Thick Junction Research Articles

In Situ Crystal Growth and Fusing-Confined Engineering of Quasi-Monocrystalline Perovskite Thick Junctions for X-ray Detection and Imaging.

Metal halide perovskites exhibit great promise for utilization in X-ray detection owing to their excellent optoelectronic properties and high X-ray attenuation capabilities. However, fabricating large-area thick films for high-performance perovskite X-ray detection remains challenging. This study develops an in situ crystal growth and fusing-confined approach to prepare high-quality, large-scale perovskite quasi-monocrystalline thick junctions. The perovskite crystals are grown in situ using a highly concentrated perovskite colloidal solution in 2-methoxyethanol. Introducing methylammonium chloride enhances grain reorganization during in situ growth and fusing-confined processes, effectively reducing grain boundaries and surface defects. This allows for the preparation of quasi-monocrystalline thick junctions of large grains (>100 μm) with high crystallinity, uniform orientation, and vertical penetration across the film thickness. Additionally, the carrier mobility and lifetime of the thick junctions are significantly enhanced. The optimized MAPbI3 detectors demonstrate an X-ray sensitivity of 2.6 × 104 μC Gyair-1 cm-2 and an exceptionally low detection limit of 1 nGyair s-1. Furthermore, inspired by a honeycomb structure, these detectors realize X-ray imaging in 64 × 64 pixels through a pixelated separation design, effectively reducing the charge-sharing effect. This study offers valuable insights into the preparation of large-scale perovskite quasi-monocrystalline thick junctions for highly sensitive X-ray detection and imaging applications.

Characterization of Photo-Crosslinked Methacrylated Type I Collagen as a Platform to Investigate the Lymphatic Endothelial Cell Response

Despite chronic fibrosis occurring in many pathological conditions, few in vitro studies examine how fibrosis impacts lymphatic endothelial cell (LEC) behavior. This study examined stiffening profiles of PhotoCol®—commercially available methacrylated type I collagen—photo-crosslinked with the photoinitiators: Lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP), Irgacure 2959 (IRG), and Ruthenium/Sodium Persulfate (Ru/SPS) prior to evaluating PhotoCol® permeability and LEC response to PhotoCol® at stiffnesses representing normal and fibrotic tissues. Ru/SPS produced the highest stiffness (~6 kilopascal (kPa)) for photo-crosslinked PhotoCol®, but stiffness did not change with burst light exposures (30 and 90 s). The collagen fibril area fraction increased, and dextran permeability (40 kilodalton (kDa)) decreased with photo-crosslinking, showing the impact of photo-crosslinking on microstructure and molecular transport. Human dermal LECs on softer, uncrosslinked PhotoCol® (~0.5 kPa) appeared smaller with less prominent vascular endothelial (VE)-cadherin (cell–cell junction) expression compared to LECs on stiffer PhotoCol® (~6 kPa), which had increased cell size, border irregularity, and VE-cadherin thickness (junction zippering) that is consistent with LEC morphology in fibrotic tissues. Our quantitative morphological analysis demonstrates our ability to produce LECs with a fibrotic phenotype, and the overall study shows that PhotoCol® with Ru/SPS provides the necessary physical properties to systematically study LEC responses related to capillary growth and function under fibrotic conditions.

Solution-processed Sb2-xBixS3 thick junctions for stable, low-noise, and sensitive X-ray detection

Solution-processed Sb2-xBixS3 thick junctions for stable, low-noise, and sensitive X-ray detection

Low-donor content approach to achieve sensitive narrowband organic photodetectors

Narrowband near-infrared (NIR) detectors are key components for various modern biomedical, agricultural, astronomical sensing as well as monitoring applications. Typically, a narrowband organic photodetector (OPD) requires thick junctions or additional optical elements, which are either tedious or cost-ineffective. Here, we adopt the low-donor content strategy in our thin-film device to realize narrowband spectral features. The much-mitigated aggregation drastically improves shunt resistance and dark current while maintaining decent photocurrent. Upon further dilution, a thinner electron transporting layer can effectively shorten the transient response to reach fast speed. n-i-p and p-i-n device configurations are also compared, which exhibits drastic changes for low-donor content OPDs. The 5 wt% D:A thin-film bulk-heterojunction OPD presents an external quantum efficiency of 49.3% at 770 nm with zero bias, and a high thermal-noise calculated specific detectivity (D*) of 1.0 × 1013 Jones (7.1 × 1012 Jones based on noise spectral density) at 0 V. Such narrowband OPD also shows a fast NIR response of 530 ns/840 ns (rise/fall) when operated at 10 kHz. The results reveal the potential for low-donor-content blend in realizing narrowband photodetection.

