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The sol–gel method based on the rapid pyrolysis process was adopted to prepare Ni1−x Cu x O (x = 0–0.1) films on glass substrates. The effects of Cu doping on the structural, morphological, electrical and optical properties of the films were characterised by X-ray diffractometer, scanning electron microscope, Hall effect instrument and ultraviolet-visible spectrophotometer, respectively. The NiO-based films have a cubic rock salt structure and it was found that the film with x = 0.06 should have minimal residual stress. The transmittance and bandgap of the films decreased with increasing Cu-doping concentration. In addition, the compactness of the films increased along with the increase of Cu-doping concentration as a whole. The carrier concentration of the films was almost invariable, but the carrier mobility was determined by the competition between the effects of the morphology and the ionised impurity scattering. The resistivity of the films first decreases and then increases, and the minimum resistivity was 182.1 Ω cm at x = 0.06.

Objective To ascertain the biomechanical effects of a degenerated L4 -L5 segment on the lower lumbar spine through a comprehensive simulation of disc degeneration. Methods A three-dimensional nonlinear finite element model of a normal L3 -S1 lumbar spine was constructed and validated. This normal model was then modified such that three degenerated models with different degrees of degeneration (mild, moderate, or severe) at the L4 -L5 level were constructed. While experiencing a follower compressive load (500 N), hybrid moment loads were applied to all models to determine range of motion (ROM), intradiscal pressure (IDP), maximum von Mises stress in the annulus, maximum shear stress in the annulus, and facet joint force. Results As the degree of disc degeneration increased, the ROM of the L4 -L5 degenerated segment declined dramatically in all postures (flexion: 5.79°-1.91°; extension: 5.53°-2.62°; right lateral bending: 4.47°-1.46°; left lateral bending: 4.86°-1.61°; right axial rotation: 2.69°-0.74°; left axial rotation: 2.69°-0.74°), while the ROM in adjacent segments increased (1.88°-8.19°). The largest percent decrease in motion of the L4 -L5 segment due to disc degeneration was in right axial rotation (75%), left axial rotation (69%), flexion (67%), right lateral bending (67%), left lateral bending right (67%), and extension (53%). The change in the trend of the IDP was the same as that of the ROM. Specifically, the IDP decreased (flexion: 0.592-0.09 MPa; extension: 0.678-0.334 MPa; right lateral bending: 0.498-0.205 MPa; left lateral bending: 0.523-0.272 MPa; right axial rotation: 0.535-0.246 MPa; left axial rotation: 0.53-0.266 MPa) in the L4 -L5 segment, while the IDP in adjacent segments increased (0.511-0.789 MPa). The maximum von Mises stress and maximum shear stress of the annulus in whole lumbar spine segments increased (L4 -L5 segment: 0.413-2.626 MPa and 0.412-2.783 MPa, respectively; adjacent segment of L4 -L5 : 0.356-1.493 MPa and 0.359-1.718 MPa, respectively) as degeneration of the disc progressively increased. There was no apparent regularity in facet joint force in the degenerated segment as the degree of disc degeneration increased. Nevertheless, facet joint forces in adjacent healthy segments increased as the degree of disc degeneration increased (extension: 49.7-295.3 N; lateral bending: 3.5-171.2 N; axial rotation: 140.2-258.8 N). Conclusion Degenerated discs caused changes in the motion and loading pattern of the degenerated segments and adjacent normal segments. The abnormal load and motion in the degenerated models risked accelerating degeneration in the adjacent normal segments. In addition, accurate simulation of degenerated facet joints is essential for predicting changes in facet joint loads following disc degeneration.

Layered perovskite films, composed of two-dimensional (2D) Ruddlesden-Popper perovskites (RPPs), show improved stability compared to their conventional three-dimensional (3D) counterparts in perovskite solar cells (PSCs). However, 2D PSCs exhibit a lower power conversion efficiency (PCE), which has been attributed to compositional inhomogeneity and nonuniform alignment of the 2D perovskite phases. Methylammonium chloride (MACl) has been adopted as an additive to improve the PCE and the operational stability of 2D PSCs, although the role of MACl in performance enhancement is unclear. In this work, time- and spatially resolved fluorescence and absorption techniques have been applied to study the composition and charge carrier dynamics in MACl-doped BA2MA4Pb5I16 (⟨n⟩ = 5) layered perovskite films. The inhomogeneous phase orientation distribution in the direction orthogonal to the substrate for undoped layered perovskite films undergoes reorganization upon MACl doping. Based on structural and crystallographic analyses, it is revealed that MACl can facilitate the crystallization of small-n 2D perovskite phases at the cost of consuming an increased amount of BA cations. Consequently, an increase in the thickness of large-n 2D perovskite phases accompanies their enhanced perpendicular alignment ([101] crystalline orientation) to the substrate, which facilitates charge carrier transport and collection by electrodes. The defect passivation of the MACl-doped layered perovskite film provided by the small-n phase is also beneficial to the photovoltaic performance of the PSC device. A maximum PCE (∼14.3%) was achieved at 6 mol % MACl doping, with this optimum level influenced by the increased interfacial roughness of the layered perovskite film caused by the edges of small-n perovskite flakes emerging on the front surface.

SAPO-11 molecular sieves were modified with different Ni contents by the in situ modification method. The Ni-modified SAPO-11 molecular sieves were used as the supports to prepare the corresponding NiW-supported catalysts for the hydroisomerization of n-hexadecane. The Ni-modified SAPO-11 and the corresponding NiW-supported catalysts were characterized by X-ray diffraction, scanning electron microscopy, N2 adsorption–desorption, NH3-temperature-programmed desorption, pyridine adsorbed infrared, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. The results showed that Ni in situ modification preserved the crystal structure of SAPO-11; increased the BET specific surface area, mesopore volume, and medium and strong Brønsted acid amount of SAPO-11; and increased the stacking number of the active phase of the catalysts. 3Ni-SAPO-11 possessed the largest BET specific surface area, mesopore volume, and medium and strong Brønsted acid amount. NiW/3Ni-SAPO-11 possessed the highest dispersion of the active phase and the highest sulfidation degree of the active metals. The results of the hydroisomerization of n-hexadecane showed that Ni in situ modification improved the catalytic activity and selectivity of the catalysts for the hydroisomerization of n-hexadecane to varying degrees. Especially, NiW/3Ni-SAPO-11 had the highest catalytic activity and isomer selectivity, and the maximum yield of isomeric hexadecane could reach 71.18%.

