Photon Energy Research Articles

Evaluation of gamma radiation shielding characteristics of FeNbSc-based alloys

This study evaluated the radiation shielding features and interaction characteristics of FeNbSc-based alloy by separately doping the base alloy (FeNbSc) with Si, Ge, Ga, and Al for application in nuclear reactor design and radioactive waste confinement. The variations of Mass attenuation coefficient (MAC), Mass energy-absorption coefficient (MEAC), Effective atomic number (Zeff), effective electron densities (Neff), Specific gamma ray constant (Γ), Gamma dose rate (Dτ), exposure buildup factors (EBF) and Energy absorption buildup factors (EABF) at different photon energies were evaluated using WinXCOM computer program. Observation from results showed that FeNbScGe alloy displayed the highest shielding characteristics among all investigated alloy samples across all photon energies. The MAC of the prepared alloy samples was significantly higher than some recently developed commercial SCHOTT radiation shielding composites at 0.662 and 1.25 MeV gamma energy. The EBF and EABF of the studied alloy samples varied to modifying elements (Si, Ge, Ga, and Al) in the investigated samples. The MEAC values of the FeNbScGe alloy investigated samples were higher than those of other investigated alloys. Hence, FeNbScGe alloy should be considered for nuclear reactor design and radioactive waste confinement.

Advances and challenges in hybrid photovoltaic-thermoelectric systems for renewable energy

Integrating thermoelectric generators (TEGs) with photovoltaic (PV) devices presents an effective strategy to enhance the power generation of PV cells, thus substantially contributing to the widespread adoption of solar energy. By harnessing both photon and heat energy from sunlight, this integration maximizes energy capture and improves overall system efficiency, thereby advancing the feasibility and scalability of solar energy generation. This article provides a timely review of the advances and challenges in hybrid photovoltaic-thermoelectric generator (PV-TEG) technology, covering fundamentals, the impact of thermal, contact, and load resistance on performance, various integration options (such as hybrid PV-TEG systems with spectral splitters, phase change materials, and thermal systems), thermal management, feasibility, economic and environmental aspects, and long-term efficiency improvements. Following a detailed analysis and review of extensive progress, PV-TEG systems demonstrate higher efficiency across diverse environmental conditions compared to standalone PV devices. Finally, we address constraints, propose potential remedies, and point out future directions in the field.

Perspective on the applications of terahertz imaging in skin cancer diagnosis

Applications of terahertz (THz) imaging technologies have advanced significantly in the disciplines of biology, medical diagnostics, and non- destructive testing in the past several decades. Significant progress has been made in THz biomedical imaging, allowing for the label-free diagnosis of malignant tumors. Terahertz frequencies, which lie between those of the microwave and infrared, are highly sensitive to water concentration and are significantly muted by water. Terahertz radiation does not cause ionization of biological tissues because of its low photon energy. Recently, terahertz spectra, including spectroscopic investigations of cancer, have been reported at an increasing rate due to the growing interest in their biological applications sparked by these unique features. To improve cancer diagnosis with terahertz imaging, an appropriate differentiation technique is required to increased blood supply and localized rise in tissue water content that commonly accompany the presence of malignancy. Terahertz imaging has been found to benefit from structural alterations in afflicted tissues. This study provides an overview of terahertz technology and briefly discusses the use of terahertz imaging techniques in the detection of skin cancer. Research into the promise and perils of terahertz imaging will also be discussed.

Impact of low dose of gamma irradiation on thin films of Bismuth Tri-iodide.

Thin films of Bismuth Tri-iodide BiI3 were synthesized on a glass substrate by the thermal vacuum deposition technique. Films were exposed to gamma radiations of two doses 10Gy and 50Gy. Structural and optical properties of films were studied through X-ray Diffraction and UV spectroscopy both before and after the gamma irradiation. The effect of gamma radiations on microstructure parameters i.e. crystallite size and the micro-strain were studied qualitatively and quantitively. The observed increase in crystallite size and decrease in micro-strain is due to localized heating of crystallites which results in the merging of small crystallites and their assembly leading to the formation of larger crystallites as evident from X-ray Diffraction after gamma irradiation. Effect on the optical constants namely refractive index and extinction coefficient for different doses was also enumerated to throw light on the change in optical density of this material on gamma irradiation. It is observed that the refractive index n increases with an increase in the doses of gamma irradiation. The increase in optical density could be attributed either to the displacement of atoms from lattice sites to the interstitial sites or to the self-assembly behavior of the crystallites on irradiation. The absorption coefficient follows Urbach's empirical relation and exhibits exponential dependency on photon energy close to the band edge. Calculating Urbach's energy provides insight into the emergence of localized states at the energy gap's edges.

