Intrinsic Research Articles

The development of transfer technologies for advanced 2D circuits integration

AbstractIn the light of the scaling limitations of conventional CMOS technology, two‐dimensional (2D) materials offer a transformative avenue for advancing Moore's law in the post‐Moore era. The technology for transferring 2D materials serves as a crucial link between their synthesis and device integration. This review provides a comprehensive assessment of advancements in the transfer technologies and integration of 2D materials, which are essential for next‐generation electronics. Firstly, state‐of‐the‐art methodologies for high‐quality, wafer‐scale transfer of 2D materials, including both wet and dry transfer methods are thoroughly reviewed. And the requirements for massive transfer of 2D materials compatible with silicon line while preserving their intrinsic properties are disscussed. Next, we focus on 2D integration techniques, paying special attention to the construction of van der Waals contacts at the 2D material/dielectric interface and 2D material/metal electrode interface. Finally, the potential for layer‐by‐layer or tier‐by‐tier transfer 2D devices for monolithic 3D integration was also discussed. This review concludes by highlighting the significant challenges that remain in leveraging the potential of 2D materials at the circuit and system levels, proposing forward‐looking development in transfer strategies.

Huge effects of hydrogen absorption on the magnetic properties of ScFe2

The effects of both hydrogen and deuterium absorption are investigated in the ScFe2 intermetallic compound by comparing its intrinsic magnetic properties with those of ScFe2H2.8 and ScFe2D3.2 compounds. It is found that H/D insertion into the hexagonal MgZn2-type crystal lattice of ScFe2 induces a huge increase in spontaneous magnetization, attributed to the volume expansion caused by H/D insertion. The increase in spontaneous magnetization amounts to 104% for ScFe2D3.2. We report for the first time the Curie point of the hydride and deuteride compounds from the analysis of the temperature dependence of the spontaneous magnetization in the frame of Kuz'min's model. Unlike spontaneous magnetization, the magnetic ordering temperature remains almost unaltered upon H insertion for the studied compositions. The ferromagnetic state is robust for all the studied compounds, none of which present antiferromagnetic behavior. No significant difference is observed in the magnetic properties for the two H/D isotopes, the dominant factor being the H/D concentration.

Chemogenetic Inhibition of Prefrontal Cortex Ameliorates Autism-Like Social Deficits and Absence-Like Seizures in a Gene-Trap Ash1l Haploinsufficiency Mouse Model

Background: ASH1L (absent, small, or homeotic-like 1), a histone methyltransferase, has been identified as a high-risk gene for autism spectrum disorder (ASD). We previously showed that postnatal Ash1l severe deficiency in the prefrontal cortex (PFC) of male and female mice caused seizures. However, the synaptic mechanisms underlying autism-like social deficits and seizures need to be elucidated. Objective: The goal of this study is to characterize the behavioral deficits and reveal the synaptic mechanisms in an Ash1l haploinsufficiency mouse model using a targeted gene-trap knockout (gtKO) strategy. Method: A series of behavioral tests were used to examine behavioral deficits. Electrophysiological and chemogenetic approaches were used to examine and manipulate the excitability of pyramidal neurons in the PFC of Ash1l+/GT mice. Results: Ash1l+/GT mice displayed social deficits, increased self-grooming, and cognitive impairments. Epileptiform discharges were found on electroencephalograms (EEGs) of Ash1l+/GT mice, indicating absence-like seizures. Ash1l haploinsufficiency increased the susceptibility for convulsive seizures when Ash1l+/GT mice were challenged by pentylenetetrazole (PTZ, a competitive GABAA receptor antagonist). Whole-cell patch-clamp recordings showed that Ash1l haploinsufficiency increased the excitability of pyramidal neurons in the PFC by altering intrinsic neuronal properties, enhancing glutamatergic synaptic transmission, and diminishing GABAergic synaptic inhibition. Chemogenetic inhibition of pyramidal neurons in the PFC of Ash1l+/GT mice ameliorated autism-like social deficits and abolished absence-like seizures. Conclusions: We demonstrated that increased neural activity in the PFC contributed to the autism-like social deficits and absence-like seizures in Ash1l+/GT mice, which provides novel insights into the therapeutic strategies for patients with ASH1L-associated ASD and epilepsy.

Intrinsically Slow Cooling of Hot Electrons in CdSe Nanocrystals Compared to CdS.