The performance degradation of organic photovoltaics is one of the main limitations to their commercialization, especially an initial, rapid degradation-period, termed as a burn-in loss. Herein, we demonstrate that burn-in loss is caused by the presence of thermodynamically unstable mixed-amorphous phase in the active layer. By using a combination of grazing incidence small angle X-ray scattering and photophysical process experiments, we observe that [6,6]-Phenyl C61 butyric acid methyl ester (PC61BM) molecules rapidly move from the finely-mixed amorphous regimes into crystalline or ordered regimes under accelerated conditions (ISOS-D-2 protocol), resulting in a fast short circuit current (Jsc) burn-in loss. Following an ultraviolet radiation (UV) light processing to control amorphous phase, the kinetics of thermally induced PC61BM crystallization can be slowed down due to the formation of the photo-induced PC61BM dimers in the active layer leading to a smaller burn-in loss. In the case of UV irradiated films, even if the molecules migrated out of amorphous phase, the PC61BM-rich phase becomes loose, rather than the compact and sphere-shaped aggregation, which has been observed in pristine films. These analyses reveal the evolution of thermodynamically unstable amorphous phases eventually leading to a decline power conversion efficiency within a short period of time. The results provide a further design basis of organic photovoltaic materials with good thermal stability and high efficient simultaneously.

The composition ratio of donor and acceptor materials in organic bulk heterojunction (BHJ) is one of the key parameters to govern the performance in organic solar cells (OSCs). Therefore, high-performance non-fullerene organic bulk heterojunction consisting of poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene))-co-(1,3-di(5-thiophene-2-yl)–5,7-bis(2-ethylhexyl) benzo[1,2-c:4,5-c′]dithiophene-4,8-dione)] (PBDB-T) and 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))–5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′]-dithiophene (ITIC) are used to investigate the correlation among various donor: acceptor (D:A) ratios, photophysical properties and photovoltaic performance. Interestingly, the function of short-circuit current (Jsc) and D:A ratios demonstrates an axisymmetric trend. When the blending ratio of D:A deviates from the optimal ratio, the symmetrically decreased Jsc is derived from a reduction in the D:A interface or amorphous region. Research on the steady-state photoluminescence (PL), the time-resolved fluorescence spectroscopy measurements, atomic force microscopic (AFM) and grazing-incidence small angle X-rays scattering (GIWAXS) indicates no significant variation in energy loss in the process of changing D:A ratios in BHJs. With high donor or acceptor content, the domain size improves significantly, but the distance of π-π stacking corresponding to molecular packing has not changed significantly, and the bi-continuous percolation pathways were not obviously influenced.

Recombination energy loss is the main impediment on improving the power conversion efficiency of organic solar cells (OSCs). The pernicious effect is usually induced by two dynamics, that is, the g...

Aiming at extending the photoresponse range of the photodetectors based on Poly(3-hexylthiophene-2,5-diyl): [6,6]-Phenyl C71 butyric acid methyl ester (P3HT: PCBM) host system, Poly [(5,6-difluoro-2,1,3-benzothiadiazole-4,7-diyl)-alt-(3,3‴-di(2-octyldodecyl)-2,2’;5’,2’’;5’’,2‴-quaterthiophen-5,5‴-diyl)] (PffBT4T-2OD) with wide spectral response range, proper energy levels and high crystallinity was integrated to fabricate ternary organic photodetectors. The PffBT4T-2OD introduces energy cascade and Forster resonance energy transfer (FRET) effect from P3HT to PffBT4T-2OD, which contributes to the photocurrent generation. Furthermore, PffBT4T-2OD creates films with desirable crystallinity to produce a favorable morphology resulting in the apparent d-spacing decrement of π-π stacking of P3HT: PCBM, which probably increases the intermolecular charge hopping efficiency. The optimal photodetector shows high on/off ratio of 6.7 × 104 with a broad spectral response from 300 nm to 800 nm via incorporating 15 wt% PffBT4T-2OD into polymer bulk heterojunction, which is an obvious improvement compared with the 2.6 × 104 on/off ratio of P3HT: PCBM. This work indicates that FRET and morphology optimization have a profound effect on photoresponse and electrical properties of organic photodetectors.

In solution-processed small molecule organic solar cells (SM-OSCs), morphology of the active layer is a critically important factor in determining photovoltaic performance improvements, which needs to be optimized by more effective morphology modulation approaches. Herein, a medium bandgap conjugated polymer, namely poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)-benzo[1,2-b:4,5-b′]dithiophene))-alt -(5,5-(1′,3′-di-2-thienyl-5′,7′-bis(2-ethylhexyl)benzo[1′,2′-c:4′,5′-c′]dithio-phene-4,8-dione))] (PBDB-T), as a morphology regulator was incorporated into the dominating binary SM system comprising of (2,2′-((5Z,5′Z)-5,5′-((3,3‴,3′′′′,4′-tetraoctyl-[2,2′:5′,2′′:5″,2‴:5‴,2′′′′-quinquethio-phene]-5,5′′′′-diyl)bis(methanyly-lidene))bis(3-ethyl-4-oxothiazoli-dine-5,2-diylidene))dimalononitrile) (DRCN5T) donor and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) acceptor to fabricate efficient ternary devices. The PBDB-T not only exhibits the better compatibility and miscibility with DRCN5T but also modulates the crystallinity and molecular arrangement of blend films, which is beneficial to enhance the charge carrier mobility to yield the higher fill factor. Photophysical investigations demonstrate that charge transfer and Forster resonance energy transfer processes coexist between PBDB-T and DRCN5T, which enables the higher short-circuit current density to bring about the efficiency improvements in ternary devices. In addition, the relationship between underlying operating mechanisms and nanoscale morphology evolution is systematically studied. Based on the interwined multi-working mechanisms involving energy transfer and two distinct charge transfer manners associated with microstructure, a 22.1% increase of the PCE was obtained for the ternary devices. These results indicate that selecting the compatible and miscible polymer donor as the third component for SM:fullerene based binary system should be an effective method for morphology optimization to further achieve high performance ternary OSCs.

