Thin Active Layer Research Articles

A Versatile Reference Electrode for Lithium Ion Battery Use

A lithium-ion battery reference electrode applicable to both laboratory and onboard vehicle use provides a high level of understanding of electrochemical processes within a cell and enables highly sophisticated, real-time electrode control that maximizes cell utilization, life, safety, and overall value. The approach taken for this work is to combine the chemical stability of LFP with miniaturization in the form of an extremely thin and porous active layer, and optimal placement within the cell by coating the active reference layer on an additional layer or separator that is inserted between the anode and cathode in the cell. This thin, porous, separator-mounted reference has no effect on the cell beyond that of an extra layer of separator. Extraction of electrode kinetic parameters and electrode-level control of DC fast charge are shown for NCMA/Graphite cells in two different formats to demonstrate the simplicity, fidelity, and robustness of the reference electrode design.

Active Layer Thickness-Dependent Reliability of Solution-Processed Indium-Gallium-Zinc Oxide Thin-Film Transistors Under Bias Stress

Amorphous indium-gallium-zinc oxide (IGZO) thin-film transistors (TFTs) have been widely investigated because of their high carrier mobility and excellent uniformity. The IGZO TFTs’ device performances have significantly advanced, and commercial products based on IGZO TFTs have been released on the display market. On the other hand, solution-processed IGZO TFTs have also been researched to reduce fabrication costs [1]. However, the electrical properties and reliability of solution-processed IGZO TFTs should be improved for display applications compared to vacuum-processed IGZO TFTs. Because the IGZO layer is deposited using different processes, the improvement method of device performance should be investigated considering the solution process characteristics compared to the vacuum process.The thickness control method is one of the different points between the solution and vacuum process. In the vacuum process, the deposition time can control the layer thickness. However, the thickness of the solution-processed IGZO layer can be controlled by the layer stacking or the molarity of the precursor solution. Then, the thin film properties of the solution-processed IGZO layer can be varied depending on thickness. Therefore, the effect of thickness on the IGZO thin film properties should be considered when investigating the device performances of solution-processed IGZO TFTs with different active layer thicknesses.In this study, we investigated the reliability of solution-processed IGZO TFTs under bias stress as active layer thickness varied. Solution-processed IGZO TFTs were fabricated on a heavily doped p-type silicon wafer and thermally grown silicon dioxide using the gate electrode and gate insulator, respectively. The IGZO layer was deposited via a spin coating process using the precursor solution, which was prepared by dissolving indium acetate, gallium nitrate, and zinc acetate into 2-methoxyethanol. After annealing and patterning the IGZO layer, aluminum source and drain electrodes were deposited using thermal evaporation. We controlled the thickness of the solution-processed IGZO layer by controlling the molarity of the precursor solution and fabricated IGZO TFTs with active layer thicknesses of 15 and 80 nm.Solution-processed IGZO TFTs with a thick active layer (Device A) exhibited a negatively shifted threshold voltage and low field-effect mobility compared to devices with a thin active layer (Device B). Moreover, Device A was more significantly influenced by the constant bias stress than Device B. The threshold voltage shift (ΔV th) of Device A was 29.6 V, and that of Device B was 19.8 V, as shown in Figure 1. In other words, the reliability of solution-processed IGZO TFTs was degraded as the active layer thickness increased. The results of electrical properties and reliability of solution-processed IGZO TFTs with different active layer thicknesses were closely related to the defect state level of the IGZO layer. We analyzed the density-of-states (DOS) of solution-processed IGZO TFTs with different active layer thicknesses using the field-effect method [2]. Devices A and B exhibited DOS levels of 1.8×1017 and 9.8×1015 cm-3eV-1, respectively. In other words, the defect states increased as the thickness of solution-processed IGZO TFTs increased. The DOS variations depending on the IGZO layer thickness were attributed to the pin holes or disorder formed during the IGZO layer deposition process. Consequently, we concluded that the thin-film properties, including the DOS level, should be carefully controlled when controlling the active layer thickness to obtain high-performance solution-processed IGZO TFTs. Figure 1

