Recently, air pollution has become more serious and started to have a dramatic effect on the health of humans in many large cities. Generally, outdoor personal protection,such as commercial masks, cannot effectively p...Recently, air pollution has become more serious and started to have a dramatic effect on the health of humans in many large cities. Generally, outdoor personal protection,such as commercial masks, cannot effectively prevent the inhalation of many pollutants. Particulate matter(PM) pollutants are a particularly serious threat to human health. Here we introduce a new efficient air filtration mat that can be used for outdoor protection. The new efficient air filter’s nanocomposite materials were successfully fabricated from poly(ε-caprolactone)/polyethylene oxide(PCL/PEO) using an electrospinning technique and solvent vapor annealing(SVA).SVA treatment endows the wrinkled fiber surface and enhances the PM2.5 capture capacity of protective masks. This nanowrinkled air filtration mat can effectively filter PM2.5 with a removal efficiency of 80.01% under seriously polluted conditions(PM2.5 particle concentration above 225 mg m-3).Our field test in Qinhuangdao indicated that the air filtration mat had a high PM2.5 removal efficiency under thick haze.Compared to commercial masks, the fabricated SVA-treated PCL/PEO air filter mat demonstrated a simpler and ecofriendly preparation process with excellent degradation characteristics, showing wide potential applications with a high filtration efficiency.展开更多
Solvent annealing is a facile method for changing the aggregated microstructure and physical properties of polymer materials. In this paper, we addressed the effects of solvent vapor annealing, including chloroform an...Solvent annealing is a facile method for changing the aggregated microstructure and physical properties of polymer materials. In this paper, we addressed the effects of solvent vapor annealing, including chloroform and water vapor, on the polymorphic transformation in both hot-pressed film and electrospun nonwoven of isotactic polybutene-1 （PB-1） by means of in situ Fourier transform infrared spectroscopy （FTIR）. The pretty rapid transition rate caused by the increased motion of molecular chains under chloroform vapor is associated with a lowest crystallinity. Also, a decreased crystallinity with the crystal transition occurred in electrospun nonwovens resulting from the relaxation of the stretched molecular chains into amorphous state rather than realignment into crystal form I predominating the crystal transition process.展开更多
A dual annealing method comprised of toluene vapor treatment and post thermal annealing was employed to fabricate polymer solar cells （PSCs） based on poly（3-hexylthiophene） （P3HT） and [ 6,6 J-phenyl-C61-butyric ...A dual annealing method comprised of toluene vapor treatment and post thermal annealing was employed to fabricate polymer solar cells （PSCs） based on poly（3-hexylthiophene） （P3HT） and [ 6,6 J-phenyl-C61-butyric acid methyl ester （PCBM） film. It is found that the P3HT crystallinity and chain ordering can be dramatically enhanced by this annealing process as compared with the films treated merely with solvent vapor annealing, which is verified by a higher X-ray diffraction intensity peak and clearly visible fibrillar crystalline domains of P3HT. The result suggests that a favorable e- quilibrium condition was established by dual annealing in the morphology reorganization. Due to the morphological improvement of active layer, the dually annealed PSCs show better overall perform- ances, with a mean power conversion efficiency of 4. 06% and an increase in each electrical parame- ter, than any solely annealed ones.展开更多
In this work,the synergistice efects of external electric field(EEF)and solvent vapor annealing to enhanceβ-phase and carrier mobility of poly(9,9-dioctylfuorene)(PFO)films were investigated.It is found that EEF can ...In this work,the synergistice efects of external electric field(EEF)and solvent vapor annealing to enhanceβ-phase and carrier mobility of poly(9,9-dioctylfuorene)(PFO)films were investigated.It is found that EEF can promote the PFOβ-phase conformation transition and orientate the PFO chains along the EEF direction with the as-sistance of polar solvent vapor annealing.PFO chain orderness is closely related to the solvent polarity.In particular,the B-phase content in the annealed film of strong polar chloroform vapor increases from 18.7%to 34.9%after EEF treatment.Meanwhile a characteristic needle-like crystal is formed in the flm,as a result,the hole mobility is en-hanced by an order of magnitude.The mechanism can be attributed to the fast polarization of solvent dipole under the action of EEF,thus forming a driving force that greatly facilitates the orientation of PFO dipole unit.Research also reveals that EEF driving of the PFO chains does not occur with an insoluble solvent vapor since the solvent molecules cannot swell the film,thus there is insufficient free volume for PFO chains to adjust their conformation.This research enriches the understanding of the relationship between solvent vapor annealing and EEF in orientation polymers,and this method is simple and controlled,and capable of integrating into large-area thin film process,which provides new insights to manufacture low-cost and highly ordered polymer films,and is of great significance to enhance carrier mobility and efficiency of photoelectric devices based on polymer condensed matter physics.展开更多
