Thermally Activated Delayed Fluorescence Materials Based on Homoconjugation Effect of Donor-Acceptor Triptycenes.

Donor-acceptor triptycences, TPA-QNX(CN)2 and TPA-PRZ(CN)2, were synthesized and their emissive properties were studied. They exhibited a blue-green fluorescence with emission lifetimes on the order of a microsecond in cyclohexane at room temperature. The long lifetime emission is quenched by O2 and is attributed to thermally activated delayed florescence (TADF). Unimolecular TADF is made possible by the separation and weak coupling due to homoconjugation of the HOMO and LUMO on different arms of the three-dimensional donor-acceptor triptycene. Organic light emitting devices (OLEDs) were fabricated using TPA-QNX(CN)2 and TPA-PRZ(CN)2 as emitters which displayed electroluminescence with efficiencies as high as 9.4% EQE.

[1]  Alexander J. M. Miller,et al.  E-type delayed fluorescence of a phosphine-supported Cu2(mu-NAr2)2 diamond core: harvesting singlet and triplet excitons in OLEDs. , 2010, Journal of the American Chemical Society.

[2]  Yong Joo Cho,et al.  High Efficiency in a Solution‐Processed Thermally Activated Delayed‐Fluorescence Device Using a Delayed‐Fluorescence Emitting Material with Improved Solubility , 2014, Advanced materials.

[3]  C. Tang,et al.  Organic Electroluminescent Diodes , 1987 .

[4]  Vladimir Bulović,et al.  Solid state solvation in amorphous organic thin films. , 2003, Physical review letters.

[5]  S. Forrest,et al.  Nearly 100% internal phosphorescence efficiency in an organic light emitting device , 2001 .

[6]  T. Swager.  Iptycenes in the design of high performance polymers. , 2008, Accounts of chemical research.

[7]  R. Friend,et al.  Optical spectroscopy of triplet excitons and charged excitations in poly(p-phenylenevinylene) light-emitting diodes , 1993 .

[8]  Lei Zhang,et al.  Thermally Activated Delayed Fluorescence Materials Towards the Breakthrough of Organoelectronics , 2014, Advanced materials.

[9]  Ho‐Hsiu Chou,et al.  Triptycene derivatives as high-Tg host materials for various electrophosphorescent devices , 2010 .

[10]  Tingting Liu,et al.  An organic molecule with asymmetric structure exhibiting aggregation-induced emission, delayed fluorescence, and mechanoluminescence. , 2015, Angewandte Chemie.

[11]  N. S. Sariciftci,et al.  Conjugated polymer-based organic solar cells. , 2007, Chemical reviews.

[12]  Stephen R. Forrest,et al.  Transient analysis of organic electrophosphorescence. II. Transient analysis of triplet-triplet annihilation , 2000 .

[13]  N. Aratani,et al.  Solution-processed anthradithiophene-PCBM p-n junction photovoltaic cells fabricated by using the photoprecursor method. , 2013, Chemical communications.

[14]  Hironori Kaji,et al.  Strategy for Designing Electron Donors for Thermally Activated Delayed Fluorescence Emitters , 2015 .

[15]  Michael A. Haase,et al.  Recent Progress in Organic Electronics: Materials, Devices, and Processes , 2004 .

[16]  Chihaya Adachi,et al.  Efficient green thermally activated delayed fluorescence (TADF) from a phenoxazine-triphenyltriazine (PXZ-TRZ) derivative. , 2012, Chemical communications.

[17]  C. Adachi,et al.  Design of efficient thermally activated delayed fluorescence materials for pure blue organic light emitting diodes. , 2012, Journal of the American Chemical Society.

[18]  C. Adachi,et al.  Highly efficient organic light-emitting diodes by delayed fluorescence , 2013 .

[19]  S. Forrest,et al.  Highly efficient phosphorescent emission from organic electroluminescent devices , 1998, Nature.

[20]  Takahiro Higuchi,et al.  High-efficiency organic light-emitting diodes with fluorescent emitters , 2014, Nature Communications.

[21]  Liangliang Sun,et al.  Thermally activated delayed fluorescence of fluorescein derivative for time-resolved and confocal fluorescence imaging. , 2014, Journal of the American Chemical Society.

[22]  Atsushi Kawada,et al.  Efficient up-conversion of triplet excitons into a singlet state and its application for organic light emitting diodes , 2011 .

[23]  Donal D. C. Bradley,et al.  Angular Dependence of the Emission from a Conjugated Polymer Light‐Emitting Diode: Implications for efficiency calculations , 1994 .

[24]  Daisuke Yokoyama,et al.  Thermally Activated Delayed Fluorescence from Sn4+–Porphyrin Complexes and Their Application to Organic Light Emitting Diodes — A Novel Mechanism for Electroluminescence , 2009, Advanced materials.

[25]  P. Magnante,et al.  Electroluminescence in Organic Crystals , 1963 .

[26]  Gregor Schwartz,et al.  White organic light-emitting diodes with fluorescent tube efficiency , 2009, Nature.

[27]  C. Adachi,et al.  Highly efficient blue electroluminescence based on thermally activated delayed fluorescence. , 2015, Nature materials.

[28]  Shih-Chun Lo,et al.  Development of dendrimers: macromolecules for use in organic light-emitting diodes and solar cells. , 2007, Chemical reviews.

[29]  Martin R. Bryce,et al.  Triplet Harvesting with 100% Efficiency by Way of Thermally Activated Delayed Fluorescence in Charge Transfer OLED Emitters , 2013, Advanced materials.

[30]  William J. Potscavage,et al.  Anthraquinone-based intramolecular charge-transfer compounds: computational molecular design, thermally activated delayed fluorescence, and highly efficient red electroluminescence. , 2014, Journal of the American Chemical Society.

[31]  C. Adachi,et al.  Enhanced electroluminescence efficiency in a spiro-acridine derivative through thermally activated delayed fluorescence. , 2012, Angewandte Chemie.

[32]  Toshihiko Imato,et al.  Electrogenerated chemiluminescence of donor-acceptor molecules with thermally activated delayed fluorescence. , 2014, Angewandte Chemie.