The crystallinity of non-fullerene acceptors as the third component has an important role on nanomorphology optimization and charge transfer dynamics of ternary organic solar cells (OSCs). Herein, efficient ternary OSCs were fabricated by incorporating two typical non-fullerene acceptors with different crystallinity, (Z)-5-{[5-(15-{5-[(Z)-(3-Ethyl-4-oxo-2-thioxo-1,3-thiazolidin-5-ylidene)methyl]-8-thia-7.9-diazabicyclo [4.3.0] nona-1 (9),2,4,6-tetraen-2-yl}-9,9,18,18-tetrakis (2-ethylhexyl)-5.14-dithiapentacyclo [10.6.0.03,10.04,8.013,17]octadeca-1(12),2,4(8),6,10,13 (17),15-heptaen-6-yl)-8-thia-7.9-diazabicyclo [4.3.0]nona-1 (9),2,4,6-tetraen-2-yl]methylidene}-3-ethyl-2-thioxo-1,3-thiazolidin-4-one (EH-IDTBR) or (5Z, 5′Z)-5,5'-((7,7'-(4,4,9,9-tetraoctyl-4,9-dihydro-s-indaceno [1,2-b:5,6-b']dithiophene-2,7-diyl)bis (benzo [c][1,2,5]thiadiazole7,4diyl)) bis(methanylylidene))bis (3-ethyl-2-thioxothiazolidin-4-one) (O-IDTBR), into the host donor/acceptor active layers comprising of poly (3-hexythiophene-2,5-diyl) (P3HT) and [6,6]-phenyl-C71-butyric acid methylester (PC71BM). As a result, the 21.5% and 22.7% increase of the power conversion efficiency (PCE) for the two ternary systems were achieved, respectively, which was attributed to the enhanced light harvesting capability, optimized bulk-heterojunction morphology and the formation of cascade energy level alignments that could introduce an additional pathway for efficient charge transfer. Although both the short-circuit current density (Jsc) and fill factor (FF) values were increased significantly by regulating the weight ratios of non-fullerene acceptors of two ternary systems, the O-IDTBR-based ternary OSCs showed the higher Jsc while P3HT:EH-IDTBR:PC71BM system exhibited the higher FF values. The main difference of improved photovoltaic performance in the two ternary systems could be associated with the different blend morphology and charge carrier mobilities. In addition, nanomorphology studies suggested that lamellar stacking coherence lengths of P3HT in face-on orientation for EH-IDTBR- and O-IDTBR-based systems can be increased from 18.48 nm to 20.94 nm and 21.67 nm respectively, resulting from the stronger crystallinity of O-IDTBR than that of EH-IDTBR, which was beneficial for charge transport in the vertical direction. These results indicate that selecting the appropriate crystalline non-fullerene acceptors may be an effective strategy to optimize nanomorphology to further achieve high efficiency ternary OSCs.

Achieving high-efficiency thick-film bulk heterojunction (BHJ) organic solar cells (OSCs) with thickness-independent power conversion efficiencies (PCEs) in a wide thickness range is still a challenge for the roll-to-roll printing techniques. The concept of diluting the transport sites within BHJ films with insulating polymers can effectively eliminate charge trapping states and optimize the charge transport. Herein, we first adopted the concept with insulating polypropylene (PP) in the efficient non-fullerene system (PM6:Y6) and demonstrated its potential to fabricate thick-film OSCs. The PP can form an insulating matrix prior to PM6 and Y6 within the BHJ film, resulting in an enhanced molecular interaction and isolated charge transport by expelling Y6 molecules. We thus observed reduced trap state density and improved charge transport properties in the PP-blended device. At around 300 nm, the PM6:Y6:PP device enjoys a high PCE of 15.5% and achieves over 100% of the efficiency of the optimal thin-film device, which is significantly improved compared to the binary PM6:Y6 counterpart. This research promotes an effective strategy with insulating polymers and provides knowledge of commercial production with response to the roll-to-roll technique demands.

Carbon nanotubes are reported as good candidates for carrier transport layers and electrodes in perovskite optoelectronics owing to their outstanding electronic and mechanical properties. In this work, perovskite and carbon nanotubes composites were fabricated by a facile solution method serving as the active layer in perovskite devices. The charge transfer mechanism between the perovskite and carbon nanotubes is different among three kinds of carbon nanotubes with different diameter. The addition of carbon nanotubes would not change the crystalline property of perovskite. Charge transfer from perovskite to carbon nanotubes at the interface was observed by spatially and temporally resolved fluorescence measurements. Carbon nanotubes serve as the effective charge transport pathways to improve the performance of photodetector by reducing the grain boundaries and pinholes in perovskite.