High-performance polyester composite nanofiltration membrane fabricated by interfacial polymerization of ribitol and trimesoyl chloride: Dye desalination performance and mechanisms

A loose nanofiltration (LNF) membrane with high permeance and excellent dye/salt selectivity is highly desirable for dye/salts recovery from textile wastewater. Herein, commercial and green ribitol (RT) was employed to fabricate the LNF membrane for dye desalination. The hydroxyl in the RT reacted with acyl chloride under the catalysis of sodium hydroxide, forming a polyester film structured with microspheres, negative charge, and hydrophilic networks. The resultant RT-M membrane possessed a smooth and thin active layer with numerous polar groups. The dye desalination performance of the RT-M membrane was tailored by controlling various IP fabrication conditions. The optimized membrane (RT-M1.0) had superior water permeance (100.3 L m−2h−1 bar−1) and satisfactory CR/Na2SO4 selectivity (281.3). Additionally, the RT-M membrane had favorable stability and antifouling properties, demonstrating excellent potential for application in dye desalination. Therefore, a novel approach for fabricating membranes with outstanding dye desalination properties by using RT was proposed to achieve resource recycling.

Near‐Infrared Imaging Highly Enhanced by Pixel‐Level Integrated Plasmonic Metasurfaces on CMOS Image Sensors

AbstractNear‐infrared (NIR) photodetection and imaging have sparked significant interests across a wide range of applications. While silicon photodiodes are commonly employed, the small light absorption coefficients of Si in NIR severely limit the performance, especially in the case of thin active Si layers. Although various light harvesting techniques are proposed to increase light absorption of Si, pixel‐level strategy for enhanced NIR imaging is still challenging in CMOS image sensors (CISs) with a pixel size in only a micron scale. In this paper, plasmonic metasurfaces are intimately integrated on top of 2.3 µm thick Si active regions of the pixels of a backside illumination (BI)‐CIS for NIR imaging for the first time. 200% improved photoresponsivity is obtained in experiments in such a planar Si layer rather than patterning the Si layer with potential damage to the active region. Numerical simulation results reveal highly enhanced light intensity in the thin active Si layer due to the presence of plasmonic metasurfaces. Significantly improved imaging brightness and signal‐to‐noise ratio of NIR imaging are demonstrated under both laser and LED illumination. This CMOS‐compatible technique is expected to hold promising potentials in applications including machine vision, iris certification, light detection and ranging (LiDAR), and optical communication in data centers.

High-Performance Flexible Hybrid Silica Membranes with an Ultrasonic Atomization-Assisted Spray-Coated Active Layer on Polymer for Isopropanol Dehydration.

Organic-inorganic hybrid silica materials, incorporating an organic group bridging two silicon atoms, have demonstrated great potential in creating membranes with excellent permselectivity. Yet, the large-scale production of polymer-supported flexible hybrid silica membranes has remained a significant challenge. In this study, we present an easy and scalable approach for fabricating these membranes. By employing a sol-gel ultrasonic spray process with a single-pass method, we deposited a thin and uniform hybrid active layer onto a porous polymer substrate. We first optimized the deposition conditions, including substrate temperature, the binary solvent ratio of the silica sol, and various ultrasonic spray parameters. The resulting flexible hybrid silica membranes exhibited exceptional dehydration performance for isopropanol (IPA)/water solutions (IPA: 90 wt%) in the pervaporation process, achieving a water flux of 0.6 kg/(m2 h) and a separation factor of around 1300. This work demonstrates that the single-pass ultrasonic spray method is an effective strategy for the large-scale production of polymer-supported flexible hybrid silica membranes.

