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The manufacture of ambient roll-to-roll (R2R) slot-die-coated organic photovoltaic (OPV) is the basis toward commercialization of OPV. The low-cost large-area encapsulation technique of stability improvement of flexible OPV module is under-investigated. The related reports on flexible encapsulation up-scaled from cell were limited. The present study develops an effective and easy encapsulation method and architecture design based on the inverted structure of ambient R2R slot-die-coated PET/ITO/ZnO/active layer/hole transport layer (HTL)/Ag. All module areas are greater than 48 cm2. The P3HT:PCBM and PV2000:PC71BM adopted as active layers have the performance conversion efficiencies of modules of 1–2.2% and 4.2%, respectively. The thermally-deposited MoO3 and slot-die-coated PEDOT:PSS HTLs are used to compare the effect of HTL on T80 lifetime of the large-area flexible R2R module under the accelerated test. The accelerated stability tests regarding to different encapsulation architectures, including damp-heat and light soaking stresses, were conducted. The intrinsic and extrinsic degradation effects are analyzed. We develop the simple encapsulation design effectively suppressing the lateral ingress of oxygen and moisture. The T80 lifetime of P3HT:PCBM-based module can be improved to be 1500 h under the damp-heat test (65 °C/65% RH). The T80 lifetime of PV2000:PC71BM-based module can last for 7000 h under the dark and ambient environment (30 °C/50 ± 20% RH).

Efficient and low-cost electrode materials for the electrochemiluminescence (ECL) reaction are highly desired for the future detection technology. Herein, we report an efficient bottom-up pathway to synthesize phosphorus-doped graphitic carbon nitride nanosheets (PCNNs) by ultra-rapid microwave irradiation. When the melamine precursor is modified with a 5 wt% diammonium hydrogen phosphate, the as-synthesized PCNNs display a very thin thickness (about 2 nm), good dispersibility in water (still stable after 2 weeks), low electron-transfer resistance (7499 Ω) and suitable band gap (2.7 eV). More importantly, the ECL intensity of the optimal PCNNs at low potential (− 1.2 to 0 V) is 26.7 times stronger than that of pure graphitic carbon nitride. The key to the excellent ECL property primarily lies in the more satisfactory sheet-like structure, faster electron transfer and better water affinity.

The aim of this study is to mitigate the loss of performance of organic photovoltaics when the device area is increased. We propose that performance reduction is a result of the poor transverse charge transport due to defects in the electron transport layer and the resistance of the transparent electrode. We modified the surface of a zinc oxide (ZnO) with ethoxylated polyethylenimine and successfully lowered the performance reduction from 30% to 15% based on two electron transport layers of ZnO and ethoxylated polyethylenimine (PEIE)-modified ZnO (ZnO/PEIE bilayer and ZnO:PEIE hybrid layer). We also deposited Ag grids on the indium-tin-oxide (ITO) substrate to facilitate transverse charge transport in the ITO.

Using high-angle-annular-dark-field (HAADF) scanning-transmission-electron microscopy (STEM), we have investigated η-precipitates in the Al-Zn-Mg-Cu (AA7050) aluminium alloy. The HAADF STEM images taken along the zone axes of [10 1 ¯ 0]η, [1 2 ¯ 10]η, and [0001]η illustrated the projected atomic-scale configurations of η-MgZn2 crystal. The precipitates developed in layer-by-layer growth, supplied with precursors such as Zn, Cu, and Mg, which were solute atoms segregated around the η/Al interfaces due to the higher lattice strain energy. Stacking faults and defect layers composed of flattened hexagons were frequently observed along the zone axes of [1 2 ¯ 10]η and [10 1 ¯ 0]η, respectively, and their formation was elucidated, similarly taking into account the layer-by-layer growth. Occasional coalescence between two precipitates yielded a complicated boundary or a twin-like boundary. Based on the differences in orientation relationships between η-types and the Al matrix reported to date, two new types of η precipitates have been recognized and named η4' and η12.

In this study, we focus on the analysis of thermal burn-in degradation behavior of organic photovoltaics (OPVs) at 85 °C under nitrogen atmosphere. In this thermal aging as the accelerated test, the thermal burn-in loss (initially rapid drop) in the power conversion efficiency (PCE) of the inverted OPV devices based on ITO/ZnO/PTB7:PC71BM/MoO3/Ag was shown over 40% PCE reduction. We systematically investigate the effects of bulk heterojunction structure and Ag electrode on thermal degradation. Moreover, we adopt two device architectures to investigate the effect of contact between the charge carrier transport layer and active layer on thermal burn-in loss. The degradation mechanism and origin of thermal burn-in loss induced by the evaporated MoO3 molecules or charge traps are proposed for the first time. The impedance analysis was conducted to verify the mechanism. Insight into the burn-in mechanism will be helpful for developing OPV fabrication strategies and designs to effectively reduce the thermal burn-in loss. The conventional OPV with the structure of ITO/MoO3/PTB7:PC71BM/ZnO/Ag remains ∼94% of its initial PCE after 500 h of thermal aging at 85 °C.

A novel non-porous separator that possesses an outstanding lithium transference number (0.92) and effectively suppresses lithium dendrite formation upon lithium deposition is developed. The separator is made of triblock copolymer poly(styrene-block-isoprene-block-sulfonated isoprene) bearing pendant lithium sulfonates and, while taking up only 30 wt% liquid electrolyte (1 M Lithium hexafluorophosphate in ethylene carbonate/diethyl carbonate/ethyl methyl carbonate (v/v/v = 4/3/3)), it allows a high ion conductivity of 10−4 S cm−1. With good mechanical strength and processing feasibility, the new non-porous separator is shown to enable dendrite-free lithium electro-deposition and stripping with flat overpotential profiles upon prolonged galvanostatic cycling of the lithium symmetrical cells in the carbonate-based electrolyte.

The synchrotron small-angle X-ray scattering (SAXS) technique was used to reveal the evolution and growth kinetics of nano-precipitates (ppts) of severely cold-rolled CoCrFeMnNi high-entropy alloy aged at 350–500 °C for different times. The nano-ppts in the as cold-rolled alloy have a radius of ∼1.2 nm, grow drastically in the early 30 min of aging at 500 °C, and reach the saturation stage at 60 min aging. The rapid increase in the size/volume fraction of the nano-ppts with the aging time is also quantitatively correlated with significant precipitation hardening, as indicated by measurements of the corresponding hardness and tensile stress-strain curve. TEM observation of the specimen aged at 500 °C for 60 min reveals many homogeneously distributed nano-ppts in the matrix, which have a radius of 2.0–2.5 nm.

