An electron transporting material of TFTTP （4-（5-hexylthiophene-2-yl）-2,6-bis（5-trifluoromethyl）thiophen-2-yl）pyridine） was investigated as a cathode buffer layer to enhance the power efficiency of organic sola...An electron transporting material of TFTTP （4-（5-hexylthiophene-2-yl）-2,6-bis（5-trifluoromethyl）thiophen-2-yl）pyridine） was investigated as a cathode buffer layer to enhance the power efficiency of organic solar cells （OSCs） based on subphthalocyanine and C60. The overall power conversion efficiency was increased by a factor of 1.31 by inserting the TFTTP interfacial layer between the active layer and metallic cathode. The inner mechanism responsible for the performance enhancement of OSCs was systematically studied with the simulation of dark diode behavior and optical field distribution inside the devices as well as the characterization of device photocurrent. The results showed that the TFTTP layer could significantly increase the built-in potential in the devices, leading to the enhanced dissociation of charge transfer excitons. In addition, by using TFTTP as the buffer layer, a better Ohmic contact at C60/metal interface was formed, facilitating more efficient free charge carrier collection.展开更多
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
The performance of an organic photovoltaic （OPV） cell based on copper phthatocyanine CuPc/C60 with a tris- （8-hydroxyquinolinato） aluminum （Alq3） buffer layer has been investigated. It was found that the power c...The performance of an organic photovoltaic （OPV） cell based on copper phthatocyanine CuPc/C60 with a tris- （8-hydroxyquinolinato） aluminum （Alq3） buffer layer has been investigated. It was found that the power conversion efficiency of the device was 1.51% under illumination with an intensity of 100 mW/cm^2, which was limited by a squareroot dependence of the photocurrent on voltage. The photocurrent optical power density characteristics showed that the OPV cell had a significant space-charge limited photocurrent with a varied saturation voltage and a three quarters power dependence on optical power density. Also, the absorption spectrum was measured by a spectrophotometer, and the results showed that the additional Alq3 layer has a minor effect on photocurrent generation.展开更多
The highest power conversion effciencies(PCEs)of perovskite solar cells(PSCs)are frequently achieved in regular(n-i-p)structures,such as the certifed 25.7%(https://www.nrel.gov/pv/celleffciency.html).Although the inve...The highest power conversion effciencies(PCEs)of perovskite solar cells(PSCs)are frequently achieved in regular(n-i-p)structures,such as the certifed 25.7%(https://www.nrel.gov/pv/celleffciency.html).Although the inverted(p-i-n)PSCs have excelled in negative hysteresis,higher stability,and simpler fabrication method,they are suffering from less effciency than that of regular devices.Additionally.展开更多
文摘An electron transporting material of TFTTP （4-（5-hexylthiophene-2-yl）-2,6-bis（5-trifluoromethyl）thiophen-2-yl）pyridine） was investigated as a cathode buffer layer to enhance the power efficiency of organic solar cells （OSCs） based on subphthalocyanine and C60. The overall power conversion efficiency was increased by a factor of 1.31 by inserting the TFTTP interfacial layer between the active layer and metallic cathode. The inner mechanism responsible for the performance enhancement of OSCs was systematically studied with the simulation of dark diode behavior and optical field distribution inside the devices as well as the characterization of device photocurrent. The results showed that the TFTTP layer could significantly increase the built-in potential in the devices, leading to the enhanced dissociation of charge transfer excitons. In addition, by using TFTTP as the buffer layer, a better Ohmic contact at C60/metal interface was formed, facilitating more efficient free charge carrier collection.
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Project 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 (Grant No. 60721001),Provincial Project (Grant No. 9140A02060609DZ0208)+1 种基金Program for New Century Excellent Talents in University (Grant No. NCET-06-0812),SRF for ROCS,SEM (Grant No. GGRYJJ08-05)Young Excellent Project of Sichuan Province (Grant No. 09ZQ026-074)
文摘The performance of an organic photovoltaic （OPV） cell based on copper phthatocyanine CuPc/C60 with a tris- （8-hydroxyquinolinato） aluminum （Alq3） buffer layer has been investigated. It was found that the power conversion efficiency of the device was 1.51% under illumination with an intensity of 100 mW/cm^2, which was limited by a squareroot dependence of the photocurrent on voltage. The photocurrent optical power density characteristics showed that the OPV cell had a significant space-charge limited photocurrent with a varied saturation voltage and a three quarters power dependence on optical power density. Also, the absorption spectrum was measured by a spectrophotometer, and the results showed that the additional Alq3 layer has a minor effect on photocurrent generation.
基金supported by the National Natural Science Foundation of China(52172205)。
文摘The highest power conversion effciencies(PCEs)of perovskite solar cells(PSCs)are frequently achieved in regular(n-i-p)structures,such as the certifed 25.7%(https://www.nrel.gov/pv/celleffciency.html).Although the inverted(p-i-n)PSCs have excelled in negative hysteresis,higher stability,and simpler fabrication method,they are suffering from less effciency than that of regular devices.Additionally.