Narrow Band Organic Photodiode with Photoresponse at 808 nm for Photoplethysmography

The fabrication and characterization of an all polymers‐based bulk heterojunction type organic photodiode having a narrowband response in the near‐infrared spectral region with full width at half‐maxima of 63 nm is reported. The active layer of the photodiode constitutes a 1:1 (by weight) blend of 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)] (PCE10) and poly{[N,N′‐bis(2‐octyldodecyl)‐naphthalene‐1,4,5,8‐bis(dicarboximide)‐2,6‐diy1]‐alt‐5,5′‐(2,2′‐dithiophene)} (N2200) deposited using solution processing. The device exhibits a linear dynamic range of 35 dB, response speed of 893 kHz, and specific‐detectivity of 109 Jones at 808 nm excitation wavelength. The narrowband response is achieved using the charge collection narrowing mechanism in a 2.7 μm thick junction device.

Spectral problems with perturbed Steklov conditions in thick junctions with branched structure

The article examines spectral problems in a domain Ω ϵ , which is the union of a domain Ω 0 and a lot of thin trees that are ε-periodically situated along a manifold on the boundary of Ω 0 . The trees possess a finite number of branching levels. At the boundaries of branches from each branching level, the perturbed Steklov spectral condition ∂ ν u ϵ = ϵ α λ ϵ ϱ i , m u ϵ is given, where α ∈ R . For a fixed ε, the problem possesses a discrete spectrum, and we analyze the asymptotic behavior of the eigenvalues and eigenfunctions as ϵ → 0 , i.e. when the number of thin trees infinitely increases and their thickness vanishes. Three qualitatively distinct cases of the asymptotic behavior of the spectrum are identified depending on the parameter α. For each case, the study provides proof of the Hausdorff convergence of the spectrum, construction of leading asymptotic terms, and justification of the asymptotic estimates for the eigenvalues and eigenfunctions. For a point in the essential spectrum of the homogenized problem, we discover finite-energy eigenoscillations localized in one or some of the thin trees, and prove the asymptotic estimates. Cases, where the Steklov condition contains α depending on the branching level, are also discussed.

Printable Thick Junctions based Lead-Free Perovskite Single Crystal Powders for X-ray Detection

Blade-coating technology is regarded as a pivotal approach for the scalable fabrication of perovskite-based devices and holds great promise for the future manufacturing of advanced X-ray flat-panel detectors. However, further...

Thickness-Dependent Charge Transport in Three Dimensional Ru(II)- Tris(phenanthroline)-Based Molecular Assemblies.

We describe here the fabrication of large-area molecular junctions with a configuration of ITO/[Ru(Phen)3]/Al to understand temperature- and thickness-dependent charge transport phenomena. Thanks to the electrochemical technique, thin layers of electroactive ruthenium(II)-tris(phenanthroline) [Ru(Phen)3] with thicknesses of 4-16 nm are covalently grown on sputtering-deposited patterned ITO electrodes. The bias-induced molecular junctions exhibit symmetric current-voltage (j-V) curves, demonstrating highly efficient long-range charge transport and weak attenuation with increased molecular film thickness (β = 0.70 to 0.79 nm-1). Such a lower β value is attributed to the accessibility of Ru(Phen)3 molecular conduction channels to Fermi levels of both the electrodes and a strong electronic coupling at ITO-molecules interfaces. The thinner junctions (d = 3.9 nm) follow charge transport via resonant tunneling, while the thicker junctions (d = 10-16 nm) follow thermally activated (activation energy, Ea ∼ 43 meV) Poole-Frenkel charge conduction, showing a clear "molecular signature" in the nanometric junctions.

Visible-Light Communication with Lighting: RGB Wavelength Division Multiplexing OLEDs/OPDs Platform.