Binary and ternary organic nanoparticles (NPs) comprising 7,7-(4,4-bis(2-Ethylhexyl)-4H-silolo [3,2-b:4,5-b′]dithiophene-2,6-diyl)bis (6-fluoro-4-(5′-hexyl-[2,2′-bithiophen]-5-yl)benzo-[c] [1,2,5]thiadiazole) (p-DTS(FBTTH2)2), poly (3-hexylthiophene) (P3HT) or/and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) were prepared by precipitation method. The formation of the organic NPs is confirmed by the atomic force microscope (AFM). The absorption spectra show that the blended organic NPs display increased interchain interactions compared to the polymer blends dissolved in the solution. The processes of exciton separation and charge transfer in the organic NPs have been investigated using time-resolved photoluminescence (TRPL) spectroscopy and anisotropy measurements. The results demonstrate that the charge transfer efficiency is improved in the NPs in comparison with that in solution, due to the enhanced interchain interactions and intimate contact between the donor and acceptor materials in NPs. Due to Forster resonance energy transfer (FRET) between P3HT and p-DTS(FBTTH2)2, the photodetectors with ternary NPs in the active layers exhibit improved on/off ratios and enhanced detectivity compared with the binary system, demonstrating the promising applications of organic NPs in the ecofriendly fabrication of organic optoelectronic devices.

Thermally induced fullerene aggregation restricts the long-term stability in organic solar cells. Herein, we demonstrate an effective method of incorporating cross-linkable small-molecule ethoxylated (2) bisphenol-A dimethacrylate (BPA2EODMA) into poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl C61 butyric acid methyl ester (P3HT:PCBM) blends to form an insoluble framework and inhibit fullerene aggregation. The BPA2EODMA exhibits excellent heat and flexural endurance characteristics, which enhance the thermal and morphological stabilities of the active layer. By systematic research with time-resolved optical spectroscopy and microscopy, the morphological changes and charge-transfer dynamics in P3HT:PCBM blends are explored to unravel the underlying mechanisms for improved photovoltaic efficiency by incorporating the cross-linker. The power conversion efficiency (PCE) increased from 3.6 to 4.2% due to the BPA2EODMA incorporation into the active layer, which is ascribed to the enhancement of exciton dissociati...

The vertical phase distribution of components in bulk heterojunction is diversified in organic solar cells (OSCs). The electron donors (acceptors) can be accumulated (depleted) at the interface of active layer and charge extraction layer. The variation of vertical phase distribution significantly influences device performance because of its impact on the charge transport and charge recombination. In order to achieve favorable vertical phase distribution in OSCs based on poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene))-co-(1,3-di(5-thiophene-2-yl)–5,7-bis(2-ethylhexyl) benzo[1,2-c:4,5-c′]dithiophene-4,8-dione)] (PBDB-T):3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))−5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′]-dithiophene (ITIC), phenyl-C71-butyric-acid-methyl ester (PC71BM) was incorporated into the binary system to fabricate ternary OSCs. In the ternary blend, PC71BM can effectively regulate the phase distribution of PBDB-T and ITIC in vertical direction, which provides favorable vertical phase distribution for charge transport. Moreover, the addition of PC71BM can also effectively increase the π-π stacking coherence length of both donor and acceptor, which facilitates charge transport and reduces the bimolecular recombination. The addition of an appropriate quantity of PC71BM can obviously improve both fill factor and short-circuit current density of the OSC based on PBDB-T:ITIC while open-circuit voltage reduces only about 0.01 V, which indicates a rational low energy loss. Consequently, the ternary OSC exhibits a best PCE of 11.0% compared to the 9.6% PCE of the binary counterpart.

Cu2ZnSnS4 (CZTS) films applicable to an absorber material in thin film solar cells were prepared at room temperature by pulsed DC magnetron sputtering from a CZTS ceramic target, and the effects of sputtering pressure on the phase, preferred orientation and composition of the deposited CZTS films were investigated. The results indicated that the dominant phase in the deposited films was Kesterite structure, only having the trace impurity phase of Cu2−xS. The preferred orientation was gradually converted from (2 2 0) to (1 1 2) with increasing sputtering pressure. Moreover, the composition of the deposited films was also affected by the sputtering pressures.

A facile method is proposed to obtain modified shorn graphene oxide (DDAB-sGO) with improved dispersion in organic solvents. Didodecyl dimethylammonium bromide (DDAB)-sGO, which exhibits good dispersibility in the nonpolar solvent o-dichlorobenzene, was obtained via the sono-Fenton reaction and DDAB ionic functionalization. DDAB-sGO was used in the preparation of conjugated polymer:fullerene blend composites. UV–visible absorption spectra, steady-state photoluminescence spectra, fluorescence decay, and grazing incidence X-ray scattering measurements were applied to characterize morphologies, structural features, and charge-transport characteristics of the composites. Doped into poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]] (PTB7):[6,6]-phenyl C71 butyric acid methyl ester (PC71BM) conjugated polymer blends, DDAB-sGO is shown to facilitate increased crystallinity and phase separation of PTB7 and PC71BM to achieve a m...

Perovskite microplates have important implications in the fields of functional electronics and optoelectronics. We report a facile strategy, antisolvent treatment for the growth of perovskite microplates. The morphology and crystalline quality of the microplates could be controlled by the amount of the chlorobenzene antisolvent used. An appropriate amount of antisolvent facilitates the formation of high-quality perovskite microplates with no residual precursor remaining. Spatially and temporally resolved fluorescence measurements demonstrate the heterogeneity of defect-state density and recombination processes in various perovskite microplate regions. The body center shows higher defect state density when compared with that at the edge or the corner of the microplate. Excessive antisolvent degrades the microplates into smaller particles. The results of this study reveal the factors that influence the crystallization process and photophysical dynamics of perovskite microplates.

Low loss optical waveguides inside aluminosilicate glasses have been successfully fabricated using direct femtosecond laser writing. To establish the influence of pulse energy and host variations on the optical waveguides have been tentatively explored and systematically studied with the help of different spectroscopic techniques. Isochronal annealing treatment effectively reduces the insertion losses to 1.01 ± 0.28 dB at 632.8 nm. A red shift of the Raman band has been observed with increasing Al 2 O 3 content due to the bond angle variations. The point defects such as non-bridging oxygen hole centers have been corroborated by the photoluminescence studies and significant red-shift has also been documented with increasing Al 2 O 3 content. In addition, there is no NBOHC defects perceived after isochronal annealing treatment inside the glass waveguides. Our results envisage that the present glass waveguides should be promising and potential for applications in passive waveguides and integrated photonic devices.

