Optical Orthogonal Frequency Division Multiplexing (OOFDM) has been proposed as a highly spectrum-efficient modulation technique, which can provide flexible spectrum assignment with fine granularity. In OOFDM-based fl...Optical Orthogonal Frequency Division Multiplexing (OOFDM) has been proposed as a highly spectrum-efficient modulation technique, which can provide flexible spectrum assignment with fine granularity. In OOFDM-based flexible optical networks, Routing and Spectrum Assignment (RSA) has become a key problem. However, widely used dynamic RSA schemes, such as Fixed Routing (FR) and K-shortest Paths (KSP) routing schemes, are not able to realize route computation based on the link state information, thus leading to poor blocking performance and inefficient resource utilization. To solve this problem, Adaptive Routing (AR) schemes, e.g., the Entire Path Searching (EPS) scheme, have been proposed recently. These schemes have low blocking probability; however, since their computational complexities are factorial, they are not suitable for use in real networks. In this paper, we propose a novel Spectrum-Scan Routing (SSR) scheme in dynamic flexible optical networks. To the best of our knowledge, SSR is the first polynomial-time AR scheme that can realize adaptive shortest-route computation. Simulation results show that our proposed SSR scheme has lower blocking probability and higher resource utilization compared with FR and EPS. Moreover, the worst-case computational complexity of SSR increases linearly with the network scale of the torus topologies, making it applicable to real networks.展开更多
All-inorganic CsPbBr_(3)perovskite solar cells(PSCs)are promising candidates to balance the stability and efficiency issues of organic-inorganic hybrid devices.However,the large energy barrier for charge transfer and ...All-inorganic CsPbBr_(3)perovskite solar cells(PSCs)are promising candidates to balance the stability and efficiency issues of organic-inorganic hybrid devices.However,the large energy barrier for charge transfer and narrow spectral response are still two challenging problems for performance improvement.We present here an organic bulkheterojunction{poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl C61 butyric acid methyl ester(P3HT:PCBM)}photoactive layer to boost the charge extraction and to widen the spectral absorption,achieving an enhanced power conversion efficiency up to 8.94%by optimizing the thickness of P3HT:PCBM photoactive layer,which is much higher than 6.28%for the pristine CsPbBr_(3)device.The interaction between the carbonyl group in PCBM and unsaturated Pb atom in the perovskite surface can effectively passivate the defects and reduce charge recombination.Furthermore,the coupling effect between PCBM and P3HT widens the spectral response from 540 to 650 nm for an increased short-circuit current density.More importantly,the devices are relatively stable over 75 days upon persistent attack by 70%relative humidity in air condition.These advantages of high efficiency,excellent long-term stability,cost-effectiveness and scalability may promote the commercialization of inorganic PSCs.展开更多
Conventional titanium oxide(TiO2) as an electron transport layer(ETL) in hybrid organic-inorganic perovskite solar cells(PSCs) requires a sintering process at a high temperature to crystalize, which is not suitable fo...Conventional titanium oxide(TiO2) as an electron transport layer(ETL) in hybrid organic-inorganic perovskite solar cells(PSCs) requires a sintering process at a high temperature to crystalize, which is not suitable for flexible PSCs and tandem solar cells with their low-temperatureprocessed bottom cell. Here, we introduce a low-temperature solution method to deposit a TiO2/tin oxide(SnO2) bilayer towards an efficient ETL. From the systematic measurements of optical and electronic properties, we demonstrate that the TiO2/SnO2 ETL has an enhanced charge extraction ability and a suppressed carrier recombination at the ETL/perovskite interface, both of which are beneficial to photo-generated carrier separation and transport. As a result, PSCs with TiO2/SnO2 bilayer ETLs present higher photovoltaic performance of the baseline cells compared with their TiO2 and SnO2 single-layer ETL counterparts. The champion PSC has a power conversion efficiency(PCE) of 19.11% with an open-circuit voltage(Voc)of 1.15 V, a short-circuit current density(Jsc) of 22.77 mA cm^-2,and a fill factor(FF) of 72.38%. Additionally, due to the suitable band alignment of the TiO2/SnO2 ETL in the device, a high Vocof 1.18 V is achieved. It has been proven that the TiO2/SnO2 bilayer is a promising alternative ETL for high efficiency PSCs.展开更多