A multichannel/multicolor visible light communication (VLC) system using entirely organic components, including organic light emitting diodes (OLEDs) and organic photodiodes (OPDs), is developed to demonstrate indoor lighting applications where the integration of OLEDs and OPDs has significant potential. To achieve this, tricolor (Red/Green/Blue(R/G/B))-selective OPD arrays for the receiver and tricolor OLED arrays for the emitter are developed. For (R/G/B)-selective OPDs, a Fabry-Pérot electrode to enhance color selectivity and a thick junction structure to effectively accommodate a wide range of driving voltages are introduced. For tricolor OLEDs, fluorescent-emitting materials are used to enhance the operating frequency in addition to introducing a cavity structure to achieve narrow emission. Utilizing these spectrally refined tricolor OPDs/OLEDs, a VLC system is designed for indoor lighting applications, and a systematic analysis of their signal-to-interference ratio dependence on the distance or angle between the transmitter and receiver is performed. The study's findings indicate the importance of emission angle-dependent wavelength shift of the OLED and the luminosity function, which varies with wavelength, in the R/G/B mixed-white-light-based VLC systems. Finally, the feasibility of VLC using tricolor OPDs/OLEDs in the real-life context of indoor white-color lighting is demonstrated, showing that the transmitted data patterns well-matched the received data patterns.

Full-thickness skin rejuvenation by a novel dual-length microneedle radiofrequency device: A proof-of-concept study using human skin.

A novel dual-length microneedle radiofrequency (DLMR) device has been developed to achieve full-thickness skin rejuvenation by stimulating the papillary and reticular dermis simultaneously. This device's dual-level targeting concept need to be validated on human skin, although its clinical efficacy has been demonstrated in a previous study. This study evaluated the dual-depth targeting capability and the ability to induce rejuvenation in each layer of vertical skin anatomy, that is, the epidermis, papillary dermis, and reticular dermis, using full-thickness human facial skin samples. Human facial skin samples were obtained from 13 Asian patients who had facelift surgery. To validate the dual-depth targeting concept, DMLR-treated skin samples were analyzed using a digital microscope, thermal imaging, and hematoloxylin and eosin (H&E) staining immediately after DLMR application. On samples stained with H&E, Masson's tricrome, and Verhoeff-Van Gieson, histological observation and morphometric analysis were performed. Total collagen assay (TCA) and quantitative real-time polymerase chain reaction (qPCR) were used to assess changes in total collagen content and mRNA expression levels of collagen types I/III and vimentin, respectively. The DLMR device successfully induced thermal stimulation in the papillary and reticular dermis. The thickness, stacks, and dermal-epidermal junction convolution of the epidermis treated with DLMR were significantly increased. Collagen bundles in the dermis treated with DLMR exhibited a notable increase in thickness, density, and horizontal alignment. Dermal collagen levels were significantly higher in the morphometric and TCA data, as well as in the qPCR data for dermal matrix proteins. Our DLMR device independently and precisely targeted the papillary and reticular dermis, and it appears to be an effective modality for implementing full-thickness rejuvenation.

Asymptotic analysis of spectral problems in thick junctions with the branched fractal structure

A spectral problem is considered in a domain that is the union of a domain and a lot of thin trees situated ‐periodically along some manifold on the boundary of The trees have finite number of branching levels. The perturbed Robin boundary condition is given on the th branching layer; are real parameters. The asymptotic analysis of this problem is made as , that is, when the number of the thin trees infinitely increases and their thickness vanishes. In particular, the Hausdorff convergence of the spectrum to the spectrum of the corresponding nonstandard homogenized spectral problem is proved, the leading terms of asymptotics are constructed, and the corresponding asymptotic estimates are justified for the eigenvalues and eigenfunctions.