Radiation-tolerant dose sensor based on undoped amorphous silicon

Single-crystal silicon diodes are replacing gas-filled dose-rate meters because they are batch-processable, mechanically robust, compact, and operable at low voltages. However, they are prone to radiation damage in high dose fields. Hydrogenated amorphous silicon (a-Si:H) provides the manufacturing and operational benefits of silicon while adding inherent radiation hardness because of its wider bandgap and disordered microstructure. Previously, sensors with tens of micrometers thick a-Si have been investigated for direct dose sensing in x-ray imaging applications. However, the limited charge carrier lifetimes of the medium can reduce the charge collection efficiency and thereby the sensitivity. If a higher density, higher Z active media is coupled to thin amorphous silicon active layers, then an additional indirect component can be added to this direct signal to exhibit ∼15 μGy/s dose-rate sensitivities at zero and low-bias (<0.5 V) operation. Here we show that thin (150, 300, 450 nm) a-Si:H optical sensors can produce external quantum efficiencies above 40% and internal quantum efficiencies that exceed 70 % over a broad band from 380 nm to 650 nm, resulting in dose-rate sensitivity even at 0 V. When the charge-collecting electrodes abutting the a-Si:H serve the dual purpose as reflective layers in a lossy Fabry-Perot cavity, then internal quantum efficiencies greater than 83 % can be realized in a 30 nm thick layer at 410 nm. Cobalt-60 gamma-ray irradiation to 100 kGy (air) shows no radiation-induced degradation for even the thicker 300 nm sample; rather, a radiation hardening effect is observed as evinced in reduced dark current.

Optical terahertz metamaterial switch controlled via high-stability CsPbBr3 microcrystals.

Dynamic control of terahertz metamaterials using thin organic perovskite active layers has been extensively researched. However, the preparation of organic perovskite devices requires strict environmental conditions, and the devices are prone to hydrolysis in air, which reduces performance. Herein, we report an optical terahertz metamaterial switch controlled via hybridization with high-stability CsPbBr3 microcrystals prepared through precipitation from a water-dimethylformamide (DMF) mixed-solution. Under light excitation, a modulation factor of 24% was achieved based on the photoelectric and photothermal effects of the CsPbBr3 microcrystals. After exposure to air for four months, the modulation factor remained essentially unchanged, demonstrating the exceptional stability of the system generated. Following the integration of CsPbBr3 microcrystals with the metamaterial, a frequency-shift of its dipole resonance and switching of Fano resonance was achieved, providing a novel approach to dynamic control of terahertz waves.

Optical detection of passive thermal lattice deformation of monolayer WS2 in van der Waals heterostructures of WS2/h-BN

Van der Waals heterostructures (vdWHs) of the constituent two-dimensional (2D) layered materials are quickly emerging as functional structures for diverse novel electronic and optoelectronic devices. To further explore the device applications of the vdWHs, an open question, which is whether the lattice of atomic thin active layer follows the deformation of its neighboring thick layers in a vdWH, needs to be clarified. Herein, the thermal deformation of WS2 monolayers in vdWHs with and without hexagonal boron nitride (h-BN) layers on SiO2/Si substrates is investigated with combined optical spectroscopies of photoluminescence (PL) and Raman scattering. With a developed strategy extracting the pure strain-induced effects from the temperature-dependent PL and Raman scattering spectroscopic results, the relative deformations of the WS2 monolayers and the h-BN layers with respect to the substrate have been identified. Both the Raman and PL results consistently reveal that the lattice variation of the WS2 monolayers passively match the deformation of the h-BN layers, and the WS2 monolayer on the SiO2/Si substrate exhibits the largest strain. These findings have not only demonstrated the passive behavior of the thermal strain of 2D semiconductor monolayers in vdWHs heterostructures, but also paved a way to tailor the thermal strain via designing and constructing vdWHs.

Short-Wave Infrared Colloidal QD Photodetector with Nanosecond Response Times Enabled by Ultrathin Absorber Layers.