The MgLiAlZn (LAZ1110) magnesium alloy was studied by in situ small-angle X-ray scattering (SAXS) to reveal the evolution of MgLi2Al θ precipitates (ppts) in the early aging stage at room temperature (RT). DSC and XRD measurements reveal θ ppts in naturally aged alloy. During 0 to 22 hours of early aging at RT, the growth and coarsening of plate-like θ nano-ppts are quantitatively resolved using SAXS in terms of the temporal evolution of the radius, thickness, and relative volume fraction. In this early aging period, the radius of θ ppts grows gradually from 3.1 to 6.9 nm with a nearly constant thickness of 3.7 nm. The relative volume fraction of θ ppts increases rapidly in the early aging stage and then more slowly in the peak aging stage at ~ 17 hours. The growth behavior of θ ppts after the peak aging stage follows the coarsening kinetics and causes hardness softening. It is supposed that the corresponding increase and decrease in hardness can be attributed to the coherency strengthening and coherency loss of the θ ppts, respectively.

A nitrogen-free and slot-die coating fabrication of perovskite solar cells combined with NIR annealing. We develop a fabrication approach of planar inverted structured perovskite solar cell (PSC) in ambient condition with a PCE of 12.4% as compared to that (13.3%) of PSC fabricated in glove box filled with nitrogen. In addition, we demonstrate an alternative post-annealed method by near-infrared (NIR) radiation to traditional heating method by oven. The annealed time by NIR can be shortened from 1500 s to 30 s and the device performance over 10% can be achieved. The present work investigates the NIR effect for different layers in the two-step processing on the cell performance. The grazing-incidence wide-angle and small-angle X-ray scattering (GIWAXS and GISAXS) techniques for the perovskite layers are performed to reveal the crystalline and nano-morphological structures of perovskite layers correlated to thermal and NIR annealing effects. Based on this approach under ambient air, we scale up to the large-area fabrication using the slot-die coating. The performance of slot-die coated PSC can achieve to 12.3%. The critical step is the control of PbI2 layer thickness. We also applied the NIR radiation to the slot-die coated PSC and the PCE of 11.4% can be achieved. Our study paves a facile way to rapid manufacture and mass production of perovskite solar cells.

In this paper we report the effect on the power conversion efficiency (PCE) and stability of photovoltaic devices after incorporating hydrogenated two-dimensional (2D) MoSe2 nanosheets into the active layer of bulk heterojunction (BHJ) organic photovoltaics (OPV). The surface properties of 2D MoSe2 nanosheets largely affect their dispersion in the active layer blend and, thus, influence the carrier mobility, PCE, and stability of corresponding devices. We treated MoSe2 nanosheets with hydrogen plasma and investigated their influence on the polymer packing and fullerene domain size of the active layer. For the optimized devices incorporating 37.5 wt% of untreated MoSe2, we obtained a champion PCE of 9.82%, compared with the champion reference PCE of approximately 9%. After incorporating the hydrogen plasma-treated MoSe2 nanosheets, we achieved a champion PCE of 10.44%—a relative increase of 16% over that of the reference device prepared without MoSe2 nanosheets. This PCE is the one of the highest ever reported for OPVs incorporating 2D materials. We attribute this large enhancement to the enhanced exciton generation and dissociation at the MoSe2–fullerene interface and, consequently, the balanced charge carrier mobility. The device incorporating the MoSe2 nanosheets maintained 70% of its initial PCE after heat-treatment at 100 °C for 1 h; in contrast, the PCE of the reference device decreased to 60% of its initial value—a relative increase in stability of 17% after incorporating these nanosheets. We also incorporated MoSe2 nanosheets (both with and without treatment) into a polymer donor (PBDTTBO)/small molecule (IT-4F) acceptor system. The champion PCEs reached 7.85 and 8.13% for the devices incorporating the MoSe2 nanosheets with and without plasma treatment, respectively—relative increases of 8 and 12%, respectively, over that of the reference. These results should encourage a push toward the implementation of transition metal dichalcogenides to enhance the performances of BHJ OPVs.

This paper reports two new fluorine-substituted polymer donors (BO2FC8, BO2FEH), with different side-chain architectures, and a new chlorine-substituted small-molecule acceptor (m-ITIC-OR-4Cl) that are capable of simultaneous charge and energy transfer as the binary blend active layer for organic photovoltaics. We first resolved the single-crystal structure of m-ITIC-OR-4Cl and then used simultaneous grazing-incidence wide- and small-angle X-ray scattering to decipher the multi-length-scale structures—such as the shape and size of aggregated domains and molecular orientation—of the blends of BO2FEH and BO2FC8 with m-ITIC-OR-4Cl. The linear side chains of BO2FC8 facilitated its packing and, thus, induced m-ITIC-OR-4Cl to form smaller disc-shaped aggregated domains (thickness: 2.9 nm) than its aggregate domain (thickness: 5.4 nm) in the blend of the branched BO2FEH. That is, the binary blend system of linear-side-chain BO2FC8 with m-ITIC-OR-4Cl featured larger interfacial areas and more pathways for charge transfer and transport, as evidenced by their carrier mobilities. The highest power conversion efficiency (PCE) of 11.0% was that for the BO2FC8:m-ITIC-OR-4Cl device, being consistent with the predicted PCE of 11.2% using machine learning based on random forest algorism; in comparison, the PCE of the BO2FEH:m-ITIC-OR-4Cl device was 6.4%. This study has not only provided insight into the photovoltaic performances of new polymer donor/small-molecule acceptor blends but has also, for the first time, deciphered the hierarchical morphologies—from molecule orientation to nano-domain shape and size—of such blend systems, linking the morphologies to the photovoltaic performances. The use of side-chain architectures suggests an approach for tuning the morphology of the polymer/small-molecule binary blend active layer for use in organic photovoltaics.

The performance of the logistics service supply chain (LSSC) is not only affected by external demand changes, but also by the decision-making behaviours of LSSC members, including logistics service...

