Bis(2,2-diphenylvinyl)spirobifluorene: An efficient and stable blue emitter for electroluminescence applications

Wu, Feitong; Shu, Ching‐Fong; Wang, Tsai-Te; Diau, Eric Wei‐Guang; Chien, Chia-Hung; Chuen, Chang-Hao; Tao, Yu‐Tai

doi:10.1016/j.synthmet.2005.06.003

Cited by 24 publications

(2 citation statements)

References 40 publications

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“…A spiro-compound with stilbene units is spiro-DPVBi 19 , which was synthesized in 52% yield by Suzuki-coupling of 2,2-diphenylvinylboronic acid and 2,2‘,7,7‘-tetrabromo-9,9‘-spirobifluorene 127 , as shown in Scheme . The synthesis of the 2,7-substituted derivate DPVSBF 122 has been reported by Wu et al Spiro-ADA 92 , which contains four phenylazodiphenylamine groups, was synthesized by Hartwig−Buchwald coupling of 4-(phenylazo)diphenylamine and 127 in 89% yield …”

Section: 5 Spiro Compounds With Stilbene and Azobenzene Unitsmentioning

confidence: 99%

Spiro Compounds for Organic Optoelectronics

et al. 2007

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Section: 5 Spiro Compounds With Stilbene and Azobenzene Unitsmentioning

confidence: 99%

Spiro Compounds for Organic Optoelectronics

et al. 2007

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“…Researchers have developed numerous techniques to avoid the deterioration of OLED devices from operational heat. For example, Wu et al 102 synthesized a more thermally stable spirobifl uorene-based 4,4′-bis(2,2-diphenylvinyl)-1,1′-bipheny (DPVBi) analogue, 2,7-bis(2,2-diphenylvinyl)-9,9′-spirobifl uorene (DPVSBF). The presence of rigid spirofl uorene linkage has effectively improved the material's glass transition temperature (T g ) and morphological stability, although it maintained most of the photophysical and electronic properties of DPVBi.…”

Section: Improving the Lifespan Of Oled Devicesmentioning

confidence: 99%

Disruptive characteristics and lifetime issues of OLEDs

Jou

Kumar

Jou

2013

Organic Light-Emitting Diodes (OLEDs)

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Influence of Molecular Dipoles on the Photoluminescence and Electroluminescence of Dipolar Spirobifluorenes

Chiang

Tseng

Chen

et al. 2008

Adv Funct Materials

122

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This Full Paper investigates a series of strongly fluorescent donor–acceptor‐substituted spirobifluorene compounds, red 2‐diphenylamino‐7‐(2,2‐dicyanovinyl)‐9,9′‐spirobifluorene (DCV), green 2‐diphenylamino‐9,9′‐spirobifluorene7‐carxoxaldehyde (CHO), and blue 2‐diphenylamino‐7‐(2,2‐diphenylvinyl)‐9,9′‐spirobifluorene (DPV), together with their spiro‐linked “dimeric” analogs, 2DCV, 2,2′‐bis(diphenylamino)‐9,9′‐spirobifluorene‐7,7′‐dicarboxaldehyde (2CHO), and 2,2′‐bis(diphenylamino)‐7,7′‐bis(2,2‐diphenylvinyl)‐9,9′‐spirobifluorene (2DPV), respectively. The emission optical density and, hence, the intensity of photoluminescence (PL) or electroluminescence (EL) of the “dimeric” analogs is presumed to increase, which is beneficial for organic light‐emitting diode (OLED) applications. The physical properties, including the dipole moments obtained from quantum chemistry calculations, emission solvatochromism, fluorescence quantum yield (Φf) as well as the EL of these six spirobifluorene compounds have been examined in detail. We found that Φf as well as OLED performance (EL efficiency and intensity) of the strongly dipolar DCV decrease significantly in the “dimeric” analog 2DCV, but less so in the moderately dipolar CHO and 2CHO, and only slightly in the weakly dipolar DPV and 2DPV. This is parallel to the intramolecular dipole moment, which is large for 2DCV, medium for 2CHO, and very small for 2DPV. Here, we show for the first time systematically that the luminescence intensity is closely correlated with the local electric field induced by the molecular dipole. A strong electric field may facilitate radiationless decay channels with a charge‐transfer nature, leading to a high quenching rate. Consistent with this conclusion, which is derived from the red DCV/2DCV and green CHO/2CHO, our new blue fluorophore DPV with an essentially zero dipole moment has successfully achieved one of the best electrofluorescent blue OLEDs. At the same time, by doping the highly dipolar DCV into an isolated environment with the low‐polarity Alq3 as the host matrix, we obtained a very high performance of saturated yellow OLEDs as well, This is possibly due to the reduction of emission‐quenching dipoles from the neighboring molecules. Our results have provided an important insight in designing luminescent materials, as follows: molecular dipole moments should be kept at a low magnitude to avoid quenching induced by a strong local electric field in the chromophore.

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Bis(2,2-diphenylvinyl)spirobifluorene: An efficient and stable blue emitter for electroluminescence applications

Cited by 24 publications

References 40 publications

Spiro Compounds for Organic Optoelectronics

Spiro Compounds for Organic Optoelectronics

Disruptive characteristics and lifetime issues of OLEDs

Influence of Molecular Dipoles on the Photoluminescence and Electroluminescence of Dipolar Spirobifluorenes

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