In this study,two fullerenes(C60,C70)and their methano-substitutions(PC61BM,PC71BM),as electron transport materials(ETMs)in perovskite solar cells(Pero-SCs),were systematically studied.As being used as ETMs,methanoful...In this study,two fullerenes(C60,C70)and their methano-substitutions(PC61BM,PC71BM),as electron transport materials(ETMs)in perovskite solar cells(Pero-SCs),were systematically studied.As being used as ETMs,methanofullerenes,though with lower electron mobility compared to the counterpart pristine fullerenes,lead to higher power conversion efficiencies(PCEs)of Pero-SCs.The difference is likely caused by the fill-out vacancies and smoother morphology of the interfaces between ETM and perovskite layers,as they were prepared by different methods.In addition,compared to C60 and PC61BM,C70 and PC71BM showed priority in terms of short-circuit current density,which should be attributed to fast free charge extraction abilities.展开更多
In this work, we demonstrate a new kind of Pt-free counter electrode for dye-sensitized solar cells(DSCs). Polypyrrole-cobalt-carbon(PPY-Co-C) nanocomposites, with the advantages of low cost and simple preparation, sh...In this work, we demonstrate a new kind of Pt-free counter electrode for dye-sensitized solar cells(DSCs). Polypyrrole-cobalt-carbon(PPY-Co-C) nanocomposites, with the advantages of low cost and simple preparation, show favorable catalytic activity in promoting tri-iodide reduction. The DSC composed of the PPY-Co-C nanocomposite electrode exhibits an acceptable energy conversion efficiency of 6.01%, a considerable short-circuit photocurrent of 15.33 mA cm-2, and a low charge-transfer resistance of 1.5 Ω cm2. The overall performance of PPY-Co-C is superior to the carbon counterparts and comparable with the platinum reference, rendering them efficient and promising counter electrode materials for DSCs.展开更多
Small molecule organic solar cells （OSCs） with the structure of indium tin oxide （1TO）/molybdenum trioxide （MOO3） （5 nm）/rubrene （x nm）/fullerene （C70） （y nm）/2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthro...Small molecule organic solar cells （OSCs） with the structure of indium tin oxide （1TO）/molybdenum trioxide （MOO3） （5 nm）/rubrene （x nm）/fullerene （C70） （y nm）/2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline （BCP） （6 nm）/aluminum （A1） （150 nm） are fabricated. The thickness of active layer for the devices is investigated in details. The results show that the optimum thicknesses of rubrene layer and C70 layer are 30 nm and 25 nm, respectively. The degradation of the device is also investigated. The result indicates that the open-circuit voltage （Voo） does not change, while the short-circuit current density （Jsc）, fill factor （FF） and power conversion efficiency （PCE） decrease continuously with time. The degradation can be attributed to the oxygen in ambient diffusing and infiltrating into the active materials and reacting with C70 in cells, which can result in the increase of interfacial series resistance.展开更多
Three new electron donating small molecules （SMs）, Pyr（EH-DPP）2, Pyr（HD-DPP）2 and PyrA（EH-DPP）2, are designed and synthesized through coupling electron rich pyrene core with electron deficient diketopyrrolopyr...Three new electron donating small molecules （SMs）, Pyr（EH-DPP）2, Pyr（HD-DPP）2 and PyrA（EH-DPP）2, are designed and synthesized through coupling electron rich pyrene core with electron deficient diketopyrrolopyrrole （DPP） terminals, of which the derived organic solar cells （OSCs） exhibit interesting structure-performance correlation. It shows that the tune of their solubilizing side chains and n-bridge for the acceptor-donor-acceptor （A-D-A） SMs can significantly alter the resultant short-circuit