The in-situ anomalous small-angle X-ray scattering (ASAXS) technique was used to investigate the strain glass transition (SGT) in as-quenched Ti48.7Ni51.3 shape memory alloy during a thermal cycle of 30 °C to the SGT temperature Tg (−50 °C) and then to 30 °C again. The Ni atoms play a critical role as point defects in the SGT mechanism and are very difficult to characterize using conventional tools. ASAXS identified the distribution of Ni atoms in nanodomains, which have a disk-like core–shell configuration with a Ni-rich shell and a highly Ni-rich core. Moreover, the morphological evolution, growth and shrinkage of the highly Ni-rich core domains during the thermal cycle through Tg are demonstrated. The enhancement and reversible behavior of the local lamellar ordering arrangement of nanodomains during the SGT process at Tg are revealed. The structural evolution and local ordering arrangement of nanodomains can play a role in hindering martensitic transformation. The ASAXS results provide new knowledge about the SGT beyond that from current simulation works. However, this corresponding structure of the nanodomains was destroyed when the specimen was heated to 250 °C.

Cs-corrected high-angle-annular-dark-field scanning-transmission-electron microscopy (Cs-corrected HAADF-STEM) was employed to examine the phases in AlCuLi alloy (AA2050), including GP(T1), GP(θ″) and GPB zones with their subsequent nanometer-sized products, T1 (Al2CuLi), θ′ (Al2Cu), and S (Al2CuMg) precipitates, respectively. Under the peak-aging condition, some solute-atom enriched clusters could still be found, and the newly-formed nucleus of GP(θ″) with a mono-layer {100} plane of Cu atoms occurred at the adjacent area of the joint between θ′ and S precipitates or the edge of an individual S precipitate. The transition of a single Cu-layer GP(θ″) → θ′ was presumed to be transformation via in-situ nucleation. The developing GP(θ″) zones and θ′ precipitates were easily subjected to soft impingement. However, hard impingement between two variants of θ′ presumably occurred, wherein one θ′ variant precipitate was blocked out by the other θ′ variant. As for the creep-ageing forming (CAF) treated sample, some precipitates of T1 and θ′ were found to have the cutting characteristic on specific ledges. Keywords: Cs-corrected HAADF-STEM, AlCuLi (AA2050) aluminium alloy, GP(θ″) zones, T1 precipitates, θ′ Precipitates, S precipitates

The aim of this study is to demonstrate a fabrication process of all-sprayed inverted organic photovoltaics. We sprayed the blend of poly(3-hexylthiophene-2,5-diyl) and [6, 6] phenyl-C61-butyric acid methyl ester as an active layer and zinc oxide prepared by a sol–gel process as an electron transport layer. The highly conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) as a semitransparent anode and alternative to Ag is sequentially spray-coated. We further utilize nitrogen (N2) plasma modification on the active layer for improving the compatibility between two layers in this work. With a combination of tuning the subsequent thermal treatment, the all-sprayed devices with good performance could be obtained. The highest power conversion efficiency (PCE) of 2.90% is achieved by optimizing the N2 plasma and thermal treatment, and the stability test is performed. Moreover, we up-scaled the all-spray-coating process to a module with three cells connected in series, and the PCE of the module is achieved to 2.44%.

Bulk heterojunction (BHJ) perovskite solar cells have recently attracted increased interest because of a significantly enhanced interface between perovskite and the n-type material in the active layer for efficient charge separation and increased power conversion efficiency (PCE). [6,6]-Phenyl-C61-butyric acid methyl ester (PC61BM) is the most commonly used n-type material in BHJ perovskite solar cells owing to its high electron mobility. However, it is very difficult to fabricate BHJ perovskite films because of the poor solubility of PC61BM in the commonly used solvent dimethylformamide (DMF). In this study, we introduced two kinds of fluorinated PC61BM (3F-PC61BM and 5F-PC61BM) as n-type materials in a BHJ perovskite film, which have higher solubility in DMF than that of PC61BM. Thus, a BHJ perovskite film can be easily fabricated in one step using a single solvent in a BHJ precursor solution system for planar perovskite solar cells. A BHJ device with a high PCE of 16.17% can be obtained by adding 0.1 wt% of 3F-PC61BM in a perovskite precursor solution to fabricate a solar cell, which outperforms the PCE of 14.12% of the pristine device. However, the addition of 5F-PC61BM decreased the PCE to lower than that of the pristine device regardless of its amount. We systematically studied the effects of the amount and type of fluorinated PC61BM on the morphology of BHJ perovskite films using SEM, AFM, GISAXS and GIWAXS. The results reveal that 3F-PC61BM can fill the pinholes between perovskite grains and passivate the defects in the pristine film. Thus, the current density (Jsc) is greatly increased. On the other hand, the self-aggregation of 5F-PC61BM in BHJ perovskite films caused the films to be full of large voids, which led to poor device performance. The dense and flat surface morphology of BHJ perovskite films containing 3F-PC61BM can also prevent the permeation of moisture into grain boundaries and enhance the device stability. Therefore, the device could maintain 80% of its original efficiency over 550 hours without any encapsulation in comparison with 240 hours for the pristine device. Our results provide a novel strategy for fabricating high-PCE and high-stability BHJ perovskite solar cells for the production of low-cost solar cells in the near future.

This paper proposes a defect detection method using laser vision with model-based segmentation for laser brazing welds on car body surface, in which a dynamic ideal surface (DIS), composed of a series of dynamic ideal contours (DIC), is first established for welding surface. The DIC model is obtained by dynamically fitting welding surface contours using the weighted cubic spline regression (WCSR) model with the fast Expectation-Maximization (Fast-EM) algorithm. Then through multi-threshold analysis on the DIC model residuals, whether the contour is defective and the nature of defect can be identified, and finally the defect can be completely separated. The whole process is fully automatic and requires no prior knowledge of defect. Experimental results show that the model-based segmentation method has managed to separate multiple types of defect effectively while meeting the actual accuracy requirements. The robustness of the proposed method has been proved through the test in the case of noise interference and unstable movement of the sensor, which helps to realize online inspection of weld defects in a factory environment.

High-resolution (HR) high-angle annular dark-field (HAADF) scanning transmission electron microscopy (STEM) has revealed the atomic lattice defects in different types of η precipitates in the Al–Zn–Mg–Cu aluminium alloy subjected to creep-age forming treatment (with a constant stress lower than its room-temperature yield strength during ageing). Along the zone axes of [110]Al//[2 1 ‾ 1 ‾ 0]η of η1 and η12, [112]Al//[2 1 ‾ 1 ‾ 0]η of η2 and [100]Al//[2 1 ‾ 1 ‾ 0]η of η13, atomic projections of (2 1 ‾ 1 ‾ 0)η have been investigated. In those types of η, elongated hexagonal lattice defects (labelled as Type I defects) can be found; they are apparently related to local disorder in atomic stackings. Furthermore, in η12, elongated hexagonal lattice defects with a much higher aspect ratio (labelled as Type II defects) are uniquely observed. These atomic lattice defects are presumably pertinent to the lattice accommodation in the course of creep-age forming. Additionally, in η1 and η12, the features of a Penrose tiling defect connecting with Type I defects are observed, and these complex defects obviously affect the growth direction of the precipitate, resulting in a nearly spherical morphology. Alternatively, several entirely-passed faulted layers in a new type of precipitate, η14, consequently bring about a new orientation relationship: (51 3 ‾ )Al//(0001)η14 and [112]Al//[2 1 ‾ 1 ‾ 0]η14. Moreover, in an atomic STEM image of η14, the significant Z-contrast gradient adjacent to the transformation front of η14 elucidates the Zn/Cu diffusion from the matrix to the precipitate along {1 1 ‾ 1 ‾ }Al planes at the interface.

