With the emergence of new materials for high-efficiency organic solar cells(OSCs),understanding and finetuning the interface energetics become increasingly important.Precise determination of the so-called pinning ener...With the emergence of new materials for high-efficiency organic solar cells(OSCs),understanding and finetuning the interface energetics become increasingly important.Precise determination of the so-called pinning energies,one of the critical characteristics of the material to predict the energy level alignment(ELA)at either electrode/organic or organic/organic interfaces,are urgently needed for the new materials.Here,pinning energies of a wide variety of newly developed donors and nonfullerene acceptors(NFAs)are measured through ultraviolet photoelectron spectroscopy.The positive pinning energies of the studied donors and the negative pinning energies of NFAs are in the same energy range of 4.3−4.6 eV,which follows the design rules developed for fullerene-based OSCs.The ELA for metal/organic and inorganic/organic interfaces follows the predicted behavior for all of the materials studied.For organic-organic heterojunctions where both the donor and the NFA feature strong intramolecular charge transfer,the pinning energies often underestimate the experimentally obtained interface vacuum level shift,which has consequences for OSC device performance.展开更多
Herein we report an electrochemical DNA biosensor for the rapid detection of sequence (5’ AAT GGA TTT ATC TGC TCT TCG 3’) specific for the breast cancer 1 (BRCA1) gene. The proposed electrochemical genosensor is bas...Herein we report an electrochemical DNA biosensor for the rapid detection of sequence (5’ AAT GGA TTT ATC TGC TCT TCG 3’) specific for the breast cancer 1 (BRCA1) gene. The proposed electrochemical genosensor is based on short oligonucleotide DNA probe immobilized onto zinc oxide nanowires (ZnONWs) chemically synthesized onto gold electrode via hydrothermal technique. The morphology studies of the ZnONWs, performed by field emission scanning electron microscopy (FESEM), showed that the ZnO nanowires are uniform, highly dense and oriented perpendicularly to the substrate. Recognition event between the DNA probe and the target was investigated by differential pulse voltammetry (DPV) in 0.1 M acetate buffer solution (ABS), pH 7.00;as a result of the hybridization, an oxidation signal was observed at +0.8 V. The influences of pH, target concentration, and non-complimentary DNA on biosensor performance were examined. The proposed DNA biosensor has the ability to detect the target sequence in the range of concentration between 10.0 and 100.0 μM with a detection limit of 3.32 μM. The experimental results demonstrated that the prepared ZnONWs/Au electrodes are suitable platform for the immobilization of DNA.展开更多
Perceptual auditory filter banks such as Bark-scale filter bank are widely used as front-end processing in speech recognition systems.However,the problem of the design of optimized filter banks that provide higher acc...Perceptual auditory filter banks such as Bark-scale filter bank are widely used as front-end processing in speech recognition systems.However,the problem of the design of optimized filter banks that provide higher accuracy in recognition tasks is still open.Owing to spectral analysis in feature extraction,an adaptive bands filter bank (ABFB) is presented.The design adopts flexible bandwidths and center frequencies for the frequency responses of the filters and utilizes genetic algorithm (GA) to optimize the design parameters.The optimization process is realized by combining the front-end filter bank with the back-end recognition network in the performance evaluation loop.The deployment of ABFB together with zero-crossing peak amplitude (ZCPA) feature as a front process for radial basis function (RBF) system shows significant improvement in robustness compared with the Bark-scale filter bank.In ABFB,several sub-bands are still more concentrated toward lower frequency but their exact locations are determined by the performance rather than the perceptual criteria.For the ease of optimization,only symmetrical bands are considered here,which still provide satisfactory results.展开更多