Ion-exchange-induced slow crystallization of 2D-3D perovskite thick junctions for X-ray detection and imaging

<h2>Summary</h2> Metal-halide perovskites have recently emerged as promising candidates for next-generation X-ray detectors, mainly benefiting from their low-temperature solution processability, chemical versatility, low cost, and excellent and tunable optoelectronic properties. However, the fabrication of perovskite thick junctions is very challenging, particularly for solution-processed thick photodiodes. Here, we report an ion-exchange strategy to prepare two-dimensional (2D)-3D perovskite thick films for directly detecting X-rays. This approach provides a facile and generic fabrication of high-quality perovskite films with various perovskite precursors, achieving uniform morphology, tunable thickness, and vertically monolithic crystal phase. The dynamic processes of the ion exchange were fully characterized and studied with multiple <i>in situ</i> and <i>ex situ</i> techniques, e.g., photoluminescence spectroscopy and X-ray diffraction. After optimization, record-high X-ray sensitivity of 1.36 × 10⁴ μC Gy_air^-1 cm^-2 and ultra-low detection limit of 4.2 nGy_air s^-1 were achieved based on the optimized (BA₂PbBr₄)_0.5FAPbI₃ detectors, demonstrated along with 32 × 32 pixel prototypical photodetector arrays.

Effect of contact lens-assisted corneal collagen crosslinking with riboflavin in keratoconus in eyes with thinnest pachymetry &lt;400 μ after removal of corneal epithelium

Purpose To study the effect of contact lens-assisted corneal collagen crosslinking (CACXL) with riboflavin in keratoconus in eyes with thinnest pachymetry <400 μ after removal of corneal epithelium, in terms of halting disease progression and if it had any serious adverse effects in terms of drop in visual acuity, corneal endothelial cell loss, or effect on the inner and outer segment (IS-OS) junction integrity at macula. Materials and Methods The study was done on patients attending the cornea department of a tertiary eye hospital who were diagnosed with progressive keratoconus. Pregnant, mentally retarded, one eyed patients or those with high expectations or poor understanding of treatment outcomes were excluded. These corneas with the thinnest pachymetry <400 μ after epithelial debridement were treated with CACXL and were followed up over a minimum period of 12 months postoperatively. Results In the 30 eyes studied, statistically significant improvement was noted in uncorrected and best-corrected visual acuity at the end of 12 months from treatment. There was statistically significant change in cylinder (P = 0.043), maximum keratometry (P = 0.018), stimulated keratometry (P = 0.024) at 12 months of follow-up postoperatively. There was no statistically significant change in spherical refraction (P = 0.136) and minimum keratometry (P = 0.865) at 12 months of follow-up postoperatively. There was no significant change in specular endothelial cell count or central macular thickness and IS-OS junction integrity at 12 months. Minimal adverse effect was seen in the form of haze persisting beyond 1 month in three cases, which could be reversed medically. Conclusion CACXL is a safe technique that offers promising results in the management of patients with progressive keratoconus and thinner pachymetry values, not amenable to treatment by standard procedure.

High performance low-bandgap (0.8 eV) single junction GaInNAsSb solar cells incorporating Au-based back surface reflectors

Low-bandgap GaInNAsSb single junction solar cells incorporating a planar Au back surface reflector for enhancing the photocurrent generation are reported. In particular, a 700 nm thick GaInNAsSb junction with a bandgap of 0.78 eV (corresponding to 6.2% N) incorporating the back reflector exhibited a short-circuit current density of 15.2 mA/cm2 for AM1.5D (1000 W/m2) illumination, when placed underneath a GaAs-filter mimicking the operation of a multijunction architecture. The corresponding external quantum efficiency represents the highest external quantum efficiency reported so far for dilute nitride solar cells with bandgaps below 0.8 eV. Electrical simulations reveal that the relatively high value of the quantum efficiency is attributed to a low p-type carrier concentration and partially to the varying doping level in the GaInNAsSb region. Moreover, the absorption coefficients for low-bandgap GaInNAsSb materials are estimated and used in a comprehensive optical analysis to understand the photon harvesting performance of the solar cells with reflector. The analysis reveals incomplete absorption in the GaInNAsSb layers for the double-pass configuration enabled by the planar back reflector pointing to the need for deploying more advanced structured reflectors. However, the structures exhibited high collection efficiencies laying the foundation for further improvements of the quantum efficiency values. Moreover, the low-bandgap dilute nitride solar cells show potential to meet the current-matching requirements in next-generation multijunction devices with five or more junctions, thus being a prospective alternative for replacing Ge as the bottom junction.