Ultrafast short-wavelength infrared (SWIR) photodetection is of great interest for emerging automated vision and spatial mapping technologies. Colloidal quantum dots (QDs) stand out for SWIR photodetection compared to epitaxial (In,Ga)As or (Hg,Cd)Te semiconductors by their combining a size-tunable bandgap and a suitability for cost-effective, solution-based processing. However, achieving ultrafast, nanosecond-level response time has remained an outstanding challenge for QD-based SWIR photodiodes (QDPDs). Here, record 4ns response time in PbS-based QDPDs that operate at SWIR wavelengths is reported, a result reaching the requirement of SWIR light detection and ranging based on colloidal QDs. These ultrafast QDPDs combine a thin active layer to reduce the carrier transport time and a small area to inhibit slow capacitive discharging. By implementing a concentration gradient ligand exchange method, high-quality p-n junctions are fabricated in these ultrathin QDPDs. Moreover, these ultrathin QDPDs attain an external quantum efficiency of 42% at 1330nm, due to a 2.5-fold enhanced light absorption through the formation of a Fabry-Perot cavity within the QDPD and the highly efficient extraction (98%) of photogenerated charge carriers. Based on these results, it is estimated that a further increase of the charge-carrier mobility can lead to PbS QDPDs with sub-nanosecond response time.

Stealthy Hyperuniform Surface Structures for Efficiency Enhancement of Organic Solar Cells

Low absorption in the thin active layer of conventional organic solar cells limits their power conversion efficiency. Structured surface layers are a common approach to diffracting incoming light, thus elongating its path through the active layer, thereby increasing the probability of absorption and hence the power conversion efficiency. While standard periodic structures diffract light into discrete angles, making them optimal only for specific wavelengths, random structures induce broadband, but nontailorable diffraction. Thus, instead, a stealthy hyperuniform structure, designed to exhibit beneficial diffraction properties is implemented: it directs the light into a predefined range of higher angles, prevents diffraction into small angles, and is thus ideal for a strong active path length enhancement. After numerical optimization of the feature height and diameter, the stealthy hyperuniform structure is fabricated in silicon by electron beam lithography and subsequently transferred into a transparent polymer via replica molding. Experimental diffraction images reveal a circular symmetric spectrum, inducing diffraction independent of the azimuthal angle and polarization of the incident light. The application of the stealthy hyperuniform structure on a 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′]dithiophene‐4,8‐dione)]: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 organic solar cell leads to a sharp increase in current density and power conversion efficiency.

Thick Active‐Layer Organic Solar Cells†

Comprehensive SummaryOrganic solar cells (OSCs) present a promising renewable energy technology due to their cost‐effectiveness, adaptability, and lightweight nature. The advent of non‐fullerene acceptors has further boosted their significance, allowing for power conversion efficiencies surpassing 19% even with an active layer thickness of about 100 nm. However, in order to achieve large scale production, it is necessary to fabricate OSCs with thicker active layers exceeding 300 nm that are compatible with large‐area printing techniques. Nevertheless, OSCs with thick active layers have inferior performance compared to those with thin active layers. To expedite the transition of OSCs from laboratory to industrial high‐throughput manufacturing, considerable efforts have been made to comprehend the performance limitations of thick active‐layer OSCs, develop novel photoactive materials that are high‐performance and tolerant towards the thickness of the active layer, and optimize the morphology of the photoactive layer and device structure. This review aims to provide a comprehensive summary of the mechanisms that lead to efficiency loss in thick active‐layer OSCs, the representative works on molecular design, and the optimization strategies for high‐performance thick active‐layer OSCs, and the remaining challenges that must be addressed.

Antifouling polymeric nanocomposite membrane based on interfacial polymerization of polyamide enhanced with green TiO2nanoparticles for water desalination

In the present investigation, the preparation and characterization of polyamide/TiO2as thin film nanocomposites (TFN) for brackish water desalination was investigated. TiO2nanoparticles (NPs) were synthesized by a green method using thyme plant extract as a reducing and capping agent. The TiO2NPs was successfully prepared in pure crystalline anatase phase with 15 nm size, and −33.1 mV zeta potential. The antimicrobial tests confirmed the antimicrobial activity of TiO2against gram-positive and gram-negative bacteria. In addition, TiO2NPs showed a good photocatalytic activity in degradation of methylene blue dye. TFN based on interfacial polymerization was enhanced by embedding 5% of the greenly synthesized TiO2NPs within the polyamide thin film active layer. The incorporation of TiO2NPs was confirmed by SEM, atomic force microscope (AFM), surface wettability, and FTIR. Membranes performance was investigated based on flux, salt rejection and fouling resistance. The antifouling was examined using bovine serum albumin (BSA) as protein fouling by dead-end cell filtration system at 2 bar. The results showed the TFN increased in water flux by 40.9% and a slight decrease in NaCl rejection (6.3%) was observed, with enhancement in antifouling properties. The flux recovery rate of the modified TFN membranes after fouling with BSA solution was enhanced by 21.5% (from 61.7% for TFC to 83.2% for TFN). Also, they demonstrated remarkable anti-biofouling behavior against both bacterial strains.

