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Photocatalytic (PC) / Photoelectrochemical (PEC) water splitting under solar light irradiation is considered as a prospective technique to support the sustainable and renewable H2 economy and to reach the ultime goal of carbon neutral. TiO2 based photocatalysts with high chemical stability and excellent photocatalytic properties have great potential for solar-to-H2 conversion. To conquer the challenges of the large band-gap and rapid recombination of photo generated electron-holepairs in TiO2, non-metal doping turns out to be economic, facile, and effective on boosting the visible light activity. The localized defect states such as oxygen vacancy and Ti3+ generated by non-metal doping are located in the band-gap of TiO2, which result in the reduction of band-gap, thus a red-shift of the absorption edge. The hetero doping atoms such as B3+, I7+, S4+/S6+, P5+ can also act as electron donors or trap sites which facilitate the charge carrier separation and suppress the recombination of electron-hole pairs. In this comprehensive review, we present the most recent advances on non-metal doped TiO2 photocatalysts in terms of fundamental aspects, origin of visible light activity and the PC / PEC behaviours for water splitting. In particular, the characteristics of different non-metal elements (N, C, B, S, P, Halogens) as dopants are discussed in details focusing on the synthesis approaches, characterization as well as the efficiency of PC and PEC water splitting. The present review aims at guiding the readers who want quick access to helpful information about how to efficiently improve the performance of photocatalysts by simple doping strategies and could stimulate new intuitive into the new doping strategies.

Herein, we present the development and characterization of Yttrium oxide (Y2O3) films and Al/Y2O3/n-Si heterojunction diodes at various substrate temperatures using a low-cost facile jet nebulizer spray pyrolysis (JNSP) technique. The X-ray powder diffraction (XRD) pattern proved polycrystalline films of Y2O3 with a cubic structure. Field emission scanning electron microscope (FESEM) images reveal very fine nanograins formation in Y2O3 films at all temperatures. Scanning probe microscopy (SPM) analysis shows very low roughness of all films. The detailed compositional/homogeneity analysis was done via energy dispersive X-ray (EDX)/e-mapping analysis. All the films exhibited a sharp absorption edge at ∼ 280 nm, and the estimated energy gap values were noticed between 4.5 to 5.5 eV. Moreover, the observed photoluminescence (PL) spectrum indicated that the intensity of emission peaks quenched ∼ 3 times, indicating the reduction of defects with substrate temperature. From the current – voltage (I-V) characteristic, the calculated ideality factor (n) value was noticed to be drastically reduced from 7.66 and 2.87 on increasing the substrate temperature. Further, the diode ideality factor, series resistance (Rs) and barrier height (ФB) were obtained from Cheung's method. The results revealed that the developed Al/Y2O3/n-Si heterojunction diode is a promising contender for optoelectronic devices.

Highly transparent nonlinear Thiourea cadmium hydrogen borate (TCHB) single crystal grown by slow evaporation method is investigated for optoelectronic applications. Single crystal XRD provides details about the lattice structure. FTIR vibrational spectroscopic study identifies the functionals that make up the crystal system. Elemental composition is determined from the EDAX spectrum. UV spectral analysis is performed to determine the transparency range, absorption edge limit, and band gap value at which the crystal can be run. The linear behavior of TCHB is analysed by studying the optical constants from the transmittance values. TG/DTA analysis is done to find out the thermal stability. Vickers microhardness test classifies TCHB as a soft material and elasticity, brittleness and other mechanical properties are assessed from the hardness value. Second harmonic optical study affirms frequency doubling of Nd:YAG laser. Third order measurements, such as, nonlinear absorption co-efficient (β), nonlinear refraction (n2) and third order susceptibility (χ3) are calculated by the Z scan technique.

We report a facile and low-cost deposition of Tin sulfide (SnS) nanosheets and its performance for Near Infra-red (NIR) Photodetection under the UV to NIR illumination. Orthorhombic phase of SnS has been observed in the phase identification analysis. The optical absorption edge was observed at 1030 nm, and the band gap was found to be 1.2 eV. Nanosheets morphology along with flakes identified from the scanning electron micrograph analysis. Photoresponse measurement was studied under dark and illumination with a constant bias voltage of 1.5 V and the enhanced photocurrent is observed. The higher spectral responsivity of 0.19 A/W at 1030 nm has been observed in spectral response curve recorded from 300 nm to 1100 nm. The cyclic photoresponse of the SnS photodetectors shows good cyclability with illumination turn on and off alternatively with the time interval of 20 s. The response time (Tr) and recovery time (Tτ) were found to be 2 s and 4 s, respectively. The detectivity Dt of the SnS nanosheets photodetector to be 9.213×1011 Jones. The wavelength-dependent photodetection shows the maximum response at 1030 nm and the higher photosensitivity. Finally, the external quantum efficiency of the fabricated NIR photodetector was found to be 27%.

The hybridization between the outmost s orbitals of metal (Bi3+, Sn2+, Pb2+, Ag+) and O 2p orbitals has been widely employed to develop innovative semiconductors with upshift valence band as well as extended visible light response, but it is still challenging to obtain photocatalyst with absorption edge of above 550 nm. Here we report a novel Sn2+-based oxyfluoride Sn2TiNbO6F (STNOF) photocatalyst with a pyrochlore structure to exhibit an extended absorption edge to 650 nm and dual functionalities of both water reduction and oxidation. Density functional theory calculations suggest that the unprecedented broad-spectrum response of STNOF is mainly ascribed to the strengthened hybridization between O 2p and Sn 5s orbitals remarkably upshifting the valence band, which is caused by the distortion and compressive strain in the SnO6F2 dodecahedron with second-order Jahn-Teller effect due to partial fluorine substitution. The structural distortion and compressive strain are experimentally confirmed by the Fourier-transformed extended X-ray absorption fine spectra. As probe tests of the photocatalytic functionalities, water reduction and oxidation half reactions were examined to see obvious H2 and O2 evolution under visible light irradiation. This work may provide an alternative strategy of developing extended visible light responsive semiconductors for promising solar energy conversion.

