The influence of an ultrathin 4-（dicyanomethylene）-2-t-butyl-6-（1,1,7,7-tetramethyljulolidyl-9-enyl）-4H-pyran （DCJTB） fluorescent dye layer at donor/acceptor heterojunction on the performance of small-molecule o...The influence of an ultrathin 4-（dicyanomethylene）-2-t-butyl-6-（1,1,7,7-tetramethyljulolidyl-9-enyl）-4H-pyran （DCJTB） fluorescent dye layer at donor/acceptor heterojunction on the performance of small-molecule organic photovoltaic （OPV） cell is studied. The structure of OPV cell is of indium-tin oxide （ITO）/copper phthalocyanine （CuPc）/DCJTB/fullerene （C60）/bathophenantbroline （Bphen）/Ag. The results show that open circuit voltage （Voc） increases to 0.57 V as the film thickness of DCJTB layer increases from 0.2 to 2.0 nm. By using an equivalent circuit model, the enhancement of VOC is found to be attributed to the reduced reverse saturation current density （Js） which is due to the lower highest occupied molecular orbital （HOMO） level in DCJTB than that in CuPc. Also, the short circuit current density （JSC） is affected when the DCJTB layer becomes thicker, resulting from the high series resistance RsA due to the low charge carrier mobility of fluorescent red dye.展开更多
Two types of organic light-emitting diodes with structures of ITO/N,N'-bis(1-naphthyl)-N,N'-diphenyl,1,1'-biphenyl-4,4'-diamine (NPB)/tris(8-hydroquinolinato)aluminum(Alq 3)/2,9-dimethyl-4,7-diphenyl-l...Two types of organic light-emitting diodes with structures of ITO/N,N'-bis(1-naphthyl)-N,N'-diphenyl,1,1'-biphenyl-4,4'-diamine (NPB)/tris(8-hydroquinolinato)aluminum(Alq 3)/2,9-dimethyl-4,7-diphenyl-l,10-phenanthroline(BCP)/Alq 3:4-dicyanomethylene-2-(tert-butyl)-6-methyl-4H-pyran(DCJTB)/Alq 3 /Al and ITO/NPB/BCP/Alq 3 /Alq 3:DCJTB/Alq 3 /Al were studied.NPB was chosen as a hole-transporting/blue-emitting layer.Alq 3 adjacent to BCP acted as a green emitting layer while that adjacent to the Al cathode acted as an electron-transporting layer.Alq 3 doped with 2 wt.% DCJTB was used as a red emitting layer.The operating principles of the devices were explained by the mechanism of F rster energy transfer and the hole and exciton blocking effect of BCP.It was found that the spectral characteristics of the devices strongly depended on the relative location between the green emitting Alq 3 layer and the BCP layer,as well as their thickness.Pure white emission with the CIE coordinates of (0.33,0.33) was achieved by mixing the three primary colors in the device with the structure of ITO/NPB(30 nm)/BCP(6 nm)/Alq 3 (30 nm)/Alq 3:DCJTB(30 nm)/Alq 3 (30 nm)/Al.The BCP layer played an important role in distributing the exciton energy among the three emitting layers to achieve a balanced white light.The white emission of this device was largely insensitive to the driving voltage (15-27 V) with the insertion of the green emitting Alq 3 layer.展开更多
The open circuit voltage （Voc） of small- molecule organic solar cells （OSCs） could be improved by doping suitable fluorescent dyes into the donor layers. In this paper, 4-（dicyanomethylene）-2-t-butyl-6-（1,1,7,7...The open circuit voltage （Voc） of small- molecule organic solar cells （OSCs） could be improved by doping suitable fluorescent dyes into the donor layers. In this paper, 4-（dicyanomethylene）-2-t-butyl-6-（1,1,7,7- tetramethyljulolidyl-9-enyl）-4H-pyran （DCJTB） was used as a dopant, and the performance of the OSCs with different DCJTB concentration in copper phthalocyanine （CuPc） was studied. The results showed that the Voc of the OSC with 50% of DCJTB in CuPc increased by 15%, compared with that of the standard CuPc/fullerene （C60） device. The enhancement of the Voc was attributed to the lower highest occupied molecular orbital （HOMO） level in the DCJTB than that in the CuPc. Also, the light absorption intensity is enhanced between 400 and 550nm, where CuPc and C6o have low absorbance, leading to a broad absorption spectrum.展开更多
基金Project partially supported by the National Natural Science Foundation of China(NNSFC)(Grant Nos.60736005 and 60425101-1)the Foundation for Innovative Research Groups of the NNSFC(Grant No.60721001)+3 种基金the Research Fund for the Dectoral Program of Higher Education(RFDP)(Grant No.20090185110020)the Program for New Century Excellent Talents in University,China(Grant No.NCET-06-0812)the Scientific Research Foundation for Returned Overseas Chinese Scholars,State Education Ministry(Grant No.GGRYJJ08-05)the Young Excellence Project of Sichuan Province,China(Grant No.09ZQ026-074)
文摘The influence of an ultrathin 4-（dicyanomethylene）-2-t-butyl-6-（1,1,7,7-tetramethyljulolidyl-9-enyl）-4H-pyran （DCJTB） fluorescent dye layer at donor/acceptor heterojunction on the performance of small-molecule organic photovoltaic （OPV） cell is studied. The structure of OPV cell is of indium-tin oxide （ITO）/copper phthalocyanine （CuPc）/DCJTB/fullerene （C60）/bathophenantbroline （Bphen）/Ag. The results show that open circuit voltage （Voc） increases to 0.57 V as the film thickness of DCJTB layer increases from 0.2 to 2.0 nm. By using an equivalent circuit model, the enhancement of VOC is found to be attributed to the reduced reverse saturation current density （Js） which is due to the lower highest occupied molecular orbital （HOMO） level in DCJTB than that in CuPc. Also, the short circuit current density （JSC） is affected when the DCJTB layer becomes thicker, resulting from the high series resistance RsA due to the low charge carrier mobility of fluorescent red dye.