The impact of the morphological stability of the donor/acceptor mixture under thermal stress on the photovoltaic properties of bulk heterojunction (BHJ) solar cells based on the poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b′]-dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]-thiophene)-2-carboxylate-2,6-diyl]/phenyl-C61-butyric acid methyl ester (PTB7-Th/PC61BM) blend is extensively investigated. Both optical microscopy and transmission electron microscopy micrographs show that long-term high-temperature aging stimulates the formation of microscale clusters, the size of which, however, is about 1 order of magnitude smaller than those observed in thermally annealed poly(3-hexylthiophene)/PC61BM composite film. The multilength-scale evolution of the morphology of PTB7-Th/PC61BM film from the scattering profiles of grazing incidence small-angle and wide-angle X-ray scattering indicates the PC61BM molecules spatially confine the self-organization of polymer chains into large doma...

Although organic–inorganic lead halide perovskite nanowires (NWs) have shown great potential in a wide range of device applications, their relatively low performance and insufficient stability represent major bottlenecks for their further development. In this study, we present an integrated approach to achieve highly efficient and long-term stable methyl ammonium lead iodide (MAPbI3) perovskite NW solar cells by combining a 4-(1,3-dimethyl-2,3-dihydro-1H-benzimidazol-2-yl)-N,N-diphenylaniline (N-DPBI)-doped poly{[N,N′-bis(2-octyldodecyl)-1,4,5,8-naphthalene diimide-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)} (P(NDI2OD-T2)) polymeric film as the electron transport layer (ETL) with an atomic-layer-deposited Al2O3-based film as the encapsulation layer. Our results indicate that N-DPBI doping can not only improve the electron extraction capability by minimizing resistive losses, but also improve the surface coverage of the P(NDI2OD-T2) ETL on the MAPbI3 NW layer. With this n-doped ETL, a remarkable power conversion efficiency (PCE) up to 18.83% is achieved, which represents the highest PCE ever reported for perovskite NW solar cells. Importantly, taking advantage of the high charge carrier mobility of MAPbI3 NWs (0.01 cm2 V−1 s−1), the large-area NW devices with an active area of 5.04 cm2 also deliver a high PCE up to 15.25%. More encouragingly, the encapsulated NW devices exhibit excellent long-term stability, retaining ∼92% of their initial efficiency after being exposed to the ambient atmosphere for more than 6000 hours. The encapsulated NW devices still remain fairly stable (∼20% loss in PCE) even after ∼1500 hours of continuous operation under AM1.5G sunlight irradiation in the ambient atmosphere. The approaches demonstrated herein can not only offer a very promising strategy for realizing high-performance and long-term stable perovskite NW solar cells, but also pave the way for future developments of perovskite NW-based optoelectronic devices.

In this article, the effect of hole transport layer (HTL) on the thermal stability of inverted polymer solar cells (PSCs) consisting of the blend of poly(3-hexylthiophene) (P3HT) and (6,6)-phenyl-C 60 butyric acid methyl ester fullerene derivative (PCBM) as active layer (AL) is investigated. The two conventional HTLs, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) and MoO 3 , were used in this study to demonstrate the effect of HTLs on the thermal stability of PSCs. The inverted devices were heated at 80–110 °C as accelerated test for different time intervals to illustrate the temporal variation of performance. The different temporal behaviors during (1) metastable period and (2) thermally unstable period are described here. Moreover, the effect of photoactive film thickness on the thermal stability of devices based on the two HTLs was considered. This study shows that the spin- and spray-coated devices exhibit different characteristics of thermal stability for the PSCs with MoO 3 and PEDOT:PSS as HTLs, respectively. The temporal behavior caused by the effect of HTL during the thermally-unstable period is quantitatively studied. This study could provide vital information required to develop high durability in commercial PSCs.

New design of Pt(II) phosphors yield near-infrared organic light-emitting diodes with high efficiency and brightness.

Solution-processed organic photovoltaics (OPVs) based on bulk-heterojunctions have gained significant attention to alleviate the increasing demend of fossil fuel in the past two decades. OPVs combined of a wide bandgap polymer donor and a narrow bandgap nonfullerene acceptor show potential to achieve high performance. However, there are still two reasons to limit the OPVs performance. One, although this combination can expand from the ultraviolet to the near-infrared region, the overall external quantum efficiency of the device suffers low values. The other one is the low open-circuit voltage (VOC) of devices resulting from the relatively downshifted lowest unoccupied molecular orbital (LUMO) of the narrow bandgap. Herein, the approach to select and incorporate a versatile third component into the active layer is reported. A third component with a bandgap larger than that of the acceptor, and absorption spectra and LUMO levels lying within that of the donor and acceptor, is demonstrated to be effective to conquer these issues. As a result, the power conversion efficiencies (PCEs) are enhanced by the elevated short-circuit current and VOC; the champion PCEs are 11.1% and 13.1% for PTB7-Th:IEICO-4F based and PBDB-T:Y1 based solar cells, respectively.

Chronic accumulation of fluoride (F−) threats human health and eventually brings about skeletal fluorosis, dental fluorosis and joint deformation, which has aroused global attention. As an emerging technique, electrosorption presented great potential in wastewater purification. The key role in electrosorption is the exploitation of economical, environmentally-friendly and efficient electrode material. Nowadays, many existing investigations on the preparation of porous carbon material focused on the introduction of extra dopant and activation reagent. However, the information concerning the preparation of pure porous biochar and the inherent environmental significance is neglected. Here, a win–win strategy, named conversion waste biomass into porous biochar, has been applied in capacitive fluorine removal. The results indicated that the capacity of porous biochar electrode was 1.28 mg/g, which was improved by 48.8% in contrast to activated carbon electrode. Furthermore, competition experiments revealed concentration-dependence interference in the present of foreign ions. Electrosorption cycle experiment manifested excellent stability of the biochar electrodes. The electrode was regenerated without consuming any chemicals and could produce current for energy recovery. More importantly, continuous-flow experiment showed that the removal efficiency of F− was 91.98% at the synthetic wastewater. High specific capacitance, low internal resistance and appropriate pore distribution were responsible for the F− removal mechanism. Overall, this work would pioneer a facile method in the preparation of low-price electrode material and their potential applications in environmental remediation.

