Wide Indirect Band Gap Research Articles

Predicting BN analogue of 8-16-4 graphyne: In silico insights into its structural, electronic, optical, and thermal transport properties

The boron nitride (BN) analogue of 8-16-4 graphyne, termed SBNyne, is proposed for the first time. Its physical properties were explored using first-principles calculations and classical molecular dynamics (MD) simulations. Phonon dispersion calculations and ab initio molecular dynamics simulations revealed that this system is dynamically stable at room temperature. We found that SBNyne exhibits a wide indirect bandgap of 4.58 eV using HSE06 and 3.20 eV using PBE. It displays strong optical absorption in the ultraviolet region while remaining transparent in the infrared and visible regions. Additionally, SBNyne exhibits significantly lower thermal conductivity compared to h-BN. Phonon spectrum analysis indicates that out-of-plane phonons predominantly contribute to the vibrational density of states only at very low frequencies, explaining its low thermal conductivity. These findings expand the knowledge of two-dimensional (2D) BN materials and open new avenues for their design and advanced technological applications.

Modeling and simulation of the structural, and optoelectronic properties of aluminum trihydride (β-[formula omitted]) for hydrogen storage

Hydrogen is a promising clean energy source, but its storage poses challenges. In this research, we conducted an in-depth study of the structural and optoelectronic properties of the β-AlH3 phase as a potential material for hydrogen storage. Using the density functional theory (DFT)-based Wien2k code, we optimized the structure of β-AlH3. Hydrogen storage properties show that β-AlH3 contains 10.1% hydrogen by weight, which is a significant amount. Electronic properties reveal that this material is a semiconductor with a wide indirect bandgap of 5.947 eV, obtained by the generalized gradient approximation with modified Becke-Johnson correction (GGA-mBJ). The optical response of β-AlH3 to photons with energies from 0 to 10 eV is also examined for a better understanding of this material. β-AlH3 exhibits a static dielectric permittivity value ε1(ω) of 2.1, indicative of its semiconducting nature. The optical conductivity σ1(ω) shows peaks at 7.25 eV and 8.5 eV, while the absorption coefficient α(ω) increases significantly above the band gap of 5.947 eV, with peaks at 7.2 eV and 9 eV. The refractive index n(ω) and extinction coefficient κ(ω) both display notable features at 7.2 eV and 9 eV, reflecting substantial electronic transitions and optical resonances.This research is crucial to understanding how this material can meet the technological demands of hydrogen storage. The results provide valuable insights into the potential of β-AlH₃ within the future energy landscape, highlighting both advances and challenges in this promising field.

Structural, electronic and optical properties of α -Si3N4, β-Si3N4 and γ-Si3N4 using density functional theory

Density Functional Theory (DFT) has in recent years gained a lot of popularity and has become an efficient and reliable tool in the study of material properties. This is specifically due to its computational convenience and excellent results in the prediction of material properties, which is aided by the development of highly efficient and accurate functionals. DFT has successfully been applied in a vast study of material at both ground and excited states. In this study based on DFT structural, optical, electronic properties and phonon frequency of silicon nitrides of different phases were studied using the GGA as exchange-correlation functional. For the electronic band gap calculation the results was obtained using the GGA and the hybrid HSE06 respectively for α -Si3N4 with space group (P31c), β-Si3N4 with space group (P63/m) and γ-Si3N4 phase polymorph with space group (14‾3d). Results obtained for the phases α -Si3N4 shows a narrow indirect band gap while β and γ -Si3N4 indicate a wide indirect band gap material for wide possible application in high temperature and high-power applications. Cohesive energy calculation and phonon frequencies were obtained to check the mechanical and dynamic stability of the three different phases. Results obtain for density of states, partial density of states and the optical properties, such as absorption coefficient, refractive index, extinction coefficient, reflectivity and electron energy loss spectra which all show good agreement with previous studies and relative experimental data.

Cage-Based 3D Tetrahexagonal Boron Nitride Crystal with Excellent Terahertz Light Absorption.