The utilization of excited charge carriers in semiconductor nanocrystals (NCs) for optoelectronic technologies has been a long-standing goal in the field of nanoscience. Experimental efforts to extend the lifetime of excited carriers have therefore been a principal focus. To understand the limits of these lifetimes, in this work, we theoretically study the time scales of pure electron relaxation in negatively charged NCs composed of two prototypical materials: CdSe and CdS. We find that hot electrons in CdSe have lifetimes that are 5 to 6 orders of magnitude longer than in CdS when the relaxation is governed only by the intrinsic properties of the materials. Although these two materials are known to have somewhat different electronic structure, we elucidate how this enormous difference in lifetimes arises from relatively small quantitative differences in electronic energy gaps and phonon frequencies, as well as the crucial role of Fröhlich-type electron-phonon couplings.

Substituent Effects on Cooperativity in Three-Component H-Bond Networks Involving Phenol-Phenol Interactions.

Cooperativity between H-bonding interactions in networks is a fundamental aspect of solvation and self-assembly in molecular systems. The interaction of a series of bisphenols, which make an intramolecular H-bond between the two hydroxyl groups, and quinuclidine was used to quantify cooperativity in three-component networks. The presence of the intramolecular H-bond in the bisphenols was established by using 1H NMR spectroscopy in solution and X-ray crystallography in the solid state. The interactions with quinuclidine were investigated using UV-vis and 1H NMR titrations, which show that the intramolecular hydrogen bonds persist in the 1:1 complexes. By varying substituents on one of the phenol groups, it was possible to measure the effect of changing the strength of the intramolecular H-bond between the hydroxyl groups on the strength of the intermolecular H-bond with quinuclidine. Strong positive cooperativity was observed between the two interactions, with increases in binding free energy of up to 16 kJ mol-1. By varying substituents on the other phenol group, which makes both an intramolecular H-bond and an intermolecular H-bond in the complex, it was possible to measure how the properties of this central hydroxyl group modulate cooperativity between the interactions with the other two functional groups. Changing the polarity of this phenol had no effect on the measured cooperativity. The results indicate that cooperativity in H-bond networks can be understood as a polar interaction between two remote functional groups that is damped by a central functional group. The extent of damping is quantified by cooperativity parameter κ, which is 0.33 for the hydroxyl group and appears to be an intrinsic property of the geometry or polarizability of the functional group rather than polarity.

Joint impact of self-heating effect and lattice stress on the design performance of Si1−xGex FinFET with advanced process integration

Abstract In advanced FinFET process simulations, a strong correlation exists between the stress induction mechanism and the severe self-heating effect (SHE). These two factors are interrelated, and their interaction further diminishes the thermal conductivity of the device. This article employs computer-aided design for three-dimensional simulations and introduces a process-oriented simulation method. We investigate the influence of various stress sources including lattice stress, channel stress, stress relaxation buffer (SRB), and source/drain (S/D) extrapolation stress on FinFET performance in different directions under self-heating conditions, specifically analyzing silicon germanium (SiGe) and germanium-based FinFET. The results indicate that, under the influence of SHE, the y–y direction stress in the device channel increases by nearly 600 MPa. Self-heating significantly affects stress distribution within the device; in simulations of germanium-based devices, the inferior intrinsic material properties and thermal conductivity of pure germanium result in a maximum lattice temperature that is substantially higher than that of pure silicon devices. The impact of SHE and lattice stress on the performance of advanced FinFET is explored, revealing that the coupling effect of self-heating and lattice stress has a profound influence on device design performance.

Spiro-Fused vs 575-Ringed Boron-Doped Polycyclic π-Systems: Selective Synthesis, Reactivity and Properties.

Incorporation of heteroatoms and/or non-hexagonal rings into polycyclic aromatic hydrocarbons (PAHs) can alter their intrinsic structures and physical properties. However, it is challenging to construct PAHs featuring boron/carbon composition and non-hexagonal combination. Herein, we disclose the selective synthesis of spiro-type and pentagon/heptagon-containing boron-doped polycyclic π-systems by the Scholl reaction. Two spiro-fused organoboranes 1 and 2 and one 575-ringed boron-doped nanographene 3 were synthesized. The key point is that the boron-edged π-system enabled unexpected spiro-formation via dearomatization, whereas the boron-centered π-system enabled desired 575-ringed π-extension via cyclodehydrogenation. The thus-obtained molecules exhibit the intriguing but fully distinct reactivity, electronic structures and properties, for instance, while 2 may react with Brønsted acid to display reversible chemochromism and further convert into 1, 3 possesses very broad absorption, short excited-state lifetime and no fluorescence nature. As disclosed, the boron atom together with the spirocycle region or 575-ringed structural motif significantly contribute to their characteristic properties. Thus, this study sheds light on control over the Scholl reaction using organoborane π-systems and will promote the exploration of more sophisticated polycyclic π-systems as organic reactive and optical scaffolds.

