Incorporation Of Er Research Articles

Optical properties of Er3+: NaYbS2 nanocrystals in oxysulfide glass-ceramics

Ternary alkali rare-earth sulfide (ALnS2) has excellent luminescent performance, showing promising application prospects in the field of light-emitting diodes and optical communication. However, the poor chemical stability of ALnS2 makes it difficult to meet the needs of practical application. Herein, we develop a new type of oxysulfide glass-ceramics containing NaYbS2 nanocrystals (NCs) through conventional melt-quenching and subsequent heat treatment. NaYbS2 NCs and Er3+: NaYbS2 NCs are successfully precipitated in oxysulfide glass-ceramics, and their optical properties are studied. NaYbS2 NCs in glass-ceramics exhibit strong concentration quenching with the increase in heat-treatment temperature. Incorporation of Er3+ ions into NaYbS2 NCs results in efficient energy transfer (ET) from Yb3+ ions to Er3+ ions with efficiency as high as 90.9%.

Improved structural and dielectric traits of Cd-Zn spinel ferrites by co-substitution of La3+ and Er3+ cations

In the present work, the effect of co-doping of rare earth (Re3+), La and Er cations on the physical and dielectric performance of Cd-Zn spinel ferrites fabricated by sol-gel auto combustion method is reported. The prepared ferrites were doubly calcinated at 550 ℃ and 750 ℃ for 2 hours and 8 hours, respectively. The obtained samples were investigated using XRD, FTIR and dielectric measurements. XRD powder patterns verified the single-phase growth of spinel structure of all the as-synthesized ferrites with Fd-3m space group. The obtained results revealed that the Lattice constant reduces with increasing Er3+ concentrations, while crystallite size showed increasing behavior with increasing Er3+ concentration. FTIR results revealed the existence of two major absorptionbands i.e. low frequency bands in range 405-428 cm-1 and high frequency bands in range 523- 550 cm-1 which are evidence of spinel structure formation. LCR measurements are used to investigate the impact of co-doping of La3+ and Er3+ on the various dielectric parameters of prepared samples in response to frequency. Dielectric constant and loss decreased with the incorporation of Er3+, while an increase in ac conductivity was observed. The observed properties reveal that the prepared materials are suitable candidates for application in the high-speed microwave and radio frequency devices.

Chemical Synthesis of ZnO:Er Nanorods for Photocatalytic H2 Evolution

The growth of one-dimensional (1D) ZnO systems has been attaining ample engrossment because of their unique photocatalytic and optoelectronic properties. In this context, we synthesized the high-quality ZnO and ZnO:Er nanorods through an inexpensive and facile solvothermal route. Morphological studies revealed that the fabricated samples correspond to nanorods. Erbium ion substitution into the host ZnO matrix was affirmed via XRD and Raman analyses. XPS analysis proposed that Er ion substitution in the Zn (II) site occurred with trivalent Er ions. The trivial diminishing of the optical band gap with the incorporation of Er into the host matrix was assessed by diffuse reflectance spectroscopy (DRS) studies. The photoluminescence spectra of both fabricated NRs display two nodes at ultraviolet and red luminescence. The fluorescence efficiency of the ZnO NRs diminished after Er doping. The ZnO and ZnO:Er NRs were measured for H2 evolution by water splitting beneath the UV light illumination. The ZnO:Er illustrated the efficient H2 evolution ability (21311 μmol h−1 g−1) in 5 h, which is higher than that of ZnO. To analyze the attained engrossing H2 outcomes, electrochemical studies were also employed. Fortunately, this is the first-ever endeavor in H2 production of the ZnO:Er NRs.