Formation of singly ionized oxygen atoms from O2 driven by XUV pulses: A toolkit for the breakup of free-electron-laser-driven diatomics

We formulate a general hybrid quantum-classical technique to describe the interaction of diatomic molecules with XUV pulses. We demonstrate the accuracy of our model in the context of the interaction of the O2 molecule with an XUV pulse with photon energy ranging from 20–42 eV. We account for the electronic structure and electron ionization quantum mechanically employing accurate molecular continuum wave functions. We account for the motion of the nuclei using classical equations of motion. However, the force of the nuclei is computed by obtaining accurate potential-energy curves of O2 up to O22+, relevant to the 20–42 eV photon-energy range, using advanced quantum-chemistry techniques. We find the dissociation limits of these states and the resulting atomic fragments and employ the velocity-Verlet algorithm to compute the velocities of these fragments. We incorporate both electron ionization and nuclear motion in a stochastic Monte Carlo simulation and identify the ionization and dissociation pathways when O2 interacts with an XUV pulse. Focusing on the O++O+ dissociation pathway, we obtain the kinetic-energy release (KER) distributions of the atomic fragments and find very good agreement with experimental results. Also, we explain the main features of the KER in terms of ionization sequences consisting of two sequential single-photon absorptions resulting in different O+ and O2+ electronic state configurations involved in the two transitions. Published by the American Physical Society 2025

Predicting Thermoelectric Performance of AlGaSbAs-based Systems for Thermo-photovoltaic Cell Applications

Abstract The development of high-performance thermoelectric (TE) materials is critical for advancing thermo-photovoltaic (TPV) technologies. To evaluate TE properties of AlGaSbAs-based systems, highlighting their potential for efficient thermal energy conversion in TPV cell applications, this paper explores and selects a new material that predict TE performance of TPV system while ensuring environmental sustainability. The study further delves into material-specific performance with a case study on AlGaSbAs, including thermal conductivity, bandgap (Eg) engineering and figure of merit using a Python simulation tool to improve the TPV cells' quantum efficiency and thermal stability. Using such a predictive computational framework, key TE parameters are quantified: figure of merit (ZT ~ 1.5–2.5), Seebeck coefficient (S: 150–300 μV/K), electrical conductivity (103–104 S/m), and thermal conductivity (κl of 0.91W/mK at 1100 K). Suitable Eg of Al0.125Ga0.875Sb0.75As0.25 (0.554 eV) ensures alignment with mid-infrared photon energies, optimizing energy conversion in TPV systems operating at 500–1200 K. Innovations include alloy engineering to enhance phonon scattering, nanostructuring to minimize lattice thermal conductivity (κl), and doping strategies to boost power factor. This study establishes AlGaSbAs as a scalable, thermally stable, and environmentally friendly material for next-generation TPV systems, providing a pathway for integrated TE and photovoltaic energy conversion solutions. The results showed that the thermal conductivity decreases with increasing temperature following a trend where it is inversely proportional to temperature which is beneficial as it suggests reduced heat loss at higher temperatures. S coefficient showed a linear increasing trend with the increasing of temperature demonstrating that the material becomes more effective at converting temperature differences into electrical voltage at higher temperatures. With controlling thermal parameters and selecting of the most suitable material, the efficiency of AlGaSbAs-based TPV cells can be significantly improved, making them more viable for high-temperature applications.

High-Performance Oxide Crystal BaTeW2O9 X-ray Detector with High Stability, Low Detection Limit, and Ultralow Dark Current Drift.

X-ray detection materials and devices have received widespread attention due to their irreplaceable role in the medical, industrial, and military fields. In this paper, BaTeW2O9 (BTW) crystal containing lone pairs of electrons with large atomic numbers and high density is reported as a new type of oxide crystal X-ray detection material. The anisotropic X-ray detection performance of the BTW single crystal (SC) is systematically studied. At 120 keV hard X-ray photon energy, the BTW SC X-ray detectors along the crystallographic a-, b-, and c-axes directions achieved high sensitivities of 371, 404, and 368 μC Gyair-1 cm-2 respectively. More importantly, no dark current drift phenomenon was observed in the BTW SC X-ray detectors. The dark current drifts along the crystallographic a-, b-, and c-axes directions are as low as 7.81 × 10-9, 8.61 × 10-9, and 7.71 × 10-9 nA cm-1 s-1 V-1, respectively. In addition, the BTW SC X-ray detector has an ultralow detection limit of 21.9 nGyair s-1. Our research provides a new X-ray detection material with potential application value and a new material design strategy for the field of radiation detection.