ZTF SN Ia DR2: An environmental study of Type Ia supernovae using host galaxy image decomposition

The second data release of Type Ia supernovae (SNe Ia) observed by the Zwicky Transient Facility has provided a homogeneous sample of 3628 SNe Ia with photometric and spectral information. This unprecedented sample size enables us to better explore our currently tentative understanding of the dependence of the host environment on SN Ia properties. In this paper, we make use of two-dimensional image decomposition to model the host galaxies of SNe Ia. We model elliptical galaxies as well as disc and spiral galaxies with or without central bulges and bars. This allows for the categorisation of SN Ia based on their morphological host environment, as well as the extraction of intrinsic galaxy properties corrected for both cosmological and atmospheric effects, through point-spread-function (PSF) convolution. We find that although this image decomposition technique leads to a significant bias towards elliptical galaxies in our final sample of processed galaxies, the overall results are still robust. By successfully modelling 728 host galaxies, we find that the photometric properties of SNe Ia found in discs and in elliptical galaxies correlate fundamentally differently with their host environment. We identified strong linear relations between light-curve stretch and our model-derived galaxy colour for both the elliptical (16.8sigma ) and disc (5.1sigma ) subpopulations of SNe Ia. Lower-stretch SNe Ia are found in redder environments, which we identify as an age and/or metallicity effect. Within the subpopulation of SNe Ia found in disc-containing galaxies, we find a significant linear trend (6.1sigma ) between light-curve stretch and model-derived local $r$-band surface brightness, which we link to the age and metallicity gradients found in disc galaxies. SN Ia colour shows little correlation with the host environment, as is seen in the literature. We do identify a possible dust effect in our model-derived surface brightness (3.3sigma ) for SNe Ia in disc galaxies.

Self-assembly of supramolecular double helix from a tetrapeptide and direct visualization by Scanning Tunneling Microscopy.

This work reports single-crystal X-ray diffraction (XRD), Scanning Tunneling Microscopy (STM), and quantum mechanics calculations of the 310-helical peptide Z-(Aib)2-L-Dap(Boc)-Aib-NHiPr (Aib, α-aminoisobutyric acid; Dap, 2,3-diaminopropionic acid; Z, benzyloxycarbonyl; Boc, t-butoxycarbonyl). The peptide forms a double-helical superstructure, studied by XRD and STM. Such architecture is rare in short peptides. Here, we show, by combining XRD, STM that this intriguing conformational feature is not driven by crystal packing; rather, it is an intrinsic property of this peptide. Indeed, the double helix is clearly detected also by STM, where crystal packing cannot be invoked. XRD reveals that intermolecular H-bonds stabilize two left-handed supra-helices (tertiary structure) that develop around a 6-fold screw axis. Then, two supra-helices are intertwined in a quaternary structure as a left-handed, double supra-helix, where C-H⋯π interactions play a crucial role. STM images show the formation of long, isolated "necklaces" (> 110 nm). They are of left and right helical handedness. Their size agrees with the XRD finding. DFT calculations allowed us to weigh the contribution of the different intermolecular interactions in the two single supra-helices and the supramolecular double-helix. Interestingly, we were able to conclude that the contribution of the C-H⋯π interactions to the binding energies is close to 50%.

Dispositional Harmony: Examining the Causal Connection Between Intrinsic and Extrinsic Properties

Having recently emerged from the philosophical doldrums, the view that there are extrinsic dispositions has provoked questions about some aspects of their nature. One of the questions is whether causal bases of such dispositions would be extrinsic as well. Adopting the dominant causal conception of dispositional properties, I argue for the thesis of dispositional harmony, or for the proposition that dispositions agree with their bases in respect of intrinsicness (or lack thereof). The proposition is at odds with the claim that the causal bases of extrinsic dispositions are intrinsic. As the claim was supported by appeal to the disposition of a key to open a door, I discuss the disposition, contending that it is intrinsic. Then I deflect a possible rejoinder by pointing out that the disposition is also multi-track. Dispositional harmony entails that if there were extrinsic dispositions, at least some extrinsic properties would be causally efficacious.

