Cr-doped Sr TiO_(3)/Ti-dopedα-Fe_(2)O_(3) heterojunction has been constructed by an ingenious way,i.e.using segregation titanium oxide on the surface of the Ti-dopedα-Fe_(2)O_(3) electrode to in situ prepare Cr-dope...Cr-doped Sr TiO_(3)/Ti-dopedα-Fe_(2)O_(3) heterojunction has been constructed by an ingenious way,i.e.using segregation titanium oxide on the surface of the Ti-dopedα-Fe_(2)O_(3) electrode to in situ prepare Cr-doped SrTiO_(3).After construction of the heterojunction,the photocurrent onset potential for water oxidation on a Ti4+dopedα-Fe_(2)O_(3) cathodically shifts by about 100 mV.Moreover,the cathodic shift of the onset potential can be preserved well even after a long time running.The results indicate the effectiveness and credibility of the fabricated heterojunction.In order to make clear the reason for the onset potential shift,the asprepared Ti-dopedα-Fe_(2)O_(3) and Cr-doped SrTiO_(3)/Ti-dopedα-Fe_(2)O_(3) samples were investigated by X-ray photoelectron spectroscopy,electrochemical impedance spectroscopy,X-ray diffraction spectroscopy,etc.Based on the experimental evidences,it is proposed that cathodic shift of the onset potential is mainly due to the enhanced charge separation at the photoanode surface.This strategy can offer a reference to construct heterojunction on other films especially for those with surface segregation.展开更多
Over one decade, various DNA sensors of carbon material-based field-effect transistors （FETs） have been inten- sively developed into an inspiring area of research and technology to substitute for the traditional met...Over one decade, various DNA sensors of carbon material-based field-effect transistors （FETs） have been inten- sively developed into an inspiring area of research and technology to substitute for the traditional method, for in- stance, fluorescence labeling detection. These FET DNA sensors have advantages of： directly read-out electrical signal, no need to label DNA molecule with fluorescer, high sensitivity, facility of miniaturization, simple device preparation process, high signal-to-noise ratio （SNR） and wide detection range. This review gives a comprehensive description on the state-of-the-art carbon-based FET DNA sensors from the aspect of both semiconductor material and structure of device. Several essential points in this research field, including sensitivity, selectivity, stability and challenges are addressed. Optimization of sensing performance and application of these devices are also discussed.展开更多
The easy oxidation and surface roughness of Cu nanowire （NW） films are the main bottlenecks for their usage in transparent conductive electrodes （TCEs）. Herein, we have developed a facile and scaled-up solution ro...The easy oxidation and surface roughness of Cu nanowire （NW） films are the main bottlenecks for their usage in transparent conductive electrodes （TCEs）. Herein, we have developed a facile and scaled-up solution route to prepare Cu NW-based TCEs by embedding Cu NWs into pre-coated smooth poly（3,4-ethylenedioxythiophene）：poly（styrenesulfonate） （PEDOT：PSS） films on poly（ethylene terephthalate） （PET） substrates. The so obtained Cu NW- PEDOT：PSS/PET films have low surface roughness （-70 nm in height）, high stability toward oxidation and good flexibility. The optimal TCEs show a typical sheet resistance of 15Ω·sq-1 at high transparency （76% at A = 550 nm） and have been used successfully to make polymer （poly（3-hexylthiophene）：phenyl-C61- butyric acid methyl ester） solar cells, giving an efficiency of 1.4%. The overall properties of Cu NW-PEDOT：PSS/PET films demonstrate their potential application as a replacement for indium tin oxide in flexible solar cells.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
Two pure hydrocarbon molecules of l,3,5-tris(9-phenyl-9H-fluoren-9-yl)benzene(mTPFB)and l,3,5-tris(2-tert-butyl-9-phenyl-9H-fluoren-9-yl)benzene(tBu-mTPFB)were synthesized.Due to the conjugation blocked connection mod...Two pure hydrocarbon molecules of l,3,5-tris(9-phenyl-9H-fluoren-9-yl)benzene(mTPFB)and l,3,5-tris(2-tert-butyl-9-phenyl-9H-fluoren-9-yl)benzene(tBu-mTPFB)were synthesized.Due to the conjugation blocked connection mode and rigid/bulky substitutions,these two materials possess high triplet energy,enabling them as good hosts for blue phosphor in PhOLEDs.By studying their thermal,electrochemical,electronic absorption and photoluminescent properties,it was found that the influence of the inert tert-butyl group on material photoelectrical properties is negligible.For instance,mTPFB and tBu-mTPFB showed very similar absorption and emission profiles,with almost the same bandgap,triplet energy and energy levels.However,the encapsulation of tert-butyl on the 2-position of 9-phenylfluorene enhanced material thermal stability.Most importantly,carrier transport properties were improved dramatically,as proved by the mono carrier device.Blue phosphorescent OLEDs hosted by tBu-mTPFB showed external quantum efficiency of 15.2%and current efficiency of 23.0 cd/A,which were much higher than that of the OLEDs based on mTPFB with the analogous structure.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.61474064 and 61504063)the Natural Science Foundation of Jiangsu Province(No.BK20150836)+2 种基金the Jiangsu National Synergetic Innovation Center for Advanced Materials(SICAM)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD,No.YX030003)the Synergistic Innovation Center for Organic Electronics and Information Displays。