Construction of tetrahedral mesh phantom for Chinese women of childbearing age.

Although the Boundary Representation (BREP) method creates detailed surface phantoms of Chinese women of childbearing age, these phantoms cannot be directly used in Monte Carlo simulations. They must first be converted into voxel phantoms, a process that may diminish some of the inherent advantages of the surface phantoms. Therefore, the aim of this study is to construct a tetrahedral mesh (TM) phantom of Chinese women of childbearing age based on the BREP phantom, incorporating micron-level structural refinements to certain organ tissues while maintaining the original model's structure. This TM phantom can be directly implemented into Monte Carlo codes to calculate the absorbed dose at different photon energies, demonstrating that both the structure and position of organ tissues affect the radiation dose. By achieving more accurate dose assessments, we can optimize radiation protection measures and reduce the potential risks to women of childbearing age.&#xD.

Attosecond Rescattering of Laser-Assisted Electron-Proton Collision in Coulomb Potential.

This study investigates the motion of an electron in a Coulomb potential driven by an intense linearly polarized XUV laser pulse analyzed using Gordon-Volkov wave functions. The wave function is decomposed into spherical partial waves to model the scattered electron wave packet after the recollision with a proton. This interaction triggers high harmonic generation, producing coherent X-ray pulses with frequencies that are integer multiples of the XUV field. The research presents a novel method for achieving atomic-scale resolution at nanometer and subfemtosecond levels, enabling observation of electron-proton collisions on an attosecond time scale. It emphasizes the coupling of fields that create resonances in the scattered electron through photon energy exchange with XUV and X-ray pulses, leading to the formation of a Rydberg electron with energy levels up to n = 27 and angular momentum components l = 13 and m = ± 1. The combination of XUV and high-frequency X-ray fields introduces new nonperturbative nonlinear phenomena characterized by differential cross sections derived using the Floquet-Lippmann-Schwinger equation in the first-order Born approximation. The analysis shows that backward-forward scattering involves XUV-electron energy exchange, with peak intensity along the laser polarization vector, while sideways scattering, dominated by X-ray-electron interaction, peaks perpendicular to the polarization. Additionally, the laser-assisted scattering process results in temporary electron capture in a dressed proton-bound state, followed by escape and ejection, with the free electron ponderomotive energy exceeding 10Up.

Opportunities for gas-phase science at short-wavelength free-electron lasers with undulator-based polarization control

Free-electron lasers (FELs) are the world's most brilliant light sources with rapidly evolving technological capabilities in terms of ultrabright and ultrashort pulses over a large range of photon energies. Their revolutionary and innovative developments have opened new fields of science regarding nonlinear light-matter interaction, the investigation of ultrafast processes from specific observer sites, and approaches to imaging matter with atomic resolution. A core aspect of FEL science is the study of isolated and prototypical systems in the gas phase with the possibility of addressing well-defined electronic transitions or particular atomic sites in molecules. Notably for polarization-controlled short-wavelength FELs, the gas phase offers new avenues for investigations of nonlinear and ultrafast phenomena in spin-orientated systems, for decoding the function of the chiral building blocks of life as well as steering reactions and particle emission dynamics in otherwise inaccessible ways. This roadmap comprises descriptions of technological capabilities of facilities worldwide, innovative diagnostics and instrumentation, as well as recent scientific highlights, novel methodology, and mathematical modeling. The experimental and theoretical landscape of using polarization controllable FELs for dichroic light-matter interaction in the gas phase will be discussed and comprehensively outlined to stimulate and strengthen global collaborative efforts of all disciplines. Published by the American Physical Society 2025

The Gaussian-Drude Lens: A Dusty Plasma Model Applicable to Observations Across the Electromagnetic Spectrum

When radiation from a background source passes through a cloud of cold plasma, diverging lensing occurs if the source and observer are well-aligned. Unlike gravitational lensing, plasma lensing is dispersive, increasing in strength with wavelength. The Drude model is a generalization of cold plasma, including absorbing dielectric dust described by a complex index of refraction. The Drude lens is only dispersive for wavelengths shorter than the dust characteristic scale (λ≪λd). At sufficient photon energy, the dust particles act like refractive clouds. For longer wavelengths λ≫λd, the optical properties of the Drude lens are constant, unique behavior compared to the predictions of the cold plasma lens. Thus, cold plasma lenses can be distinguished from Drude lenses using multi-band observations. The Drude medium extends the applicability of all previous tools, from gravitational and plasma lensing, to describe scattering phenomena in the X-ray regime.