current density and power conversion efficiency （PCE） in OSCs. The Pyr（EH-DPP）2 with short side chains displays broader absorption and higher hole mobility than the Pyr（HD-DPP）2 with long side chains. Although showing planar structure, the acetylene bridge-incorporated PyrA（EH-DPP）2 adapts an undesired edge-on packing and strong aggregation in film, leading to non-ideal morphology and poor miscibility with fullerene acceptors. As a result, the PCE of the solar cell based on Pyr（EH-DPP）2 is several times higher than those based on Pyr（HD-DPP）： and PyrA（EH-DPP）2, indicating the A-D-A combination of polyaromatics with DPP would be the promising skeleton for developing photovoltaic semiconductors.展开更多
This paper describes the NiiMi process designed to treat landscape water. The main aim of the research was to investigate the feasibility of NiiMi for removing organic and nutriment materials from landscape water. Dur...This paper describes the NiiMi process designed to treat landscape water. The main aim of the research was to investigate the feasibility of NiiMi for removing organic and nutriment materials from landscape water. During the batch-scale NiiMi operation, the removal rates of color ranged from 66.7%o-80% , of turbidity from 31.7%-89.3%o, of chemical oxygen demand （COD） from 7%-36.5%, of total phosphor （TP） from 43%-84.2%, of soluble phosphate from 42.9%-100%, of total nitrogen （TN） from 4.2%-46.7%, and of NH4^＋-N from 39.3%-100% at the hydraulic loading of 0.2 m^3/（m^2·d）. Results showed that the removal efficiencies of COD, TP, soluble phosphate and TN decreased with the decline in the temperature. The NiiMi process had a strong shock loading ability for the removal of the organics, turbidity, TP, soluble phosphate, TN and NH4^＋-N. Three sodium chloride tracer studies were conducted, labeled as TS 1, TS2, and TS3, respectively. The mean hydraulic retention times （mean HRTs） were 31 h and 28 h for TSI and TS2, respectively, indicating the occurrence of a dead zone volume of 12% and 20% for TS 1 and TS2, respectively. TS 1 and TS2 displayed the occurrence of short-circuiting in the NiiMi system. The comparison results between TS1 and TS2 were further confirmed in the values obtained for some indicators, such as volumetric efficiency （e）, short-circuiting （S）, hydraulic efficiency （2） and number of continuously stirred tank reactors （N）.展开更多
Ternary strategy has been considered as an efficient method to achieve high performance polymer solar cells(PSCs). A power conversion efficiency(PCE) of 17.22% is achieved in the optimized ternary PSCs with10 wt% MF1 ...Ternary strategy has been considered as an efficient method to achieve high performance polymer solar cells(PSCs). A power conversion efficiency(PCE) of 17.22% is achieved in the optimized ternary PSCs with10 wt% MF1 in acceptors. The over 8% PCE improvement by employing ternary strategy is attributed to the simultaneously increased JSCof 25.68 mA cm^-2, VOCof 0.853 V and FF of 78.61% compared with Y6 based binary PSCs. The good compatibility of MF1 and Y6 can be confirmed from Raman mapping, contact angle,cyclic voltammetry and morphology, which is the prerequisite to form alloy-like state. Electron mobility in ternary active layers strongly depends on MF1 content in acceptors due to the different lowest unoccupied molecular orbital(LUMO) levels of Y6 and MF1, which can well explain the wave-like varied FF of ternary PSCs. The third-party certified PCE of 16.8% should be one of the highest values for single bulk heterojunction PSCs. This work provides sufficient references for selecting materials to achieve efficient ternary PSCs.展开更多
The properties of Al-doped Zn O(AZO) play an important role in the photovoltaic performance of inverted polymer solar cells(PSCs), which is used as electron transport and hole blocking buffer layers. In this work, we ...The properties of Al-doped Zn O(AZO) play an important role in the photovoltaic performance of inverted polymer solar cells(PSCs), which is used as electron transport and hole blocking buffer layers. In this work, we study the effects of Al-doping level in AZO on device performance in detail. Results indicate that the device performance intensely depends on the Al-doping level. The AZO thin films with Al-doping atomic percentage of 1.0% possess the best conductivity. The resulting solar cells show the enhanced short current density and the fill factor(FF) simultaneously, and the power conversion efficiency(PCE) is improved by 74%, which are attributed to the reduced carrier recombination and the optimized charge transport and extraction between AZO and the active layer.展开更多
