a molecular design of chrysene‐based deep‐blue emissive materials (TC, TpPC, TpXC, and TmPC), in which chrysene as a core is functionalized with different triphenylamine moieties to realize a fine‐tuning deep‐blue fluorescence with superior electroluminescent (EL) performance. The photophysical analyses and density functional theory (DFT) calculations disclose that TC, TpPC, and TpXC possess HLCT characteristics with intense deep‐blue emission in the solid‐state, good hole‐transporting ability, and high thermal and electrochemical stabilities. They are successfully employed as non‐doped emitters in simple structured OLEDs (ITO/PEDOT : PSS : NF/emitter/TPBi/LiF : Al). In particular, TC‐based device emits a deep‐blue light with an emission peak at 446 nm and CIE color coordinates of (0.148, 0.096), a maximum external quantum efficiency (EQEmax) of 4.31%, and a low turn‐on voltage of 2.8 V.

show abstract

“…On the basis of the core-side concept, blue chromophores with high PLQYs, such as anthracene and chrysene, have been selected as core groups in previous studies. 8,9,16,19 We previously synthesized fluorescent blue-light emitters with high EL performances by replacing bulky side groups in the core group or substituting various types of aromatic amine groups with inductive effects. 8−20 In the current work, a high-PLQY blue-chromophore pyrene moiety displaying high thermal stability was selected as the core group and a diphenylamine (DPA) moiety was selected as the side group to introduce an electron-donation effect and hence improve the EL efficiency of the emitters.…”

mentioning

confidence: 99%

High Efficiency and Long Lifetime of a Fluorescent Blue-Light Emitter Made of a Pyrene Core and Optimized Side Groups

Jung

Kang

Lee

et al. 2018

ACS Appl. Mater. Interfaces

Self Cite

View full text Add to dashboard Cite

In this study, four emitters of blue light are synthesized by selecting pyrene with its high photoluminescence quantum yield (PLQY) as the core group and variants of the electron-donating diphenylamine (DPA) as side groups. The four compounds have different numbers, sizes, and substitution positions of alkyl groups on the DPA. Each of the four compounds when doped in OLED devices shows a high current efficiency (CE) of over 7 cd A and a high external quantum efficiency (EQE) of over 7.5%. In addition, the compounds yield electroluminescence (EL) spectra showing peaks with narrow full width at half-maximum (fwhm) values of 37-40 nm and hence indicative of high color purity. Moreover, one compound N1,N6-bis(5-( tert-butyl)-2-methylphenyl)-N1,N6-bis(2,4-dimethylphenyl)pyrene-1,6-diamine (3Me-1Bu-TPPDA), shows a very high EQE of 9.25% and a very long lifetime with an LT95 of 471 h.

show abstract

Highly efficient emitters of ultra-deep-blue light made from chrysene chromophores

Abstract: The chrysene group, with its large band gap and high stability, was selected as a central core structure for ultra-deep-blue emitters. The effects of different side groups on the intrinsic properties of the chrysene core were systematically investigated.

Cited by 50 publications

References 60 publications

Recent Progress of Singlet‐Exciton‐Harvesting Fluorescent Organic Light‐Emitting Diodes by Energy Transfer Processes

Recent Progress of Singlet‐Exciton‐Harvesting Fluorescent Organic Light‐Emitting Diodes by Energy Transfer Processes

Rational Design of Chrysene‐Based Hybridized Local and Charge‐Transfer Molecules as Efficient Non‐Doped Deep‐Blue Emitters for Simple‐Structured Electroluminescent Devices

High Efficiency and Long Lifetime of a Fluorescent Blue-Light Emitter Made of a Pyrene Core and Optimized Side Groups

Contact Info

Product

Resources

About