Compositional dependence of the linear and nonlinear optical characteristics of dye–polymer composite (DPC) films based on methylcellulose-methylene blue (MC-MB) were studied. The absorbance spectra were used to estimate absorption edge, optical density, skin depth, optical band gap energy, and Urbach's parameters for all DPC films. The direct allowed optical band gap energy decreased from 6.29 eV for pure MC to 5.95 eV when doped with 2.5 wt.% of MB. The dispersion of the refractive index is discussed in terms of both the single-oscillator Wemple–DiDomenico and single Sellmeier oscillator models. The nonlinear optical characteristics such as the third-order nonlinear optical susceptibility and nonlinear refractive index were calculated using the dispersive oscillator parameters obtained from the single-oscillator model. The observed improvements in the linear and nonlinear optical characteristics of MC upon incorporating MB make the present DPC a potential candidate for multifunctional applications like optoelectronic and photonic devices.

The present study reports the sol–gel synthesis and characterization of pure titania and metal-ion (Manganese) modified photocatalysts. The XRD results of pure titania confirmed the tetragonal structure having anatase as the predominant crystalline phase with no conspicuous presence of any secondary phase. In the modified photocatalysts, the shift in the peak position toward lower 2θ value reflects that manganese is occupying Ti position in TiO2 matrix. The position and width of the Raman peaks of the modified photocatalysts varies with oxygen vacancy and Mn doping level. Ti3+ and oxygen vacancies increased in the modified photocatalysts indicating a remarkable redshift of the absorption edge. Photoluminescence studies confirmed the formation of oxygen vacancy in TiO2 lattice and a decrease in intensity was observed after doping of Mn ions in TiO2. The maximum electrical conductivity of 2.85 × 10–2 S/cm was delivered by Mn2+@TiO2- D photocatalyst, which is more than fourfold of the pure TiO2 photocatalyst. Photocatalytic activity performances were evaluated by irradiating the sample degradation of methylene blue dye under visible light exposure. Mn2+@TiO2-C photocatalyst exhibits great improvement of photocatalytic activity (96%) within 120 min. It is found that Mn2+ doped TiOp2 hotocatalyst bleaches MB much faster than pure TiO2 since the transition metal ions can enhance photocatalytic activity. Mn2+@TiO2-C exhibited two times higher degradation activity toward MB compared to pure TiO2 suggesting that doping Mn2+ into TiO2 could very much enhance the photocatalytic performance and thus aid in environmental application.

In this paper, we develop a new technique for quantitative analysis of the near region of X-ray absorption spectra that is based on the extraction of spectrum descriptors and machine learning. The use of descriptors (edge position, intensity and curvature of minima and maxima, and tangent of the slope of the absorption edge) allows solution of the problem of systematic differences between theoretical calculations and experimental data, reducing the dimension of the problem and thereby improving the accuracy of machine-learning algorithms. We obtain analytical relations between the spectrum descriptors and the parameters of the local atomic structure of a substance, which extend the range of applicability of the empirical Natoli rule and analysis of the chemical shift of spectra to arbitrary classes of chemical compounds.

Ptychographic coherent diffraction imaging (CDI) allows the visualization of both the structure and chemical state of materials on the nanoscale, and has been developed for use in the soft and hard X-ray regions. In this study, a ptychographic CDI system with pinhole or Fresnel zone-plate optics for use in the tender X-ray region (2–5 keV) was developed on beamline BL27SU at SPring-8, in which high-precision pinholes optimized for the tender energy range were used to obtain diffraction intensity patterns with a low background, and a temperature stabilization system was developed to reduce the drift of the sample position. A ptychography measurement of a 200 nm thick tantalum test chart was performed at an incident X-ray energy of 2.500 keV, and the phase image of the test chart was successfully reconstructed with approximately 50 nm resolution. As an application to practical materials, a sulfur polymer material was measured in the range of 2.465 to 2.500 keV including the sulfur K absorption edge, and the phase and absorption images were successfully reconstructed and the nanoscale absorption/phase spectra were derived from images at multiple energies. In 3 GeV synchrotron radiation facilities with a low-emittance storage ring, the use of the present system will allow the visualization on the nanoscale of the chemical states of various light elements that play important roles in materials science, biology and environmental science.

Photoluminescent materials are advanced cutting-edge heat-rejecting materials capable of reemitting a part of the absorbed light through radiative/non-thermal recombination of excited electrons to their ground energy state. Photoluminescent materials have recently been developed and tested as advanced non-white heat-rejecting materials for urban heat mitigation application. Photoluminescent materials has shown promising cooling potential for urban heat mitigation application, but further developments should be made to achieve optimal photoluminescence cooling potential. In this paper, an advanced mathematical model is developed to explore the most efficient methods to enhance the photoluminescence cooling potential through estimation of contribution of non-radiative mechanisms. The non-radiative recombination mechanisms include: (1) Transmission loss and (2) Thermal losses including thermalization, quenching, and Stokes shift. The results on transmission and thermal loss mechanisms could be used for systems solely relying on photoluminescence cooling, while the thermal loss estimations can be helpful to minimize the non-radiative losses of both integrated photoluminescent-near infrared (NIR) reflective and stand-alone photoluminescent systems. As per our results, the transmission loss is higher than thermal loss in photoluminescent materials with an absorption edge wavelength (λAE) shorter than 794 nm and quantum yield (QY) of 50%. Our predictions show that thermalization loss overtakes quenching in photoluminescent materials with λAE longer than 834 nm and QY of 50%. The results also show that thermalization, quenching, and Stokes shift constitute around 56.8%, 35%, and 8.2% of the overall thermal loss. Results of this research can be used as a guide for the future research to enhance the photoluminescence cooling potential for urban heat mitigation application.

In this paper, the optical and luminescent properties of gallium phosphide (GaP) and spectral characteristics of GaP p-n, m-s structures for studying the energy-band structure of GaP were considered. Based on literature data, the absorption coefficient dependence was constructed near and above the fundamental absorption edge of the photon energy hν=2-6 eV in GaP (300 K) to discuss the obtained experimental results. The results of the photosensitivity spectra study of Au-n-GaP, Au-p-GaP Schottky barriers are presented, which were produced by the chemical deposition of Au nanoscale (~15 nm) on the GaP surface. By comparing the absorption spectrum of GaP with the photocurrent spectra of Au-n-GaP and Au-p-GaP structures in the visible and ultraviolet (UV) region of the spectrum, it has been established that usually the photocurrent (

Inorganic perovskite absorbers are promising candidates for next-generation photovoltaics due to their good thermal and light stabilities. Halide-mixed CsPbIxBr3−x reach a compromise between its structural tolerance and absorption edge, yet the power conversion efficiencies (PCEs) of the asfabricated cells can be considerably limited by the nonideal quality of solution-processed films. Here we demonstrated a fumigation strategy on colloidal perovskite films using dual-O-donor ethyl acetate (EA). By in-situ monitoring this stage with grazing-incidence wide-angle X-ray scattering technology, we reveal that EA fumigation would impose ripening barrier on colloidal inorganic perovskites and hence slow down the nucleation rate, leading to an intermediate state for processing high-crystallinity and oriented perovskite films with improved photophysical properties. An optimized PCE of 16.6% was finally yielded upon wide-bandgap (1.9 eV) perovskite absorber.