The nanoscale morphology within the photoactive layer of organic solar cells is critical in determining the power conversion efficiency (PCE). Here, we draw attention to the roles of molecular arrangement, and domain ...The nanoscale morphology within the photoactive layer of organic solar cells is critical in determining the power conversion efficiency (PCE). Here, we draw attention to the roles of molecular arrangement, and domain size in improving performance, which can be tuned by subjecting the photovoltaic materials to solvent vapor annealing (SVA). In our PTB7-Th:ITIC devices, the PCE can be improved by exposing the device to solvent vapor for 60 s after solution casting. The solvent vapor prolongs reorganizational time and increases molecular ordering and domain size/phase separation, which are sub-optimal in pristine PTB7-Th:ITIC blend films. This improved morphology results in better charge mobility, reduced recombination, and ultimately an improved PCE from 7.1% to 7.9% when using CS2 as the annealing solvent. This simple SVA technique can be applied to a range of OPV systems where the molecular ordering is inferior within the as-cast photoactive layer.展开更多
Optimizing the photoactive layer morphology is a simple,promising way to improve the power conversion efficiencies(PCEs)of organic solar cells(OSCs).Here,we compared different post-processing treatments on PM6:Y6 blen...Optimizing the photoactive layer morphology is a simple,promising way to improve the power conversion efficiencies(PCEs)of organic solar cells(OSCs).Here,we compared different post-processing treatments on PM6:Y6 blend films and relevant effects on device performances,including as-cast,thermal annealing and solvent annealing.This solvent annealing processes can effectively improve the vertical distribution and aggregation of polymer donors and small molecule acceptors,then optimize the active layer film morphology,ultimately elevating PCE.Thus,one of champion efficiencies of 18.01%was achieved based on the PM6:Y6 binary OSCs.In addition,a relatively high light utilization efficiency(2.53%)was achieved when a transparent electrode made of Cu(1 nm)and Ag(15 nm)was utilized to fabricate a semitransparent OSC with a remarkable PCE of 13.07%and 19.33%average visible-light transmittance.These results demonstrated that carefully optimizing morphology of active layer is conducive to achieving a high-performance OSC.展开更多
The grain boundaries and interface properties in the active layers of perovskite solar cells(PSCs)are important factors affecting the performances of the devices.In this work,a simple and fast concomitant annealing pr...The grain boundaries and interface properties in the active layers of perovskite solar cells(PSCs)are important factors affecting the performances of the devices.In this work,a simple and fast concomitant annealing process is established by inducing the secondary growth of the grains using the anti-solvent o-dichlorobenzene(o-PhCl2)or chlorobenzene(PhCl)to suppress the volatilization of solvent molecules during the FA0.80MA0.15Cs0.05Pb(I0.85Br0.15)3(FA,CH5N2+,formamidine;MA,CH3NH3+,methylamine)film annealing procedure.The effects of anti-solvent molecules on the phase transformation,grain boundary fusion and morphology evolution of perovskite films are systematically investigated by X-ray diffraction(XRD)and scanning electron microscopy(SEM).The results indicate that anti-solvent molecules can inhibit solvent evaporation in the active layers and promote crystallite dissolution and ordered secondary growth along the surfaces of large grains.That can promote the formation of large grains and the passivation of surface defects,and can be favorable for the separation and transportation of photocarriers in the active layer.Consequently,the power conversion efficiency(PCE)of PSCs can be effectively improved,with a PCE of 20.72%being achieved by a secondary growth perovskite film optimized with o-PhCl2.Moreover,the efficiency remains at 85%of its initial value after 2400 h of treatment in a natural indoor environment with a relative humidity of 45±5%.展开更多
Nanopattem transformation behaviors of polyisoprene-block-polystyrene-block-poly（2-vinylpyridine） （PI-b-PS-b-P2VP） asymmetric ABC triblock copolymer were investigated systematically with various control para- mete...Nanopattem transformation behaviors of polyisoprene-block-polystyrene-block-poly（2-vinylpyridine） （PI-b-PS-b-P2VP） asymmetric ABC triblock copolymer were investigated systematically with various control para- meters, including different solvents for polymer solution and annealing conditions in this paper. Ordered nanopattern of PI-b-PS-b-P2VP with hexagonal cylinders could be obtained when PI-b-PS-b-P2VP toluene solution was spin-coated on silicon substrate followed by toluene vapor annealing process. When the film with hexagonal and cylindrical nanopattern was exposed to saturated toluene vapor, the order-order transition of cylindrical nanopattern to parallel nanopattern was observed due to the strong selectivity of toluene to PS and PI blocks. Furthermore, fingerprint nanopattern could also be obtained by solvent annealing in tetrahydrofuran vapor. The nanopattern trans- formation was due to different selectivity of solvents and incompatibilities of the three blocks of PI-b-PS-b-P2VP under various solvent annealing conditions.展开更多
