Sharp Absorption Edge Research Articles

Analysis on the shape of α-Sn CQDs

In the search for materials alternate to bulk HgCdTe for high performance infrared imaging applications, colloidal quantum dots (CQDs), particularly HgTe CQDs, have gained traction owing to acceptable detector performance with easy preparation and low cost. In this article, we evaluate α-Sn CQDs, an environmentally less reactive and less toxic alternative to HgTe, for infrared sensing applications. Ab initio density functional theory calculations are used to study the shape-dependent stability, electronic bandgap, and absorption coefficient of α-Sn CQD nanoparticles (NPs). We consider three possible CQD shape constructions—Wulff, shell-by-shell, and spherical. The CQD of Wulff construction is predicted to be the most stable. However, we find that the size, not the shape, of the NP has a strong effect on the bandgap and absorption coefficient. Consequently, a sharp absorption edge is expected even in an ensemble of CQDs with different shapes. Importantly, the shape determines the position of the band edges with respect to vacuum, and thus offers a possibility of choosing the shape to improve alignment with the energy levels of ligands to enable efficient drift transport, instead of a slower and less efficient hopping transport.

Ion Beam-Induced modification in the optical properties of the bilayer of nano-structured amorphous selenium and multi-walled carbon Nanotubes: A study by 70 MeV Ni Ions

In this study, we report improved physical properties of selenium with multi-walled carbon nanotubes (MWCNTs) resulting from a homogeneous mixture of CNT-Se bi-layer thin film by using swift heavy ion irradiation. FESEM micrographs clearly showed the inter-diffusion of Se nanoparticles into MWCNTs following swift heavy ion (SHI) irradiation, EDX validates the elemental composition. The existence of different phonon modes (LO mode and D, G, G' bands) has been found in the Raman spectra of the investigated bi-layer thin films. UV–Visible spectroscopic analysis of pristine CNT-Se thin films show two sharp absorption edges at ∼670 nm and ∼340 nm. After swift heavy ion irradiation, the sharp absorption edge at ∼670 nm exhibits a blue shift, whereas the absorption edge at ∼340 nm exhibits a red shift, confirming the homogeneous mixing of two layers. These remarkable shifts found in the optical properties of CNT-Se bi-layer make the investigated material feasible for many optoelectronic device applications.

Computational Insight into the Physical Properties of Bulk MP (M = Li, Na, K) for Energy Applications.

In this study, we applied density functional theory to compute the electronic, optical, and thermal properties of MP (M = Li, Na, K). We find that the materials under consideration are stable, owing to the lack of negative frequencies in the phonon spectra. LiP exhibits an indirect band gap of 1.43 eV. NaP and KP have direct band gaps of 1.67 and 1.76 eV, respectively. The family of these composites shows strong absorption, observed by their very sharp absorption edges and confirmed by their direct transition from the valence to conduction band. They exhibit strong absorption below 4.0 eV in the optical spectra, which could serve in a solar cell device. The thermal calculations show high zT values of 0.74, 0.78, and 0.64 at 300 K for LiP, NaP, and KP, respectively. Thus, our results could be promising for electronic and thermal devices.

Study of blue-light emission properties of WO3:Eu microstructures

Structural, surface morphological, optical absorption and emission properties of 0–5% Eu doped WO3 samples are studied. The samples are synthesised by acidic precipitation method. The structural analysis reveals that the sample has ‘room-temperature monoclinic’ structure. The average crystallite size of the undoped sample is ∼58.57 nm and it decreases to 34.72 nm after doping of Eu at 5%. The undoped sample has hexagonal disc-like grain structures with average diameter of ∼0.84 μm. All the samples show a sharp absorption edge above 350 nm. The transmittance of the samples increases above 400 nm and reaches its maximum at ∼490 nm. The extinction coefficient of the undoped sample is minimum at 390 nm and it has a relatively smaller value than that of the doped samples. The optical bandgap of the undoped sample is found to be 3.56 eV and it decreases to 3.28 eV with the increase of concentration of Eu to 5%. Analyses of PL spectra show that the undoped sample under 355 nm UV excitation produces a broad blue emission band with five maxima at ∼403, 414, 435, 473 and 495 nm due to band-to-band transitions and transitions involving intrinsic defects. A blue emission band centred at ∼435 nm is increased by two-fold after doping of Eu at 1%. In addition, a secondary emission band is found at ∼505 nm due to formation of an aggregate defect (F2 centre). When the doping concentration is increased to 5%, another secondary band is observed at 610 nm due to interstitial Eu3+ centre. The enhancement of the blue emission band is attributed to formation of oxygen vacancies due to substitution of W6+ ions by Eu3+ ions. The enhanced blue light in the sample doped with 1% of Eu has potential application in WLED as well as other light emitting applications.