Femto-second laser irradiation on P3HT:PCBM solutions have been demonstrated to have a significant impact on the conformational structures and photovoltaic performance of the resultant thin films. The crystallinity and edge-on/face-on conformations of P3HT and the aggregation of PCBM can be manipulated by controlling the wavelength (400–800 nm) and illumination duration (1–3 h) of the lasers. Grazing incidence wide- and small-angle X-ray scattering (GIWAXS and GISAXS) have been simultaneously utilized to characterize the nanostructures of the P3HT:PCBM blend films spin-cast from pristine and laser-irradiated solutions. The results show that the crystallinity, π-π* stacking and face-on conformations of P3HT can be enhanced as a result of the laser irradiation at 500 nm for 3 h. Furthermore, the diffusion and aggregation of PCBM molecules are suppressed by the photo-induced dimerization, as evidenced by the Raman spectra of the films cast from laser-irradiated PCBM solutions. The time-resolved fluorescence decay profiles show the charge transfer efficiency is improved, which may correlate to the supramolecular ordering of the polythiophene chains and the optimized phase separation in P3HT:PCBM composite. In the P3HT:PCBM active layer of the organic solar cells, more efficient charge transport and fine interpenetrating networks can be achieved due to the improved conformational microstructures. Consequently, the short-circuit current densities and power conversion efficiencies can be enhanced in organic solar cells based on the laser-irradiation processed P3HT:PCBM solutions.

The molecular packing and optical properties of exposed and buried layers (i.e. the layers at the top surface and near the substrate, respectively) were systematically studied in 6,13-Bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) films coated by spin-coated (SC) and droplet-pinned-crystallization (DPC) methods. Buried layers in both films exhibit intense photoluminescence (PL) resembling the behaviors of the molecules in dilute solution ascribing to weak π-π stacking, while the exposed layers show extremely weak PL due to strong crystallinity. Polarized excitation PL spectra demonstrate that molecular orientation of the buried layers is quasi-ordered in the film coated by DPC method and completely disordered in the film coated by SC method. Besides, the strong crystallinity of the exposed TIPS-pentacene is verified by grazing incident wide-angle X-ray scattering measurement. The distinct differences in optical and structural properties between the exposed and buried layers indicate that TIPS-pentacene films are inhomogeneous in vertical direction due to interfacial effect, which affects the performance of photodiode fabricated with both films. The understanding of the molecular packing correlated fluorescence in TIPS-pentacene films is vital for optimizing the film structure to achieve high performance organic electronic devices.

Perovskite microfibers with high crystallinity were synthesized with aqueous self-assembling method. The crystallization dynamics of perovskite were studied by in-situ X-ray diffraction, demonstrating that the optimum crystallization time is 9 h. Spatially and temporally resolved fluorescence measurement clearly shows the different recombination mechanism at the interface and bulk regions in the perovskite microfibers. The photodetector based on perovskite microfiber exhibits high photo-response sensitivity and on/off ratio due to the high crystallinity and relatively long carrier lifetime. This research will be beneficial for low-dimension perovskite synthesis and optoelectronics application.

2-Chlorophenyl isocyanate (CI) reacts with didodecyl dimethyl ammonium bromide (DDAB) functionalized graphene oxide (DDAB-GO) dispersed in ortho-dichlorobenzene under mild conditions. The CI treatment complements DDAB functionalization to further decrease the hydrophilicity of pristine GO sheets. The resulting CI–DDAB-GO exhibits improved compatibility with the conjugated polymer poly(3-hexylthiophene) (P3HT), compared to DDAB-GO. CI–DDAB-GO sheets can be homogeneously dispersed when blended with P3HT, resulting in an improved morphology compared to P3HT:DDAB-GO composites. The incorporation of CI–DDAB-GO can effectively reduce the dark current of photo-diodes based on P3HT composites, showing potential to enhance the performance of electronic devices based on conjugated polymer composites.

Mn and Ce were loaded on metal–organic frameworks (MOFs) via impregnation and in situ doping methods. The catalytic capacities of the obtained composite materials were evaluated in the selective catalytic reduction (SCR) of NO. The existing form of Mn–Ce in the MOF originates from different doping methods and its effect on the catalytic performance was investigated. Mn–Ce introduced by impregnation was deposited on the surface of the MOF and exhibited high catalytic efficiency of more than 98% from 200 °C to 300 °C. According to the results of BET, XRD, XPS, and ICP analyses, it was concluded that Mn–Ce introduced via the in situ doping method was inserted in the crystal lattice structure of the MOF, which resulted in an enlarged surface area, low Mn concentration, and poor redox property as compared to that introduced via the impregnated method. By exploring these factors, it was proven that the limited redox ability was the direct reason that resulted in the low activity of the MnCeMOF. Using thermal decomposition, the in situ doped Mn–Ce was liberated from the MnCeMOF crystal lattice and subsequently, exhibited recovered redox properties and catalytic activity. In this study, we proved that different doping methods lead to different forms of Mn–Ce in the MOF, which exhibit different redox properties and thus directly lead to different catalytic performance.