Morphology control of perovskite films is of critical importance for high-performance photovoltaic devices. Although solvent vapor annealing(SVA) treatment has been widely used to improve the film quality efficiently,...Morphology control of perovskite films is of critical importance for high-performance photovoltaic devices. Although solvent vapor annealing(SVA) treatment has been widely used to improve the film quality efficiently, the detailed mechanism of film growth is still under construction, and there is still no consensus on the selection of solvents and volume for further optimization. Here, a series of solvents(DMF, DMSO, mixed DMF/DMSO) were opted for exploring their impact on fundamental structural and physical properties of perovskite films and the performance of corresponding devices. Mixed solvent SVA treatment resulted in unique benefits that integrated the advantages of each solvent, generating a champion device efficiency of 19.76% with improved humidity and thermal stability. The crystallization mechanism was constructed by conducting grazing-incidence wide-angle x-ray diffraction(GIWAXS) characterizations, showing that dissolution and recrystallization dominated the film formation. A proper choice of solvent and its volume balancing the two processes thus afforded the desired perovskite film. This study reveals the underlying process of film formation, paving the way to producing energy-harvesting materials in a controlled manner towards energy-efficient and stable perovskite-based devices.展开更多
基金supported by the National Natural Science Foundation of China (21473153 and 51771162)Support Program for the Top Young Talents of Hebei Province+2 种基金China Postdoctoral Science Foundation (2015M580214)Research Program of the College Science & Technology of Hebei Province (ZD2018091)the Scientific and Technological Research and Development Program of Qinhuangdao City (201701B004)
文摘Recently, air pollution has become more serious and started to have a dramatic effect on the health of humans in many large cities. Generally, outdoor personal protection,such as commercial masks, cannot effectively prevent the inhalation of many pollutants. Particulate matter(PM) pollutants are a particularly serious threat to human health. Here we introduce a new efficient air filtration mat that can be used for outdoor protection. The new efficient air filter’s nanocomposite materials were successfully fabricated from poly(ε-caprolactone)/polyethylene oxide(PCL/PEO) using an electrospinning technique and solvent vapor annealing(SVA).SVA treatment endows the wrinkled fiber surface and enhances the PM2.5 capture capacity of protective masks. This nanowrinkled air filtration mat can effectively filter PM2.5 with a removal efficiency of 80.01% under seriously polluted conditions(PM2.5 particle concentration above 225 mg m-3).Our field test in Qinhuangdao indicated that the air filtration mat had a high PM2.5 removal efficiency under thick haze.Compared to commercial masks, the fabricated SVA-treated PCL/PEO air filter mat demonstrated a simpler and ecofriendly preparation process with excellent degradation characteristics, showing wide potential applications with a high filtration efficiency.
基金financially supported by the Special Foundation of Taishan Mountain Scholar Constructive Programthe National Natural Science Foundation of China(No.21174074)+3 种基金Shandong Provincical Key R&D Program(No.2015GGX102019)Shandong Provincial Natural Science Fund for Distinguished Young Scholars(No.JQ201213)the Nature Science Foundation of Shandong Province(No.ZR2013BM004)the Yellow River Delta Scholar program(Office of National University Science&Technology Park Administrative Committee(China University of Petroleum))
文摘Solvent annealing is a facile method for changing the aggregated microstructure and physical properties of polymer materials. In this paper, we addressed the effects of solvent vapor annealing, including chloroform and water vapor, on the polymorphic transformation in both hot-pressed film and electrospun nonwoven of isotactic polybutene-1 （PB-1） by means of in situ Fourier transform infrared spectroscopy （FTIR）. The pretty rapid transition rate caused by the increased motion of molecular chains under chloroform vapor is associated with a lowest crystallinity. Also, a decreased crystallinity with the crystal transition occurred in electrospun nonwovens resulting from the relaxation of the stretched molecular chains into amorphous state rather than realignment into crystal form I predominating the crystal transition process.