The emerging trends in the combinatorial chemistry and drug design have led to the development of drug candidates with greater lipophilicity, high molecular weight and poor water solubility. The poor water solubility often leads to low bioavailability and therapy efficacy of oral administration. Herein, take itraconazole (ITZ), a poorly soluble antifungal agent, as a model drug, we demonstrate a general strategy that nano-amorphous formulation of ITZ with mesoporous silica nanospheres (MSNs) as nanocarriers can result in great enhancement of both the ITZ loading and releasing performance. We find that the sphere diameters and specific surface areas of MSNs have the potential in influencing the amorphous condition of ITZ, further affecting the ITZ loading and releasing behavior. The results indicate that the MSNs with diameter of around 50 nm can load high content (≥37.5 wt%) of ITZ with pure amorphous state, which results in almost 100% in vitro releasing (in simulated gastric fluid) and great enhancement of in vivo bioavailability (1.5 fold greater than that of commercial product Sporanox). Our nano-amorphous strategy for poorly soluble drugs with MSNs as nanocarriers would show great promising in the enhancement of bioavailability and therapy efficacy for oral administration of drugs with poor water solubility.

Controlling the crystallization and morphology of perovskite films is crucial for the fabrication of high-efficiency perovskite solar cells. For the first time, we investigate the formation mechanism of the drop-cast perovskite film from its precursor solution, PbCl2 and CH3NH3I in N,N-dimethylformamide, to a crystalline CH3NH3PbI3–xClx film at different substrate temperatures from 70 to 180 °C in ambient air and humidity. We employed an in situ grazing-incidence wide-angle X-ray scattering (GIWAXS) technique for this study. When the substrate temperature is at or below 100 °C, the perovskite film is formed in three stages: the initial solution stage, transition-to-solid film stage, and transformation stage from intermediates into a crystalline perovskite film. In each stage, the multiple routes for phase transformations are preceded concurrently. However, when the substrate temperature is increased from 100 to 180 °C, the formation mechanism of the perovskite film is changed from the “multistage formatio...

The performance of hybrid perovskite-based light-emitting diodes (LEDs) is markedly enhanced by the application of a NiOx electrode interlayer and moderate methylamine treatment. A hybrid perovskite-based LED exhibits a peak luminous efficiency of 15.9 cd A-1 biased at 8.5 V, 407.65 mA cm-2 , and 65 300 cd m-2 , showing a distinctive impact for future applications.

Two D-π-A-A molecules (MIDTP and TIDTP) composed of an electron-rich ditolylamino group (D) and an electron-deficient 5-dicyanovinylenylpyrimidine (A-A) fragment bridged together with indeno[1,2-b]thiophene (IDT) were synthesized. These molecules provide an opportunity to examine in-depth the impact of side-chain variations (methyl vs p-tolyl) on the crystallization behaviors, solid-state morphology, physical properties, and optoelectronic characteristics relevant for practical applications. X-ray analyses on single-crystal structures indicate that methyl-substituted MIDTP forms "coplanar antiparallel dimers" via C-H···S interactions and organizes into an ordered slip-staircase arrays. In contrast, p-tolyl-bearing TIDTP shows "cofacial centrosymmetric dimers" via π-π interactions and packs into a less-ordered layered structures. The X-ray diffraction analyses upon thermal treatment are consistent with a superior crystallinity of MIDTP, as compared to that of TIDTP. This difference indicates a greater propensity to organization by introduction of the smaller methyl group versus the bulkier p-tolyl group. The increased propensity for order by MIDTP facilitates the crystallization of MIDTP in both solution-processed and vacuum-deposited thin films. MIDTP forms solution-processed single-crystal arrays that deliver OFET hole mobility of 6.56 × 10(-4) cm(2) V(-1) s(-1), whereas TIDTP only forms amorhpous films that gave lower hole mobility of 1.34 × 10(-5) cm(2) V(-1) s(-1). MIDTP and TIDTP were utilized to serve as donors together with C70 as acceptor in the fabrication of small-molecule organic solar cells (SMOSCs) with planar heterojunction (PHJ) or planar-mixed heterojunction (PMHJ) device architectures. OPV devices based on higher crystalline MIDTP delivered power conversion efficiencies (PCEs) of 2.5% and 4.3% for PHJ and PMHJ device, respectively, which are higher than those of TIDTP-based cells. The improved PCEs of MIDTP-based devices are attributed to better hole-transport character.

We systematically investigated the thermal effects of drying process as well as thermal annealing on morphology and performance of inverted polymer solar cells (PSCs) fabricated by roll-to-roll (R2R) slot-die coating. Power conversion efficiency (PCE) of PSCs layer is strongly influenced by bulk heterojunction (BHJ) active layer. Compared to the conventional annealing process, we demonstrate that the drying process for transforming the wet active layer into solid-state film (an early polymer crystallization step) in the R2R process is a critical control of morphological evolution to the desired structure. We have demonstrated that a significant improvement in performance of inverted PSCs can be achieved by tuning the parameters in the drying process prior to the annealing process. This study provides the mechanistic understanding of how the drying and annealing processes affect the morphological evolution regarding to the crystallinity, BHJ structure and interface between layers. Moreover, with respect to environmental concerns, halogen-free are carried out as an alternative solvent to halogenated solvents. We successfully incorporate halogen-free solvent, o-xylene, with an elevated drying temperature for improving the performance of R2R slot-die coated inverted solar cells.