For the state-of-the-art organic solar cells(OSCs),PEDOT:PSS is the most popularly used hole transport material for the conventional structure.However,it still suffers from several disadvantages,such as low conductivi...For the state-of-the-art organic solar cells(OSCs),PEDOT:PSS is the most popularly used hole transport material for the conventional structure.However,it still suffers from several disadvantages,such as low conductivity and harm to ITO due to the acidic PSS.Herein,a simple method is introduced to enhance the conductivity and remove the additional PSS by water rinsing the PEDOT:PSS films.The photovoltaic devices based on the water rinsed PEDOT:PSS present a dramatic improvement in efficiency from 15.98%to 16.75%in comparison to that of the untreated counterparts.Systematic characterization and analysis reveal that although part of the PEDOT:PSS is washed away,it still leaves a smoother film and the ratio of PEDOT to PSS is higher than before in the remaining films.It can greatly improve the conductivity and reduce the damage to substrates.This study demonstrates that finely modifying the charge transport materials to improve conductivity and reduce defeats has great potential for boosting the efficiency of OSCs.展开更多
Hierarchically ordered macro-mesoporous TiO2 films (Ti-Ma-Me) were fabricated on fluorine-doped tin oxide (FTO) substrates through the confinement self-assembly method. The prepared Ti-Ma-Me possesses periodically ord...Hierarchically ordered macro-mesoporous TiO2 films (Ti-Ma-Me) were fabricated on fluorine-doped tin oxide (FTO) substrates through the confinement self-assembly method. The prepared Ti-Ma-Me possesses periodically ordered structure and a large specific surface area, which was applied as an interfacial layer between the nanocrystalline TiO2 film (P25-TiO2) and FTO electrode in the dye-sensitized solar cell (DSSC). The introduction of a Ti-Ma-Me interfacial layer increased the shortcircuit current density (Jsc) from 7.49 to 10.65 mA/cm2 and the open-circuit voltage (Voc) from 0.65 to 0.70 V as the result of its improved light harvesting efficiency by allowing for the high roughness factor and enhanced multiple internal reflection or scattering as well as reducing the back-transport reaction by blocking direct contact between the electrolyte and FTO electrode. Therefore, the photovoltaic conversion efficiency (η) was improved by 83% from 3.04% to 5.55%, as compared to a device using a bare P25 TiO2 photoanode.展开更多
Three model polythiophenes,PTCBT,PTCFBT and PFTCBT,have been synthesized to investigate the effect of fluorination on photovoltaic performance of polythiothenes.Compared with PTCBT,PFTCBT with F atom on TC unit shows ...Three model polythiophenes,PTCBT,PTCFBT and PFTCBT,have been synthesized to investigate the effect of fluorination on photovoltaic performance of polythiothenes.Compared with PTCBT,PFTCBT with F atom on TC unit shows a narrower optical bandgap(1.79 eV),higher crystallinity,and ideal morphology in the active layer,leading to a higher short-circuit current density(J_(SC))of 11.84 mA/cm^2 and a power conversion efficiency(PCE)of 5.93%.The lock-up function of fluorine enhances polythiophene backbone planarity and molecular packing.展开更多
基金supported in part by projects of National 863 Program under Grant No.2012AA011301National 973 Program under Grants No. 2010CB328203, No. 2010CB328205National Natural Science Foundation of China under Grant No. 61201188