Non-fullerene ternary organic solar cells (OSCs) are new promising candidates for future applications in the area of organic photovoltaics. However, their low short-circuit current (JSC) values impede efforts at increasing their power conversion efficiency (PCE) levels. Maximizing the JSC is one of the critical elements for enabling high performances of OSCs. To improve the JSC of the non-fullerene ternary OSCs based on poly[[2,6′-4,8-di(5-ethylhexylthienyl)benzo[1,2-b:3,3-b]dithiophene][3-fluoro-2[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]]:3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′]-dithiophene (PTB7-Th:ITIC), a polymer of poly[N-9′′-hepta-decanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT) was added to the binary system. The PCDTBT was shown to embed in both PTB7-Th and ITIC, and introduced dual Forster resonance energy transfer (FRET) effects in the resulting ternary system. In addition, the PCDTBT may have decreased the molecular coherence lengths of PTB7-Th and ITIC and influenced the charge transport. Furthermore, the PCDTBT apparently also decreased the d-spacing of the π–π stacking of PTB7-Th and ITIC, which likely increased the intermolecular charge hopping efficiency. Doping an appropriate amount of PCDTBT in the system yielded an increase in the JSC from 13.89 to 16.71 mA cm−2. The increased JSC resulted in a 15% enhancement of the PCE, which indicated that introducing dual FRET effects is an effective way to enhance the JSC and thus the performance of the OSCs.

Objective: To compare biomechanical behaviors of lumbar lateral interbody fusion with and without posterior fixation. Methods: Three kinds of three-dimensional nonlinear finite element models of lumbar vertebrae (L3-S1) were developed: traditional lateral interbody fusion with bilateral pedicle 4 screws and 2 rods internal fixation; only lateral interbody fusion; intact model. The models were supported to a 500N follower load with a 7.5-N.m moment of flexion, extension,lateral bending,and rotation. The change of the range of motion (ROM) and intervertebral disc pressure (IDP) of the surgical segment and adjacent segments are compared. Results: Compared with the intact model, both surgical methods reduce the range of motion at the surgical segment in all motion modes, but have almost no effect on adjacent segments. The addition of fixation induce the further reduction of ROM in the surgical segment, and the ROM is almost 0° in all motion modes except for rotation. While for the model of only lateral interbody fusion, the ROM range from 0.4° to 2.2°. Moreover, the variation of the intervertebral disc pressure in surgery groups are extremely subtle in all the segments and all the postures. Conclusion: Compared to the only lateral interbody fusion,the traditional internal fixation with bilateral pedicle 4 screws and 2 rods for lateral interbody fusion showed more bimechanical stability of the surgical segment. The extra fixation for lumbar lateral interbody fusion is indispensable for surgeon.

Despite the importance of ice-nucleating particles (INPs) for climate and precipitation, our understanding of these particles is far from complete. Here, we investigated INPs at three coastal marine sites in Canada, two at mid-latitude (Amphitrite Point and Labrador Sea) and one in the Arctic (Lancaster Sound). For Amphitrite Point, 23 sets of samples were analyzed, and for Labrador Sea and Lancaster Sound, one set of samples was analyzed for each location. At all three sites, the ice-nucleating ability on a per number basis (expressed as the fraction of aerosol particles acting as an INP) was strongly dependent on the particle size. For example, at diameters of around 0.2 µm, approximately 1 in 106 particles acted as an INP at −25 ∘C, while at diameters of around 8 µm, approximately 1 in 10 particles acted as an INP at −25 ∘C. The ice-nucleating ability on a per surface-area basis (expressed as the surface active site density, ns) was also dependent on the particle size, with larger particles being more efficient at nucleating ice. The ns values of supermicron particles at Amphitrite Point and Labrador Sea were larger than previously measured ns values of sea spray aerosols, suggesting that sea spray aerosols were not a major contributor to the supermicron INP population at these two sites. Consistent with this observation, a global model of INP concentrations under-predicted the INP concentrations when assuming only marine organics as INPs. On the other hand, assuming only K-feldspar as INPs, the same model was able to reproduce the measurements at a freezing temperature of −25 ∘C, but under-predicted INP concentrations at −15 ∘C, suggesting that the model is missing a source of INPs active at a freezing temperature of −15 ∘C.

Two-dimensional (2D) transition metal dichalcogenides (TMDCs) are attractive for their novel physical properties. However, the photoluminescence (PL) quantum yield of TMDCs has been limited, due to their abundant defects and strong many-body effect. Here, we present a vertical energy funneling channel which is constructed in organic–inorganic heterostructures comprising MoSe2, pentacene and graphene oxide. These heterostructures show efficient PL enhancement (3.7 times) ratio of monolayer MoSe2. Besides, the PL signal is further increased as high as 4.7 times at low temperature due to reduced electron-phonon interactions and also sensitive to the gradient magnetic field. Apart from the efficient PL enhancement, the photocarrier pumping efficiency which is modulated by energy offset of top layer and external field is >130 times greater than that in isolated MoSe2. These findings focused on manipulating the efficient photocarrier transfer open up a new route to adjust the luminescent properties of monolayer TMDCs for designing future 2D material based optoelectronic devices.

Tuning molecular weight fractions is one of the most important strategies for optimizing the morphology of bulk heterojunctions (BHJs) to obtain high-performance organic solar cells. Here, we investigate the effects of molecular weight fractions on the performance of state-of-the-art PM6:Y6 BHJ solar cells. A remarkable blueshift in the photoluminescence spectra can be observed with the introduction of the PM6 component. The electroluminescent and morphological analyses indicate that this observation can be attributed to increased charge-transfer state energy and an intermolecular interaction between donor and acceptor, leading to open circuit voltage (V OC) variations in the photovoltaic device. The transient absorption spectra confirm that the optimized donor:acceptor (D:A) ratio can suppress the generation of polarons and achieve high efficiency exciton dissociation. The results of atomic force microscopy and neutron reflectometry reveal that higher acceptor contents promote the formation of a desirable interpenetrating network and enable high fill factors and short-circuit currents to be obtained.