Synthesisation of Zinc Oxide Nanowires via Hybrid Microwave-Assisted Sonochemical Technique at Various Microwave Power

Zinc oxide nanowires (ZnO NWs) have been successfully synthesized via a hybrid microwave-assisted sonochemical technique (HMAST) using zinc acetate dehydrate as starting material. The optimized parameters were set at 12.5 mM solution concentration and a rapid deposition time of 60 minutes. The microwave power was varied from 100 to 800 Watts and the effect of microwave power on the morphological, structural, and optical properties ofthe ZnO NWs has also been studied. Results showed an aligned, uniformly distributed hexagonal wurtzite structure of ZnO NWs was produced, which were augmented at 600 W microwave power, having the smallest diameter size of 29.66 nm. The XRD graph showed that the ZnO NWs produced are highly crystalline, exhibiting the sharpest and narrowest intensity of (002) peaks and a crystallite size of 18.60 nm. The transmittance spectra obtained by UV-Vis would be 89.72%, having a sharp absorption edge, implying the lower particle size of ZnO as well as exhibiting high absorbance in the ultraviolet region, indicating good crystallinity. From the findings, it can be confirmed that the microwave-assisted method helped in improving the formation of higher quality ZnO NWs that can be befittingly applied in many devices such as photocatalysts and sensors due to their excellent electrochemical properties.

Photon attenuation computational software tools - A comparative study

Various photon attenuation software tools are being used widely by researchers to evaluate the radiation shielding parameters of the elements/compounds/composites theoretically. Attempts are being made by a few researchers to update and develop software tools of these kinds. However, the efficacy of these tools in terms of their comparison is yet to be explored. Thus, an attempt has been made in the present study to compare & explore the best tool among the widely used and most trusted tools, such as Phy-X, XCOM, FFAST and XMuDat photon attenuation databases, to evaluate the shielding parameters of PVA-based composites filled with bismuth and tungsten, and also for materials such as bismuth, tungsten, gold, copper, platinum, lead and barite. Careful analysis of the data obtained computationally and experimentally shows that, although the Phy-X tool provides various shielding parameters with multiple choices in the selection of energy range, it is noticed that this tool needs to be figured out for obtaining the absorption edges of the composites of interest precisely. The XCOM database provides sharp absorption edges; however, this tool gives multiple values of mass attenuation coefficients corresponding to a particular absorption edge energy. On the other hand, The FFAST tool provides sharp absorption edges along with X ray fine structure. However, the tool restricts to work with elements and compounds in the energy range 1 keV–433 keV, which limits the utilization of this tool. Furthermore, the XMuDat tool has a limiting option to work with the materials available in its library/database and provides the mass attenuation coefficient and four other parameters. However, the XMuDat provides a large number of data points, which helps to identify any minute deviation in the values of the parameters. Therefore, the present study suggests that the XMuDat tool is much more advantageous and reliable than the other tools for the detailed study of various radiation shielding parameters.

Reformed dielectric features in single phase orthorhombic nickel vanadate complex oxides and the significance of the lattice dynamics in the optoelectrical features

V(1-x)2Ni3xO5-δ compounds are prepared by high-temperature solid-state reactions for mole fractions x = 0.04, 0.05, and 0.06. Micro-Raman spectrum with an excitation wavelength of 540 nm reveals 12 well-resolved phonon modes corresponding to the orthorhombic alpha-polymorphic phase of Vanadium Pentoxide and an extra vibrational mode excited by the tetravalent vanadium cation. A sharp absorption edge is observed from 500 nm to 650 nm in the diffuse reflectance spectrum with the rate of absorption increasing slightly, directly proportional to the x value. Kubelka-Munk plots reveal band gap reduction due to the negative Moss-Burstein shift that is attributed to the Ni2+ occupancy at the lattice sites creating electron deficiency. Frequency-dependent AC conductivity, studied in the frequency range 1 KHz to 1 MHz at room temperature exhibited DC-like conductivity in the low-frequency region, and the Jonsher Power Law fit gives the σdc values increasing with Ni ion concentration. AC conductivity at 1MHZ shows an elevation from 1.6 × 10−03 Sm−1 through 4.8 × 10−03 Sm−1 reaching 13.6 × 10−03 Sm−1 by increasing the concentration of Ni2+ ions. The dielectric constant at 250 °C, is observed to increase from 395, through 1447 to 2614, for mole fractions 0.04,0.05 and 0.06 respectively making this multivalent vanadate system a potential candidate for optoelectric and solid oxide fuel cell applications.