文摘Optical Orthogonal Frequency Division Multiplexing (OOFDM) has been proposed as a highly spectrum-efficient modulation technique, which can provide flexible spectrum assignment with fine granularity. In OOFDM-based flexible optical networks, Routing and Spectrum Assignment (RSA) has become a key problem. However, widely used dynamic RSA schemes, such as Fixed Routing (FR) and K-shortest Paths (KSP) routing schemes, are not able to realize route computation based on the link state information, thus leading to poor blocking performance and inefficient resource utilization. To solve this problem, Adaptive Routing (AR) schemes, e.g., the Entire Path Searching (EPS) scheme, have been proposed recently. These schemes have low blocking probability; however, since their computational complexities are factorial, they are not suitable for use in real networks. In this paper, we propose a novel Spectrum-Scan Routing (SSR) scheme in dynamic flexible optical networks. To the best of our knowledge, SSR is the first polynomial-time AR scheme that can realize adaptive shortest-route computation. Simulation results show that our proposed SSR scheme has lower blocking probability and higher resource utilization compared with FR and EPS. Moreover, the worst-case computational complexity of SSR increases linearly with the network scale of the torus topologies, making it applicable to real networks.
基金the Fundamental Research Funds for the Central Universities(21620348 and 21618409)the National Natural Science Foundation of China(61774139,U1802257)the Natural Science Foundation of Guangdong Province(2019B151502061)。
文摘All-inorganic CsPbBr_(3)perovskite solar cells(PSCs)are promising candidates to balance the stability and efficiency issues of organic-inorganic hybrid devices.However,the large energy barrier for charge transfer and narrow spectral response are still two challenging problems for performance improvement.We present here an organic bulkheterojunction{poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl C61 butyric acid methyl ester(P3HT:PCBM)}photoactive layer to boost the charge extraction and to widen the spectral absorption,achieving an enhanced power conversion efficiency up to 8.94%by optimizing the thickness of P3HT:PCBM photoactive layer,which is much higher than 6.28%for the pristine CsPbBr_(3)device.The interaction between the carbonyl group in PCBM and unsaturated Pb atom in the perovskite surface can effectively passivate the defects and reduce charge recombination.Furthermore,the coupling effect between PCBM and P3HT widens the spectral response from 540 to 650 nm for an increased short-circuit current density.More importantly,the devices are relatively stable over 75 days upon persistent attack by 70%relative humidity in air condition.These advantages of high efficiency,excellent long-term stability,cost-effectiveness and scalability may promote the commercialization of inorganic PSCs.
基金supported by the National Key Research and Development of China (2018YFB1500103 and 2018YFB0704100)the National Natural Science Foundation of China (61574145, 61874177, 51502315 and 61704176)+1 种基金Zhejiang Provincial Natural Science Foundation (LR16F040002)Zhejiang Energy Group (znkj-2018-118)
文摘Conventional titanium oxide(TiO2) as an electron transport layer(ETL) in hybrid organic-inorganic perovskite solar cells(PSCs) requires a sintering process at a high temperature to crystalize, which is not suitable for flexible PSCs and tandem solar cells with their low-temperatureprocessed bottom cell. Here, we introduce a low-temperature solution method to deposit a TiO2/tin oxide(SnO2) bilayer towards an efficient ETL. From the systematic measurements of optical and electronic properties, we demonstrate that the TiO2/SnO2 ETL has an enhanced charge extraction ability and a suppressed carrier recombination at the ETL/perovskite interface, both of which are beneficial to photo-generated carrier separation and transport. As a result, PSCs with TiO2/SnO2 bilayer ETLs present higher photovoltaic performance of the baseline cells compared with their TiO2 and SnO2 single-layer ETL counterparts. The champion PSC has a power conversion efficiency(PCE) of 19.11% with an open-circuit voltage(Voc)of 1.15 V, a short-circuit current density(Jsc) of 22.77 mA cm^-2,and a fill factor(FF) of 72.38%. Additionally, due to the suitable band alignment of the TiO2/SnO2 ETL in the device, a high Vocof 1.18 V is achieved. It has been proven that the TiO2/SnO2 bilayer is a promising alternative ETL for high efficiency PSCs.