We report a novel protocol for achieving highly efficient and stable indium-tin-oxide (ITO)-free large-area perovskite solar cells (PeSCs) by introducing thiol-functionalized self-assembled monolayers (SAMs) to modify the interfacial properties of the devices. Two SAM molecules, 3-mercaptopropyltrimethoxysilane (MPTMS) and (11-mercaptoundecyl)trimethylammonium bromide (MUTAB), are employed as the seed layer for an ultrathin Ag transparent electrode and cathode buffer layer (CBL), respectively. Our results indicate that both SAMs can afford admirable interfacial properties. The thiol groups on the MPTMS SAM can interact with the incident Ag atoms, thereby lowering the percolation thickness of the Ag film to 8 nm. The resulting ultrathin Ag film provides several remarkable features for use as the transparent electrode in PeSCs, including a low resistance of ∼6 Ω sq−1, high average transmittance up to ∼78%, and high robustness against solvents and mechanical deformation. In addition to using the MPTMS SAM as the seed layer, the double-end functionalized MUTAB can not only covalently bond to the Ag surface for SAM formation, but also induce the formation of favorable interfacial dipoles to turn a high work-function (WF) Ag electrode into an efficient low-WF electrode. With these desired interfacial properties, the resulting devices deliver a power conversion efficiency (PCE) up to 16.2%. Notably, a high PCE up to ∼16% can be secured for large-area devices (1.2 cm2) with a SAM-modified ultrathin Ag electrode, which represents the highest performance ever reported for PeSCs with similar active areas. More significantly, the resulting devices also possess good ambient stability without the need for rigorous encapsulation.

Engineering the interface between the active layer and the electrodes has proven to be a promising strategy to enhance the power conversion efficiency (PCE) of hybrid perovskite solar cells (PeSCs). Here, we present an effective approach to achieve highly efficient PeSCs by inserting an easy-accessible hexamethonium bromide (HMB)-doped [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) film between the active perovskite layer and the Ag cathode. This doped interfacial layer delivers several remarkable features for use in PeSCs, including solution processability, good electrical conductivity, fine work-function tunability of the Ag electrode, and general applicability to different fullerene materials. As a consequence, planar-heterojunction PeSCs deliver a PCE up to ∼18%, showing an approximately 5.6-fold enhancement compared with the control device using an undoped PC61BM layer. In particular, benefitting from the high conductivity of this doped film, a prominent PCE as high as 15.58% can be achieved even when a large thickness of the PC61BM layer (120 nm) is used. To the best of our knowledge, this is the highest performance ever reported for PeSCs with a PC61BM thickness more than 100 nm. More encouragingly, large-area PeSCs (active area = 1.2 cm2) via the doctor-blade coating technique also exhibit a remarkable PCE (15.23%) and good long-term stability under an inert atmosphere. Our results indicate that the HMB-doped PC61BM film is a promising interfacial layer for PeSCs and can be compatible with high throughput roll-to-roll manufacturing processes.

Replacing toxic halogenated solvents with eco-friendly solvents will be necessary for the upscaling and mass production of organic photovoltaics (OPVs). In this study, toluene (Tol), a halogen-free solvent, was employed in the fabrication of molecular solar cells, achieving a power conversion efficiency (PCE) higher than that obtained when using a chlorinated counterpart, chloroform (CF). SMPV1, a two-dimensional conjugated small molecule, was used as the donor and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as the acceptor to form bulk heterojunction (BHJ) OPVs. The as-cast device formed using Tol displayed a PCE of 5.4%, higher than that (4.8%) achieved using CF. Combining the effects of thermal annealing and polydimethylsiloxane (PDMS) as a solvent additive, the PCEs of devices prepared using Tol and CF reached 6.20 and 5.52%, respectively. Solvent vapor annealing (SVA), a powerful tool for controlling the morphology of the active layer, had a great impact on the device performance. Tol, tetrahydrofuran (THF), carbon disulphide (CS2), and hexane (Hex) were tested as halogen-free solvents for SVA treatment. Tol- and THF-SVA had positive effects on PCEs, reaching 7.04 and 6.50%, respectively. The enhancement arose mainly from the improvement in the fill factor, due to morphological manipulation and favorable phase separation. CS2- and Hex-SVA treatment had negative effects on the short-circuit current density and, hence, the overall PCE. A PCE of greater than 7% is the highest performance reported to date when using a halogen-free solvent to prepare small-molecule solar cells.

The synchrotron small-angle X-ray scattering (SAXS) technique was used to investigate the morphological evolution of Guinier-Preston (GP) zones in 80% cold-rolled Al0.2CoCrFeNi high-entropy alloy aged at 550 °C for different times. The hardness profile exhibited double-peaked aging behavior. HRTEM observations revealed the appearance of the GP zones in specimens aged for two peak aging times. The SAXS analysis demonstrated that, according to their evolutions of relative volume fraction and size, the two groups of GP zones could be divided into GP1 and GP2 zones from 1 h of aging. The corresponding peaks in volume fraction and in size of GP1 and GP2 zones were correlated to the first and the second peak aging, respectively, indicating precipitation hardening by GP1 and GP2 zones. In addition, mechanical properties measured by tensile tests showed a trend similar to that of the hardness variation. The increasingly large particles after 1 h of aging detected by SAXS were also observed by TEM in 100 h over-aged specimens and identified as an AlNi-rich L12 phase. Based on the combined investigations of SAXS and TEM, the precipitation sequence in 80% cold-rolled Al0.2CoCrFeNi alloy aged at 550 °C is GP1 → GP2 → L12.

Low dark current organic photodetectors (OPDs) with a conventional structure consisting of poly(3-hexylthiophene) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) as active layer have been fabricated by spray-coating. Tuning the thickness of active layer and thermal annealing process for the spray-coated OPDs results in a remarkable performance with a low dark current density (Jd) of 2.90 × 10–8 A/cm2 at reverse bias of 1 V. The impact of thermal annealing on the performance of sprayed OPDs is also investigated by the impedance analysis for mechanistic understanding. Our results demonstrate that the optimization of PCBM cluster and interfacial contact between the active layer and the metal electrode tailored by thermal annealing, respectively, could effectively reduce the Jd and increase the sensitivity of sprayed OPDs. The control of PCBM cluster is more important than the interfacial contact between the layers for improving Jd. In addition, structural characterization of the active layer studied by...

The annotation of Early Esophageal Cancer (EEC) in gastroscopic images is mainly performed by clinicians in clinic, In order to reduce subjective and fatigue manual annotation works, computer-aided annotation is needed for accurate diagnosis. This study develops an automatic annotation method to annotate EEC in gastroscopic images. We initially designed a new segmentation method named "Saliency Guided Superpixel Segmentation", to rapidly find the salient regions and their surrounding regions. Then, a two-step annotation strategy of EEC, which is based on the "relationships between the salient regions and EEC regions", was proposed. The first step is to detect the salient EEC regions and the second step is the left unsalient EEC regions. Finally, the two kinds of lesion regions are combined together to obtain the annotation results. 267 EEC images and 285 normal images were used to validate the proposed method. The experimental results show that, the detection rate and Dice similarity coefficients of our method were 97.14% and 74.53%, respectively. Compared with other patch-based or superpixel-based state-of-the-art methods, our method showed better performance. Thus, it has a good prospect for clinical application.