Ultraviolet photodetector based on RbCu2I3 microwire

Copper-based halide perovskites have shown great potential in lighting and photodetection due to their excellent photoelectric properties, good stability and lead-free nature. However, as an important piece of copper-based perovskites, the synthesis and application of RbCu2I3 have never been reported. Here, we demonstrate the synthesis of high-quality RbCu2I3 microwires (MWs) by a fast-cooling hot saturated solution method. The prepared MWs exhibit an orthorhombic structure with a smooth surface. Optical measurements show the RbCu2I3 MWs have a sharp ultraviolet absorption edge with 3.63 eV optical band gap and ultra-large stokes shift (300 nm) in photoluminescence. The subsequent photodetector based on a single RbCu2I3 MW shows excellent ultraviolet detection performance. Under the 340 nm illumination, the device shows a specific detectivity of 5.0 × 109 Jones and a responsivity of 380 mA·W−1. The synthesis method and physical properties of RbCu2I3 could be a guide to the future optoelectronic application of the new material.

Realizing a strong visible-light absorption band in piezoelectric 2D carbon nitride sheets for enhanced piezocatalysis

Piezoelectric photocatalytic water splitting is a viable approach to generate renewable energy and carbon nitride sheets (CNs) has emerged as a promising material. However, the narrow solar absorption range of CNs due to its wide-band-gap hinders its further development and practical applications. In this study, CNs with a strong visible-light absorption band and a sharp absorption edge beyond 574 nm are successfully prepared by developing a fluorination and defluorination strategy. Experimental results show that introducing cyano groups into the framework of CNs as well as the accompanied nitrogen vacancies at the edges maintains high piezoelectricity and that the separation of photo-generated electron-hole pairs by the piezo-polarization charges is enhanced in the modulated CNs. Under simultaneous visible-light exposure and the ultrasonic irradiation, the modulated CNs loaded with Pt cocatalyst as a photocatalyst show a superior photocatalytic hydrogen evolution rate of 13.53 mmol g−1 h−1, which is one of the highest record reported so far for carbon nitride-based materials. Theoretical calculations reveal that the introduction of cyano into CNs leads to a suitable band gap for visible light, which dramatically improves the photocatalytic ability. This study advances the investigation of piezoelectric photocatalytic water splitting, and is also an enabling technology for piezoelectric semiconductors for their practical applications.

Studies on nano crystalline copper doped Nickel Zinc ferrites for optoelectronic applications

Investigation of optical and dielectric properties of nanocrystalline Ni0.65Zn0.35 Cu x Fe(2-2x/3) O4 (for x = 0.00–0.05 in steps of 0.01) ferrites synthesized using hydrothermal route is successfully carried out. Two distinct analytical spectroscopic methods with Dichloro – 5,6-Dicyano – 1,4-Benzo quinone (DDQ) and Bromo Phenol Blue (BPB) are adopted to observe the UV–visible absorption spectroscopy in the dispersed solutions of all samples. The formation of ion pair complex in the presence of BPB results in two distinct absorption edges in the visible region, around 440 nm and 580 nm in the present ferrite samples. Application of Tauc's formalism gives rise to two optical band gap values Eg1 and Eg2 in the range of 2.12–2.40 eV and 3.583–3.674 eV, respectively. The formation of charge transfer complex with all sample solutions in presence of DDQ reagent results in sharp absorption edges in the UV-region around 306 nm wavelength. An initial rise followed by continuous drop in band gap values ranging from 3.814 to 3.824 eV is observed from Tauc's plots. The optimum refractive index (n) values calculated for the three types of band gap values using empirical relations display the optical absorption potentiality of Ni–Cu–Zn nano ferrites in both Visible and UV – regions. Variation of band gap values is ascribed to the lattice strain effect, quantum confinement and narrowing band gap effects. Real part of dielectric constant (ε′), dielectric loss factor (tanδ) and ac-conductivity(σac) are studied for all samples at room temperature with in the frequency range of 42 Hz to 5 MHz. The values of ε′ and tanδ are observed to decrease with increase in frequency, while that of σac are found to increase with increase in frequency. Improved dielectric properties, existence of optical band-gap values observed in the present Ni–Cu–Zn ferrites promote these materials for their utility in optoelectronic devices and high frequency applications.