基金the National Natural Science Foundation of China(51303118,91333204)the Natural Science Foundation of Jiangsu Province(BK20130289)+3 种基金the Ph.D.Programs Foundation of Ministry of Education of China(20133201120008)the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Scientific Research Foundation for Returned Scholars,Ministry of Education of ChinaBeijing National Laboratory for Molecular Sciences,State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials
文摘In this study,two fullerenes(C60,C70)and their methano-substitutions(PC61BM,PC71BM),as electron transport materials(ETMs)in perovskite solar cells(Pero-SCs),were systematically studied.As being used as ETMs,methanofullerenes,though with lower electron mobility compared to the counterpart pristine fullerenes,lead to higher power conversion efficiencies(PCEs)of Pero-SCs.The difference is likely caused by the fill-out vacancies and smoother morphology of the interfaces between ETM and perovskite layers,as they were prepared by different methods.In addition,compared to C60 and PC61BM,C70 and PC71BM showed priority in terms of short-circuit current density,which should be attributed to fast free charge extraction abilities.
基金supported by the National Basic Research Program of China(2011CBA00702)the National Natural Science Foundation of China(21322101)+1 种基金Ministry of Education(B12015,113016A,ACET-13-0296)the Fundamental Research Funds for the Central Universities
文摘In this work, we demonstrate a new kind of Pt-free counter electrode for dye-sensitized solar cells(DSCs). Polypyrrole-cobalt-carbon(PPY-Co-C) nanocomposites, with the advantages of low cost and simple preparation, show favorable catalytic activity in promoting tri-iodide reduction. The DSC composed of the PPY-Co-C nanocomposite electrode exhibits an acceptable energy conversion efficiency of 6.01%, a considerable short-circuit photocurrent of 15.33 mA cm-2, and a low charge-transfer resistance of 1.5 Ω cm2. The overall performance of PPY-Co-C is superior to the carbon counterparts and comparable with the platinum reference, rendering them efficient and promising counter electrode materials for DSCs.
基金supported by the Natural Science Foundation of Guangdong Province of China (No.06025173)
文摘Small molecule organic solar cells （OSCs） with the structure of indium tin oxide （1TO）/molybdenum trioxide （MOO3） （5 nm）/rubrene （x nm）/fullerene （C70） （y nm）/2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline （BCP） （6 nm）/aluminum （A1） （150 nm） are fabricated. The thickness of active layer for the devices is investigated in details. The results show that the optimum thicknesses of rubrene layer and C70 layer are 30 nm and 25 nm, respectively. The degradation of the device is also investigated. The result indicates that the open-circuit voltage （Voo） does not change, while the short-circuit current density （Jsc）, fill factor （FF） and power conversion efficiency （PCE） decrease continuously with time. The degradation can be attributed to the oxygen in ambient diffusing and infiltrating into the active materials and reacting with C70 in cells, which can result in the increase of interfacial series resistance.
基金supported by the National Natural Science Foundation of China(51473142,21674093,21374075)the Major State Basic Research Development Program(2014CB643503)International Science and Technology Cooperation Program of China(2016YFE0102900)
文摘Three new electron donating small molecules （SMs）, Pyr（EH-DPP）2, Pyr（HD-DPP）2 and PyrA（EH-DPP）2, are designed and synthesized through coupling electron rich pyrene core with electron deficient diketopyrrolopyrrole （DPP） terminals, of which the derived organic solar cells （OSCs） exhibit interesting structure-performance correlation. It shows that the tune of their solubilizing side chains and n-bridge for the acceptor-donor-acceptor （A-D-A） SMs can significantly alter the resultant short-circuit current density and power conversion efficiency （PCE） in OSCs. The Pyr（EH-DPP）2 with short side chains displays broader absorption and higher hole mobility than the Pyr（HD-DPP）2 with long side chains. Although showing planar structure, the acetylene bridge-incorporated PyrA（EH-DPP）2 adapts an undesired edge-on packing and strong aggregation in film, leading to non-ideal morphology and poor miscibility with fullerene acceptors. As a result, the PCE of the solar cell based on Pyr（EH-DPP）2 is several times higher than those based on Pyr（HD-DPP）： and PyrA（EH-DPP）2, indicating the A-D-A combination of polyaromatics with DPP would be the promising skeleton for developing photovoltaic semiconductors.