基金Supported by the National Natural Science Foundation of China(10904002)the Excellent Young Scholars Research Fund of Beijing Institute of Technology(2009Y0408)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry(3040036821101)
文摘A dual annealing method comprised of toluene vapor treatment and post thermal annealing was employed to fabricate polymer solar cells （PSCs） based on poly（3-hexylthiophene） （P3HT） and [ 6,6 J-phenyl-C61-butyric acid methyl ester （PCBM） film. It is found that the P3HT crystallinity and chain ordering can be dramatically enhanced by this annealing process as compared with the films treated merely with solvent vapor annealing, which is verified by a higher X-ray diffraction intensity peak and clearly visible fibrillar crystalline domains of P3HT. The result suggests that a favorable e- quilibrium condition was established by dual annealing in the morphology reorganization. Due to the morphological improvement of active layer, the dually annealed PSCs show better overall perform- ances, with a mean power conversion efficiency of 4. 06% and an increase in each electrical parame- ter, than any solely annealed ones.
基金Supported by the National Natural Science Foundation of China(Nos.91333103,21574053).
文摘In this work,the synergistice efects of external electric field(EEF)and solvent vapor annealing to enhanceβ-phase and carrier mobility of poly(9,9-dioctylfuorene)(PFO)films were investigated.It is found that EEF can promote the PFOβ-phase conformation transition and orientate the PFO chains along the EEF direction with the as-sistance of polar solvent vapor annealing.PFO chain orderness is closely related to the solvent polarity.In particular,the B-phase content in the annealed film of strong polar chloroform vapor increases from 18.7%to 34.9%after EEF treatment.Meanwhile a characteristic needle-like crystal is formed in the flm,as a result,the hole mobility is en-hanced by an order of magnitude.The mechanism can be attributed to the fast polarization of solvent dipole under the action of EEF,thus forming a driving force that greatly facilitates the orientation of PFO dipole unit.Research also reveals that EEF driving of the PFO chains does not occur with an insoluble solvent vapor since the solvent molecules cannot swell the film,thus there is insufficient free volume for PFO chains to adjust their conformation.This research enriches the understanding of the relationship between solvent vapor annealing and EEF in orientation polymers,and this method is simple and controlled,and capable of integrating into large-area thin film process,which provides new insights to manufacture low-cost and highly ordered polymer films,and is of great significance to enhance carrier mobility and efficiency of photoelectric devices based on polymer condensed matter physics.
基金supported by the Natural Science Foundation of Hubei Province (Grant no. 2018CFA055)the National Natural Science Foundation of China (Grants no. 21774097)
文摘The nanoscale morphology within the photoactive layer of organic solar cells is critical in determining the power conversion efficiency (PCE). Here, we draw attention to the roles of molecular arrangement, and domain size in improving performance, which can be tuned by subjecting the photovoltaic materials to solvent vapor annealing (SVA). In our PTB7-Th:ITIC devices, the PCE can be improved by exposing the device to solvent vapor for 60 s after solution casting. The solvent vapor prolongs reorganizational time and increases molecular ordering and domain size/phase separation, which are sub-optimal in pristine PTB7-Th:ITIC blend films. This improved morphology results in better charge mobility, reduced recombination, and ultimately an improved PCE from 7.1% to 7.9% when using CS2 as the annealing solvent. This simple SVA technique can be applied to a range of OPV systems where the molecular ordering is inferior within the as-cast photoactive layer.
基金supported by the National Science Fund for Distinguished Young Scholars(21925506)the National Natural Science Foundation of China(U21A20331,51773212,81903743,51875384)+2 种基金Ningbo S&T Innovation 2025 Major Special Programme(2018B10055)CAS Key Project of Frontier Science Research(QYZDBSSW-SYS030)Ningbo Natural Science Foundation(2021J192)。
文摘Optimizing the photoactive layer morphology is a simple,promising way to improve the power conversion efficiencies(PCEs)of organic solar cells(OSCs).Here,we compared different post-processing treatments on PM6:Y6 blend films and relevant effects on device performances,including as-cast,thermal annealing and solvent annealing.This solvent annealing processes can effectively improve the vertical distribution and aggregation of polymer donors and small molecule acceptors,then optimize the active layer film morphology,ultimately elevating PCE.Thus,one of champion efficiencies of 18.01%was achieved based on the PM6:Y6 binary OSCs.In addition,a relatively high light utilization efficiency(2.53%)was achieved when a transparent electrode made of Cu(1 nm)and Ag(15 nm)was utilized to fabricate a semitransparent OSC with a remarkable PCE of 13.07%and 19.33%average visible-light transmittance.These results demonstrated that carefully optimizing morphology of active layer is conducive to achieving a high-performance OSC.