Polysorbate- and DNA-Mediated Synthesis and Strong, Stable, and Tunable Near-Infrared Photoluminescence of Plasmonic Long-Body Nanosnowmen.

Direct photoluminescence (PL) from metal nanoparticles (NPs) without chemical dyes is promising for sensing and imaging applications since this offers a highly tunable platform for controlling and enhancing the signals in various conditions and does not suffer from photobleaching or photoblinking. It is, however, difficult to synthesize metal NPs with a high quantum yield (QY), particularly in the near-infrared (NIR) region where deep penetration and reduced light scattering are advantageous for bioimaging. Herein, we designed and synthesized Au-Ag long-body nanosnowman structures (LNSs), facilitated by polysorbate 20 (Tween 20). The DNA-engineered conductive junction between the head and body parts results in a charge transfer plasmon (CTP) mode in the NIR region. The junction morphology can be controlled by the DNA sequence on the Au core, and polythymine and polyadenine induced thick and thin junctions, respectively. We found that the LNSs with a thicker conductive junction generates the stronger CTP peak and PL signal than the LNSs with a thinner junction. The Au-Ag LNSs showed much higher intensities in both PL and QY than widely studied Au nanorods with similar localized surface plasmon resonance wavelengths, and notably, the LNSs displayed high photostability and robust, sustainable PL signals under continuous laser exposure for >15 h. Moreover, the PL emission from Au-Ag LNSs could be imaged in a deeper scattering medium than fluorescent silica NPs. Finally, highly robust PL-based cell images can be obtained using Au-Ag LNSs without significant signal change while repetitively imaging cells. The results offer the insights in plasmonic NIR probe design, and show that chemical dye-free LNSs can be a very promising candidate with a high QY and a robust, reliable NIR PL signal for NIR sensing and imaging applications.

148 Fibrillin-rich microfibrils: Key components of dermal-epidermal junction architecture?

Understanding skin health and disease across global populations is of great importance yet the majority of studies focus primarily on individuals with lightly-pigmented skin. We obtained skin biopsies from photoprotected buttock of healthy, young (18-40 years; n = 33) individuals of black African, South Asian, Hispanic and white European ancestries. Our study cohort demonstrated diversity of pigmentation levels, with skin types ranging from lightest to darkest according to Individual Typology Angle (ITA) – an objective spectrophotometric skin colour classification consisting of 6 groups: ‘very light’; ‘light’; ‘intermediate’; ‘tan’; ‘brown’; and ‘dark’. In the ‘dark’ and ‘brown’ groups, epidermal thickness and dermal-epidermal junction (DEJ) convolution were significantly increased as compared to those in the ‘light’ and ‘very light’ groups, whereas measurements for the ‘tan’ and ‘intermediate’ groups were midway (P < 0.001). Fibrillin-rich microfibrils (FRM) are located at the DEJ in candelabra-like cascades, with concentration at the base of rete pegs. The distribution of FRM was assessed across all skin types; for individuals in ‘dark’ or ‘brown’ groups FRM were significantly more abundant (44.5% and 40.2%, respectively) than those in ‘light’ and ‘very light’ groups (28.6% and 26.9%, respectively), whereas those in the ‘tan’ or ‘intermediate’ groups were midway (33.7% and 30.8%, respectively; P < 0.001). A positive correlation exists between DEJ convolution and FRM abundance (r = 0.379; P < 0.001) suggesting that FRM may contribute to DEJ structure and integrity. This study demonstrates that fundamental differences exist in skin structure and composition in individuals of diverse geographical ancestry and suggest a role for FRM in DEJ architecture.

How to Reduce Charge Recombination in Organic Solar Cells: There are Still Lessons to Learn from P3HT:PCBM

AbstractSuppressing charge recombination is key for organic solar cells to become commercial reality. However, there is still no conclusive picture of how recombination losses are influenced by the complex nanoscale morphology. Here, new insight is provided by revisiting the P3HT:PCBM blend, which is still one of the best performers regarding reduced recombination. By changing small details in the annealing procedure, two model morphologies are prepared that vary in phase separation, molecular order, and phase purity, as revealed by electron tomography and optical spectroscopy. Both systems behave very similarly with respect to charge generation and transport, but differ significantly in bimolecular recombination. Only the system containing P3HT aggregates of high crystalline quality and purity is found to achieve exceptionally low recombination rates. The high‐quality aggregates support charge delocalization, which assists the re‐dissociation of interfacial charge‐transfer states formed upon the encounter of free carriers. For devices with the optimized morphology, an exceptional long hole diffusion length is found, which allows them to work as Shockley‐type solar cells even in thick junctions of 300 nm. In contrast, the encounter rate and the size of the phase‐separated domains appear to be less important.