Variations in the Physical Properties of RF-Sputtered CdS Thin Films Observed at Substrate Temperatures Ranging from 25 °C to 500 °C.

CdS films with a wide range of substrate temperatures as deposition parameters were fabricated on Corning Eagle 2000 glass substrates using RF magnetron sputtering. The crystallographic structure, microscopic surface texture, and stoichiometric and optical properties of each CdS film deposited at various substrate temperatures were observed to be highly temperature-dependent. The grown CdS thin films revealed a polycrystalline structure in which a cubic phase was mixed based on a hexagonal wurtzite phase. The relative intensity of the H(002)/C(111) peak, which represents the direction of the preferential growth plane, enhanced as the temperatures climbed from 25 °C to 350 °C. On the contrary, the intensity of the main growth peak at the higher temperatures of 450 °C and 500 °C was significantly reduced and exhibited amorphous-like behavior. The sharp absorption edge revealed in the transmission spectrum shifted from the long wavelength to the short wavelength region with the rise in the substrate temperature. The bandgap showed a tendency to widen from 2.38 eV to 2.97 eV when the temperatures increased from 25 °C to 350 °C. The CdS films grown at the temperatures of 450 °C and 500 °C exhibited glass-like transmittance with almost no interference fringes of light, which resulted in wide bandgap values of 3.09 eV and 4.19 eV, respectively.

Performance of RF sputtered V2O5 interface layer in p-type CdTe/Ag Schottky diode

In this work, vanadium pentoxide (V2O5) thin films were successfully grown on soda-lime glass by RF magnetron sputtering technique under an oxygen partial pressure of 10−6 m-bar at room temperatures. Systematically, the characterization of V2O5 films was carried out to study the impact of different sputtered power on the growth, structural and optical properties. XRD results revealed that films exhibit a preferred orientation along with the (001) plane, including an orthorhombic structure at the low RF power. The crystal growth corresponding (001) and (110) planes were suppressed as well as the intensity of peak (003) and (401) planes increased with increasing RF power. It was examined that at the high RF power, thin films show mixed oxide of VO2 and V2O5. A uniform spherical grains morphology was observed by FESEM micrographs. The thin films exhibited good transmittance above 80%, and a sharp absorption edge was found for all samples about 412 nm. Moreover, Two Schottky structures, Ag/V2O5/CdTe and Ag/CdTe were fabricated to investigate the performance of Schottky diode (SD) with the V2O5 interface layer between metal and semiconductor junctions for solar cell applications. The SD parameters such as ideality factor, barrier height, and interface resistance were also calculated. It was found that Ag/V2O5/CdTe diode performs well at room temperature. The saturation current increases from 1.03 μA to 8.39 μA with the insertion of the V2O5 interface layer (IF). Consequently, the V2O5 layer plays a vital role in enhancing the diode's performance.

Synthesis of 1D Bi2O3 nanostructures from hybrid electrospun fibrous mats and their morphology, structure, optical and electrical properties