In recent findings, a new classification of 1D and 2D tetrahexagonal boron nitrides (th-BN) consisting of square and hexagonal rings has been documented. These materials exhibit impressive properties such as the tunable band gap, strong optical absorption, suitable sign-tunable Poisson's ratio, and high ideal strength, making them promising for applications in nano- and opto-electronic industries. Stimulated by these studies, we have designed a cage-based three-dimensional tetrahexagonal boron nitride (3D th-B6N6) structure, which demonstrates excellent thermal, dynamic, and mechanical stability, including exceptional cohesive and formation energies of 6.66 and -0.93 eV per atom. Unlike direct band gap 1D and 2D tetrahexagonal boron nitride semiconductors, the proposed 3D tetrahexagonal boron nitride exhibits an insulating nature, with a wide indirect band gap of 6.175 eV at the HSE06 level. Moreover, in contrast to the unequal chemical bonding and ultraviolet optical absorption observed in the 2D th-BN sheet, all B and N atoms form a fully sp3-hybridized bonded 3D th-B6N6 structure, with excellent terahertz light absorption in the range of 0.3-10 THz. Notably, it also exhibits a Debye temperature of 1304.55 K and substantial phonon inelastic scattering. Our study introduces the BN family with novel properties and potential applications.

Lyophilization strategy to synthesize ultrafine NaCl template for preparation of photocatalytic BiOCl nanoplates via chemical vapor deposition

Two-dimensional (2D) bismuth oxychloride (BiOCl) has attracted increasing attention in nanoelectronics, catalysis, energy storage, and the environment, attributed to its wide indirect band gap and large surface area. However, the imprecise control of the catalytic site on the substrate makes it challenging to produce 2D BiOCl in large quantities economically. Here, we developed lyophilization to create ultrafine NaCl templates to obtain a higher yield of 2D BiOCl nanoplates than traditional substrates using a chemical vapor deposition (CVD) method. In contrast to ball milling or recrystallization, lyophilization can produce the sodium chloride (NaCl) in the ice lattice domain, resulting in ultrafine NaCl particles after removing water. Moreover, the NaCl particles synthesized by lyophilization showed lower crystallinity with partially distorted structures, such as twisted octahedral structures and the structure with Na+ separated from other atoms by an ice lattice. In addition, our method offers an opportunity to introduce and engineer the oxygen vacancies (OVs) on 2D BiOCl to narrow the band gap, improve the separation of photogenerated carriers, and enhance their photocatalytic efficiency by 17.2 times. Thus, our work opens a new avenue to produce 2D BiOCl by tuning the substrate in CVD growth and inspires a new strategy to promote the performance of 2D photocatalysts.

Synthesis of anhydrous lanthanum acetate. Analysis of it’s structural, thermal and electronic properties

Acetate complexes of rare earth elements are extensively studied compounds known for their diverse properties and potential applications and lanthanum acetate hydrate is commercially available. In this work, a powdered anhydrous lanthanum acetate (La(CH3COO)3) sample was prepared by dissolving lanthanum oxide (La2O3) in an excess of acetic acid (CH3COOH) and distilled water (H2O), followed by direct evaporation at 150 °C. The decomposition of La(CH3COO)3 was studied, showing initiation around 300 °C and conclusion at ≥700 °C, with four distinct thermal events (I–IV) of mass loss. Gas phase identification revealed acetone and carbon dioxide as decomposition products, indicating pyrolytic decarboxylation. The final thermal effect (IV) is linked to the decomposition of La2O2CO3 to La2O3. The DFT refinement of atomic coordinates of hydrogen atoms, which were unavailable from experiment, was successfully performed. Obtained structural data was checked using vibrational spectroscopy method. The calculated electronic band structure of La(CH3COO)3 indicates it as an indirect wide band gap material with values of direct transition close to indirect. The optical bandgap is found to be 5.49 eV, suggesting that the charge transfer in La(CH3COO)3 can be optically activated with wavelengths shorter than 226 nm, which falls within the deep UV (DUV) region.