AlGaN-based multiple quantum well structures grown by plasma-assisted molecular beam epitaxy were investigated for their use in light-emitting diode (LED) structures. Initial testing was carried out on 20 pairs of AlxGa(1−x)N/AlyGa(1−y)N quantum well structures with different levels of compositional inhomogeneities in the alloy, introduced by appropriate choice of deposition conditions. It was observed that these conditions did not change the overall absorption edge, but generated a strong red-shifted photoluminescence peak. A series of LEDs with similar quantum well structures in the active region were grown, fabricated and tested. Our results indicate that deliberate introduction of compositional inhomogeneities in the quantum wells increased their electroluminescence intensity by an order of magnitude, but similar to the photoluminescence results, shifted the peak from 320 nm to 350 nm. Additionally, for these devices, no efficiency reduction was observed up to an injection of 60 mA for a device area of 0.25 mm2. These improvements may be attributed to carrier trapping mechanisms in the AlGaN well layers at deliberately introduced deep potential minima, which are likely to arrest both their overflow and their transport to extended defect states. The growth conditions also improve the p-doping efficiency and reduce the probability of leakage of carriers into the p-type layers through defect states. However, the increased efficiency and reduced droop comes at the cost of a red-shift of the electroluminescence peak.

Deep-ultraviolet nonlinear optical (DUV NLO) materials are attracting increasing attention because of their structural diversity and complexity. Using the two-dimensional (2D) crystal structure prediction method combined with the first-principles calculations, here we propose layered 18-membered-ring (18MR) boron oxide B2O3 polymorphs as high-performance NLO materials. 18MR-B2O3 with the AA and AB stackings are potential DUV NLO materials. The superior performing 18MR-B2O3AB has an unprecedentedly high second harmonic generation coefficient of 1.63 pm V-1, the largest among the DUV NLO materials, three times larger than that of the advanced DUV NLO material KBe2BO3F2 and comparable to that of beta-BaB2O4. Its unusually large birefringence of 0.196 at 400 nm guarantees the phase-matching wavelength lambda(PM) to reach this material's extreme absorption edge of approximate to 154 nm.

Achieving highly conductive p-type AlGaN with an absorption edge below 260 nm still remains a challenge. In this work, Mg-doped AlxGa1–xN (x ∼ 0.6) layers were grown by taking advantage of interfac...

Indacenodithiophene (IDT) derivatives are kinds of the most representative and widely used cores of small molecule acceptors (SMAs) in organic solar cells (OSCs). Here we systematically investigate the influence of end-group fluorination density and position on the photovoltaic properties of the IDT-based SMAs IDIC-nF (n = 0, 2, 4). The absorption edge of IDIC-nF red-shifts with the π-π stacking and crystallinity improvement, and their electronic energy levels downshift with increasing n. Due to the advantages of Jsc and FF as well as acceptable Voc, the difluorinated IDIC-2 F acceptor based OSCs achieve the highest power conversion efficiency (PCE) of 13%, better than the OSC devices based on IDIC and IDIC-4 F as acceptors. And the photovoltaic performance of the PTQ10: IDIC-2 F OSCs is insensitive to the active layer thickness: PCE still keep high values of 12.00% and 11.46% for the devices with active layer thickness of 80 and 354 nm, respectively. This work verifies that fine and delicate modulation of the SMAs molecular structure could optimize photovoltaic performance of the corresponding OSCs. Meanwhile, the thickness-insensitivity property of the OSCs has potential for large-scale and printable fabrication technology.

In recent research, the zinc oxide (ZnO) semiconductor nano particles have received a lot of attention due to its unique physical, chemical, magnetic and optoelectronic properties. The present study focuses on the photo physical and optoelectronic properties of ZnO nanostructures. To attain better optical and optoelectronic properties for light emitting diodes, solar cells and photo detectors, the rare earth transition metal ions, specifically gadolinium (Gd) were doped into ZnO nano material. Gadolinium-doped ZnO nano materials have been synthesized by a simple chemical deposition method. The structural, morphological, optical properties of synthesized samples have been investigated by various techniques, including x-ray diffraction (XRD), UV-absorption spectroscopy, and photo luminescence spectroscopy. X-ray diffraction analysis confirmed the formation of pure single phase with a particle size in the range of 30–42 nm. Optical absorption studies demonstrates that the absorption edge of the Gd:ZnO appeared to shift towards the longer wavelength due to the charge transfer between the ZnO valence or conduction band and rare earth ion 4f energy level. The band gap of the doped ZnO samples was found to be decreases and it varies from 3.2 eV to 3.1 eV due to the quantum confinement of the charge carriers in ZnO. These results provide a new approach to design ZnO nano particles with enhanced photochemical properties, light emitting electronics and solar cells.

The van der Waals material Bi2S3 is a potential solar absorber, but its optoelectronic properties are not fully explored and understood. Here, using theoretical calculations and various experimental techniques under different temperature and hydrostatic pressure conditions, the optoelectronic properties of Bi2S3 are determined. The fundamental absorption edge and photoreflectance transition value has been found to be ∼1.30 eV at room temperature, which is the optimum value, giving a maximum solar cell power conversion efficiency according to the Shockley–Queisser limit for a single-junction solar cell. Temperature-dependent measurements reveal that the total energy change of the fundamental gap between 20 and 300 K is significant at ∼0.16 eV, compared to conventional semiconductors. Theoretical predictions show that Bi2S3 possesses an indirect band gap with the band nesting surrounding. The combination of experimental methods such as photoreflectance, absorption, and photoluminescence clearly shows that the direct optical transition dominates above the indirect one. Therefore, we reveal Bi2S3 as a nesting-like band gap semiconductor with a strong absorption edge and excitonic emission.