-roaming dynamics in the formation of following two-photon double ionization of ethanol and aminoethanol

Roaming reactions involving a neutral fragment of a molecule that transiently wanders around another fragment before forming a new bond are intriguing and peculiar pathways for molecular rearrangement. Such reactions can occur for example upon double ionization of small organic molecules, and have recently sparked much scientific interest. We have studied the dynamics of the -roaming reaction leading to the formation of after two-photon double ionization of ethanol and 2-aminoethanol, using an XUV-UV pump-probe scheme. For ethanol, we find dynamics similar to previous studies employing different pump-probe schemes, indicating the independence of the observed dynamics from the method of ionization and the photon energy of the disruptive probe pulse. Surprisingly, we do not observe a kinetic isotope effect in ethanol-, in contrast to previous experiments on methanol where such an effect was observed. This distinction indicates fundamental differences in the energetics of the reaction pathways as compared to the methanol molecule. The larger number of possible roaming pathways compared to methanol complicates the analysis considerably. In contrast to previous studies, we additionally analyze a broad range of dissociative ionization products, which feature distinct dynamics from that of and allow initial insight into the action of the disruptive UV-probe pulse.

Simulations of the potential for diffraction enhanced imaging at 8 kev using polycapillary optics

Conventional x-ray radiography relies on attenuation differences in the object, which often results in poor contrast in soft tissues. X-ray phase imaging has the potential to produce higher contrast but can be difficult to utilize. Instead of grating-based techniques, analyzer-based imaging, also known as diffraction enhanced imaging (DEI), uses a monochromator crystal with an analyzer crystal after the object. Analyzer-based systems most commonly employ synchrotron sources to provide adequate intensity, and typically use higher photon energies. In this work, a simulation has been devised to assess the potential for a polycapillary-based system. A polycapillary collimating optic has previously been shown to greatly enhance the intensity of the beam diffracted from the monochromatizing crystal. Detailed simulation of the optic is computationally intensive and requires comprehensive knowledge of the internal shape of the optic, so a simple geometric model using easier to obtain optic output data was developed and compared to the more detailed simulation. After verification, refraction band visibility was used as a quality parameter to address the effectiveness of the polycapillary-based DEI system at x-ray photon energies of 8 and 17.5 keV. The result shows promise for a polycapillary-coupled analyzer-based system even at low x-ray photon energy.

Er2O3-Doped Lead Borate Glasses: Advanced Optical and Radiation Shielding Performance

Abstract A new glass system with the composition 60B2O3 + 30PbF2 + (10−x)K2O + x Er2O3 (x = 0 to 3 mol%) were synthesized using the melt-quenching technique and comprehensively analyzed to evaluate their structural, optical, mechanical, and radiation shielding properties. Increasing Er2O3 concentration enhanced the density (from 4.260 to 4.89 g/cm3) and reduced the molar volume (from 29.28 to 28.98 cm3/mol), indicating a denser and more compact glass matrix. Optical studies revealed increased UV absorbance, a red shift in the cutoff wavelength, and a reduction in the optical energy gap from 3.487 to 3.335 eV (direct transitions). Urbach energy values increased from 0.722 to 1.083 eV, signifying heightened structural disorder. Enhanced refractive index and extinction coefficients further underscored the glasses’ potential for optical applications. Mechanical analyses demonstrated a significant increase in all elastic moduli, including Young’s, bulk, and shear moduli, with Er2O3 incorporation, indicating improved rigidity and mechanical stability. The radiation shielding performance of the glasses was assessed across photon energies of 0.015–15 MeV, incorporating both experimental data and machine learning (ML)-based predictions of mass attenuation coefficients (MAC). The ML model, developed using a neural network architecture, successfully predicted MAC values with high accuracy, demonstrating excellent agreement with XCOM-calculated results. Key shielding parameters, including half-value layer (HVL), effective atomic number (Zeff), and buildup factors (EABF and EBF), improved significantly with higher Er2O3 content. BPKE3 glass, with the highest Er2O3 concentration, exhibited the best shielding efficiency, outperforming conventional shielding materials in terms of lower HVL and buildup factors, coupled with higher MAC and Zeff values. This study highlights the dual role of Er2O3-doped lead borate glasses as efficient optical and radiation shielding materials. Machine learning effectively predicts shielding parameters, aiding material optimization for applications in nuclear, medical, and industrial fields.