First-principles insights into the structural, mechanical, electronic, optical, and thermophysical properties of XSrBr3 (X = Na, Ga, and Tl) perovskites: Implications for optoelectronic applications

Non-toxic halide perovskite compounds possess critical inherent and improved features for use in optoelectronic devices. The present work summarizes the physical properties of cubic halide perovskites XSrBr3 (X = Na, Ga, and Tl) based on first-principles theory. The structural, electrical, optical, mechanical, and thermophysical properties of these compounds are studied to assess their potential utility in optoelectronics field. GGA-PBE and GGA-PBEsol functionals were utilized to determine the lattice properties, cell volumes, and formation energies of the compounds. The negative formation energies support the compounds' structural stability. The compounds' bandgaps were computed using the GGA-PBE and Hybrid-HSE06 functionals. Each of the three compounds has a wide indirect bandgap. Optoelectronic devices such as UV detectors, solar panel antireflection coatings, OLED, QLED, and waveguides benefit from a greater static dielectric constant, broad absorption spectra, and low visible reflectance. The elastic stiffness constants Cij use the necessary conditions to demonstrate that the NaSrBr3, GaSrBr3, and TlSrBr3 perovskite structures are mechanically stable. The elastic modulus and other trustworthy properties imply that perovskites are mechanically ductile and soft. In conclusion, the investigation indicates the potential applications of these perovskite materials in photovoltaic and optoelectronic technologies.

Synthesis, crystal structure of Ca6Sb2O11 from experiments and DFT-electron structure calculation

This article reports a new perovskite compound Ca6Sb2O11. The X-ray powder diffraction technique was used to analyze its crystal structure. The results show that Ca6Sb2O11 has a tetragonal structure with the I4/m space group, and the lattice parameters are a = b = 5.658 (1) Å, c = 7.984 (1) Å, α = β = γ = 90°. It exhibits a typical A4B'2B″2X12-x anoxic multi-perovskite structure with rock-salt ordering of the B-site cations. The compound's chemical composition and valence states were characterized through scanning electron microscopy-energy dispersion spectrum (SEM-EDS) and X-ray photoelectron spectroscopy (XPS). The presence of oxygen vacancies was confirmed by electron paramagnetic resonance (EPR) spectroscopy. A chemical and structure transition temperature and the full melting temperature of Ca6Sb2O11 were measured, with values of 1515 ± 3 K and 1720 ± 3 K, respectively. The density functional theory (DFT)-electron structure calculation results show that Ca6Sb2O11 is an indirect wide-band gap (∼4.47 eV) semiconductor material, which agrees well with the experimental value (∼4.38 eV) obtained through diffuse reflection spectroscopy (DRS). Moreover, the top of the valence band and bottom of the conduction band are mainly contributed to by O-2p and Ca-3d states, respectively.

Unexpected thermal transport properties of MgSiO3 monolayer at extreme conditions

The thermal transport properties of mantle minerals are of paramount importance to understand the thermal evolution processes of the Earth. Here, we perform extensively structural searches of two-dimensional MgSiO3 monolayer by CALYPSO method and first-principles calculations. A stable MgSiO3 monolayer with Pmm2 symmetry is uncovered, which possesses a wide indirect band gap of 4.39 eV. The calculations indicate the lattice thermal conductivities of MgSiO3 monolayer are 49.86 W (mK)−1 and 9.09 W (mK)−1 in x and y directions at room temperature. Our findings suggest that MgSiO3 monolayer is an excellent low-dimensional thermoelectric material with high ZT value of 4.58 from n-type doping in the y direction at 2000 K. The unexpected anisotropic thermal transport of MgSiO3 monolayer is due to the puckered crystal structure and the asymmetric phonon dispersion as well as the distinct electron states around the Fermi level. These results offer a detailed description of structural and thermal transport properties of MgSiO3 monolayer at extreme conditions.

New stable inorganic BX (X= P, As, Sb) biphenylene and graphenylene monolayers: A first-principles investigation

Porous two-dimensional (2D) materials with semiconducting property are promising candidates for a variety of multifunctional energy harvesting applications. Motivated by the successful synthesis of porous organic biphenylene and graphenylene materials, herein, we demonstrate the ground-state properties of a new family of b-BX and g-BX monolayers inorganic biphenylene and graphenylene monolayers using first-principles calculations based on density functional theory. Stability tests show that the b-BX and g-BX monolayers are energetically, mechanically, dynamically, and thermally stable. Moreover, g-BX (X = As, Sb) monolayers are auxetic 2D materials. According to the HSE06 electronic band structure results, these monolayers of b-BX and g-BX exhibit moderate and wide indirect bandgap semiconducting properties. These novel ground state properties of b-BX and g-BX monolayers demonstrate their aforementioned potential applications in addition to optoelectronic, thermoelectric, and flexible electronics. Besides all these newly proposed b-BX and g-BX monolayers expand the family of inorganic biphenylene and graphenylene non-magnetic materials.

