Easily synthesized and cheap carbazole- or phenoxazine-based hosts for efficient yellow phosphorescent OLEDs

Blaževičius, Dovydas; Kručaitė, Gintarė; Shahnawaz, Shahnawaz; Swayamprabha, Sujith Sudheendran; Zaleckas, Ernestas; Jou, Jwo‐Huei; Grigalevičius, Saulius

doi:10.1016/j.optmat.2021.111251

Cited by 4 publications

(6 citation statements)

References 25 publications

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“…Its melting point as 198 °C and the glass transition temperature (Tg) as 66 °C was recorded using (TGA). While (DSC) characterization confirmed the high crystallinity of the host materials [37] (See details Scheme S2).…”

Section: Thermal Characteristicsmentioning

confidence: 79%

“…The phenoxazine-based host material was prepared using an approach similar to our previously reported work [37] which was carried out by the simple one-step synthetic route as shown in Scheme 1. 3,3-Bis(phenoxazin-10-ylmethyl)oxetane (BPMO) host was obtained by N-alkylation reaction of phenoxazine (1) with 3,3-bis(chloromethyl)oxetane using potassium tert-butoxide in tetrahydrofuran (THF).…”

Section: Synthesismentioning

confidence: 99%

“…The melting point is found to be at 199 • C through DSC calculation. The complete synthesis of material is described in our previously reported journal [37].…”

Section: Synthesismentioning

confidence: 99%

“…The TGA and DSC curves were recorded at a 10 • C/min heating rate in a nitrogen environment. A Bruker Reflex II thermos-system was used to perform differential scanning calorimetry (DSC) measurements [37]. Phosphorescence characteristic of BPMO was recorded in THF solution on a Hitachi F-7000 fluorescence spectrophotometer (Edinburgh Intruments Ltd, Livingston, United Kingdom) with a delay time of 6.25 ms at low-temperature 77 K to determine the triplet energy (E t ).…”

Section: Characterization and Measurementsmentioning

confidence: 99%

“…Herein, we report easily synthesized and cheap phenoxazine-based host material synthesized by modest one-step reaction technique and utilized in the fabrication of solution-processed organic LED devices [34][35][36][37]. We fabricated solution-processable candlelight organic LED devices using host materials 3,3-bis(phenoxazin-10-ylmethyl)oxetane (BPMO) and 4,4 -Bis(N-carbazolyl)-1,1 -biphenyl (CBP) along with an orange-red tris(2phenylquinoline)iridium(III) (Ir(2-phq) 3 ) and a yellow emitter iridium(III) bis(4-phenylthieno [3,2-c]pyridinato-N,C2')acetylacetonate (PO-01) resulting in a simpler device architecture.…”

Section: Introductionmentioning

confidence: 99%

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Highly Efficient Candlelight Organic Light-Emitting Diode with a Very Low Color Temperature

et al. 2021

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Low color temperature candlelight organic light-emitting diodes (LEDs) are human and environmentally friendly because of the absence of blue emission that might suppress at night the secretion of melatonin and damage retina upon long exposure. Herein, we demonstrated a lighting device incorporating a phenoxazine-based host material, 3,3-bis(phenoxazin-10-ylmethyl)oxetane (BPMO), with the use of orange-red and yellow phosphorescent dyes to mimic candlelight. The resultant BPMO-based simple structured candlelight organic LED device permitted a maximum exposure limit of 57,700 s, much longer than did a candle (2750 s) or an incandescent bulb (1100 s) at 100 lx. The resulting device showed a color temperature of 1690 K, which is significantly much lower than that of oil lamps (1800 K), candles (1900 K), or incandescent bulbs (2500 K). The device showed a melatonin suppression sensitivity of 1.33%, upon exposure for 1.5 h at night, which is 66% and 88% less than the candle and incandescent bulb, respectively. Its maximum power efficacy is 23.1 lm/W, current efficacy 22.4 cd/A, and external quantum efficiency 10.2%, all much higher than the CBP-based devices. These results encourage a scalable synthesis of novel host materials to design and manufacture high-efficiency candlelight organic LEDs.

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Section: Thermal Characteristicsmentioning

confidence: 79%

Section: Synthesismentioning

confidence: 99%

“…The melting point is found to be at 199 • C through DSC calculation. The complete synthesis of material is described in our previously reported journal [37].…”

Section: Synthesismentioning

confidence: 99%

Section: Characterization and Measurementsmentioning

confidence: 99%