In this work, we designed and synthesized a novel spirocyclic compound functionalized spiro[fluorene-9,9＇- xanthene] with carbazole group （2-carbazolyl-spiro[fluorene-9,9＇-xanthene], SFX-Cz） via Friedel-Crafts and...In this work, we designed and synthesized a novel spirocyclic compound functionalized spiro[fluorene-9,9＇- xanthene] with carbazole group （2-carbazolyl-spiro[fluorene-9,9＇-xanthene], SFX-Cz） via Friedel-Crafts and Ullmann reaction, which is expected to own high thermal and morphological stability, and good carrier injection/ transporting properties due to the excellent hole transporting characteristics of carbazole and cruciform structure of spiro[fluorene-9,9＇-xanthene]. The carbazole end-capped spiro[fluorene-9,9＇-xanthene] SFX-Cz based PhOLEDs with Flrpic as phosphor emitter have been researched by varying dopant concentration, which exhibit the maximum EQEs of 8.9%, 7.4%, 9.1%, and 4.7% with the doping increasing from 10% to 50%. The higher performance PhOLEDs are independent on concentration variation from 10% to 30%, which suggests the bulky steric hindrance of SFX-Cz might be a potential canditate for high performance and inexpensive device with simplified process.展开更多
In this work, a novel molecule pyridinylfluorene/triphenylamine hybrid （TPyFTPA） with bulky steric hindrance effects has been synthesized successfully by substituting 9-（pyridine-2-yl）-fluoren-9-yl with triphenyla...In this work, a novel molecule pyridinylfluorene/triphenylamine hybrid （TPyFTPA） with bulky steric hindrance effects has been synthesized successfully by substituting 9-（pyridine-2-yl）-fluoren-9-yl with triphenylamine （TPA） via Friedel-Crafts reaction, which possesses good thermal stability and triplet energy （ET） of 420 ℃ with 5% weight loss and 2.86 eV, respectively. Moreover, the bulky steric hindrance material shows high stable morphology by heating to 200 ℃ without finding melting phenomena and crystallization that is demonstrated by differential scanning calorimetry （DSC） curve. The bulky pyridinylfluorene end-capped TPA has been used as host material for blue phosphorescent organic light-emitting diodes （PhOLEDs） with maximum external quantum efficiencies （EQEs） of 2.7%, 3.7%, and 3.5%, at the doping ratios of 10%, 30%, and 40%, respectively. The performances of TPyFTPA-based blue PhOLEDs own wide concentration ranging from 10% to 40%, which indicates the bulky TPyFTPA might be a potential candidate for inexpensive products with simplifying process for the applications in full-color display and solid state lighting.展开更多
Two new iridium complexes with C^N=N type ligand （i.e., Ir（BFPPya）3{tris[3,6-bis（4-fluorophenyl）pyridazine]iridium（III）} and Ir（BDFPPya）3{tris[3,6-bis（2,4-di-fluorophenyl）pyridazine]iridium（III）}） attach...Two new iridium complexes with C^N=N type ligand （i.e., Ir（BFPPya）3{tris[3,6-bis（4-fluorophenyl）pyridazine]iridium（III）} and Ir（BDFPPya）3{tris[3,6-bis（2,4-di-fluorophenyl）pyridazine]iridium（III）}） attaching with fluorine atoms, were synthesized and the effects of fluorination on the material properties and device performance were investigated. Compared with our previously reported fluorine-free analogue material, that is Ir（BPPya）3{tris[3,6-bis（phenyl）pyridazine]iridium（III）}, blue shifts in the emission spectra as well as in the long wavelength region of the absorptions were observed. The photoluminescence quantum yield （PLQY） （0.44 and 0.84 vs. 0.29）, phosphoresces lifetime （0.88 and 1.31 vs. 0.66 gs）, and oxidation potential （1.10 and 1.37 vs. 0.95 V） increased obviously after fluorinating the ligand. In contrast, the thermal stability of the iridium complexes decreased slightly （Td： 435 and 402 vs. 440 ℃）. In the density functional theory （DFT） calculations, by comparing the steric shape of the three ligands within one optimized molecule, orientational differences among the complexes were observed. In OLED device studies, bluish green electroluminescence with peak emission of 500 nm, using the electron-transporting host of TPBI [2,2＇,2＂-（1,3,5-benzenetriyl）tris（1-phenyl-lH-benzimidazole）] and the most fluorinated dopant of Ir（BDFPPya）3, was achieved with maximum efficiency of 20.3 cd/A. On one hand this efficiency is not satisfactory considering a high PLQY of 0.84. On the other hand with the similar device structure, that the （HOMO-LUMO）s of all the dopants are wrapped within that of the host TPBI, and all the triplet energies of the dopants are smaller than that of the host TPBI, it is abnormal that the ordering of device efficiencies is contradictory to that of PLQY. Assisting with the phosphorescent spectrum of TPBI and the absorption spectra of the dopant, the contradiction was interpreted reasonably.展开更多
We demonstrate threefold directional light concentration from an organic light-emitting diode luminaire for use in spot lighting and other applications where high intensity illumination is required.The concentrating l...We demonstrate threefold directional light concentration from an organic light-emitting diode luminaire for use in spot lighting and other applications where high intensity illumination is required.The concentrating luminaire comprises four triangular,large-area green electrophosphorescent organic light emitting diodes(PHOLEDs)deposited on plastic substrates and assembled into a pyramidal structure with an open base that serves as the light exit aperture.The PHOLED surfaces are highly reflective to direct the emission from the devices to the aperture independent of the original emission position within the pyramid.The far-field intensity profile of the concentrator has a‘batwing’distribution that meets the requirements for general lighting for uniform illumination of planar surfaces.展开更多
文摘In this work, we designed and synthesized a novel spirocyclic compound functionalized spiro[fluorene-9,9＇- xanthene] with carbazole group （2-carbazolyl-spiro[fluorene-9,9＇-xanthene], SFX-Cz） via Friedel-Crafts and Ullmann reaction, which is expected to own high thermal and morphological stability, and good carrier injection/ transporting properties due to the excellent hole transporting characteristics of carbazole and cruciform structure of spiro[fluorene-9,9＇-xanthene]. The carbazole end-capped spiro[fluorene-9,9＇-xanthene] SFX-Cz based PhOLEDs with Flrpic as phosphor emitter have been researched by varying dopant concentration, which exhibit the maximum EQEs of 8.9%, 7.4%, 9.1%, and 4.7% with the doping increasing from 10% to 50%. The higher performance PhOLEDs are independent on concentration variation from 10% to 30%, which suggests the bulky steric hindrance of SFX-Cz might be a potential canditate for high performance and inexpensive device with simplified process.