Avascular necrosis of the femoral head (ANFH) is difficult to treat due to high pressure and hypoxia, and reduced levels of growth factors such as bone morphogenetic protein (BMP), and vascular endothelial growth factor (VEGF). We generated a novel calcium phosphate (CPC) composite scaffold, which contains BMP-VEGF-loaded poly-lactic-co-glycolic acid (PLGA) microspheres (BMP-VEGF-PLGA-CPC). The BMP-VEGF-loaded microspheres have an encapsulation efficiency of 89.15% for BMP, and 78.55% for VEGF. The BMP-VEGF-PLGA-CPC scaffold also demonstrated a porosity of 62% with interconnected porous structures, and pore sizes of 219 μm and compressive strength of 6.60 MPa. Additionally, bone marrow mesenchymal stem cells (BMSCs) were seeded on scaffolds in vitro. Further characterization showed that the BMP-VEGF-PLGA-CPC scaffolds were biocompatible and enhanced osteogenesis and angiogenesis in vitro. Using a rabbit model of ANFH, BMP-VEGF-PLGA-CPC scaffolds were implanted into the bone tunnels of core decompression in the femoral head for 6 and 12 weeks. Radiographic and histological analysis demonstrated that the BMP-VEGF-PLGA-CPC scaffolds exhibited good biocompatibility, and osteogenic and angiogenic activity in vivo. These results indicate that the BMP-VEGF-PLGA-CPC scaffold may improve the therapeutic effect of core decompression surgery and be used as a treatment for ANFH.

A novel nanocomposite of P3HT and Ag nanoparticles (Ag-P3HT) has been synthesized by laser ablation. The fluorescence wavelength of the nanocomposite can be tuned by varying the ablation duration. The steady-state emission maximum at 580 nm for pristine P3HT shows significant blueshift to wavelengths ranging from 520 to 550 nm for Ag-P3HT. NMR, FTIR and XPS spectroscopy confirm that chemical links are formed between P3HT and silver nanoparticles (NPs) in the nanocomposite. For the sample with an emission maximum at 530 nm, 1H NMR spectra indicate that 66% of the P3HT thiophene ring protons are replaced by Ag NPs. Time-resolved spectroscopy demonstrates that charge transfer efficiency increases for Ag-P3HT and this is attributed to the enhanced intimate interfacial contact between the chemically-bonded metal NPs and polymer chains. The synthetic route outlined provides a one-pot and green strategy for producing metal-organic polymeric materials, with controlled luminescence wavelengths and efficient photoinduced charge transfer that meet the requirement for developing high-performance organic light-emitting and photovoltaic devices.

Graphene derivatives have been intensively investigated as the electron transporting layer and conductive electrodes in perovskite optoelectronic devices. In this work, reduced graphene oxide (RGO) dispersed in nonpolar solvent was achieved by surfactant assisted phase transfer method. The hybrid perovskite/RGO film was prepared by antisolvent treatment. The volume ratio between perovskite and RGO solution is an important parameter that affects the perovskite device performance. The optimal ratio is 1:10 in perovskite photodetector owing to the high photocurrent and on/off ratio. However, lower or larger ratio would result in insufficient charge transfer or short circuit respectively. The spatially and temporally resolved measurements reveal the detailed charge transfer and transport process in the perovskite and RGO blends. RGO coupled with perovskite not only promotes charge transfer, but serves as the transport pathways, resulting in the improved performance of the device.

To enhance the photocatalytic activity of TiO2, a new preparation method has been proposed to synthesize the catalysts by introducing Cu-MOF as a precursor and performing a blackening process via a mixture with NaBH4 for TiO2 nanoparticles (CuO-TiO2(mb)). The results showed that the removal efficiency of xylene under ultraviolet and visible light over CuO-TiO2(mb) was 3.45 times higher than that of the catalysts prepared by impregnation of CuO on the surfaces of TiO2 (CuO-TiO2(d)) and 12.12 times higher than that of pure TiO2 nanoparticles. Analyses by the X-ray diffraction, scanning electron microscopy, and transmission electron microscopy indicated that the introduction of Cu-MOF as a precursor on the surface of the catalyst resulted in CuO-TiO2(mb) presenting a lower grain size compared with TiO2 nanoparticles and CuO-TiO2(d). The results of X-ray photoelectron spectroscopy, diffuse reflectance spectrum and photoluminescence indicated that blackening process narrowed the bind gap width and shortened the band gap from 2.95 eV to 1.32 eV, introduced the coexistence of Ti4+, Ti3+, Cu2+ and Cu+ in CuO-TiO2(mb) decreased the recombination rate of e--h+, which greatly improved the light response of CuO-TiO2(mb) under ultraviolet and visible light, resulting in the benefit to the photocatalytic reaction.

CuO films were prepared by sol-gel spin coating technique and annealed at 500 °C for different durations, where Cl− was especially introduced into preparation processes to enhance the crystallinity of the CuO films. The morphology of the prepared CuO films with monoclinic structure was compact, and the average granule size of the films was about 200 nm. The bandgap values of prepared CuO films were in the range of 1.44–1.49 eV, the carrier concentrations were in the order of 1016 cm−3, and the resistivity was in the range of 139–300 Ω·cm. All results indicated the prepared CuO films should be suitable for using as absorber candidate of thin-film solar cell.

Perylene diimide (PDI) nanowires were fabricated by saturated antisolvent pressure induced method. The antisolvent facilitates PDI molecules aggregation forming clusters because of the local supersaturation at the interface. When the cluster size reaches critical size, the antisolvent would promote clusters assembling along one-dimension gradually. The decreased decay lifetime of PDI nanowires illustrates the changeable PDI molecule conformation and decreased trap-state density. Temporally and spatially resolved fluorescence measurement reveals the uniform and ordered arrangement in individual nanowire. The π-electron delocalization along the π-π stacking direction is in favor of long-range charge migration. The applied bias on PDI nanowires enables electrons migration along the π-electron delocalization rapidly, resulting in more than 3 orders of magnitude current increment.