Organic near‐infrared photodetectors with photoconductivity‐enhanced performance

AbstractOrganic near‐infrared (NIR) photodetectors with essential applications in medical diagnostics, night vision, remote sensing, and optical communications have attracted intensive research interest. Compared with most conventional inorganic counterparts, organic semiconductors usually have higher absorption coefficients, and their thin active layer could be sufficient to absorb most incident light for effective photogeneration. However, due to the relatively poor charge mobility of organic materials, it remains challenging to inhibit the photogenerated exciton recombination and effectively extract carriers to their respective electrodes. Herein, this challenge was addressed by increasing matrix conductivities of a ternary active layer (D–A–D structure NIR absorber [2TT‐oC6B]:poly(N,N′‐bis‐4‐butylphenyl‐N,N′‐bisphenyl)benzidin [PolyTPD]:[6,6]‐phenyl‐C61‐butyric acid methyl ester [PCBM] = 1:1:1) upon in situ incident light illumination, significantly accelerating charge transport through percolated interpenetrating paths. The greatly enhanced photoconductivity under illumination is intrinsically related to the unique donor–acceptor molecular structures of PolyTPD and 2TT‐oC6B, whereas stable intermolecular interaction has been verified by systematic molecular dynamics simulation. In addition, an ultrafast charge transfer time of 0.56 ps from the NIR aggregation‐induced luminogens of 2TT‐oC6B absorber to PolyTPD and PCBM measured by femtosecond transient absorption spectroscopy is beneficial for effective exciton dissociation. The solution‐processed organic NIR photodetector exhibits a fast response time of 83 μs and a linear dynamic range value of 111 dB under illumination of 830 nm. Therefore, our work has opened up a pioneering window to enhance photoconductivity through in situ photoirradiation and benefit NIR photodetectors as well as other optoelectronic devices.

Flexible Solution-Processed Electron-Transport-Layer-Free Organic Photovoltaics for Indoor Application

Organic photovoltaics (OPVs) have unique advantages of low weight, mechanical flexibility, and solution processability, which make them exceptionally suitable for integrating low-power Internet of Things devices. However, achieving improved operational stability together with solution processes that are applicable to large-scale fabrication remains challenging. Their major limitation arises due to the instable factors that occur both inside the thick active film and from the ambient environment, which cannot be completely resolved via the current encapsulation techniques used for flexible OPVs. Additionally, thin active layers are highly vulnerable to point defects, which result in low yield rates and impede the laboratory-to-industry translation. In this study, flexible fully solution-processed OPVs with improved indoor efficiency and long-term operational stability than that of conventional OPVs with evaporated electrodes are achieved. Benefiting from the oxygen and water vapor permeation barrier of the spontaneously formed gallium oxide layers on the exposed eutectic gallium-indium surface, fast degradation of the OPVs with thick active layers is prevented, maintaining 93% of its initial Pmax after 5000 min of indoor operation under 1000 lx light-emitting diode (LED) illumination. Additionally, by using the thick active layer, spin-coated silver nanowires could be directly used as bottom electrodes without complicated flattening processes, thereby substantially simplifying the fabrication process and proposing a promising manufacturing technique for devices with high-throughput energy demands.

Enhanced light absorption of organic solar cells based on stopped-trench metal grating.