文摘In this work, a novel molecule pyridinylfluorene/triphenylamine hybrid （TPyFTPA） with bulky steric hindrance effects has been synthesized successfully by substituting 9-（pyridine-2-yl）-fluoren-9-yl with triphenylamine （TPA） via Friedel-Crafts reaction, which possesses good thermal stability and triplet energy （ET） of 420 ℃ with 5% weight loss and 2.86 eV, respectively. Moreover, the bulky steric hindrance material shows high stable morphology by heating to 200 ℃ without finding melting phenomena and crystallization that is demonstrated by differential scanning calorimetry （DSC） curve. The bulky pyridinylfluorene end-capped TPA has been used as host material for blue phosphorescent organic light-emitting diodes （PhOLEDs） with maximum external quantum efficiencies （EQEs） of 2.7%, 3.7%, and 3.5%, at the doping ratios of 10%, 30%, and 40%, respectively. The performances of TPyFTPA-based blue PhOLEDs own wide concentration ranging from 10% to 40%, which indicates the bulky TPyFTPA might be a potential candidate for inexpensive products with simplifying process for the applications in full-color display and solid state lighting.
基金financially supported by the National Natural Science Foundation of China(61077021,61076016)the Nanjing University of Posts and Telecommunications(NY212076,NY212050)
文摘Two new iridium complexes with C^N=N type ligand （i.e., Ir（BFPPya）3{tris[3,6-bis（4-fluorophenyl）pyridazine]iridium（III）} and Ir（BDFPPya）3{tris[3,6-bis（2,4-di-fluorophenyl）pyridazine]iridium（III）}） attaching with fluorine atoms, were synthesized and the effects of fluorination on the material properties and device performance were investigated. Compared with our previously reported fluorine-free analogue material, that is Ir（BPPya）3{tris[3,6-bis（phenyl）pyridazine]iridium（III）}, blue shifts in the emission spectra as well as in the long wavelength region of the absorptions were observed. The photoluminescence quantum yield （PLQY） （0.44 and 0.84 vs. 0.29）, phosphoresces lifetime （0.88 and 1.31 vs. 0.66 gs）, and oxidation potential （1.10 and 1.37 vs. 0.95 V） increased obviously after fluorinating the ligand. In contrast, the thermal stability of the iridium complexes decreased slightly （Td： 435 and 402 vs. 440 ℃）. In the density functional theory （DFT） calculations, by comparing the steric shape of the three ligands within one optimized molecule, orientational differences among the complexes were observed. In OLED device studies, bluish green electroluminescence with peak emission of 500 nm, using the electron-transporting host of TPBI [2,2＇,2＂-（1,3,5-benzenetriyl）tris（1-phenyl-lH-benzimidazole）] and the most fluorinated dopant of Ir（BDFPPya）3, was achieved with maximum efficiency of 20.3 cd/A. On one hand this efficiency is not satisfactory considering a high PLQY of 0.84. On the other hand with the similar device structure, that the （HOMO-LUMO）s of all the dopants are wrapped within that of the host TPBI, and all the triplet energies of the dopants are smaller than that of the host TPBI, it is abnormal that the ordering of device efficiencies is contradictory to that of PLQY. Assisting with the phosphorescent spectrum of TPBI and the absorption spectra of the dopant, the contradiction was interpreted reasonably.
基金funding support from Universal Display Corporation.
文摘We demonstrate threefold directional light concentration from an organic light-emitting diode luminaire for use in spot lighting and other applications where high intensity illumination is required.The concentrating luminaire comprises four triangular,large-area green electrophosphorescent organic light emitting diodes(PHOLEDs)deposited on plastic substrates and assembled into a pyramidal structure with an open base that serves as the light exit aperture.The PHOLED surfaces are highly reflective to direct the emission from the devices to the aperture independent of the original emission position within the pyramid.The far-field intensity profile of the concentrator has a‘batwing’distribution that meets the requirements for general lighting for uniform illumination of planar surfaces.