Layered binary semiconductor materials have attracted significant interest as field emitters due to their low work function, mechanical stability, high thermal and electrical conductivity. Herein, we report a systematic experimental and theoretical investigation of SnS nanoflakes synthesized using a simple, low-cost, and non-toxic hot injection method for field emission studies. The field emission studies were carried out on SnS nanoflakes thin film prepared using a simple spin coat technique. The x-ray diffraction (XRD) and Raman spectroscopy analysis revealed an orthorhombic phase of SnS. Scanning electron microscopy (SEM) analysis revealed that as-synthesized SnS has flakes-like morphology. The formation of pure-phase SnS nanoflakes was further confirmed by x-ray photoelectron spectroscopy (XPS) analysis. The UV-Visible-NIR spectroscopy analysis shows that SnS nanoflakes have a sharp absorption edge observed in the UV region and have a band gap of ∼ 1.66 eV. In addition, the first-principles density functional theory (DFT) calculations were carried out to provide atomic-level insights into the crystal structure, band structure, and density of states (DOS) of SnS nanoflakes. The field emission properties of SnS nanoflakes were also investigated and found that SnS nanoflakes have a low turn-on field (∼ 6.2 V/μm for 10 μA/cm2), high emission current density (∼ 104 μA/cm2 at 8.0 V/μm), superior current stability (∼ 2.5 hrs for ∼ 1 μA) and a high field enhancement factor of 1735. The first principle calculations the predicted lower work function of different surfaces, especially for the most stable SnS (001) surface ( = 4.32 eV), is believed to be responsible for the observed facile electron emission characteristics. We anticipate that the SnS could be utilized for future vacuum nano/microelectronic and flat panel display applications due to the low turn-on field and flakes-like structure.

We have synthesized inverse-perovskite-type oxysilicides and oxygermanides represented by R3SiO and R3GeO (R = Ca and Sr) and studied their characteristics in the search for nontoxic narrow band gap semiconductors. These compounds exhibit a sharp absorption edge around 0.9 eV and a luminescence peak in the same energy range. These results indicate that the obtained materials have a direct-band electronic structure, which was confirmed by hybrid DFT calculations. These materials, made from earth abundant and nontoxic elements and with a relatively light electron/hole effective mass, represent strong candidates for nontoxic optoelectronic devices in the infrared range.

The current work investigates the morphology, crystallinity and photoelectrochemical (PEC) performance of bismuth sulfide/silver sulfide/zinc oxide nanorods (Bi2S3/Ag2S/ZnO NRAs) photoelectrodes as prepared at different annealing temperature. ZnO NRAs was initially grown hydrothermally, deposited in sequence with Ag2S and Bi2S3 via successive ionic layer adsorption and reaction (SILAR) method before undergoing the annealing treatment. The optimised photoelectrode (Bi2S3/Ag2S/ZnO NRAs-400 °C) possesses an optical bandgap of 1.60 eV extending the absorption edge of ZnO to visible light spectrum. The current-voltage characterization of Bi2S3/Ag2S/ZnO NRAs photoelectrodes revealed that the photocurrent density and photoconversion efficiency were strongly dependent on the annealing temperature. The PEC study shows that the photoelectrode annealed at 400 °C achieved impressive photocurrent density of 12.95 mA/cm2 at +0.5 V (vs Ag/AgCl/saturated KCl) under 100 mW/cm2 illumination with superior photoconversion efficiency of 12.63%. This improvement is due to the cascade-designed band structure alignment of Bi2S3/Ag2S/ZnO/ITO and to the brilliant role of Ag2S as an intermediate layer that reduced random chance of electron-hole (e−-h+) pairs recombination and improved the electrons collection efficiency. This work is highly anticipated to give contribution on further utilisation of Bi2S3/Ag2S/ZnO NRAs as a promising semiconductor material in PEC related applications.

In this study, the influences of bromine-based etching (Br etching) of narrow band gap CuInSe2 (CIS) absorbers and Cu(In,Ga)Se2 absorbers with various single Ga gradings (CIS:Ga) on the properties of solar cells were investigated. Absorbers with narrow absorption edge energies (Eabs) of 1.0-1.02 eV, ideal for the application as a bottom cell in a tandem device, were fabricated using a modified three-stage process and subjected to Br etching. The evolution of surface flatness and their optical and electrical properties upon Br etching were investigated. Br etching typically reduced the root-mean-square deviation of the surface roughness height (Rq) for a CIS:Ga absorber from several hundreds to several tens of nanometers, whereas for some CIS absorbers, Rq reduction was limited by the remaining voids. Moreover, Br etching reduced the leakage current across the pn junction. The high shunt resistances (Rsh) typically up to >10 kΩ·cm2 were obtained by introduction of Br etching. However, etching sometimes adversely increased the VOC deficit. The investigation of the minority carrier lifetime and diode parameters revealed that back-surface recombination in CIS and low-Ga CIS:Ga solar cells increased as the absorber layer thickness decreased. A higher Ga grading significantly reduced back-surface recombination. Narrow band gap CIGS solar cells with improved surface flatness and high VOC were achieved by introducing Br etching and proper Ga grading.

The temperature dependences of the optical absorption edges of Zn doped GaAs semiconductor crystals have been measured from 300 to 560 K. The temperature dependence of the optical absorption in the Urbach edges is adequately reproduced by a Bose-Einstein model. Analysis of experimental results gave us the opportunity to offer an explicit function of two arguments (photon energy and temperature) for the absorption coefficient of doped crystals in the Urbach edge region.

Research work has found that doping or forming defects in semiconductor materials can enhance their catalytic efficiency in the visible light region. Therefore, the first-principles study is used to systematically research the electronic structures and the photocatalytic properties in the visible region of pure ZnO, N–ZnO, VZn–ZnO, and VZn–N–ZnO. The analytical results show that the ZnO is a semiconductor of direct band gap, and its absorption edge is in the ultraviolet region, while N doping, VZn, or both can make the ZnO show light absorption coefficient in the region of visible light, the absorption coefficient of VZn–N–ZnO system in the visible light is the largest, which imply that co-doping of N and VZn is benefit for improving the photocatalytic efficiency of ZnO in the visible range. According to the analysis of the density of states, the visible light absorption is mainly caused by the intra-band transitions of the electrons in O 2p and N 2p.