Green approach to synthesis polymer composites based on chitosan with desired linear and non-linear optical characteristics

The current study used sustainable and green approaches to convey polymer composites with desired optical properties. The extracted green tea dye (GTD) enriched with ligands was used to synthesize zinc metal complexes. Green chitosan biopolymer incorporated with green synthesized metal complex using casting technique was used to deliver polymer composites with improved optical properties. The FTIR-ATR was used to identify the functional groups of the GTD, pure CS, and functional groups surrounding the synthesized zinc metal complex. Distinguished ATR bands were observed in green tea dye spectra, such as OH, C = O, and NH functional groups ascribed to various polyphenols. The ATR bands of the zinc metal complex compared to GDT established that GDT is crucial to capturing zinc cations and producing the Zn2+-metal complex. The broadness of the bands observed in CS-based composites inserted with the Zn2+- metal complex confirms strong interaction among the components of polymer composites. The XRD achievements confirm that CS films with different Zn2+- metal complex concentrations transferred to an amorphous composite. The XRD pattern of composite films establishes that the zinc metal complex scarified the crystalline phases of chitosan. Linear optical properties such as absorption, refractive index (n), and optical dielectric parameters were improved. The absorption edge of the composite’s films shifted to lower photon energies. Various models were used to determine the optical band gap. The band gap drops from when chitosan is loaded with a 36% Zn2+-metal complex. The Spitzer-Fan method is used to get the dielectric constant, and the Drude Lorentz oscillator model was used to calculate vital optical parameters, including N/m*, τ, and µopt. The W-D single oscillator model was used to determine the Eo and Ed parameters. The values of optical moments (M−1 and M−3) were calculated with the help of the W-D model. The oscillator’s strength () and wavelength () were determined via the Sellmeier model using the linear refractive index. The first-order nonlinear ( ), second-order non-linear () and third-order nonlinear optical susceptibility () were determined for all the films.

A thin film optoelectronic photodetector of spherical and linear resonators via one-pot synthesis of Bi(III) oxide/polypyrrole nanocomposite

We report the fabrication and characterization of a Bi(III) oxide/polypyrrole (Bi2O3/Ppy) nanocomposite thin film optoelectronic photodetector synthesized by a simple one-pot method. The nanocomposite consists of spherical Bi2O3 nanoparticles embedded in a Ppy matrix, forming a porous structure with a high surface area. The XRD analysis reveals that the Bi2O3 nanoparticles have a poly-crystalline nature with a crystal size of 40 nm and an optical bandgap of 2.86 eV. The SEM images show that the nanoparticles are agglomerated into clusters of about 100 nm in diameter, with pores of about 200 nm in width. The device exhibits a high sensitivity to light, as evidenced by the increase of the photocurrent density (Jph) from − 0.06 mA.cm−2 in the dark to -0.12 mA.cm−2 under illumination at -2.0 V. The device also shows a wavelength-dependent response, with the highest responsivity (R) of 1.0 and 0.9 mA/W and detectivity (D) of 0.221 × 109 and 0.20 × 109 Jones at photon energies of 3.6 eV and 2.8 eV, respectively. The Bi2O3/Ppy nanocomposite is a promising material for low-cost, high-performance optoelectronic applications, making it a superior choice over many contemporary devices reported in recent literature.

Energy Aggregation for Illuminating Upconversion Multicolor Emission Based on Ho3+ Ions.

Lanthanide-doped upconversion luminescent nanoparticles (UCNPs) have garnered extensive attention due to their notable anti-Stokes shifts and superior photostability. Notably, Ho3+-based UCNPs present a complex energy level configuration, which poses challenges in augmenting their luminescence efficiency. Herein, a rational design strategy was used to enhance the upconversion luminescence intensity of Ho3+ ions by improving the photon absorption ability and energy utilization efficiency. Efficient absorption and transfer of excitation light energy were achieved through carefully selected host materials, precisely controlled sensitizers, and the design of external energy antennas using organic dyes, enhancing upconversion luminescence. Due to the attenuation effect of hydroxyl vibration on upconversion luminescence, the nanomaterials exhibit multicolor luminescent characteristics in different solution environments. Significantly, the composites exhibit intense upconversion of red light in aqueous solution, showing great application potential in biomedicine and colorimetry.

