Influence of the pendant substituent at the C1 position of a spirobifluorene scaffold on the electronic properties

Sicard, Lambert; Brouillac, Clément; Leclerc, Nicolas; Fall, Sadiara; Zimmerman, Nicolas; Jeannin, Olivier; Rault-Berthelot, Joëlle; Quinton, Cassandre; Poriel, Cyril

doi:10.1039/d3qm01106b

“…There is an important difference between both Trim-C3 and Trim-C4 on one side and Trim-C1 on the other side. Indeed, in Trim-C1, such as in many C1-based fluorenes, previously reported in literature, [50,51] π-π interactions are detected (see Figure S45). In Trim-C1, the interactions involve the central terfluorene core and the cofacial fluorene units.…”

Section: Forschungsartikelsupporting

confidence: 62%

Spirobifluorene Trimers: High Triplet Pure Hydrocarbon Hosts for Highly Efficient Blue Phosphorescent Organic Light‐Emitting Diodes

Ari,

Yang,

Quinton

et al. 2024

Angewandte Chemie

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Pure aromatic hydrocarbon materials (PHC) represent a new generation of host materials for phosphorescent OLEDs (PhOLEDs), free of heteroatoms. They reduce the molecular complexity, can be easily synthesized and are an important direction towards robust devices. As heteroatoms can be involved in bonds dissociations in operating OLEDs through exciton induced degradation process, developing novel PHCs appear particularly relevant for the future of this technology. In the present work, we report a series of extended PHCs constructed on the assembly of three spirobifluorene fragments. The resulting positional isomers present a high triplet energy level, a wide HOMO/LUMO difference and improved thermal and morphological properties compared to previously reported PHCs. These characteristics are beneficial for the next generation of host materials for PhOLEDs and provide relevant design guidelines. Used as host in blue‐emitting PhOLEDs, which are still the weakest link of the field, a very high EQE of 24 % and low threshold voltage of 3.56 V were obtained with a low‐efficiency roll‐off. This high performance strengthens the position of PHC strategy as an efficient alternative for OLED technology and opens the way to a more simple electronic.

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Unraveling the Configuration Modulation in Spiro‐Based Through‐Space Charge Transfer Materials

Qu,

Zheng,

Zhou

et al. 2024

Angewandte Chemie

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Thermally activated delayed fluorescence (TADF) materials hold promise for optoelectronic applications. Among various design strategies, through‐space charge transfer (TSCT) systems offer the potential for enhanced performance. However, the relationship between molecular configuration and TSCT properties remains unclear compared to traditional through‐band charge transfer materials. In this study, we investigated the influence of spatial configuration on TSCT features and electronic properties of triplet excited states in these TSCT materials. By manipulating the spatial arrangement between donor and acceptor segments using different spiro skeletons, a series of TSCT materials (DMB2‐DMB5) was synthesized. Together with the parent molecule, DM‐B, these materials exhibited completely different TADF characteristics, demonstrating the impact of spatial arrangements on their optoelectronic properties. Thus, the external quantum efficiency of these materials ranged from as high as 28.0% (DMB2) to as low as 3.6% (DMB5) due to variations in their TADF characteristics. Our findings highlight the significance of spatial configuration, beyond distance alone, in influencing TSCT properties when donor and acceptor segments are sufficiently close. This insight provides valuable guidance for developing advanced TSCT materials and advancing TADF systems with improved performance and functionality.

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Spirobifluorene Trimers: High Triplet Pure Hydrocarbon Hosts for Highly Efficient Blue Phosphorescent Organic Light‐Emitting Diodes

Ari,

Yang,

Quinton

et al. 2024

Angew Chem Int Ed

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0

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Pure aromatic hydrocarbon materials (PHC) represent a new generation of host materials for phosphorescent OLEDs (PhOLEDs), free of heteroatoms. They reduce the molecular complexity, can be easily synthesized and are an important direction towards robust devices. As heteroatoms can be involved in bonds dissociations in operating OLEDs through exciton induced degradation process, developing novel PHCs appear particularly relevant for the future of this technology. In the present work, we report a series of extended PHCs constructed on the assembly of three spirobifluorene fragments. The resulting positional isomers present a high triplet energy level, a wide HOMO/LUMO difference and improved thermal and morphological properties compared to previously reported PHCs. These characteristics are beneficial for the next generation of host materials for PhOLEDs and provide relevant design guidelines. Used as host in blue‐emitting PhOLEDs, which are still the weakest link of the field, a very high EQE of 24 % and low threshold voltage of 3.56 V were obtained with a low‐efficiency roll‐off. This high performance strengthens the position of PHC strategy as an efficient alternative for OLED technology and opens the way to a more simple electronic.

show abstract

Influence of the pendant substituent at the C1 position of a spirobifluorene scaffold on the electronic properties

Abstract: 1-Substituted fluorenes have emerged in recent years among the most efficient functional materials for phosphorescent and thermally activated delayed fluorescent OLEDs. The position C1 of the fluorene is indeed highly...

Cited by 6 publications

References 54 publications

Spirobifluorene Trimers: High Triplet Pure Hydrocarbon Hosts for Highly Efficient Blue Phosphorescent Organic Light‐Emitting Diodes

Spirobifluorene Trimers: High Triplet Pure Hydrocarbon Hosts for Highly Efficient Blue Phosphorescent Organic Light‐Emitting Diodes

Unraveling the Configuration Modulation in Spiro‐Based Through‐Space Charge Transfer Materials

Spirobifluorene Trimers: High Triplet Pure Hydrocarbon Hosts for Highly Efficient Blue Phosphorescent Organic Light‐Emitting Diodes

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