Accurate evaluation of image quality not only characterizes system performance but also allows quantitative understanding of various image quality factors and the resulting image quality changes. The presampled modulation transfer function (MTF) can be useful in determining system resolution characteristics and response reduction caused by certain image quality factors. Although many studies have been conducted to accurately measure the MTF, there is still ample room for investigation of factors that affect the measured MTF for a task-based assessment using a semitransparent edge. In this study, we focus on the effects of scattered radiation from the edge on MTF measurement. The edge enhancement effect confirmed by a previous study is verified using Monte Carlo simulation; influences on the MTF due to air gaps and scattered radiation from objects are investigated. This effect by scattered radiation from an edge is also confirmed in our simulation. The results show that as air gaps change, the effect on the MTF also changes; that is, as air gaps increase, the MTF peak shifts to lower spatial frequencies. When scatter is introduced by adding an object, the MTF obtained using a semitransparent edge in the low spatial frequency is higher than that of the opaque edges for RQA9. Thus, when using such an edge, the X-ray energy should be set such that the K absorption edge of the edge material is not exceeded. Further the experimental geometry, such as air gaps, and the effect of low spatial frequency due to scattered radiation should be considered.

The Bi3+-containing semiconductors have been widely reported as potential photocatalyst candidates for water-splitting and environmental pollution problems. This work reported a new kind Bi-heterojunction of LiBiO2/Bi2O3, which was synthesized by the facile hydrothermal reactions. The XRD (X-Ray powder diffraction) measurement was applied to investigate the phase formations. The composite crystals developed in the well-crystallized ultrathin nanosheets with the thickness about 320 nm. The UV–visible absorption indicated that LiBiO2/Bi2O3 heterojunction has a similar optical absorption edge to that of LiBiO2 (2.04 eV). This confirms the heterojunction has the actively optical abilities in visible wavelength region. The photocatalytic activities were tested by photo-degradation effects of rhodamine B (RhB) dye and colorless phenol solutions under the visible light irradiation. The experiments suggested that the photocatalysis activities could be greatly improved via coupling Bi2O3 in LiBiO2/Bi2O3 heterojunctions. The migration of light-induced charge-carriers adopts a typical direct Z-scheme in LiBiO2 and LiBiO2/Bi2O3 heterojunctions.

This work demonstrates a combination technique of X-ray ptychography and the extended X-ray absorption fine structure (ptychography-EXAFS) method, which can determine the interatomic distances of bulk materials at the nanoscale. In the high-resolution ptychography-EXAFS method, it is necessary to use high-intense coherent X-rays with a uniform wavefront in a wide energy range, hence a ptychographic measurement system installed with advanced Kirkpatrick–Baez mirror focusing optics is developed and its performance is evaluated. Ptychographic diffraction patterns of micrometre-size MnO particles are collected by using this system at 139 energies between 6.504 keV and 7.114 keV including the Mn K absorption edge, and then the EXAFS of MnO is derived from the reconstructed images. By analyzing the EXAFS spectra obtained from a 48 nm × 48 nm region, the nanoscale bond lengths of the first and second coordination shells of MnO are determined. The present approach has great potential to elucidate the unclarified relationship among the morphology, electronic state and atomic arrangement of inhomogeneous bulk materials with high spatial resolution.

Tin dioxide (SnO2) thin-film has been deposited on a glass substrate by pulsed laser deposition technique under different deposition parameters. The effects of varying the parameters of Q-switched Nd-YAG laser such as laser power, frequency, and laser pulse repetition are studied by examining the optical properties. The pulsed laser-deposited SnO2 films were investigated under both vacuum and an argon background pressure of 10−3 mbar. The optical properties result shows a considerable shift in the optical spectra. The absorption edge in the absorption spectrum at high laser repetition (200 pulses per second) shifts to a higher wavelength region after pumping the argon gas. This indicates pumping the argon gas to the vacuum increasing the absorption of the film. In addition, the transmittance of the films starts at a higher wavelength when pumping argon gas. Increasing the pressure by pumping the argon might influence the film deposition and then might increase the absorption. It also indicates the start of transmittance at a lower energy in the absence of argon gas. The reflectance reduces slowly with increasing the wavelength after pumping the argon gas. This might be attributed to the increase in the vacuum pressure which affects the speediness of the film absorption.

As an n-type oxide semiconductor, Ga2O3 shows great promise in solar-blind ultraviolet (UV) photodetectors due to its adequate band gap, high absorption coefficient, high thermal and chemical stability, high breakdown voltage, and high sensitivity to UV light. In order to investigate the photoresponse of the Ga2O3 photodetector with different crystallization status, we fabricated a series of β-Ga2O3 thin films on a sapphire substrate via pulsed laser deposition with different deposition temperatures from 250°C to 650°C. X-ray diffraction and scanning electron microscopy result showed crystallization enhancement due to the increasing of deposition temperature, and the crystallization procedure started at ∼ 450°C. Optical analysis indicated a blue shift present at the absorption edge (from 4.6 eV to 5.1 eV) with temperature increasing from 450°C to 650°C, showing modulation feasibility in the band gap due to temperature dependence. In addition, all samples showed high transmittance (over 90%) over the entire visible spectrum. Film detectors fabricated by these samples showed high photoresponse and high light/dark current ratio (ILight/IDark) on Ga2O3 deposited at 450°C. Transmission electron microscopy result for film deposited at 450°C showed that the top and bottom regions of films contained both amorphous and crystalline Ga2O3, while there was no crystallization in the middle area of the film, indicating that a combined amorphous-crystalline Ga2O3 film with adequate ratio of crystalline state can significantly enhance the photoresponse while restraining the dark current.

The numerical model was developed of local heating a semiconductor material by laser pulses with wavelength at the area of the material intrinsic absorption edge. The mechanism of heating by nano- and picosecond pulses is based on the effect of thermal shifting the edge of the semiconductor absorption, while for femtosecond pulses the edge is shifted under acting the electric field of a light wave. The material heating by nano- and picosecond pulses can be of two types: spot-like and linear-like. In the case of femtosecond pulses the spot-like heating is realized. It was found that the local heating is accompanied by the material structure change, which corresponds to the character of heating.

There is great interest in transition metal-doped InSe because of its high nonlinearity and ultrafast response time at higher light fluence. Herein, Ag-doped InSe nanofilms were precisely manufactured using a direct current-radio frequency sputtering method, and their ultrafast broadband nonlinear optical responses in near-infrared were systematically researched. Ag-doped InSe nanofilm exhibited a broadband nonlinear optical response (800–1100 nm) and ultrafast carrier absorption (

Electron transfer is key to the operation of devices based on molecular (organic) semiconductors. Others have shown that electron transfer in the solid state often proceeds on sub-50 fs timescales, the details of which can be difficult to temporally resolve using pump–probe spectroscopy. A popular technique to measure average time scales for such rapid electron-transfer events is the core-hole clock implementation of resonant Auger electron spectroscopy at a single X-ray absorption edge. This is often done on relatively small molecules with core-excited states that are highly localized. We have used resonant Auger spectroscopy to probe sub-50 fs electron dynamics of two relatively large model organic semiconductors: Cu phthalocyanine (CuPc) along with its fluorinated analog, F16CuPc. We have interrogated electron dynamics simultaneously at N and C K-edges, along with calculations of initial and final states participating in the core-excited states. Our measurements show that the electron dynamics differ substantially across the two absorption edges for a given molecule, and that there are significant differences at a given edge between the two derivatives. X-ray spectroscopy calculations suggest that the extension of π-electron density onto peripheral F atoms in F16CuPc is implicated in the large change in ultrafast electron dynamics upon fluorination. We believe our results have important implications for analysis of core-hole clock measurements on relatively large organic semiconductors.