The aim of this study was to produce Bi2O3 nanowires using a combination of sol–gel process and electrospinning methods and a solution based on a 13% solution of polyacrylonitrile (PAN) in N,N-dimethylformamide (DMF) containing 1.5 g of bismuth (III) nitrate pentahydrate (Bi(NO3)3·5H2O). The obtained fibrous composite mats were dried at room temperature for 24 h followed by the calcination process in air at two different temperatures of 400 °C and 600 °C. Analysis of the morphology of the fabricated Bi2O3 nanomaterials based on TEM images showed that the obtained ceramic structures could be classified as one-dimensional Bi2O3 nanostructures, with the sizes of the presented structures being 260 nm, 125 nm and 200 nm for diameter, and 5.5μm , 2 μm and 2.125 μm for length, respectively. Moreover, further analysis of the morphology of the obtained Bi2O3 nanostructures with the use of SEM showed that their diameters ranged from 150 to 500 nm when a calcination temperature of 400 °C was employed, while Bi2O3 nanowires with diameters ranging from 150 to 450 nm were obtained at 600 °C. To analyse the chemical composition and oscillatory transitions of atoms vibrating between the oscillatory levels in the molecules of the produced 1D nanostructures, and to determine the functional groups existing therein, EDX and FTIR were used. Transmission peaks in FTIR spectra recorded for wave numbers in the range of 400–4000 cm-1 were due to the presence of vibrations in Bi–O bonds, which correspond to the structure of Bi2O3. In addition, a detailed analysis of optical constants of one-dimensional Bi2O3 nanostructures fabricated using a combination of sol–gel process, electrospinning and calcination methods has been presented in this paper for the first time. Optical studies based on the recorded UV–Vis spectra showed that the obtained Bi2O3 nanowires were characterized by sharp absorption edges of radiation in the near-ultraviolet range, with sharp absorption edges falling at wavelengths of 400 nm, regardless of the applied temperature during the calcination process. The study of optical constants showed that the Bi2O3 nanostructures exhibited refractive indices of 2.62 and 2.53 at temperatures of 400 °C and 600 °C, respectively, while dielectric constants were 6.87 and 6.42, respectively. The final stage of the study was the determination of the width of energy gaps of the produced bismuth oxide nanostructures, which were found to be 3.19 and 2.97 eV, respectively. The presented results of morphology and optical properties of the obtained one-dimensional Bi2O3 semiconductor nanostructures indicate a potential possibility to apply this type of materials for the production of a new generation of dye-sensitized photovoltaic cells (DSSCs).

Growing MASnI3 perovskite single-crystal films by inverse temperature crystallization

Perovskite single-crystal films are promising candidates for high-performance perovskite optoelectronic devices due to their optoelectrical properties. However, there are few reports of single-crystal films of tin based perovskites. Here, for the first time, we realize the controllable growth and preparation of lead-free tin perovskite MASnI3 single crystals via inverse temperature crystallization (ITC) strategy with γ–butyrolactone (GBL) as solvent. The solubility characteristics of MASnI3 in GBL are clarified by quantitative analytical method. Highly repeatability experiments are further demonstrated using this unique solubility and ITC properties. Sequentially, using space limiting method, tin perovskite MASnI3 single-crystal thin films are fabricated with micron-scale thickness, which is highly desired for efficient tin perovskite solar cells. Our MASnI3 single-crystal thin films show typical single-crystalline features including strongly optical absorbance with sharp absorption edges, pure-phase x-ray diffraction patterns, and absence of Sn(IV) x-ray photoelectron spectroscopy. We believe that our findings will further broaden the application prospects of tin perovskite MASnI3 single crystals and cause a new upsurge in exploring the field of lead-free perovskite single-crystal growth.

Optoelectronics properties of Janus SnSSe monolayer for solar cells applications

Highly demanding efficiency, scaling and cost led the researchers to predict and synthesize two-dimensional transition metal dichalcogenides for advanced technology. Using the first-principles calculations, we study the optoelectronic properties, and device absorption efficiency of Janus SnSSe monolayer. The Janus SnSSe exist in two different phases, 1T and 2H structures. We find the 1T structure dynamically more stable than the 2H structure due lower energy and no-negative frequencies in the phonon spectra. The 1T SnSSe possess semiconducting nature with an indirect band-gap of 1.61 eV. The Janus SnSSe possesses a strong absorption having sharp absorption edges, showing the transition of electron to the conduction band from the valence band. We find that the Janus SnSSe strongly absorb light below 4.0 eV, which show its prominent applications for solar cell. A strong absorption from infra-red to the ultra-violet region of light spectrum make it promising in the optical devices. Furthermore, the wider band gap nature having strong device absorption-efficiency could make it suitable for the top cell in the tandem architecture.

A remarkable effect of substrate temperature on novel Al/Y2O3/n-Si heterojunction diodes performance fabricated by facile jet nebulizer spray pyrolysis for optoelectronic applications

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 4.9 eV. Moreover, the observed photoluminescence (PL) spectrum indicated number of emission peaks in the grown films. From the current – voltage (I-V) characteristic, the calculated ideality factor (n) value was noticed to be drastically reduced from 7.66 to 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.