The high power conversion efficiency of bulk heterojunction (BHJ) polymer solar cells can be achieved from either low crystallinity (P3TI) or high crystallinity (P6TI) of isoindigo-based donor–acceptor alternating copolymers blended with PC71BM by controlling nanophase separation using additives. P3TI shows similar device performance regardless of the type of additives, while P6TI is significantly affected by whether the additive is aliphatic or aromatic. To understand the interplays of crystallinity of polymers and the type of additive on the formation of nanomorphology of BHJ, we employed the simultaneous grazing-incidence small- and wide-angle X-ray scattering (GISAXS and GIWAXS) technique to perform the quantitative investigation. By incorporating additives, the PC71BM molecules can be easily intercalated into the P3TI polymer-rich domain and the size of the PC71BM clusters is reduced from about 24 nm to about 5 nm by either aliphatic 1,8-diiodooctane (DIO) or aromatic 1-chloronaphthalene (CN). On comparison, it is found to be more difficult for PC71BM molecules to be intercalated into the highly crystalline P6TI dense domain, and the PC71BM molecules have a higher tendency to be self-aggregated, which results in a larger size of PC71BM clusters of about 58 nm. The clusters can be reduced to about 7 nm by DIO and 13 nm by CN. The presence of crystallites in the P6TI domain can interact with the additive to tailor the crystallization of PC71BM clusters to a size similar to that of P6TI crystallites (∼12 nm) and form a connected network for efficient charge transportation. Thus, the power conversion efficiency of P6TI:PC71BM reaches its maximum of 7.04% using aromatic CN additives. This is a new finding of the effect of crystallinity, which is not observed in the common low crystalline donor–acceptor alternating copolymers such as PTB7. Our results provide a useful guideline to manipulate the desired morphology of BHJ films constructed from alternating copolymer with different crystallinity, which is critical for achieving high power conversion efficiency of solar cells.

Indoor utilization of emerging photovoltaics is promising; however, efficiency characterization under room lighting is challenging. We report the first round-robin interlaboratory study of performance measurement for dye-sensitized photovoltaics (cells and mini-modules) and one silicon solar cell under a fluorescent dim light. Among 15 research groups, the relative deviation in power conversion efficiency (PCE) of the samples reaches an unprecedented 152%. On the basis of the comprehensive results, the gap between photometry and radiometry measurements and the response of devices to the dim illumination are identified as critical obstacles to the correct PCE. Therefore, we use an illuminometer as a prime standard with a spectroradiometer to quantify the intensity of indoor lighting and adopt the reverse-biased current-voltage (I-V) characteristics as an indicator to qualify the I-V sampling time for dye-sensitized photovoltaics. The recommendations can brighten the prospects of emerging photovoltaics for indoor applications.

This study demonstrates that the hydrogen storage rate (HSR) of nanoporous carbon supported platinum nanocatalysts (NC) is determined by their heterojunction and geometric configurations. The present NC is synthesized in an average particle size of ~1.5 nm by incipient wetness impregnation of Pt4+ at carbon support followed by annealing in H2 ambient at 102–105 °C. Among the steps in hydrogen storage, decomposition of H2 molecule into 2 H atoms on Pt NC surface is the deciding factor in HSR that is controlled by the thickness of Pt NC. For the best condition, HSR of Pt NC in 1~2 atomic layers thick (4.7 μg/g min) is 2.6 times faster than that (1.3 μg/g min) of Pt NC with higher than 3 atomic layers thick.

Morphological evolution and phase transformation of metastable intermediate precipitates are critical to their mechanical properties for the non-isothermal processing. During the non-isothermal precipitation, the formation of the new phases usually couples with structural evolution. Traditional structural characterization has limitation to resolve comprehensive changes simultaneously. In this study, we report direct observation, precipitation sequence, and the details of concurrent morphological and structural changes of various intermediate precipitates during non-isothermal heating in the Al–Cu systems with different pretreatments. The structural heterogeneity during the non-isothermal precipitation processes is resolved into coexistence of two different precipitate phases and quantitatively studied in terms of the phase transition and the morphological evolution. This paper presents the in situ small- and wide-angle synchrotron x-ray scattering (SAXS and WAXS) to refine and to identify the mixed structural information during multiple precipitation stages. The WAXS results show that the precipitation sequence is θ″ → (θ″ + θ′) → θ′ → (θ″ + θ) → θ upon heating. Due to the fact of the specifically oriented SAXS intensity, the evolution of the aforementioned phase transformation is resolved by the refinement of the SAXS intensity integrated over the selected area. These methods reveal multiscale information that is not trivial comparing to the traditional characterization methods.

The formation mechanism of a spray-coated film is different from that of a spin-coated film. This study employs grazing incidence small- and wide-angle X-ray Scattering (GISAXS and GIWAXS, respectively) quantitatively and systematically to investigate the hierarchical structure and phase-separated behavior of a spray-deposited blend film. The formation of PCBM clusters involves mutual interactions with both the P3HT crystal domains and droplet boundary. The processing control and the formed hierarchical structure of the active layer in the spray-coated polymer/fullerene blend film are compared to those in the spin-coated film. How the different post-treatments, such as thermal and solvent vapor annealing, tailor the hierarchical structure of the spray-coated films is quantitatively studied. Finally, the relationship between the processing control and tailored BHJ structures and the performance of polymer solar cell devices is established here, taking into account the evolution of the device area from 1 × 0.3 and 1 × 1 cm2. The formation and control of the special networks formed by the PCBM cluster and P3HT crystallites, respectively, are related to the droplet boundary. These structures are favorable for the transverse transport of electrons and holes.

A facile and environmentally benign microwave heating approach was developed to prepare yolk-shell porous Fe-doped graphitic carbon nitride (YPFCN) microarchitectures by using low-cost melamine, graphite and iron as raw materials for the first time. The as-synthesized samples were well characterized by various analytical techniques. Results showed that Fe-doping could induce intrinsic electronic and band structure modulation of g-C3N4, resulting in its absorbance edge up to 460 nm, consequently. The derived bandgap of YPFCN was estimated to be 2.71 eV with a decrease of 0.10 eV compared to that of undoped g-C3N4 (2.81 eV). Besides, the YPFCN photocatalyst showed excellent visible-light driven photocatalytic activity toward Rhodamine B (RhB) and Methyl orange (MO) presumably as a result of large surface area, efficient separation of photo-generated carries, shorter carrier lengths, and higher visible-light absorption efficiency. The removal ability of RhB and MO of YPFCN was about 1.2 and 1.5 times higher than that of pure g-C3N4, respectively.