Nowadays, lead-free metal halide perovskite materials have become more popular in the field of commercialization owing to their potential use in solar cells and for other optoelectronic applications. In this study, we used density functional theory to determine the different optoelectronic properties, such as structural, optical, electronic, and elastic properties, of pure CsSnBr3 and metal (Cr/Mn) alloyed CsSnBr3. The present study suggests high absorption with a narrow band gap, a high dielectric effect, high conductivity, and reasonable reflectivity in the visible region under metal alloying. The calculated absorption coefficients indicate that the absorption edge mainly shifted (red-shift) towards the lower energy region in the event of alloying, and a clear peak was observed in the visible region. The creation of an intermediate state (dopant level) in the band structure of the alloying samples allows excited photoelectrons to transfer from the valence band to the conduction band. The alloying materials exhibit a highly ductile nature and are mechanically stable as pristine samples. The alloying effects seen in the present investigation suggest that Mn-alloyed CsSnBr3 is remarkable, showing appropriate characteristics for use in solar cell devices and for other optoelectronic applications in comparison with other lead-free (toxin-free) perovskite materials.

Building novel van der Waals (vdW) heterostructures is of great interest and is important to improve the performance of individual two-dimensional materials. Using first-principles calculations, we demonstrate that the constructed blue phosphorus/MoSe2 (P2/MoSe2) vdW heterostructure has a unique type-II band alignment and a suitable bandgap (about 1.63 eV) for optoelectronic applications. Its electronic and optical properties depend strongly on the applied vertical electric field. The quasi-particle bandgap of the P2/MoSe2 can be linearly modulated by about 1.11 eV under the applied electric field and the type-II band alignment persists in a broad range. Meanwhile, the negative electric field induces a significant red-shift of the optical absorption edge of P2/MoSe2, greatly enhancing its absorption for the visible and near-infrared lights, which is desirable for optoelectronic applications. More importantly, the observed interlayer excitons with large binding energy (more than 600 meV) can be preserved under the applied electric field, being very much beneficial for the real separation of photoexcited carriers. These results indicate that the P2/MoSe2 vdW heterostructure can become a good candidate for optoelectronic devices.

Anodization was used to obtain a nanotubular TiO2 photoanode on F–SnO2 glass. Subsequent annealing in the CH4 atmosphere promoted the C-doping and improved the crystallinity of the TiO2 nanotubes. The pulsed laser deposition was applied to cover the nanotubes with Bi2O3, serving as a hole transport material. X-ray photoelectron spectroscopy analyses of the doped samples reveal a shift in the valence band's maximum position towards lower binding energy as compared to those observed for the undoped samples (annealed in the air). The doping positively affects the absorption by shifting the absorption edge to 567 nm. I–V measurements under illumination show that the C-doping of TiO2 increases the current density following the absorbance results. The highest open circuit voltage was reached for the samples with the 300 °C-deposited Bi2O3 layer, pointing to better quality of the p-n junction, hence of the contact between Bi2O3 and TiO2. This in situ annealing provided the formation of close contact between Bi2O3 and TiO2, which enabled a faster charge transport as compared to the contact obtained with no annealing or even with post annealing.

We have characterized highly conductive Si-doped GaN films with a high electron mobility of 112 cm2V−1s−1 at an electron concentration of 2.9 × 1020 cm−3, prepared using pulsed sputtering deposition (PSD). With an increase in the doping concentration, the absorption edge was found to shift toward a higher energy level, owing to the Burstein-Moss effect, thus making this material suitable for the transparent conductive tunneling electrodes of visible and ultraviolet-A light-emitting diodes. The full width at half maximum value of the near-band-edge (NBE) emissions in a photoluminescence spectrum measured at 77 K was as small as 185 meV, even for the sample with the highest electron concentration of 2.9 × 1020 cm−3. Such sharp NBE emissions from PSD-grown heavily Si-doped GaN films can be explained by an analytical model with a low compensation ratio θ of around 0.1, which is consistent with the exceptionally high observed electron mobility. These results indicate the strong potential of the low-temperature PSD growth technique for the formation of high-quality, heavily Si-doped GaN.

Herein, highly transparent and conductive In2O3 films were deposited by reactive high power impulse magnetron sputtering from a metal target without thermal assistance. Film deposition was performed at room temperature using oxygen flow rates selected based on target voltage hysteresis, and the obtained films were compared in terms of structure and electrical/optical properties. Notably, the use of high plasma density, peak power, and ionization efficiency resulted in the formation of highly crystalline films featuring a small grain size and a columnar structure with a preferred orientation. The minimal carrier concentration of 1.6 × 1021 cm−3 was observed for films deposited in metallic mode; the carrier mobility of these films increased from 23 to 51 cm2 V−1 s−1 as the oxygen flow rate increased from 7 to 10 sccm. Moreover, the oxygen flow rate significantly affected the conductivity of In2O3 films, which ranged from semiconductor-like to insulator. The visible-light transmittance of In2O3 films exceeded 85% when oxygen flow rate larger than 7sccm. The absorption edge of as-prepared films was located close to 350 nm and shifted to lower wavelengths with increasing oxygen flow rate, which was explained by the Burstein–Moss effect. The infrared transmittance of In2O3 films was strongly dependent on the deposition mode. In agreement with Drude's theory, films deposited in transition mode at room temperature were highly transparent and conductive, which was ascribed to the use of controlled In:O ratios, whereas films deposited in other modes were shown to exhibit either excellent conductivity (metallic mode) or good optical transmittance (poisoning mode).