Photothermal Catalysts, Light and Heat Management: From Materials Design to Performance Evaluation

AbstractPhotothermal catalysis, a frontier in heterogeneous catalysis, combines light‐driven and thermally enhanced chemical reactions to optimize energy use and reaction efficiencies at catalytic active sites. By leveraging photothermal conversion, this approach links renewable energy sources with industrial chemical processes, offering significant potential for sustainable applications. This review categorizes photothermal catalysis into three types: light‐driven thermocatalysis, thermally enhanced photocatalysis, and photo‐thermo coupling catalysis. Each category is analyzed, emphasizing mechanisms, performance factors, and the role of advanced materials such as plasmonic nanoparticles, semiconductors, and hybrid composites in enhancing light absorption, thermal distribution, and catalytic stability. Key challenges include achieving uniform thermal and photonic energy distributions within catalytic reactors and developing accurate performance evaluation metrics. Applications such as CO₂ reduction, ammonia synthesis, and plastic upcycling highlight the environmental and industrial relevance of this technology. The review identifies limitations and suggests innovations in materials design and energy‐storing mechanisms to enable continuous catalytic processes. Future directions emphasize photothermal catalysis's potential to transform sustainable energy systems and advance green chemical production. This synthesis aims to guide research and foster practical adoption of photothermal technologies at an industrial scale.

Transmission spectroscopy of CF4 molecules in intense x-ray fields

The nonlinear interaction of x rays with matter is at the heart of understanding and controlling ultrafast molecular dynamics from an atom-specific viewpoint, providing new scientific and analytical opportunities to explore the structure and dynamics of small quantum systems. At increasingly high x-ray intensity, the sensitivity of ultrashort x-ray pulses to specific electronic states and emerging short-lived transient intermediates is of particular relevance for our understanding of fundamental multiphoton absorption processes. In this work, intense x-ray free-electron laser (XFEL) pulses at the European XFEL are combined with a gas cell and grating spectrometer for a high-intensity transmission spectroscopy study of multiphoton-induced ultrafast molecular fragmentation dynamics in CF4. This approach unlocks the direct intrapulse observation of transient fragments, including neutral atoms, by their characteristic absorption lines in the transmitted broadband x-ray spectrum. The dynamics with and without initially producing fluorine K-shell holes are studied by tuning the central photon energy. The absorption spectra are measured at different FEL intensities to observe nonlinear effects. Transient isolated fluorine atoms and ions are spectroscopically recorded within the ultrashort pulse duration of a few tens of femtoseconds. An isosbestic point that signifies the correlated transition between intact neutral CF4 molecules and charged atomic fragments is observed near the fluorine K edge. The dissociation dynamics and the multiphoton absorption-induced dynamics encoded in the spectra are theoretically interpreted. Overall, this study demonstrates the potential of high-intensity x-ray transmission spectroscopy to study ultrafast molecular dynamics with sensitivity to specific intermediate species and their electronic structure. Published by the American Physical Society 2025

Self-absorption effects of internal luminescence in one-dimensional nanowires with and without localized states

Recent rigorous demonstration of self-absorption (SA) effects of internal luminescence in solids [H. G. Ye et al. Sci. Bull. 62, 1525 (2017)] has opened a breach in the solid wall behind which the SA processes and effects occur but cannot be directly probed inside the solid. Herein, we attempt to present a further theoretical consideration of the SA effects of internal luminescence occurring inside a nanowire with Urbach band-tail states. The consideration begins with an ideal luminescence spectrum with δ-line shape and then goes to the cases of luminescence spectra with Lorentzian, Gaussian, and localized-state ensemble (LSE) line shapes, respectively. A quantitative consideration of the SA effects in the spectral features of external luminescence spectra along with the nanowire axis is established for the variables of temperature, transmission distance, and photon energy. Generally, it is found that the self-absorption of internal luminescence can have a significant impact on the spectral features of external luminescence, depending on the three above-mentioned variables. In particular, the influence of SA on the three key spectral parameters, including intensity, peak position, and full width at half maximum (FWHM) of external LSE luminescence, is unveiled, providing a quantitative explanation for a few experimental phenomena reported in the literature. In addition, some interesting phenomena, i.e., nearly no peak shift with increasing the transmission distance, etc., have been predicted. These results more deeply establish the theoretical foundation of self-absorption, which is of positive significance for the regulation and enhancement of optoelectronic devices.