Here, the influence of dimensional parameters of the trench metal grating on the absorption efficiency of organic solar cells (OSCs) was evaluated. The plasmonic modes were calculated. Due to the capacitance-like charge distribution in a plasmonic configuration, the platform width of grating has a significant influence on the intensity of wedge plasmon polaritons (WPPs) and Gap surface plasmon (GSPs). Stopped-trench gratings would lead to better absorption efficiency than thorough-trenched gratings. The stopped-trench gratings (STG) model with a coating layer showed 77.01% integrated absorption efficiency, which is 19.6% better than previously reported works with 19% less photoactive materials. This model offered 18% integrated absorption efficiency, better than an equivalent planar structure without a coating layer. Specifying the areas with maximum generation on the structure helps us to manage and reduce the thickness and volume of the active layer to control the recombination losses and the cost. We rounded the edges and corners with a curvature radius of 30 nm to investigate tolerance during fabrication. Results demonstrated that the integrated absorption efficiency profile of the blunt model is slightly different from the integrated absorption efficiency profile of the sharp model. Finally, we have studied the wave impedance (Zx) inside the structure. Between the spectrum of λ =∼700 nm to λ=900 nm, an extremely high wave impedance layer was formed. It creates an impedance mismatch between layers and helps us to better trap the incident light ray. STG with a coating layer (STGC) is a promising way to produce OCSs with extremely thin active layers.

A thin Si nanowire network anode for high volumetric capacity and long-life lithium-ion batteries

Silicon nanowires (Si NWs) have been widely researched as the best alternative to graphite anodes for the next-generation of high-performance lithium-ion batteries (LIBs) owing to their high capacity and low discharge potential. However, growing binder-free Si NW anodes with adequate mass loading and stable capacity is severely limited by the low surface area of planar current collectors (CCs), and is particularly challenging to achieve on standard pure-Cu substrates due to the ubiquitous formation of Li+ inactive silicide phases. Here, the growth of densely-interwoven In-seeded Si NWs is facilitated by a thin-film of copper-silicide (CS) network in situ grown on a Cu-foil, allowing for a thin active NW layer (<10 µm thick) and high areal loading (≈1.04 mg/cm2) binder-free electrode architecture. The electrode exhibits an average Coulombic efficiency (CE) of >99.6% and stable performance for >900 cycles with ≈88.7% capacity retention. More significantly, it delivers a volumetric capacity of ≈1086.1 mA h/cm3 at 5C. The full-cell versus lithium manganese oxide (LMO) cathode delivers a capacity of ≈1177.1 mA h/g at 1C with a stable rate capability. This electrode architecture represents significant advances toward the development of binder-free Si NW electrodes for LIB application.

Organic solar cells pros and cons: Outlooks toward semitransparent cell efficiency and stability

Organic solar cells (OSCs) are promising for low emissive photovoltaic technology. Excitonic absorption and charge generation to transport process OSC energy loss lessening are central. In this context, donor–acceptor barrier offset, related binding, and thermal effect on energy loss are the key challenge. Semitransparent organic solar cell visible band transmission and near infrared band absorption are anticipated. Near infrared band absorption in a Si material solar cell is higher that supports more energy conversion. Moreover, greater carrier selectivity and open circuit voltage (Voc) is incredible to increase the energy efficiency. OSC utmost absorption but carrier generation and charge transfer state donor–acceptor barrier offset increases carrier recombination loss. Upon analysis of small molecule donors and polymers along with non-fullerene and previously studied fullerene acceptors, it is realized that active material morphology, thickness, and interface design are impending to overcome the energy loss. For efficiency–transparency trade-off as well as stability problem lessening purpose thin active materials and interface, their absorption band tenability and carrier selectivity are main requisites. In this scope, very thin non-fullerene acceptors in ternary blend heterostructures and innovative-transparent hole transport layers can play a vital role. Therefore, recombination loss lessening and transparency purpose near infrared band absorbent thin active layer ternary blend and transparent electrodes of a thin hetero-interface predominant field effect over the thermal effect are reported in the efficiency and stability scope.