Improving the performance and reducing the manufacturing costs are the main directions for the development of organic solar cells in the future. Here, the strategy that uses chemical structure modification to optimize the photoelectric properties is reported. A new narrow bandgap (1.30 eV) chlorinated non-fullerene electron acceptor (Y15), based on benzo[d][1,2,3] triazole with two 3-undecyl-thieno[2′,3′:4,5] thieno[3,2-b] pyrrole fused -7-heterocyclic ring, with absorption edge extending to the near-infrared (NIR) region, namely A-DA'D-A type structure, is designed and synthesized. Its electrochemical and optoelectronic properties are systematically investigated. Benefitting from its NIR light harvesting, the fabricated photovoltaic devices based on Y15 deliver a high power conversion efficiency (PCE) of 14.13%, when blending with a wide bandgap polymer donor PM6. Our results show that the A-DA'D-A type molecular design and application of near-infrared electron acceptors have the potential to further improve the PCE of polymer solar cells (PSCs).

Eu3+-doped Zn2SiO4/ZnO phosphor-based composites were prepared using a simple thermal treatment method. The effect of Eu3+ content on the morphological and photoluminescence performance was examined using XRD, FTIR, FESEM, UV–Vis, and PL measurement. The existence of two crystal phases by the XRD measurement confirmed the development of zincite (ZnO) and zinc silicate (Zn2SiO4) crystal phases. Besides, the FTIR spectra and FESEM micrograph support the XRD result by verifying ZnO and Zn2SiO4 phase formation through the existence of their characteristic Zn–O–Si and Zn–O vibration modes with the decrement of SiO4 broad absorption band as the Eu3+ concentration increased. Also, UV–Vis absorption spectra presented by the composite samples displayed a broad absorbance that confirmed the addition of Eu3+ ions in the ZnO/Zn2SiO4 has caused the absorption edge of the curve having red shift. The photoluminescence spectrum showed red shift light emissions at 485 and 615 nm, associating with the Zn2SiO4 crystal phase, in addition to the ZnO crystal phase. From the interesting results achieved, this ZnO/Zn2SiO4 phosphor-based composite material can be a potent candidate in optoelectronic applications.

Undoped, Al-doped and Al-B co-doped ZnO transparent semiconductor thin films were deposited on glass substrates by sol-gel method and spin coating technique. This study investigated the influence of Al (2 at.%) doping and Al (2 at.%)-B (1 or 2 at.%) co-doping on the microstructural, surface morphological, electrical and optical properties of the ZnO-based thin films. XRD analysis indicated that all as-prepared ZnO-based thin films were polycrystalline with a single-phase hexagonal wurtzite structure. The substitution of extrinsic dopants (Al or Al-B) into ZnO thin films can significantly degrade the crystallinity, refine the microstructures, improve surface flatness, enhance the optical transparency in the visible spectrum and lead to a shift in the absorption edge toward the short-wavelength direction. Experimental results showed that the Al-doped and Al-B co-doped ZnO thin films exhibited high average transmittance (&gt, 91.3%) and low average reflectance (&lt, 10%) in the visible region compared with the ZnO thin film. The optical parameters, including the optical bandgap, Urbach energy, extinction coefficient and refractive index, changed with the extrinsic doping level. Measured results of electrical properties revealed that the singly doped and co-doped samples exhibited higher electron concentrations and lower resistivities than those of the undoped sample and suggested that 2 at.% Al and 1 at.% B were the optimum dopant concentrations for achieving the best electrical properties in this study.

In this work, Copper oxide nanofiller with different contents (0.05, 0.5, 1, and 2 wt% CuO) were embedded in DGEBA epoxy matrix using ultrasonic wave and casting processing technique. This study deals to assess and investigate the CuO fillers impact on various properties of CuO/DGEBA hybrid polymer nanocomposites (CuO/DGEBA-HPNCs). The structural modifications were tracked using X-ray diffraction (XRD) patterns and Fourier transform infrared spectra. XRD profiles demonstrated that the crystallinity of samples increases with an increase of CuO nanoparticles (CuO NPs) contents, which improved the crystallinity of CuO/DGEBA-HPNCs. The interplanar distance, particle size, and the average inter-crystalline separation were also calculated and investigated. Interactions between CuO NPs and DGEBA polymer matrix were reported using the correlated FTIR analysis and XRD results, which was related to the formation of new absorption bands for the 1 wt% and 2 wt% CuO NPs samples. The UV–Vis investigation showed that the absorption edge values exhibited a red-shift with the rise in CuO NPs, due to interactions between the doping and the DGEBA matrix owing to the formation of charge transfer. Furthermore, the dielectric characteristics such as dielectric permittivity (ɛ′, ɛ″), electrical modulus (M′, M″), and dielectric AC impedance (Z′, Z″) of the CuO/DGEBA-HPNCs were performed at room temperature as a function of CuO nanofiller contents and frequency. Experimental modulus data were successfully fitted to Havriliak–Negami model. AC impedance spectroscopy was carried out to disclose the CuO/DGEBA-HPNCs as a function of various CuO NPs fillers. The obtained dielectric parameters, using fitting curves, were altered by the CuO NPs filler concentration. The results showed the ability to use the samples in optoelectronic devices.

Sb-ZnO (SZO) thin films were formed on n-Si semiconductor and sapphire by dual ion beam sputtering (DIBS) technique. Structural and optical parameters of SZO sputtered grown film were determined by ellipsometry and field emission scanning electron microscopy (FE-SEM), and I-V analysis of the SZO/n-Si heterojunction device in dark. A smooth film without any grain boundaries is observed in SEM analysis. The bandgap (Eg) of the grown SZO film is obtained and the value of Eg obtained is 3.92 eV. A high refractive index in the range of n=1.85-2.08 is shown by the deposited SZO film in the ultraviolet (UV)-visible region, moreover, it can be seen from the ellipsometry analysis that the fundamental absorption edge is obtained near the UV region. A rectification ratio of ~ 16 times is observed at ±4 V for SZO/n-Si heterojunction. The Study concludes that SZO material has the potential to be used in the application dealing with the UV region of the light spectra.

Within the last decades, electro-optic (EO) modulators based on the quantum confined Stark effect (QCSE) in quantum well structures came to prominence for high-speed optical networks. When an external electric field is applied to such a quantum structure, it bends the energy levels and shifts the absorption edge to smaller energies. In addition, the overlap between electron and hole wave functions decreases, which diminishes the amount of absorption [1] . This technique is ultimately limited to the time scale necessary to change the electric field on the attached electrodes. Moreover, largest modulation of the energy levels can be achieved for structures with a strong confinement and large excition binding energies. Hence, low dimensional materials like quantum dots (QDs) in combination with intense THz pulses which provide the electric field driver, are promising candidates for sub-picosecond all-optical switching of optical absorption. Pioneering work has been performed by Pein and co-workers [2] wherein they report on a THz-field induced QCSE in CdSe/CdS colloidal QDs. However, due to difficulties to generate THz radiation with the electric field in the MV/cm range, necessary to alter the optical transmission, THz field enhancing structures have been employed.