Concentration Effects on Characteristics of Gas Sensors Based on SnO<sub>2</sub>:Sb<sub>2</sub>O<sub>3</sub> Thin Films

In this research, SnO2 nanostructure thin films were fabricated by spray pyrolysis method, using concentration of tin (Sn) salt solution deposited on a glass substrate at temperature of 450 °C. The tin solution was prepared by solves 2.2563gm of SnCl2.2H2O (molecular weight 219.4954 g/mole) in 100 ml of ethanol, then add 60 drops of pure hydrochloric acid ( HCl) using drop by drop technique. Different concentrations of antimony oxide (1%, 2%, 3%, 4%) hve been used to depose the thin films. The structure has been examined by X-ray diffraction technique, which shown that all films are polycrystalline with tetragonal rutile crystalline structure with preferential orientation in the (200) direction and, grain size decreases with increasing doping concentration. Optical measurements shown that the films are transparently in the visible region, with an average transmittance more then 80% and, sharp absorption edge nearly at 350 nm, the nature of the optical transition were direct allowed with band gap varies between (2.97 - 3.75 eV) which is directly proportional to doping concentration. The results also show that the doping has led to improved the response time of the sensing. Two kinds of gases NO2 and NH3 have been used to test the sensing performance, at different operating temperatures (R.T, 100, 200, 250, 300 and 350) oC , and bias voltage (3 Volt). For NO2 gas the highest sensitivity was 77%, the shortest response time 2.9 s and the recovery time 19 s, while for NH3 gas sensitivity was 11.5%, the response time 4.1 s and the shortest recovery time 20s,

Vibrational study of lead bromide perovskite materials with variable cations based on Raman spectroscopy and density functional theory

AbstractMetal halide‐based perovskite semiconductors exhibit excellent optoelectronic properties such as a sharp absorption edge, high absorption coefficients, and a small recombination rate. Mixed compositions result in a variation of the structure of these perovskite materials, which also influences their electronic properties. Even though huge progress in synthesis and device fabrication has been made, still systematic investigations of structural properties of lead halide‐based perovskites are missing. Here, we systematically investigate the vibrational features of lead bromide‐based perovskites using Raman spectroscopy and density functional theory (DFT). We have performed these investigations using MA+, FA+, and Cs+ as cations in the lead bromide structures and determined the vibrational modes both from Raman experiments and DFT simulations. We find a clear dependence of the Raman band wavenumbers on the chosen cations. The structural differences are reflected in the different line‐width broadening of Raman bands, charge distribution on the cations and the extent of their interactions with the bromide anions.

Double Free: A Promising Route toward Moisture-Stable Hypotoxic Hybrid Perovskites

Double Free: A Promising Route toward Moisture-Stable Hypotoxic Hybrid Perovskites

Synthesis, characteristics, and photocatalytic activity of zinc oxide nanoparticles stabilized on the stone surface for degradation of metronidazole from aqueous solution

Background: The presence of antibiotics such as metronidazole in wastewater even at low concentrations requires searching for a suitable process such as advanced oxidation process (AOP) to reduce the level of pollutants to a standard level in water. Methods: In this study, zinc oxide (ZnO) nanoparticles were synthesized by thermal method using zinc sulfate (ZnSO4 ) as a precursor, then, stabilized on stone and was used as a catalyst, in order to degrade metronidazole by photocalytic process. Effective factors on the removal efficiency of metronidazole including the initial metronidazole concentration, contact time, pH, and 0.9 gL-1 ZnO stabilized on the stone surface were investigated. Results: The X-ray diffraction (XRD) studies showed that the synthesized nanomaterials have hexagonal Wurtzite structure. Also, scanning electron microscopy (SEM) analysis revealed that the average crystalline size of the synthesized ZnO particles was in the range of 1.9-3.2 nm. The spectra represented a sharp absorption edge at 390 nm for ZnO nanoparticles corresponding to band gap of 3.168 eV. The BET-BJH specific surface area of the synthesized ZnO nanoparticles was 25.504 m2 /g. The EDS spectrum of ZnO nanoparticles showed four peaks, which were identified as Zn and O. The maximum removal efficiency was 98.36% for the synthetic solution under a specific condition (pH = 11, reaction time = 90 minutes, ZnO concentration = 0.9 gL-1, and the initial concentration of metronidazole = 10 mgL-1). The photocatalytic degradation was found to follow pseudo-first-order degradation kinetics. Conclusion: Therefore, the ZnO nanoparticles synthesized by thermal decomposition are suitable and effective photocatalytic materials for degradation of pharmaceutical contaminants.