Photovoltaic technologies photo-thermal challenges: Thin active layer solar cells significance

Massive energy demand and source of energy usages is the key root of global emission and climate change. Solar photovoltaic (PV) is low carbon energy technology currently 3.2% share of global electricity supply. The rapid progress of solar PV is vastly related to increase energy efficiency and lessening of active materials usage. This paper solar PV present significance and most prospective PV materials technical challenges are reviewed for its future advancement. Among the challenges solar energy absorption-related dynamic photo-thermal effect on cells or modules is vital. Transparent passivation contact materials with lower temperature coefficient (TC) and thin active layer resulted in lowering both dynamic photo-thermal outcome and optical to electrical energy gap. Thin active layer minor bulk recombination and sub-band parasitic absorption lessening purpose transparent conductive materials (TCM) based proper band barrier heterointerface is impending. It can optimize desired band absorption and photo-coupling with selective carrier induces greater efficiency. Earlier research though explains it on carrier selectivity prejudice, but how it can lessen the near infrared band optical and associated thermal influence is essential to illustrated. Passivation and TC interrelations hence, field related drift is control over diffusion process loss in advanced bifacial and thin active layer PV technology. Loss lessening pathways thin wafer-based Si, thin film CdTe, organic and perovskite photo coupling with advanced TCM, thus, Si/CdTe and Si/perovskite tandem cells along with OSC building integrated transparent photovoltaic technologies advancement pathways are reported.

Methanol Vapor Retards Aging of PIM-1 Thin Film Composite Membranes in Storage

Physical aging of glassy polymers leads to a decrease in permeability over time when they are used in membranes. This hinders the industrial application of high free volume polymers, such as the archetypal polymer of intrinsic microporosity PIM-1, for membrane gas separation. In thin film composite (TFC) membranes, aging is much more rapid than in thicker self-standing membranes, as rearrangement within the thin active layer is relatively fast. Liquid alcohol treatment, which swells the membrane, is often used in the laboratory to rejuvenate aged self-standing membranes, but this is not easily applied on an industrial scale and is not suitable to refresh TFC membranes because of the risk of membrane delamination. In this work, it is demonstrated that a simple method of storage in an atmosphere of methanol vapor effectively retards physical aging of PIM-1 TFC membranes. The same method can also be utilized to refresh aged PIM-1 TFC membranes, and one-week methanol vapor storage is sufficient to recover most of the original CO2 permeance.

Hydrochemistry of surface waters in a permafrost headwater catchment in the Northeastern Tibetan Plateau

The permafrost headwater catchments in the Tibetan Plateau (TP) have experienced extensive permafrost degradation, which may cause major changes in riverine solutes. However, surface water hydrochemistry and its influencing factors in such catchments are poorly understood. Hydrochemistry data for different surface waters were obtained for the Yakou catchment in the Northeastern TP. The results indicate that the ionic and organic concentrations of frozen soil seeps (FSS) were higher on the north-facing slope compared to the south-facing slope, and that FSS may be involved in streamflow generation processes and in determining the spatial pattern of riverine solutes. The north-facing slope of the catchment has a thin active layer and wet moisture conditions compared to the south-facing slope; hence supra-permafrost water, with high ionic concentrations, can drain to the ground surface as FSS in the riparian zone and then recharge the surface ponding water and the main stream water. The high ionic concentrations of the supra-permafrost water and FSS can be attributed to intense rock weathering and evaporative effect, together with the high mobility of elements and the transport of organic matter. The tributaries, with low ionic concentrations, comprise a mixture of infiltrating precipitation and diluted supra-permafrost water. Carbonate weathering is the dominant weathering type within the catchment, but the weathering of evaporite and silicate is more important on the north-facing and south-facing slopes, respectively, and chemical weathering on the north-facing slope may be enhanced by strong physical erosion during repeated freeze–thaw cycles due to the wet conditions. The results indicate that the surface water hydrochemistry is heterogeneous on the different hillslope units, and that a thicker active layer under climate change may lead to a shift of hydrological and hydrochemical pathways, and thus a decrease in water and solute flux from the hillslopes, with underlying permafrost, to the river channel.