Synthesis and characterization of spiro-linked poly(terfluorene): a blue-emitting polymer with controlled conjugated length

Wu, Feitong; Dodda, Rajasekhar; Reddy, D. S.; Shu, Ching‐Fong

doi:10.1039/b205334a

Cited by 91 publications

(57 citation statements)

References 50 publications

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“…[10,11] Among the many derivatives of fluorene, molecules based on spirobifluorene building blocks have shown particularly impressive performance. [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] Recently, Bo and co-workers have reported the synthesis of a spirobifluorene polymer that exhibits extraordinary thermal and color stability. [28] A monodisperse oligomeric spirobifluorene compound Mod I (Scheme 1) has also been synthesized and used as a blue light-emitting material.…”

Section: Introductionmentioning

confidence: 99%

A Molecular Glass for Deep‐Blue Organic Light‐Emitting Diodes Comprising a 9,9′‐Spirobifluorene Core and Peripheral Carbazole Groups

Tang

Liu

Lü

et al. 2007

Adv Funct Materials

178

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Novel fluorene‐based compounds, TCPC‐6 and TCPC‐4, with rigid central spirobifluorene cores and peripheral carbazole groups are synthesized using the Suzuki coupling reaction. The optical, electrochemical, and thermal properties of these compounds are characterized. The compounds show strong deep‐blue emission both in solution and as thin films. Both TCPC‐6 and TCPC‐4 exhibit amorphous morphologies in the solid state with high glass transition temperatures (Tg) of 108 and 143 °C, respectively. Atomic force microscopy (AFM) measurements indicate that high‐quality amorphous films of these novel compounds can be prepared by spin‐coating. The oxidation potentials of TCPC‐6 and TCPC‐4 are significant lower than that of model compounds without peripheral carbazole groups, which suggests that these compounds have relatively high highest occupied molecular orbital (HOMO) energy levels and better hole‐injection capabilities. Light‐emitting devices fabricated by spin‐coating films of these molecules exhibit deep‐blue emission with Commission Internationale de l'Eclairage (CIE) chromaticity coordinates (x, y) of (0.16, 0.05); the devices fabricated using spin‐coated TCPC‐6 and TCPC‐4 layers exhibit high luminance efficiencies of 1.35 and 0.90 cd A–1 (with external quantum efficiencies of 3.72 and 2.47 %), respectively.

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Section: Introductionmentioning

confidence: 99%

A Molecular Glass for Deep‐Blue Organic Light‐Emitting Diodes Comprising a 9,9′‐Spirobifluorene Core and Peripheral Carbazole Groups

Tang

Liu

Lü

et al. 2007

Adv Funct Materials

178

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“…[4] Many attempts were thus focused on frustrating the intermolecular interactions between adjacent polymer chains by introducing bulky functional groups, [5] dendronization, [6] the use of crosslinkable moieties, [7] and spiro-functionalization of the polymer backbone. [8] A different explanation [9] of the poor spectral stability of PFs was suggested after the experimental demonstration that the appearance of the low-energy band correlates with the presence of fluorenone groups in the polymer backbone. [10] The idea that fluorenones could be responsible for the green-light emission was substantiated by the synthesis of poly-and oligofluorenes containing a precise number of fluorenone moieties that exhibit green emission, even in dilute solution.…”

Section: Introductionmentioning

confidence: 99%

Insight into the Role of Oxidation in the Thermally Induced Green Band in Fluorene‐Based Systems

Grisorio

Suranna

Mastrorilli

et al. 2007

Adv Funct Materials

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The causes of the spectral instability of poly[9,9‐dioctylfluoren‐2,7‐diyl‐co‐2′,7′‐spiro(cyclohexane‐1,9′‐fluorene)] during thermal annealing in air, which leads to a green photoluminescence (PL) emission band, are investigated. The Igreen/Iblue ratio evolution (I = intensity) is found to be independent of the amount of monoalkylfluorene defects, despite the fact that their presence might be regarded as a trigger for the radical process leading to polymer degradation in the presence of a trace amount of metal catalyst. Furthermore, the absence of a correlation between the degree of oxidation of the material and the Igreen/Iblue ratio indicates that the spatial disposition of fluorenones formed during the thermal degradation of the material, rather than their amount, is to be strictly related to the Igreen/Iblue ratio. The evidenced formation of fluorenone agglomerates, which could be considered the cause for the consistent increase in the Igreen/Iblue ratio during a thermal oxidation of a polyfluorene, confirms that the radical mechanism can also involve dialkylfluorene systems. Finally, the higher resistance to thermal degradation shown by spirocyclohexane fluorene units with respect to dioctylfluorene ones allows the synthesis of new, spectrally stable, fluorene‐based copolymers.

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“…It was reported that this bathochromic shift is the result of the different dielectric constant of the environment. [10] However, branches that are too bulky and possess a rigid structure might lead to conformational changes of the main chain in the solid state, i.e., variations in the twist angle between neighboring aryl rings, thus give rise to this shift. [11,12] This is despite the fact that the rigid branches on the polymer backbone will reduce the interchain interaction and restrict the formation of aggregates or excimers between polymer chains.…”

Section: Resultsmentioning

confidence: 99%

Di‐Channel Polyfluorene Containing Spiro‐Bridged Oxadiazole Branches

Zhu

Wen

Feng

et al. 2005

Macromol. Rapid Commun.

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Summary: A p–n di‐channel copolymer based on polyfluorene (PF) has been designed and prepared. Branches containing oxadiazole units are attached to the PF backbone through the spiro‐structure and act as channels to improve the electron affinity; these branches form a steric ‘di‐channel’ framework with the polymer backbone. The polymer possesses excellent thermal stability. The lowest unoccupied molecular orbital energy level of the polymer is significantly altered in comparison with poly(9,9‐dioctylfluorene‐2,7‐diyl).Schematic of the di‐channel polyfluorene synthesized here and the mechanism of energy transfer through the structure.magnified imageSchematic of the di‐channel polyfluorene synthesized here and the mechanism of energy transfer through the structure.

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Synthesis and characterization of spiro-linked poly(terfluorene): a blue-emitting polymer with controlled conjugated length

Cited by 91 publications

References 50 publications

A Molecular Glass for Deep‐Blue Organic Light‐Emitting Diodes Comprising a 9,9′‐Spirobifluorene Core and Peripheral Carbazole Groups

A Molecular Glass for Deep‐Blue Organic Light‐Emitting Diodes Comprising a 9,9′‐Spirobifluorene Core and Peripheral Carbazole Groups

Insight into the Role of Oxidation in the Thermally Induced Green Band in Fluorene‐Based Systems

Di‐Channel Polyfluorene Containing Spiro‐Bridged Oxadiazole Branches

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