The surface plasmon resonance (SPR) of metallic nanomaterials, such as gold (Au) and silver (Ag), has been extensively exploited to improve the optical absorption, the charge carrier transport, and the ultimate device performances in organic photovoltaic cells (OPV). With the incorporation of diverse metallic nanostructures in active layers, buffer layers, electrodes, or between adjacent layers of OPVs, multiple plasmonic mechanisms may occur and need to be distinguished to better understand plasmonic enhancement. Steady-state photophysics is a powerful tool for unraveling the plasmonic nature and revealing plasmonic mechanisms such as the localized surface plasmon resonance (LSPR), the propagating plasmon-polariton (SPP), and the plasmon-gap mode. Furthermore, the charge transfer dynamics in the organic semiconductor materials can be elucidated from the transient photophysical investigations. In this review article, the basics of the plasmonic mechanisms and the related metallic nanostructures are briefly introduced. We then outline the recent advances of the plasmonic applications in OPVs emphasizing the linkage between the photophysical properties, the nanometallic geometries, and the photovoltaic performance of the OPV devices.

A dumbbell-shaped polyrotaxane based on polytetrahydrofuran bis (3-aminopropyl) terminated and α-cyclodextrins using polyamidoamine (PAMAM) dentrimers as bulky stoppers was successfully prepared. The1H NMR results show that the peaks of α-CDs in these polyrotaxanes are broadened compared with pure α-CDs. Wide-angle X-ray diffraction (XRD) measurements of the resulting polyrotaxanes suggest to produce a channel-type crystalline structure of inclusion complex. Thermogravimetric analysis (TGA) of the resultant polyrotaxanes show that α-CDs are significantly stabilized by the formation of the inclusion complexes.

In low-temperature SCR, corn straws pyrolysis carbon (CS) was prepared as a catalyst support and activated carbon (AC) was a comparison. Manganese (7 wt.%) was loaded respectively on this two supports (Mn/AC and Mn/CS). In 50°C~300°C SCR experiment, the highest NO conversion by using CS is 36.6 Vol.% at 300°C, while AC 37.9 Vol.% at 200°C. After loaded the manganese element, NO conversion increases with the temperature. At 300°C, Mn/AC has the highest NO conversion (81.9 Vol.%), while Mn/AC is 65.3 Vol.%. The sulfur resistance performance test shows that NO conversion decreases with the increasing of SO2 concentration. In the 400ppm SO2 fuel gas at 300°C, using Mn/CS, NO conversion reduces 16.7 Vol.%, however, using Mn/AC, it reduces 22.6 Vol.%. It is promising to apply biomass pyrolysis carbon modified catalyst.

Two catalysts (V2O5/AC and V2O5/CNTs) with different loadings, prepared by impregnation method, were used to research the DeNOx activity under N2and CO2atmospheres respecitively at the temperature range from 100°C to 300°C using a fixed bed reactor. Effects of temperature, loading and support on the DeNOx activity were studied. The results show that the NO conversion of the both catalysts increases with the reaction temperature. The loading and support have significant effects on the activities. 9%V2O5/AC and 9%V2O5/CNTs yielded 80% and 66.6% NO conversion at 250°C respectively under N2atmosphere, however, they yielded 78.1% and 75.1% respectively under CO2atmosphere.

We report nanoporous Ni, Ni–Fe, and Ni–Pt as catalysts for hydrogen generation from hydrolytic dehydrogenation of ammonia borane (NH3BH3, AB). The Ni and Ni–Fe nanoparticles with diameters of 20–25 nm were synthesized by a colloidal method in starch-containing aqueous solution. They exhibited considerable in situ catalytic performance but severely lost activity after separating from the reaction solution. Nanoporous Ni1−xPtx (x = 0.01, 0.08 and 0.19) with particle size below 5 nm was prepared from the isolated Ni nanoparticles through a replacement reaction. After centrifugation, drying, washing, and annealing, the obtained nanoporous Ni–Pt could attain remarkable activity, high hydrogen generation rate and efficiency, and low activation energy.

A series of polyimides (PIs) with various side-chain structures were prepared via copolymerization of pyromellitic dianhydride, 3,3′-dimethyl-4,4′-methylenediamine and three functional diamines: 4-(4-octyloxybenzoyloxy)biphenyl-3′,5′-diaminobenzoate (C8-BPDA), 4-octyloxybiphenyl-3′,5′-diaminobenzoate (C8-PDA) and 4-(4-butoxybenzoyloxy)biphenyl-3′,5′-diaminobenzoate (C4-BPDA). PIs derived from C8-BPDA and C4-BPDA exhibited excellent rubbing resistance in comparison with PI from C8-PDA and the pretilt angle could be controlled over 89° after rubbing. Thermogravimetric analysis showed that the thermal degradation of PIs under nitrogen atmosphere occurred above 320 °C, and PI derived from C8-BPDA showed the best thermal stability. Wide-angle X-ray diffraction patterns indicated an amorphous morphology of the PIs, and the PIs also had outstanding solubility in polar aprotic solvents. The resultant PI films were light colored and maintained high transparency in the visible light region. By increasing the rigidity of side-chains, the rubbing resistance and the thermal stability of PIs could be promoted at the same time. © 2012 Society of Chemical Industry

The aim of our study was to construct macroporous calcium phosphate bone cements (CPCs) with enhanced osteogenic potential. For this purpose, 300 mM sodium dodecyl sulfate (SDS) as an air-entraining agent was added to the liquid phase and 1, 5, and 10% simvastatin (SIM) was homogenized with the solid phase. The physical and mechanical characteristics of the test samples were investigated. Biological properties of the new CPCs were examined after intramuscular and endosteal implantation in rabbits. The introduction of SDS produced interconnected macropores and did not significantly affect initial setting time, transformation of solid phase to hydroxyapatite, and biocompatibility of CPCs. Large amounts (10 wt %) of SIM could decrease the compressive strength and induce severe muscular necrosis and inflammatory reaction. Small amounts (1 wt %) of SIM were compatible with the CPCs did not affect the physico-chemical properties or biocompatibility and were sufficient to enhance the osteogenic potential of macroporous CPCs. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:2991–3000, 2012.