Crystal structure, electronic structure and thermal stability of new phosphate Sr2In(PO4)(P2O7)

Searching for new phosphates is of special significance to enrich the basic database of the structure and properties for developing inorganic materials. Here, we present a new phosphate Sr2In(PO4)(P2O7) which crystallizes to a monoclinic cell (S.G. P21/c), with the lattice parameters of a = 6.5832(3) Å, b = 6.8984(3) Å, c = 19.813(1) Å, β=99.562(1)°, V = 887.3(1) Å3, and Z = 2. The three-dimensional frame of this structure is made of InO6, PO4, P2O7, SrO8, and SrO9 units. The co-existence of P2O7 and PO4 was confirmed by IR spectra assignment. The VB maximum and CB minimum of Sr2In(PO4)(P2O7) are dominated by In-s and O-p state, respectively. Combining the calculated electronic structure with measured UV–Vis diffuse reflectance spectrum, this phosphate shows a wide indirect energy band-gap. DTA indicates that its melt point is about 1245 °C. The large band gap and high thermal stability would be catering for the material requirement in futural optical or other functional application fields.

Theoretical investigation of structural, electronic, elastic, and optical properties of rubidium-based perovskites RbSrX3 (X = Cl, Br) for optoelectronic device applications – A DFT study

The search for environment-friendly lead-free halide perovskites is an emerging research area due to their crucial application in the field of photovoltaics and optoelectronics. So, in this current work, the structural, electronic, elastic, thermal, and optical properties of rubidium-based cubic halide perovskites RbSrX3 (X = Cl, Br) are investigated by the full potential linearized augmented plane wave (FP-LAPW) method in the context of density functional theory (DFT). The Generalized Gradient Approximation (GGA) of Perdew-Burke-Ernzerhof (PBE) is implemented as the exchange-correlation potential. The structural stability of these compounds in the cubic phase is studied and the values of their formation energies and ionic filling fraction (IFF) have been assessed. The band structure and DOS plots reveal a wide indirect bandgap at zero pressure. The elastic constants of these compounds are evaluated, and from Blackman's and Every's diagrams, they are found to be elastically stable with a ductile and anisotropic nature. The optical parameters of these compounds imply that they show good response in the ultraviolet region. Thus, by experimentally synthesizing these compounds their potential application in the development of optoelectronic devices working in UV range can be assessed.

Stability, electronic and optical properties of buckled XO (X = Ge, Cu) graphenylene monolayers: A first-principles study

The demand for sustainable semiconducting devices that can be used in various applications necessitates the development of revolutionary materials with multifunctional properties. Using van der Waals interactions corrected first-principles density functional theory (DFT) calculations, we propose porous g-XO (X = Ge, Cu) inorganic graphenylene monolayers. These monolayers extend the family of synthesized porous organic graphenylene materials. Stability checks reveal that the g-XO monolayers are energetically, mechanically, dynamically, and thermally stable. Additionally, g-GeO monolayer is auxetic 2D material. The auxetic property of g-GeO monolayer could be advantageous for important applications in mechanics and tissue engineering, electromechanical devices, and flexible electronics. Based on the HSE06 electronic band structure results, these g-CuO and g-GeO monolayers exhibit wide and ultra-wide indirect bandgap semiconducting properties, respectively. The satisfactory absorption coefficient of 104–105 cm−1 spanning the visible to UV region implies their potential for optoelectronics and UV shields applications. Our theoretical results provide a hints for the potential of these porous g-XO monolayers in energy harvesting/conversion, nanofiltration membranes, optoelectronic, thermoelectric, and flexible electronics.

First-principles calculations to investigate structural, elastic, mechanical, electronic and optical characteristics of RbSrX3(X = Cl, Br)

The inorganic cubic perovskites RbSrCl3 and RbSrBr3 have been studied for structural, phonon, elastic, mechanical, electronic and optical properties using first principles calculations based on Density Functional Theory. The structures are optimized and found stable with lattice constants 5.70 Å and 6.00 Å for RbSrCl3 and RbSrBr3 respectively. The stability is further validated by formation energy and phonon calculations. The bulk modulus, shear modulus, Young’s modulus, Pugh ratio, Poisson ratio, Cauchy pressure and other parameters are calculated using elastic constants to endorse the mechanical stability. The electronic structure revealed that both under study materials are indirect wide band gap material with band gap of 7.74 eV (RbSrCl3) and 6.54eV (RbSrBr3) with TB-mBJ. The density of states are consistent to band structures. The optical parameters such as dielectric constant, refractive index, reflectivity, absorption, optical conductivity and energy loss are calculated in response to incident electromagnetic radiation up to 30eV for their potential use in optoelectronic devices.