文摘This paper describes the NiiMi process designed to treat landscape water. The main aim of the research was to investigate the feasibility of NiiMi for removing organic and nutriment materials from landscape water. During the batch-scale NiiMi operation, the removal rates of color ranged from 66.7%o-80% , of turbidity from 31.7%-89.3%o, of chemical oxygen demand （COD） from 7%-36.5%, of total phosphor （TP） from 43%-84.2%, of soluble phosphate from 42.9%-100%, of total nitrogen （TN） from 4.2%-46.7%, and of NH4^＋-N from 39.3%-100% at the hydraulic loading of 0.2 m^3/（m^2·d）. Results showed that the removal efficiencies of COD, TP, soluble phosphate and TN decreased with the decline in the temperature. The NiiMi process had a strong shock loading ability for the removal of the organics, turbidity, TP, soluble phosphate, TN and NH4^＋-N. Three sodium chloride tracer studies were conducted, labeled as TS 1, TS2, and TS3, respectively. The mean hydraulic retention times （mean HRTs） were 31 h and 28 h for TSI and TS2, respectively, indicating the occurrence of a dead zone volume of 12% and 20% for TS 1 and TS2, respectively. TS 1 and TS2 displayed the occurrence of short-circuiting in the NiiMi system. The comparison results between TS1 and TS2 were further confirmed in the values obtained for some indicators, such as volumetric efficiency （e）, short-circuiting （S）, hydraulic efficiency （2） and number of continuously stirred tank reactors （N）.
基金This work was supported by the National Natural Science Foundation of China(61805009,61675017,61975006)China Postdoctoral Science Foundation(2018M641170)+1 种基金Beijing Natural Science Foundation(4192049)The authors gratefully acknowledge the assistance of the Shanghai Synchrotron Radiation Facility(beamline BL16B1)for GWAIXS and GISAXS measurements.
文摘Ternary strategy has been considered as an efficient method to achieve high performance polymer solar cells(PSCs). A power conversion efficiency(PCE) of 17.22% is achieved in the optimized ternary PSCs with10 wt% MF1 in acceptors. The over 8% PCE improvement by employing ternary strategy is attributed to the simultaneously increased JSCof 25.68 mA cm^-2, VOCof 0.853 V and FF of 78.61% compared with Y6 based binary PSCs. The good compatibility of MF1 and Y6 can be confirmed from Raman mapping, contact angle,cyclic voltammetry and morphology, which is the prerequisite to form alloy-like state. Electron mobility in ternary active layers strongly depends on MF1 content in acceptors due to the different lowest unoccupied molecular orbital(LUMO) levels of Y6 and MF1, which can well explain the wave-like varied FF of ternary PSCs. The third-party certified PCE of 16.8% should be one of the highest values for single bulk heterojunction PSCs. This work provides sufficient references for selecting materials to achieve efficient ternary PSCs.
基金supported by the National Natural Science Foundation of China(No.61377031)the Scientific Research Foundation of Zhejiang Ocean University(No.Q1444)
文摘The properties of Al-doped Zn O(AZO) play an important role in the photovoltaic performance of inverted polymer solar cells(PSCs), which is used as electron transport and hole blocking buffer layers. In this work, we study the effects of Al-doping level in AZO on device performance in detail. Results indicate that the device performance intensely depends on the Al-doping level. The AZO thin films with Al-doping atomic percentage of 1.0% possess the best conductivity. The resulting solar cells show the enhanced short current density and the fill factor(FF) simultaneously, and the power conversion efficiency(PCE) is improved by 74%, which are attributed to the reduced carrier recombination and the optimized charge transport and extraction between AZO and the active layer.