Ni-rich nanodomains and Ti3Ni4 nanoprecipitates in the strain glass of Ni-rich Ti-Ni shape memory alloys (SMAs) play an important role in the origin and characteristic control of the strain glass transition. Ni-rich nanodomains are formed in the quenching process and dissolve during isothermal aging. Ti3Ni4 nanoprecipitates nucleate, grow and coarsen during aging. This study performed in situ small-angle X-ray scattering (SAXS) and ex situ X-ray diffraction to investigate the structural evolutions with aging time of nanoparticles in Ti48.7Ni51.3 SMA aged isothermally at 250 °C in terms of relative volume fraction, radius, thickness, orientation, lattice ordering, and morphology. The mechanism and kinetics of the concurrent phase evolutions of Ni-rich nanodomains and Ti3Ni4 nanoprecipitates are revealed and discussed in detail. Frequency-dependent storage modulus vs. temperature at different frequencies for different aging times was measured to characterize the strain glass transition. Quantitative correlation of all structural evolutions and kinetics of Ni-rich and Ti3Ni4 nanoparticles with respect to the variation and loss of the strain glass transition during aging times of 0 to 20 h is presented. The roles of different nanoparticles in causing or suppressing the strain glass behavior are also experimentally revealed.

In this study, a novel perovskite quantum dot (QD) spray-synthesis method is developed by combining traditional perovskite QD synthesis with the technique of spray pyrolysis. By utilizing this new technique, the synthesis of cubic-shaped perovskite QDs with a homogeneous size of 14 nm is demonstrated, which shows an unprecedented stable absolute photoluminescence quantum yield ≈100% in the solution and even in the solid-state neat film. The highly emissive thin films are integrated with light emission devices (LEDs) and organic light emission displays (OLEDs). The color conversion type QD-LED (ccQD-LED) hybrid devices exhibit an extremely saturated green emission, excellent external quantum efficiency of 28.1%, power efficiency of 121 lm W-1 , and extraordinary forward-direction luminescence of 8 500 000 cd m-2 . The conceptual ccQD-OLED hybrid display also successfully demonstrates high-definition still images and moving pictures with a 119% National Television System Committee 1931 color gamut and 123% Digital Cinema Initiatives-P3 color gamut. These very-stable, ultra-bright perovskite QDs have the properties necessary for a variety of useful applications in optoelectronics.

A NASICON-type structured solid electrolyte of precursor for Li1.3Al0.5Ti1.3Nb0.2 (PO4)3 with high lithium-ion conductivity was prepared with solid-state reaction. Two samples have same structures without impurity phases. The highest total electrical conductivities of sintered pellets made with two methods of press method and tape casting calculated at 25°C were 4.65×10-4 S/cm and 7.1×10-4 S/cm, respectively. The conductivity of sample synthesized with tape casting is significantly increased, but relative density is 90% which is lower than relative density of 96% for sintered pellets synthesized with press method.

Vacuum-sublimed inorganic cesium lead halide perovskite thin films are prepared and integrated in all-vacuum-deposited solar cells. Special care is taken to determine the stoichiometric balance of the sublimation precursors, which has great influence on the device performance. The mixed halide devices exhibit exceptional stabilized power conversion efficiency (11.8%) and promising thermal and long-term stabilities.

This work verifies the neutron flux for a modified zero-power-reactor facility using neutron activation. Ten foils are activated and counted to illustrate the precise neutron spectrum at a particular location inside the reactor core through the computerized software Spectrum Analysis by Neutron Detector-II (SAND-II). In addition, neutron spectra derived from 11 different locations are compared with the computational results from the WIMS reactor analytical software, respectively, and then the neutron distribution with various energy groups inside the reactor core is rearranged. A quantified index, AT, is also introduced to compare the experimental and computational results. In this work, the ATs are evaluated as 2.28 {+-} 0.48, which implies a slight discrepancy between the computational and experimental results. Moreover, a softer neutron spectrum evaluated by the WIMS calculation is verified by further examining the experimental data. Recommendations on how to apply the WIMS calculations are also offered.

A nondestructive measurement of spent fuel pins from the Taiwan Research Reactor has been performed at the Institute of Nuclear Energy Research. The analysis is based on a simplified balance equation for integrated flux and a series of one-group burnup-dependent microscopic cross-section libraries. A semiempirical test is used for evaluating the burnup values of two different kinds of spent fuel pins [natural uranium (0.7% [sup 235]U) and enriched uranium (7.0 % [sup 235]U)] by the [sup 134]Cs/ [sup 137]Cs activity ratio. Results are compared with radio-chemical burnup measurements. The agreement is within 3.8%, which verifies the accuracy of this method. The results are also compared with a theoretical estimation by the ORIGEN-II code. This indicates that the ORIGEN-II code's library might have an overestimated [sigma][sub a]([sup 133]Cs), which leads to a [sup 134]Cs/[sup 137]Cs ratio that would result in a burnup value [approximately]24 to 35% lower than the measured data.

A set of unified constitutive equations is presented that predict the asymmetric tension and compression creep behaviour and recently observed double primary creep of pre-stretched/naturally aged aluminium-cooper-lithium alloy AA2050-T34. The evolution of the primary micro- and macro-variables related to the precipitation hardening and creep deformation of the alloy during creep age forming (CAF) are analysed and modelled. Equations for the yield strength evolution of the alloy, including an initial reversion and subsequent strengthening, are proposed based on a theory of concurrent dissolution, re-nucleation and growth of precipitates during artificial ageing. We present new observations of so-called double primary creep during the CAF process. This phenomenon is then predicted by introducing effects of interacting microstructures, including evolving precipitates, diffusing solutes and dislocations, into the sinh-law creep model. In addition, concepts of threshold creep stress σ t h and a microstructure-dependant creep variable H, which behave differently under different external stress directions, are proposed and incorporated into the creep model. This enables prediction of the asymmetric tension and compression creep-ageing behaviour of the alloy. Quantitative transmission electron microscopy (TEM) and related small-angle X-ray scattering (SAXS) analysis have been carried out for selected creep-aged samples to assist the development and calibration of the constitutive model. A good agreement has been achieved between the experimental results and the model. The model has the potential to be applied to creep age forming of other heat-treatable aluminium alloys.