Requirements for Making Thick Junctions of Organic Solar Cells based on Nonfullerene Acceptors

Organic bulk‐heterojunction solar cells based on the newly developed nonfullerene electron acceptors have the potential for very low‐cost energy production. However, to enable large‐scale production with common printing techniques, the active layer thicknesses need to be increased by up to an order of magnitude, which is currently not possible without significant loss in performance. Herein, the requirements for making nonfullerene acceptor (NFA)‐based solar cells with thick active layers and high efficiencies are clarified. The charge carrier mobility, unintentional doping concentrations, and bimolecular recombination prefactor in the model high‐efficiency system PM6 (Poly[(2,6‐(4,8‐bis(5‐(2‐ethylhexyl‐3‐fluoro)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)]):Y6 (2,2′‐((2Z,2′Z)‐((12,13‐bis(2‐ethylhexyl)‐3,9‐diundecyl‐12,13‐dihydro‐[1,2,5]thiadiazolo[3,4‐e]thieno[2″,3″:4′,5′]thieno[2′,3′:4,5]pyrrolo[3,2‐g]thieno[2′,3′:4,5]thieno[3,2‐b]indole‐2,10‐diyl)bis(methanylylidene))bis(5,6‐difluoro‐3‐oxo‐2,3‐dihydro‐1H‐indene‐2,1‐diylidene))dimalononitrile) are determined. The results are implemented in a combined electro‐optical device model, which is used to determine the effect of varying these parameters on the efficiency. The results show that a mobility imbalance and doping can lead to improved performance at large thicknesses, partially contradicting previous studies performed on fullerene‐based systems. The findings highlight the importance of determining electron and hole mobilities selectively, as well as characterizing recombination and doping concentrations.

A recalculation of the efficiency limit in crystalline Si/Si tandem solar cells

We determine the limiting efficiency for monolithic tandem solar cells that employ crystalline silicon for the top-cell as well as for the bottom cell. In such a design, the top-cell extends over the region of very high generation rate that forms at the front of the device. Consequently, the design benefits from a high excess carrier density in the top-cell, resulting in a voltage in the tandem device that is more than twice the voltage of equally thick single junction solar cells. Considering Coulomb-enhanced Auger recombination coefficient, we find a maximum efficiency of 30.7% for a total device thickness of 500 μm wherein the top cell thickness amounts to 2.15 μm, representing gain of 1.1% (abs) with respect to the limiting efficiency of single junction devices.

Evaporated Perovskite Thick Junctions for X-Ray Detection.

X-ray detection is widely utilized in our daily life, such as in medical diagnosis, security checking, and environmental monitoring. However, most of the commercial X-ray detectors are based on inorganic semiconductors, e.g., Si, CdTe, and Ge, which require complex and costly fabrication processes. Metal halide perovskites have recently emerged as a set of promising candidates for ionizing radiation detection, owing to the high attenuation coefficient, long carrier lifetime, and excellent charge transport properties. Perovskite single crystals have been successfully implemented in X-ray detection, but the fragile single crystals limit the device fabrication and the integration with a read-out circuit. In addition, it is hard to reach inch-size single crystals for real application. Flexible devices based on perovskite films or composite films have also been reported, but either the thickness or charge transport properties are limited by the solution processes. In this work, we introduced thermal co-evaporation to deposit highly efficient formamidinium lead iodide perovskite films. Considering the trade-off between X-ray absorption and charge transport, we optimized the active layer thickness and achieved large-area and flexible X-ray detectors with state-of-the-art device performance, including extremely low dark current and noise, fast response, and high sensitivity of 142.1 μC Gyair-1 cm-2.