基金mostly supported by the National Key Research and Development Program of China(2017YFA0206600)the Key Research Program of Frontier Science,Chinese Academy of Sciences(QYZDB-SSW-SLH006)+1 种基金the National Natural Science Foundation of China(61674141,51972300,21975245)the support from the Hundred Talents Program(Chinese Academy of Sciences)。
文摘For the state-of-the-art organic solar cells(OSCs),PEDOT:PSS is the most popularly used hole transport material for the conventional structure.However,it still suffers from several disadvantages,such as low conductivity and harm to ITO due to the acidic PSS.Herein,a simple method is introduced to enhance the conductivity and remove the additional PSS by water rinsing the PEDOT:PSS films.The photovoltaic devices based on the water rinsed PEDOT:PSS present a dramatic improvement in efficiency from 15.98%to 16.75%in comparison to that of the untreated counterparts.Systematic characterization and analysis reveal that although part of the PEDOT:PSS is washed away,it still leaves a smoother film and the ratio of PEDOT to PSS is higher than before in the remaining films.It can greatly improve the conductivity and reduce the damage to substrates.This study demonstrates that finely modifying the charge transport materials to improve conductivity and reduce defeats has great potential for boosting the efficiency of OSCs.
基金supported by the National Natural Science Foundation of China (20971125, 21031005, 21050110428 & 21006116)Beijing Municipal Natural Science Foundation (2082022)+2 种基金the Foundation for State Key Laboratory of Multi-phase Complex Systems (MPCS-2011-D-15)State Key Laboratory of Biochemical Engineering (2010KF-09)the CAS Research Fellowship for International Young Scientists (2010Y1GB5)
文摘Hierarchically ordered macro-mesoporous TiO2 films (Ti-Ma-Me) were fabricated on fluorine-doped tin oxide (FTO) substrates through the confinement self-assembly method. The prepared Ti-Ma-Me possesses periodically ordered structure and a large specific surface area, which was applied as an interfacial layer between the nanocrystalline TiO2 film (P25-TiO2) and FTO electrode in the dye-sensitized solar cell (DSSC). The introduction of a Ti-Ma-Me interfacial layer increased the shortcircuit current density (Jsc) from 7.49 to 10.65 mA/cm2 and the open-circuit voltage (Voc) from 0.65 to 0.70 V as the result of its improved light harvesting efficiency by allowing for the high roughness factor and enhanced multiple internal reflection or scattering as well as reducing the back-transport reaction by blocking direct contact between the electrolyte and FTO electrode. Therefore, the photovoltaic conversion efficiency (η) was improved by 83% from 3.04% to 5.55%, as compared to a device using a bare P25 TiO2 photoanode.
基金supported by the National Natural Science Foundation of China(U1401244,21374025,21372053,21572041,51503050)the Key Laboratory of Nanosystem and Hierarchical Fabrication(CAS)+2 种基金State Key Laboratory of Luminescent Materials and Devices(2016-skllmd-05)Youth Association for Promoting Innovation(CAS)Center for Excellence in Nanoscience(CAS)
文摘Three model polythiophenes,PTCBT,PTCFBT and PFTCBT,have been synthesized to investigate the effect of fluorination on photovoltaic performance of polythiothenes.Compared with PTCBT,PFTCBT with F atom on TC unit shows a narrower optical bandgap(1.79 eV),higher crystallinity,and ideal morphology in the active layer,leading to a higher short-circuit current density(J_(SC))of 11.84 mA/cm^2 and a power conversion efficiency(PCE)of 5.93%.The lock-up function of fluorine enhances polythiophene backbone planarity and molecular packing.