基金the National Natural Science Foundation of China(21676188)the Science and Technology Plan Project of Tianjin(19ZXNCGX00020)the National Key R&D Program of China(2016YFB0401303)。
文摘The grain boundaries and interface properties in the active layers of perovskite solar cells(PSCs)are important factors affecting the performances of the devices.In this work,a simple and fast concomitant annealing process is established by inducing the secondary growth of the grains using the anti-solvent o-dichlorobenzene(o-PhCl2)or chlorobenzene(PhCl)to suppress the volatilization of solvent molecules during the FA0.80MA0.15Cs0.05Pb(I0.85Br0.15)3(FA,CH5N2+,formamidine;MA,CH3NH3+,methylamine)film annealing procedure.The effects of anti-solvent molecules on the phase transformation,grain boundary fusion and morphology evolution of perovskite films are systematically investigated by X-ray diffraction(XRD)and scanning electron microscopy(SEM).The results indicate that anti-solvent molecules can inhibit solvent evaporation in the active layers and promote crystallite dissolution and ordered secondary growth along the surfaces of large grains.That can promote the formation of large grains and the passivation of surface defects,and can be favorable for the separation and transportation of photocarriers in the active layer.Consequently,the power conversion efficiency(PCE)of PSCs can be effectively improved,with a PCE of 20.72%being achieved by a secondary growth perovskite film optimized with o-PhCl2.Moreover,the efficiency remains at 85%of its initial value after 2400 h of treatment in a natural indoor environment with a relative humidity of 45±5%.
基金Supported by the National Natural Science Foundations of China（Nos.51273048, 51203025） and the Natural Science Foundation of Guangdong Province, China（No.S2012040007725）.
文摘Nanopattem transformation behaviors of polyisoprene-block-polystyrene-block-poly（2-vinylpyridine） （PI-b-PS-b-P2VP） asymmetric ABC triblock copolymer were investigated systematically with various control para- meters, including different solvents for polymer solution and annealing conditions in this paper. Ordered nanopattern of PI-b-PS-b-P2VP with hexagonal cylinders could be obtained when PI-b-PS-b-P2VP toluene solution was spin-coated on silicon substrate followed by toluene vapor annealing process. When the film with hexagonal and cylindrical nanopattern was exposed to saturated toluene vapor, the order-order transition of cylindrical nanopattern to parallel nanopattern was observed due to the strong selectivity of toluene to PS and PI blocks. Furthermore, fingerprint nanopattern could also be obtained by solvent annealing in tetrahydrofuran vapor. The nanopattern trans- formation was due to different selectivity of solvents and incompatibilities of the three blocks of PI-b-PS-b-P2VP under various solvent annealing conditions.
基金supported by the National Natural Science Foundation of China (Grant Nos. 21734009, 51473009, 21225209, 91427303, and 61805138)Portions of this research were carried out at beamline 7.3.3 at the Advanced Light Source,Molecular Foundry,Lawrence Berkeley National Laboratory,which was supported by the DOE,Office of Science,and Office of Basic Energy Sciences。
文摘Morphology control of perovskite films is of critical importance for high-performance photovoltaic devices. Although solvent vapor annealing(SVA) treatment has been widely used to improve the film quality efficiently, the detailed mechanism of film growth is still under construction, and there is still no consensus on the selection of solvents and volume for further optimization. Here, a series of solvents(DMF, DMSO, mixed DMF/DMSO) were opted for exploring their impact on fundamental structural and physical properties of perovskite films and the performance of corresponding devices. Mixed solvent SVA treatment resulted in unique benefits that integrated the advantages of each solvent, generating a champion device efficiency of 19.76% with improved humidity and thermal stability. The crystallization mechanism was constructed by conducting grazing-incidence wide-angle x-ray diffraction(GIWAXS) characterizations, showing that dissolution and recrystallization dominated the film formation. A proper choice of solvent and its volume balancing the two processes thus afforded the desired perovskite film. This study reveals the underlying process of film formation, paving the way to producing energy-harvesting materials in a controlled manner towards energy-efficient and stable perovskite-based devices.