Preparation of Organic N-Fused Perylenediimide-MXene Hybrid Material for Robust Versatile Memristive Device

Abstract Two-dimensional (2D) MXene nanomaterials have shown great promise for electronic devices, attributed to their metal-resembling conductivity and abundant surface functional groups. However, the utilization of intrinsic property of MXene into memristors remains challenging due to its free electron conducting behavior rather than semiconducting property. Here, a N-fused perylenediimide organic semiconductor (CBIN) with conjugated skeleton and heteroatoms (O, S, N) is designed to successfully actuate the surface modification of MXene. The organic CBIN-decorated MXene demonstrates remarkable bipolar memristive properties, such as low threshold voltages of approximate ±1.4 V, exalted retention time exceeding 104 s, and outstanding environmental stability even after exposure to ultraviolet and X-ray irradiations. Furthermore, the CBIN-MXene hybrid memristive device can mimic synaptic plasticity and holds potential for information encoding as QR codes and image recognition processing. This study provides efficient guidelines for implementing MXene-based memristors by organic semiconductor modulation and opens up possibilities of extending their functionalities into information encryption and neuromorphic computing applications.

Ti3AlC2 single crystal growth via controlling horizontal temperature gradient

ABSTRACTGrowth of single‐crystal MAX phases is crucial for studying their intrinsic physical properties. Although Ti3AlC2 is one of the most popular MAX phases for the study of high‐temperature structural materials as well as a precursor for MXene, the growth of Ti3AlC2 single crystals remains a challenge owing to the limited solubility of graphite in the Ti melt via the self‐flux method. In this study, a horizontal temperature gradient was used to resolve the dissolution of graphite in the melt and its diffusion rate. Ti3AlC2 single crystals with an area of 9 mm2 were successfully produced under horizontal temperature gradients. It was tentatively proposed that the crystallinity of Ti3AlC2 single crystals could be reflected by the intensity ratio of the in‐plane and c‐axial phonon vibration modes in the Raman spectra of the MAX phase.

Topography immune-responsive silk films for skin regeneration.

Scar formation and chronic refractory wounds pose a significant threat to public health, with abnormal immune regulation as a key characteristic. However, topography, a crucial factor influencing immune responses, has not been adequately considered in the design of wound dressings. In this study, we constructed a hierarchical structure on silk fibroin (SF) films by combining soft lithography and femtosecond laser ablation, without altering the intrinsic properties of SF. The discontinuity in the hierarchical structure induced a transformation in the morphology of macrophage RAW264.7 cells from round to spindle or pancake-like shapes, leading to phenotypic polarization toward M2 or M1. The timely transition from M1 to M2 polarization and the balance between these states promoted fibroblast L929 cells to express mRNA for FN, coll-I, TGF-β1, and α-SMA. The hierarchical structure of SF films facilitates full-thickness wound repair in vivo by regulating inflammation and promoting neovascularization and collagen deposition. Thus, hierarchical topography presents a promising strategy for the design of immunomodulatory wound dressings.

A genetically encoded anomalous SAXS ruler to probe the dimensions of intrinsically disordered proteins

Intrinsically disordered proteins (IDPs) adopt ensembles of rapidly fluctuating heterogeneous conformations, influencing their binding capabilities and supramolecular transitions. The primary conformational descriptors for understanding IDP ensembles-the radius of gyration (RG), measured by small-angle X-ray scattering (SAXS), and the root mean square (rms) end-to-end distance (RE), probed by fluorescent resonance energy transfer (FRET)-are often reported to produce inconsistent results regarding IDP expansion as a function of denaturant concentration in the buffer. This ongoing debate surrounding the FRET-SAXS discrepancy raises questions about the overall reliability of either method for quantitatively studying IDP properties. To address this discrepancy, we introduce a genetically encoded anomalous SAXS (ASAXS) ruler, enabling simultaneous and direct measurements of RG and RE without assuming a specific structural model. This ruler utilizes a genetically encoded noncanonical amino acid with two bromine atoms, providing an anomalous X-ray scattering signal for precise distance measurements. Through this approach, we experimentally demonstrate that the ratio between RE and RG varies under different denaturing conditions, highlighting the intrinsic properties of IDPs as the primary source of the observed SAXS-FRET discrepancy rather than shortcomings in either of the two established methods. The developed genetically encoded ASAXS ruler emerges as a versatile tool for both IDPs and folded proteins, providing a unified approach for obtaining complementary and site-specific conformational information in scattering experiments, thereby contributing to a deeper understanding of protein functions.