β -rays induced displacement damage on epitaxial 4H-SiC revealed by exciton recombination

One of the most interesting wide-bandgap semiconductor is 4H-SiC that has an indirect wide-bandgap of 3.3 eV. This material holds great potential to develop power devices that find applications in the field of high-voltage and high-temperature electronics and harsh environments. In this study, we employed complementary noninvasive characterization techniques, including micro-Raman, optical absorption, steady-state, and time-resolved photoluminescence spectroscopy, to investigate the characteristics of a 12 μm thick epitaxial layer of 4H-SiC grown on 4H-SiC. Furthermore, we explored the impact of ionizing radiation on this material, utilizing β-rays and two x-ray sources. The doses are in the range of 1–100 kGy for electrons with energy of 2.5 MeV, 16 kGy for the first x-ray source (an x-ray tube with a W target operating at an anode bias voltage of 28 kV), and 100 kGy for the second x-ray source (an x-ray tube with a W target operating at an anode bias voltage of 100 kV). When exposed to the electron beam, the excitonic band at 3.2 eV exhibits a reduction in its lifetime as the deposited dose increases. In particular, in samples characterized by a greater amount of native defects, both extended and point defects, this effect becomes evident at lower deposited doses. Conversely, in the samples subjected to x-ray irradiation, these effects are not observed. These findings indicate that electron beam irradiation triggers the formation of defects associated with atomic displacement. Ultimately, we have examined the impact of thermal treatments in air, ranging from 100 to 900 °C, to investigate the recovery characteristics of 4H-SiC.

Density functional theory study of the electronic and optical properties of pentagraphyne nanotubes.

Pentagraphyne (PG-yne), a recently predicted two-dimensional (2D) carbon allotrope with appealing properties, has opened up possibilities for a wide range of applications. In this study, we investigate the structural, electronic, optical, and electrical transport properties of a novel one-dimensional (1D) system called pentagraphyne nanotubes (PG-yneNTs), formed by rolling a PG-yne sheet, using density functional theory (DFT) calculations. We design PG-yneNTs with diameters ranging from 6.94 Å to 13.62 Å and employ state-of-the-art theoretical calculations to confirm their energetic, dynamic, and thermodynamic stability. Our electronic band structure calculations reveal that all these nanotubes are wide indirect band gap semiconductors. Remarkably, PG-yneNTs exhibit superior optical properties, including high absorption coefficients and absorption spectra covering the visible regime of the electromagnetic spectrum, making them potential candidates for visible-light-driven photocatalysis and solar cells. Interestingly, both the electronic and optical band gaps increase with the diameter of the nanotubes. Additionally, the observation of negative differential resistance (NDR) phenomena in (4, 0) PG-yneNT suggests their potential applications in NDR devices such as fast switches, frequency multipliers, and memory devices.

First-principles investigation of structural, electronic, and optical properties of cubic halide perovskite RbSrI3

In this article, the structural, electronic, and optical properties of lead-free cubic halide perovskite RbSrI3 are investigated by the first principles method that employs the density functional theory (DFT). This study implements the full potential linearized augmented plane wave (FP-LAPW) method with the generalized gradient approximation of Perdew-Burke-Ernzerhof (PBE-GGA) as the exchange-correlation potential. The structural stability of the compound is calculated using the Murnaghan equation of state, and the band structure calculations show the presence of a wide indirect bandgap of 3.32 eV. The optical response of the compound over the energy spectrum of 0–12 eV is studied and the compound exhibits good reflectance of 30.73 % at 7.66 eV and absorption of 112.45 × 104 cm−1 at 11.74 eV in the ultraviolet region. The values of reflectivity R(ω) and absorption coefficient α(ω) indicate that the compound shows potential in the fabrication of UV-related optoelectronic devices.