文摘Cr-doped Sr TiO_(3)/Ti-dopedα-Fe_(2)O_(3) heterojunction has been constructed by an ingenious way,i.e.using segregation titanium oxide on the surface of the Ti-dopedα-Fe_(2)O_(3) electrode to in situ prepare Cr-doped SrTiO_(3).After construction of the heterojunction,the photocurrent onset potential for water oxidation on a Ti4+dopedα-Fe_(2)O_(3) cathodically shifts by about 100 mV.Moreover,the cathodic shift of the onset potential can be preserved well even after a long time running.The results indicate the effectiveness and credibility of the fabricated heterojunction.In order to make clear the reason for the onset potential shift,the asprepared Ti-dopedα-Fe_(2)O_(3) and Cr-doped SrTiO_(3)/Ti-dopedα-Fe_(2)O_(3) samples were investigated by X-ray photoelectron spectroscopy,electrochemical impedance spectroscopy,X-ray diffraction spectroscopy,etc.Based on the experimental evidences,it is proposed that cathodic shift of the onset potential is mainly due to the enhanced charge separation at the photoanode surface.This strategy can offer a reference to construct heterojunction on other films especially for those with surface segregation.
文摘Over one decade, various DNA sensors of carbon material-based field-effect transistors （FETs） have been inten- sively developed into an inspiring area of research and technology to substitute for the traditional method, for in- stance, fluorescence labeling detection. These FET DNA sensors have advantages of： directly read-out electrical signal, no need to label DNA molecule with fluorescer, high sensitivity, facility of miniaturization, simple device preparation process, high signal-to-noise ratio （SNR） and wide detection range. This review gives a comprehensive description on the state-of-the-art carbon-based FET DNA sensors from the aspect of both semiconductor material and structure of device. Several essential points in this research field, including sensitivity, selectivity, stability and challenges are addressed. Optimization of sensing performance and application of these devices are also discussed.
文摘The easy oxidation and surface roughness of Cu nanowire （NW） films are the main bottlenecks for their usage in transparent conductive electrodes （TCEs）. Herein, we have developed a facile and scaled-up solution route to prepare Cu NW-based TCEs by embedding Cu NWs into pre-coated smooth poly（3,4-ethylenedioxythiophene）：poly（styrenesulfonate） （PEDOT：PSS） films on poly（ethylene terephthalate） （PET） substrates. The so obtained Cu NW- PEDOT：PSS/PET films have low surface roughness （-70 nm in height）, high stability toward oxidation and good flexibility. The optimal TCEs show a typical sheet resistance of 15Ω·sq-1 at high transparency （76% at A = 550 nm） and have been used successfully to make polymer （poly（3-hexylthiophene）：phenyl-C61- butyric acid methyl ester） solar cells, giving an efficiency of 1.4%. The overall properties of Cu NW-PEDOT：PSS/PET films demonstrate their potential application as a replacement for indium tin oxide in flexible solar cells.
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supported by the National Natural Science Foundation of China(61474064,61504063)funding from Nanjing University of Posts and Telecommunications (NY214085,NY214177)+5 种基金the Natural Science Foundation of Jiangsu Province(BK20150836)the National Basic Research Program of China (2015CB932200)the National Synergistic Innovation Center for Advanced Materials(SICAM)Synergistic Innovation Center for Organic Electronics and Information DisplaysPriority Academic Program Development of Jiangsu Higher Education Institutions(PAPD,YX03001)funding from Key Laboratory for Organic Electronics & Information Displays
文摘Two pure hydrocarbon molecules of l,3,5-tris(9-phenyl-9H-fluoren-9-yl)benzene(mTPFB)and l,3,5-tris(2-tert-butyl-9-phenyl-9H-fluoren-9-yl)benzene(tBu-mTPFB)were synthesized.Due to the conjugation blocked connection mode and rigid/bulky substitutions,these two materials possess high triplet energy,enabling them as good hosts for blue phosphor in PhOLEDs.By studying their thermal,electrochemical,electronic absorption and photoluminescent properties,it was found that the influence of the inert tert-butyl group on material photoelectrical properties is negligible.For instance,mTPFB and tBu-mTPFB showed very similar absorption and emission profiles,with almost the same bandgap,triplet energy and energy levels.However,the encapsulation of tert-butyl on the 2-position of 9-phenylfluorene enhanced material thermal stability.Most importantly,carrier transport properties were improved dramatically,as proved by the mono carrier device.Blue phosphorescent OLEDs hosted by tBu-mTPFB showed external quantum efficiency of 15.2%and current efficiency of 23.0 cd/A,which were much higher than that of the OLEDs based on mTPFB with the analogous structure.