We developed and applied an improved theoretical model to optimize characteristics of highly efficient textured solar cells (SCs). The model accounts for all recombination mechanisms, including nonradiative exciton recombination and recombination in the space-charge region (SCR). To compare the theoretical results with an experiment, we proposed empirical formula for the external quantum efficiency (EQE), which describes its experimental spectral dependencies near the absorption edge. The proposed approach allows modeling short-circuit current and photoconversion efficiency in the textured crystalline silicon solar cells. The theoretical results, compared to the experimental measurements, were used to optimize the key parameters of the SCs, such as the base thickness, doping level and others.

The coexistence of Mott localized $f$ states with wide conduction and valence bands in $f$-electron semiconductors results, quite generically, in a complex optical response with the nature of the absorption edge difficult to resolve both experimentally and theoretically. Here, we combine a dynamical mean-field theory approach to localized $4f$ shells with an improved description of band gaps by a semilocal exchange-correlation potential to calculate the optical properties of the light rare-earth fluorosulfides $Ln\mathrm{SF}$ ($Ln=\mathrm{Pr}$, Nd, Sm, Gd) from first principles. In agreement with experiment, we find the absorption edge in SmSF to stem from $\mathrm{S}\text{\ensuremath{-}}3p$ to $\mathrm{Sm}\text{\ensuremath{-}}4f$ transitions, while the Gd compound behaves as an ordinary $p\text{\ensuremath{-}}d$ gap semiconductor. In the unexplored PrSF and NdSF systems we predict a rather unique occurrence of strongly hybridized $4f\text{\ensuremath{-}}5d$ states at the bottom of the conduction band. The nature of the absorption edge results in a characteristic anisotropy of the optical conductivity in each system, which may be used as a fingerprint of the relative energetic positions of different states.

Single crystal sapphire was synthesized by chemical transport of Al-O generated by the reaction of polycrystalline Al2O3 ceramic and carbon. Using C-axis oriented polycrystalline Al2O3 ceramics as a seed crystal in the deposition temperature range, a C-axis sapphire crystal (Φ5xL35 mm) was grown at a temperature range of 700–1000 °C, and the growth rate in the C-axis direction was about 3.5 mm/h. The transmittance in the visible to infrared region of the synthesized sapphire is a theoretical value (transmission loss is lower than 0.1 %/cm), and the absorption edge was less than 200 nm (the band gap is 6.2 eV), which is shorter than the absorption edge (240 nm) of the commercially available single crystal (band gap 5.2 eV) synthesized by the Czochralski method. The dislocation density in this material was extremely low, and it was confirmed by lattice image observation that it was a high-quality single crystal with very few defects.

Excellent nonlinear optical materials simultaneously meet the requirements of large SHG response, phase-matching capability, wide transparency windows, considerable energy band-gap, good thermal stability and structure stability. Herein, two new promising nonlinear optical (NLO) crystals LiMII (IO3 )3 (MII =Zn and Cd) are rationally designed by the aliovalent substitution strategy from the commercialized α-LiIO3 with the perfect parallel alignment of IO3 groups. Compared with parent α-LiIO3 and related AI2 MIV (IO3 )6 , the title compounds exhibit more stable covalent 3D structure, and overcome the racemic twinning problem of AI2 MIV (IO3 )6 . More importantly, both compounds inherit NLO-favorable structure merits of α-LiIO3 and show larger SHG response (≈14× and ≈12×KDP), shorter absorption edge (294 and 297 nm) with wider energy band-gap (4.21 and 4.18 eV), good thermal stability (460 and 430 °C), phase-matching behaviors, wider optical transparency window and good structure stability, achieving an excellent balance of NLO properties.

This paper investigates the properties of Copper–Selenium heterojunction nanowires before and after implantation. Heterojunction between Cu and Se was formed using the template method, assisted by chronoamperometry technique. Implantation in heterojunction nanowires was performed with 80 MeV Ni6+ ions for different fluencies ranging from 1 × 1011 to 1 × 1013 ions/cm2. XRD studies show that no peak shifting takes place after implantation, but a significant variation in peak intensity was observed. Plane orientation and increased crystal quality may be the probable cause for variation in plane intensity. UV–Visible study for optical behavior shows a red shift in the absorption edge along with a decrease in the optical band gap. I–V measurements before and after implantation revealed an increase in the rectification behavior of Schottky junction, which may be due to the interface smoothing and a decrease in junction barrier height during implantation.

The optical absorption coefficient α and electrical conduction as a function of temperature of the semiconductor Cu3In5Se9, an ordered defect compound which crystallizes in a tetragonal structure with space group P$$ \bar{4} $$2c, have been studied. The band gap energy EG varies between 0.994 eV and 0.983 eV in the temperature range between 25 and 300 K. The exponential variation of α with photon energy, observed just below the fundamental absorption edge, confirms the existence in Cu3In5Se9 of the Urbach’s tail. The phonon energy hνp associated with this tail is 101 meV. This is about three times higher than the highest optical phonon mode reported for Cu3In5Se9 from infrared reflectivity spectra. The origin of this high energy is attributed due to the contribution of localized modes produced by structural disorders due to deviation from ideal stoichiometry and donor–acceptor defects pairs. From the analysis of electrical data of n-type Cu3In5Se9 in the temperature range from 80 K to 300 K, it was found that above 100 K the electrical conduction is due to the activation of two shallow donor levels of about 40 meV and 80 meV, probably due to selenium vacancies.

Ultraviolet (UV) photodetector was fabricated on Mg0.2Zn0.8O nano-rod film synthesized by laser sintering method. The X-ray diffraction pattern shows that Mg0.2Zn0.8O film grows along c-axis orientation with a wurtzite structure. Absorption edge locates at 351 nm and the band gap is determined to − 3.53 eV. The UV photodetector has a response peak at − 328 nm corresponding to a saturation responsivity of 0.196 A·W−1 at 20 V bias. The UV/visible rejection ratio of the photodetector is close to 2 orders of magnitude. The super perfect photo-electronic performance of the detector illustrates that laser sintering method has a vital advantage to synthesized Mg0.2Zn0.8O nano-film for UV photodetector.