基金supported by the National Natural Science Foundation of China (Grant Nos.60877005 and 60777025)the Beijing Natural Science Foundation (Grant No.2062019)+4 种基金Beijing NOVA Program (Grant No.2006B20)Program for New Century Excellent Talents in University(Grant No.NCET-08-0717)State Key Project of Basic Research (Grant No.2010CB327704)Key Project of Ministry of Education (Grant No.109009)the 111 Project (Grant No.B08002)
文摘Two types of organic light-emitting diodes with structures of ITO/N,N'-bis(1-naphthyl)-N,N'-diphenyl,1,1'-biphenyl-4,4'-diamine (NPB)/tris(8-hydroquinolinato)aluminum(Alq 3)/2,9-dimethyl-4,7-diphenyl-l,10-phenanthroline(BCP)/Alq 3:4-dicyanomethylene-2-(tert-butyl)-6-methyl-4H-pyran(DCJTB)/Alq 3 /Al and ITO/NPB/BCP/Alq 3 /Alq 3:DCJTB/Alq 3 /Al were studied.NPB was chosen as a hole-transporting/blue-emitting layer.Alq 3 adjacent to BCP acted as a green emitting layer while that adjacent to the Al cathode acted as an electron-transporting layer.Alq 3 doped with 2 wt.% DCJTB was used as a red emitting layer.The operating principles of the devices were explained by the mechanism of F rster energy transfer and the hole and exciton blocking effect of BCP.It was found that the spectral characteristics of the devices strongly depended on the relative location between the green emitting Alq 3 layer and the BCP layer,as well as their thickness.Pure white emission with the CIE coordinates of (0.33,0.33) was achieved by mixing the three primary colors in the device with the structure of ITO/NPB(30 nm)/BCP(6 nm)/Alq 3 (30 nm)/Alq 3:DCJTB(30 nm)/Alq 3 (30 nm)/Al.The BCP layer played an important role in distributing the exciton energy among the three emitting layers to achieve a balanced white light.The white emission of this device was largely insensitive to the driving voltage (15-27 V) with the insertion of the green emitting Alq 3 layer.
基金Acknowledgements This work was partially supported by the National Natural Science Foundation of China （NSFC） （Grant Nos. 60736005 and 60425101-1）, the Foundation for Innovative Research Groups of the NSFC （No. 60721001）, the Provincial Program （No. 9140A02060609DZ0208）, Doctoral Fund of Ministry of China （No. 20090185110020）, the National Hi- Tech Research and Development Program of China （No. 2007AA03Z424）, the Project Sponsored by SRF for ROCS, SEM （No. GGRYJJ08-05）, and Young Excellence Project of Sichuan （No. 09ZQ026-074）.
文摘The open circuit voltage （Voc） of small- molecule organic solar cells （OSCs） could be improved by doping suitable fluorescent dyes into the donor layers. In this paper, 4-（dicyanomethylene）-2-t-butyl-6-（1,1,7,7- tetramethyljulolidyl-9-enyl）-4H-pyran （DCJTB） was used as a dopant, and the performance of the OSCs with different DCJTB concentration in copper phthalocyanine （CuPc） was studied. The results showed that the Voc of the OSC with 50% of DCJTB in CuPc increased by 15%, compared with that of the standard CuPc/fullerene （C60） device. The enhancement of the Voc was attributed to the lower highest occupied molecular orbital （HOMO） level in the DCJTB than that in the CuPc. Also, the light absorption intensity is enhanced between 400 and 550nm, where CuPc and C6o have low absorbance, leading to a broad absorption spectrum.