Species mass transfer governs the selectivity of gas diffusion electrodes toward H2O2 electrosynthesis

The meticulous design of advanced electrocatalysts and their integration into gas diffusion electrode (GDE) architectures is emerging as a prominent research paradigm in the H2O2 electrosynthesis community. However, it remains perplexing that electrocatalysts and assembled GDE frequently exhibit substantial discrepancies in H2O2 selectivity during bulk electrolysis. Here, we elucidate the pivotal role of mass transfer behavior of key species (including reactants and products) beyond the intrinsic properties of the electrocatalyst in dictating electrode-scale H2O2 selectivity. This tendency becomes more pronounced in high reaction rate (current density) regimes where transport limitations are intensified. By utilizing diffusion-related parameters (DRP) of GDEs (i.e., wettability and catalyst layer thickness) as probe factors, we employ both short- and long-term electrolysis in conjunction with in-situ electrochemical reflection-absorption imaging and theoretical calculations to thoroughly investigate the impact of DRP and DRP-controlled local microenvironments on O2 and H2O2 mass transfer. The mechanistic origins of diffusion-dependent conversion selectivity at the electrode scale are unveiled accordingly. The fundamental insights gained from this study underscore the necessity of architectural innovations for mainstream hydrophobic GDEs that can synchronously optimize mass transfer of reactants and products, paving the way for next-generation GDEs in gas-consuming electroreduction scenarios.

Bioinspired adaptive lipid-integrated bilayer coating for enhancing dynamic water retention in hydrogel-based flexible sensors

While hydrogel-based flexible sensors find extensive applications in fields such as medicine and robotics, their performance can be hindered by the rapid evaporation of water, leading to diminished sensitivity and mechanical durability. Despite the exploration of some effective solutions, such as introducing organic solvents, electrolytes, and elastomer composites, these approaches still suffer from problems including diminished conductivity, interface misalignment, and insufficient protection under dynamic conditions. Inspired by cell membrane structures, we developed an adaptive lipid-integrated bilayer coating (ALIBC) to enhance water retention in hydrogel-based sensors. Lipid layers and long-chain amphiphilic molecules are used as compact coating and anchoring agents on the hydrogel surface, mimicking the roles of lipids and membrane proteins in cell membranes, while spare lipids from aggregates within hydrogels can migrate to the surface to combat dehydration under deformation. This lipid-integrated bilayer coating prevents the water evaporation of hydrogels at both static and dynamic states without affecting the inherent flexibility, conductivity, and no cytotoxicity. Hydrogel-based sensors with ALIBC exhibited significantly enhanced performance in conditions of body temperature, extensive deformation, and long-term dynamic sensing. This work presents a general approach for precisely controlling the water-retaining capacity of hydrogels and hydrogel-based sensors without compromising their intrinsic physical properties.

An Intrinsic Characterization of Shannon’s and Rényi’s Entropy

All characterizations of the Shannon entropy include the so-called chain rule, a formula on a hierarchically structured probability distribution, which is based on at least two elementary distributions. We show that the chain rule can be split into two natural components, the well-known additivity of the entropy in case of cross-products and a variant of the chain rule that involves only a single elementary distribution. The latter is given as a proportionality relation and, hence, allows a vague interpretation as self-similarity, hence intrinsic property of the Shannon entropy. Analogous characterizations are given for the Rényi entropy and its limits, the min-entropy and the Hartley entropy.

Biochemical basis and therapeutic potential of mitochondrial uncoupling in cardiometabolic syndrome.