Green hydrogen is identified as one of the prime clean energy carriers due to its high energy density and a zero emission of CO_(2).A possible solution for the transport of H_(2)in a safe and low-cost way is in the fo...Green hydrogen is identified as one of the prime clean energy carriers due to its high energy density and a zero emission of CO_(2).A possible solution for the transport of H_(2)in a safe and low-cost way is in the form of liquid organic hydrogen carriers(LOHCs).As an alternative to loading LOHC with H_(2)via a two-step procedure involving preliminary electrolytic production of H_(2)and subsequent chemical hydrogenation of the LOHC,we explore here the possibility of electrochemical hydrogen storage(EHS)via conversion of proton of a proton donor into a hydrogen atom involved in covalent bonds with the LOHC(R)via a protoncoupled electron transfer(PCET)reaction:2nH^(+)+2ne^(-)+Rox■n H_(2)^(0)Rred.We chose 9-fluorenone/fluorenol(Fnone/Fnol)conversion as such a model PCET reaction.The electrochemical activation of Fnone via two sequential electron transfers was monitored with in-situ and operando spectroscopies in absence and in presence of different alcohols as proton donors of different reactivity,which enabled us to both quantify and get the mechanistic insight on PCET.The possibility of hydrogen extraction from the loaded carrier molecule was illustrated by chemical activation.展开更多
Plasmonic metal electrodes with subwavelength nanostructures are promising for enhancing light harvesting in photovoltaics.However,the nonradiative damping of surface plasmon polaritons(SPPs)during coupling with sunli...Plasmonic metal electrodes with subwavelength nanostructures are promising for enhancing light harvesting in photovoltaics.However,the nonradiative damping of surface plasmon polaritons(SPPs)during coupling with sunlight results in the conversion of the excited hot-electrons to heat,which limits the absorption of light and generation of photocurrent.Herein,an energy recycling strategy driven by hotelectron emission for recycling the SPP energy trapped in the plasmonic electrodes is proposed.A transparent silver-based plasmonic metal electrode(A-PME)with a periodic hexagonal nanopore array is constructed,which is combined with a luminescent organic emitter for radiative recombination of the injected hot-electrons.Owing to the suppressed SPP energy loss via broadband hot-electron emission,the A-PME achieves an optimized optical transmission with an average transmittance of over 80%from 380 to 1200 nm.Moreover,the indium-tin-oxide-free organic solar cells yield an enhanced light harvestingwith a power conversion efficiency of 16.1%.展开更多
基金the financial support from the Swedish Research Council(project grants no.2016-05498,2016-05990,and 2020-04538)the Swedish Energy Agency(grant.no.45411-1)+1 种基金by the Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linköping University(Faculty Grant SFO Mat LiU no.200900971)support from the Wallenberg Wood Science Center(WWSC).
文摘With the emergence of new materials for high-efficiency organic solar cells(OSCs),understanding and finetuning the interface energetics become increasingly important.Precise determination of the so-called pinning energies,one of the critical characteristics of the material to predict the energy level alignment(ELA)at either electrode/organic or organic/organic interfaces,are urgently needed for the new materials.Here,pinning energies of a wide variety of newly developed donors and nonfullerene acceptors(NFAs)are measured through ultraviolet photoelectron spectroscopy.The positive pinning energies of the studied donors and the negative pinning energies of NFAs are in the same energy range of 4.3−4.6 eV,which follows the design rules developed for fullerene-based OSCs.The ELA for metal/organic and inorganic/organic interfaces follows the predicted behavior for all of the materials studied.For organic-organic heterojunctions where both the donor and the NFA feature strong intramolecular charge transfer,the pinning energies often underestimate the experimentally obtained interface vacuum level shift,which has consequences for OSC device performance.
基金the Ministry of Higher Education Malaysia for the ERGS grant(600/RMI/st/ERGS/5/3/fst12/2011)Universiti Teknologi MARA for financial support via postgraduate teaching assistant scheme(UPTA)to Nur Azimah Mansor for conducting this research.
文摘Herein we report an electrochemical DNA biosensor for the rapid detection of sequence (5’ AAT GGA TTT ATC TGC TCT TCG 3’) specific for the breast cancer 1 (BRCA1) gene. The proposed electrochemical genosensor is based on short oligonucleotide DNA probe immobilized onto zinc oxide nanowires (ZnONWs) chemically synthesized onto gold electrode via hydrothermal technique. The morphology studies of the ZnONWs, performed by field emission scanning electron microscopy (FESEM), showed that the ZnO nanowires are uniform, highly dense and oriented perpendicularly to the substrate. Recognition event between the DNA probe and the target was investigated by differential pulse voltammetry (DPV) in 0.1 M acetate buffer solution (ABS), pH 7.00;as a result of the hybridization, an oxidation signal was observed at +0.8 V. The influences of pH, target concentration, and non-complimentary DNA on biosensor performance were examined. The proposed DNA biosensor has the ability to detect the target sequence in the range of concentration between 10.0 and 100.0 μM with a detection limit of 3.32 μM. The experimental results demonstrated that the prepared ZnONWs/Au electrodes are suitable platform for the immobilization of DNA.