Improved performance of double Cs2AgBiBr6 perovskite solar cells by engineering passivation defects with Co2+ additives

Cs2AgBiBr6, a double perovskite structure, offers potential as a stable and non-toxic alternative to organic lead perovskites. However, challenges such as poor film quality and a wide indirect band gap have limited its applications. In this study, we introduced Co2+ cations into the precursor solution to slow down Cs2AgBiBr6 film crystallization kinetics. This intervention led to improved film quality, larger grain sizes, reduced defect densities, band gap modulation, and increased solar cell efficiency. Additionally, Co2+ B-site substitution effectively reduced bromine vacancies in the pristine perovskite, mitigating carrier defect recombination. Co2+ also lowered the band gap of Cs2AgBiBr6 and adjusted energy level arrangements, facilitating carrier transport, enhancing electron-hole extraction, and improving conductivity. We investigated the optimal Co2+ addition ratio and elucidated the enhancement mechanisms. The introduction of Co2+ increased power conversion efficiency from 2.11 % to 3.50 % and short-circuit current density from 3.88 to 4.88 mA/cm2. This study offers a straightforward method to enhance Cs2AgBiBr6-based solar cells.

Computational insight into the fundamental physical properties of ternary ABCl3 chloroperovskites compounds using the DFT approach

In this research, the ternary non-centrosymmetric chloroperovskites compounds of the form ABCl3 (A = Rb and B = Be, Mg) are investigated extensively to predict the structural, mechanical, and optoelectronic properties with DFT incorporated in WIEN2K code. The crystalline structure of interested chloroperovskites is identified to be cubic, non-centrosymmetric, and stable. The elastic constants Cij, bulk modulus, criteria of Pugh ratio, and the Born criteria confirm the ductility and mechanical stability of ternary RbBeCl3 and RbMgCl3 materials. Electronic properties such as the band structures and density of states are examined with the most widely recognized TB-mBJ potential approximation. RbBeCl3 shows semiconducting behaviour with an indirect wide band gap energy of 3.74 eV from R-Γ symmetries points, while RbMgCl3 is assumed to be an insulator that possesses indirect wide band gap energy of 6.28 eV from R-Γ. It is identified that the ABCl3 (A = Rb and B = Be, Mg) non-centrosymmetric compounds change the behavior from wide band gap semiconductors to perfect insulators when the ‘B’ site in ABCl3 varies from ‘Be’ to ‘Mg’ element. In the electromagnetic range from 0 eV to 40 eV of incident photons energy, several parameters in optical properties that includes the dielectric function, refractive index, absorption coefficient, optical conductivity, extinction coefficient, and energy loss function are investigated for the quest of potential applications of interested non-centrosymmetric cubic systems in modern photovoltaic technologies. These outcomes may add inclusive understanding within ultraviolet ranges for photovoltaic applications.

Investigation on elastic, optical and thermoelectric properties of 2D MgX (X= O, S, Se, Te) materials under DFT framework

The first principles study of two-dimensional magnesium (Mg) chalcogenides (X = O, S, Se, Te) in square lattice (s-MgX) and hexagonal phases (h-MgX) is investigated for the first time. Except for h-MgSe and h-MgTe, all the square lattice and hexagonal structures in MgX compounds are dynamically stable, agreeing to phonon dispersion calculations. The electronic band structure and projected density of states of s- and h-MgX materials provided insight into the essence of electronic properties of these compounds. All s- and h-MgX compounds are found to be indirect wide band gap semiconductors, according to calculations using PBE and HSE06 functionals. The effective mass, mobility and relaxation time of electrons and holes carriers from the band structure of s- and h-MgX are examined to acquire a better intuition into these materials. Along the zigzag direction, h-MgTe has a largest mobility as well as relaxation time of 78104.92 cm2 V−1s−1 and 64385.56 fs, respectively in the entire MgX series. Additionally, we examined their mechanical stability through elastic characteristics, and the derived elastic parameters and polar graphs of Young's modulus and Poisson's ratio verifying their mechanical stability. In application of parallel and perpendicular field polarizations, the optical properties of s- and h-MgX are examined. The thermoelectric properties of the complete s- and h-MgX series are examined for the temperature range from 50 K to 800 K. The results of the present study reveal that s-MgO and h-MgS are the better thermoelectric materials in the considered series. Finally, since these compounds are mostly UV-active, they may find useful applications in UV-protectant and UV-photodetectors materials.