Mild uncoupling of oxidative phosphorylation is an intrinsic property of all mitochondria, allowing for adjustments in cellular energy metabolism to maintain metabolic homeostasis. Small molecule uncouplers have been extensively studied for their potential to increase metabolic rate, and recent research has focused on developing safe and effective mitochondrial uncoupling agents for the treatment of obesity and cardiometabolic syndrome (CMS). Here, we provide a brief overview of CMS and cover the recent mechanisms by which chemical uncouplers regulate CMS-associated risk-factors and comorbidities, including dyslipidemia, insulin resistance, steatotic liver disease, type 2 diabetes, and atherosclerosis. Additionally, we review the current landscape of uncoupling agents, focusing on repurposed FDA-approved drugs and compounds in advanced preclinical or early-stage clinical development. Lastly, we discuss recent molecular insights by which chemical uncouplers enhance cellular energy expenditure, highlighting their potential as a new addition to the current CMS drug landscape, and outline several limitations that need to be addressed before these agents can successfully be introduced into clinical practice.

Spray Black Coating for High‐Efficiency Light Absorption

AbstractBlack coatings have emerged as a research focus due to their excellent light absorption performance over a wide wavelength range. They play a crucial role in precision optical devices and solar thermal applications. Among various preparation methods, spray coating has attracted great attention due to its simple preparation process, low cost, scalability, and applicability to complex structures. Herein, the recent progress in spray black coatings is comprehensively presented. Various spray coating methods employed in the preparation of black coatings, including air spraying, ultrasonic spraying, electrostatic spraying, spray pyrolysis, and thermal spraying are summarized and compared. Black spray coatings based on metal sulfide, metal oxide, cermet, polymer, and carbon are then reviewed. In addition to the intrinsic absorption properties of the black coatings, light‐trapping structures are key to achieving high‐efficiency light absorption. Typical structural design strategies for enhancing absorption are highlighted. Moreover, the trade‐off between absorptance and adhesion in the design of robust spray black coatings is indicated. The remaining challenges and outlook for the spray black coatings are discussed. This review is expected to provide valuable guidelines for the future development of spray black coatings.

Probing the heating of the neutral atomic interstellar medium in the Dwarf Galaxy Survey through infrared cooling lines

Star formation in galaxies is regulated by dynamical and thermal processes. In the Milky Way and star-forming galaxies with similar metallicity, the photoelectric effect on small dust grains usually dominates the heating of the neutral atomic gas, which constitutes the main star-forming gas reservoir. In more metal-poor galaxies, the lower dust-to-gas mass ratio together with the higher occurrence and luminosity of X-ray sources suggest that other heating mechanisms may be at play. We aim to determine the contribution of the photoelectric effect, photoionization by UV and X-ray photons, and ionization by cosmic rays to the total heating of the neutral gas in a sample of 37 low-metallicity galaxies. In particular, we wish to assess whether X-ray sources can be a significant source of heating. We also attempt to recover the intrinsic X-ray fluxes and compare them with observations when available. We used the statistical code MULTIGRIS together with a photoionization grid of Cloudy models propagating radiation from stellar clusters and potential X-ray sources to the ionized and neutral gas. This grid includes physical parameters such as metallicity, gas density, ionization parameter, and radiative source properties. We describe a galaxy as a combination of many 1D components linked by a few physical hyperparameters. We used infrared cooling lines as constraints to evaluate the most likely combinations and parameters. We constrained the heating fractions for the main mechanisms for the first time in a low-metallicity galaxy sample. We show that for the higher metallicity galaxies, the photoelectric effect dominates the neutral gas heating. At metallicities below $1/8$ the Milky Way value, cosmic rays and photoionization can become predominant. We computed an observational proxy for the photoelectric effect heating efficiency on polycyclic aromatic hydrocarbons (PAHs) using the total cooling traced by We show that this proxy can match theoretical expectations when accounting for the fraction of the heating due to the photoelectric effect according to our models. Finally, we show that it is possible to predict the X-ray fluxes reasonably well in the $0.3-8$\,keV band from the gas cooling lines for most of the galaxies observed in this band. With the current grid and assumptions, determining the exact heating fraction due to cosmic rays remains difficult, but we speculate that heating from X-ray sources is more important. As expected from the low abundance of dust and PAHs in metal-poor galaxies, heating mechanisms other than the photoelectric effect heating must be accounted for. Bright X-ray sources may deposit their energy on large scales in such transparent, dust-poor interstellar medium, and thus they represent promising avenues to understand the physical properties of the main star-forming gas reservoir in galaxies. The modeling strategy adopted here makes it possible to recover the global intrinsic radiation field properties when X-ray observations are unavailable, such as in early universe galaxies.