Ideal host and guest system in phosphorescent OLEDs

Jeon, Woo Sik; Park, Tae‐Jin; Kim, Sun Young; Pode, Ramchandra; Jang, Jin; Kwon, Jang Hyuk

doi:10.1016/j.orgel.2008.11.012

Cited by 191 publications

(140 citation statements)

References 24 publications

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“…Unfortunately, both host-guest LEC and OLED devices show weak current eciency less than 0.2 cd A −1 . This can be explained by the unsuitable energy level of UM01 and host material [18]. Recently, the eciency of the LECs devices can be improved by the addition of ionic liquid (IL) [1921].…”

Section: Resultsmentioning

confidence: 99%

Highly Efficient Blue LECs Using Charged Iridium Complexes

et al. 2015

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Section: Resultsmentioning

confidence: 99%

Highly Efficient Blue LECs Using Charged Iridium Complexes

et al. 2015

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“…[4a, 27] In Figure 7 c, we find that the features in the EL spectra of devices resulted only from the red emission of [OsA C H T U N G T R E N N U N G (bpftz) 2 A C H T U N G T R E N N U N G (PPhMe 2 ) 2 ], thus indicating that TCTA and TPBI functioned as effective blockers to confine carriers and excitons within the EML. Figure 8 displays the behavior of the corresponding OS2-based devices.…”

Section: Abstract In Chinesementioning

confidence: 99%

Spiro‐Configured Bipolar Host Materials for Highly Efficient Electrophosphorescent Devices

Hung

Chen

et al. 2011

Chemistry An Asian Journal

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In this study, we synthesized and characterized a series of spirobifluorene-based bipolar compounds (D2 ACN, DNPACN, DNTACN, and DCzACN) in which a dicyano-substituted biphenyl branch, linked orthogonally to a donor biphenyl branch bearing various diarylamines, acted as an acceptor unit allowing fine-tuning of the morphological stability, triplet energy, bipolar transport behavior, and the HOMO and LUMO energy levels. The promising physical properties of these new compounds, together with their ability to transport electrons and holes with balanced mobilities, made them suitable for use as host materials in highly efficient phosphorescent organic light-emitting diodes (PhOLEDs) with green iridium-based- or red osmium-based phosphors as the emitting layer (EML). We adopted a multilayer structure to efficiently confine holes and electrons within the EML, thus preventing exciton diffusion and improving device efficiency. The device incorporating D2 ACN doped with the red emitter [Os(bpftz)(2)(PPhMe(2))(2)] (bpftz=3-(trifluoromethyl)-5-(4-tert-butylpyridyl)-1,2,4-triazolate) gave a saturated red electrophosphorescence with CIE coordinates of (0.65, 0.35) and remarkably high efficiencies of 20.3 % (21 cd A(-1)) and 13.5 Lm W(-1) at a practical brightness of 1000 cd m(-2).

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“…Since Bebq 2 and beryllium complexes have very good electron transporting characteristics with high electron mobility of ~10 -4 cm 2 /Vs (Y. Liu et al, 2001;Vanslyke et al, 1991;J.-H. Lee et al, 2005) and narrow band gap, Bebq 2 can make a suitable candidate for the host of red emitting PHOLEDs (Jeon et al, 2008a(Jeon et al, , 2008bJeon et al, 2009;Pode et al, 2009 Table 5. HOMO, LUMO and triplet energy levels of some fluorescent host materials for PHOLEDs…”

Section: Discussionmentioning

confidence: 99%

“…Consequently, the selection of suitable host candidates is a critical issue in fabricating high efficiency PHOLEDs. More recently in order to address device performance and manufacturing constraints, an ideal host-guest system to produce a high efficiency phosphorescent device using a narrow band gap fluorescent host to prevent the hole/or electron trapping has been presented (Jeon et al, 2008a(Jeon et al, , 2008bJeon et al, 2009;Pode et al, 2009 3. Multiple quantum well structure 3.1 Introduction Organic light emitting diodes (OLEDs) have attracted considerable attention because of their potential applicability to flat-panel displays (FPDs) (Sheats et al, 1996;Shen et al, 1997;Friend et al, 1999), backlighting, and candidates for the next generation lighting (Destruel et al, 1999;, owing to wide viewing angle, low driving voltage, thin, light-weight, and possibly also flexible displays.…”

Section: Phosphorescent Oled Devicesmentioning

confidence: 99%