基金Project(61072087) supported by the National Natural Science Foundation of ChinaProject(20093048) supported by Shanxi ProvincialGraduate Innovation Fund of China
文摘Perceptual auditory filter banks such as Bark-scale filter bank are widely used as front-end processing in speech recognition systems.However,the problem of the design of optimized filter banks that provide higher accuracy in recognition tasks is still open.Owing to spectral analysis in feature extraction,an adaptive bands filter bank (ABFB) is presented.The design adopts flexible bandwidths and center frequencies for the frequency responses of the filters and utilizes genetic algorithm (GA) to optimize the design parameters.The optimization process is realized by combining the front-end filter bank with the back-end recognition network in the performance evaluation loop.The deployment of ABFB together with zero-crossing peak amplitude (ZCPA) feature as a front process for radial basis function (RBF) system shows significant improvement in robustness compared with the Bark-scale filter bank.In ABFB,several sub-bands are still more concentrated toward lower frequency but their exact locations are determined by the performance rather than the perceptual criteria.For the ease of optimization,only symmetrical bands are considered here,which still provide satisfactory results.
基金financially supported by the Swedish Research Council(grant 2016-05990)the Knut and Alice Wallenberg Foundation(H2O2 and Cellfion)the Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Link?ping University(Faculty Grant SFO-Mat-Li U No.200900971)。
文摘Green hydrogen is identified as one of the prime clean energy carriers due to its high energy density and a zero emission of CO_(2).A possible solution for the transport of H_(2)in a safe and low-cost way is in the form of liquid organic hydrogen carriers(LOHCs).As an alternative to loading LOHC with H_(2)via a two-step procedure involving preliminary electrolytic production of H_(2)and subsequent chemical hydrogenation of the LOHC,we explore here the possibility of electrochemical hydrogen storage(EHS)via conversion of proton of a proton donor into a hydrogen atom involved in covalent bonds with the LOHC(R)via a protoncoupled electron transfer(PCET)reaction:2nH^(+)+2ne^(-)+Rox■n H_(2)^(0)Rred.We chose 9-fluorenone/fluorenol(Fnone/Fnol)conversion as such a model PCET reaction.The electrochemical activation of Fnone via two sequential electron transfers was monitored with in-situ and operando spectroscopies in absence and in presence of different alcohols as proton donors of different reactivity,which enabled us to both quantify and get the mechanistic insight on PCET.The possibility of hydrogen extraction from the loaded carrier molecule was illustrated by chemical activation.
基金ARC Centre of Excellence for Future Low-Energy Electronics Technologies(FLEET)Collaborative Innovation Center of Suzhou Nano Science&Technology+3 种基金Jiangsu Provincial Research Scheme of Natural Science for Higher Education Institutions,Grant/Award Number:19KJB510056the Natural Science Foundation of Jiangsu Province of China,Grant/Award Number:BK20190815the 333 program,Grant/Award Number:BRA2019061National Natural Science Foundation of China,Grant/Award Numbers:11804084,12074104,62075061,61905171,51873138。
文摘Plasmonic metal electrodes with subwavelength nanostructures are promising for enhancing light harvesting in photovoltaics.However,the nonradiative damping of surface plasmon polaritons(SPPs)during coupling with sunlight results in the conversion of the excited hot-electrons to heat,which limits the absorption of light and generation of photocurrent.Herein,an energy recycling strategy driven by hotelectron emission for recycling the SPP energy trapped in the plasmonic electrodes is proposed.A transparent silver-based plasmonic metal electrode(A-PME)with a periodic hexagonal nanopore array is constructed,which is combined with a luminescent organic emitter for radiative recombination of the injected hot-electrons.Owing to the suppressed SPP energy loss via broadband hot-electron emission,the A-PME achieves an optimized optical transmission with an average transmittance of over 80%from 380 to 1200 nm.Moreover,the indium-tin-oxide-free organic solar cells yield an enhanced light harvestingwith a power conversion efficiency of 16.1%.