Structural, optical, and photocatalytic activity of ZnS:Er nanoparticles

ZnS and Er (2 at%) doped ZnS nanoparticles (NPs) were synthesized through coprecipitation process. EDAX analysis confirmed that the presence of Er (III) ions in the prepared sample with an anticipated stoichiometry. TEM analyses displayed that the prepared NPs showed near spheroid shapes with an average size ranging from 4.8 to 5.2 nm. XRD measurements confirmed the authentic incorporation of Er (III) ions in the ZnS lattice. DRS measurements certified that Er (III) doping declines the ZnS bandgap from 3.72 to 3.56 eV. Magnetic measurements revealed that the Er-doped ZnS NPs displayed soft ferromagnetism and became better at higher doping concentrations. The Er (2 at%) doped ZnS NPs exhibited a higher rhodamine B dye degradation rate than the ZnS. Hence, the Er doped ZnS NPs are promising materials for dye degradation and optoelectronics.

Structural, microstructural, spectral, and dielectric properties of erbium substituted spinel ferrites

The Erbium substituted manganese spinel ferrites were prepared via the microemulsion route. The average crystallite size varies from 10.21 to 17.41 nm, while the lattice constant observes to increase from 8.473 to 8.509 Å. X-ray density increases with the incorporation of Er3+ ions in manganese ferrites. The characteristic bands lie in the range of 410–560 cm−1 which confirms the cubic structure of synthesized ferrites. The band variation is evidence of the successful substituting of Er3+ ions in manganese spinel ferrites lattices. Bond lengths increase with the increase of Er3+ content. The dielectric constant, dielectric loss, and tan loss decrease as frequency and Erbium concentration increase. Scanning electron microscopy (SEM) micrographs reveal the decrease in grain size with Er3+ in manganese ferrites. The obtained results suggested that synthesized ferries can be potential candidates for high-frequency applications.

A high‐performance transition‐metal phosphide electrocatalyst for converting solar energy into hydrogen at 19.6% STH efficiency

AbstractThe construction of high‐efficiency and low‐cost non‐noble metal bifunctional electrocatalysts for water electrolysis is crucial for commercial large‐scale application of hydrogen energy. Here, we report a novel strategy with erbium‐doped NiCoP nanowire arrays in situ grown on conductive nickel foam (Er‐NiCoP/NF). Significantly, the developed electrode shows exceptional bifunctional catalytic activity, which only requires overpotentials of 46 and 225 mV to afford a current density of 10 mA cm−2 for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), respectively. Density functional theory calculations reveal that the appropriate Er incorporation into the NiCoP lattice can significantly modulate the electronic structure with the d‐band centers of Ni and Co atoms by shifting to lower energies with respect to the Fermi level, and optimize the Gibbs free energies of HER/OER intermediates, thereby accelerating water‐splitting kinetics. When assembled as a solar‐driven overall water‐splitting electrolyzer, the as‐prepared electrode shows a high and stable solar‐to‐hydrogen efficiency of 19.6%, indicating its potential for practical storage of intermittent energy.

Sol-Gel Route for the Synthesis of CoFe2-x Er x O4 Nanocrystalline Ferrites and the Investigation of Structural and Magnetic Properties for Magnetic Device Applications.

This study reports the formation of Er-doped nanocrystalline cobalt ferrite with the formula CoFe2–xErxO4 (0.0 ≤ x ≤ 0.10) from nontoxic metal precursors Co(NO3)2·6H2O, Fe(NO3)3·9H2O, and Er(NO3)3·5H2O through an easy and economical sol–gel route in which citric acid is served as the chelating agent. The as-prepared powder was annealed at 700 °C for 3 h in ambient air to get the required spinel structure. The annealed samples were subjected to structural and magnetic characterization. The X-ray diffraction (XRD) data of the samples confirmed the cubic spinel structure formation. The average crystallite size evaluated from XRD data increased from 21 to 34 nm with the substitution of Er due to the larger atomic size of Er3+ than Fe3+. Moreover, the crystallite size obtained from XRD data are well matched with the particle size measured from transmission electron microscopy images. The lattice parameters obtained from XRD data agree well with the values estimated from theoretical cation distribution and Rietveld refinement calculation. The hysteresis curve exhibits the particles are soft ferromagnetic and the coercivity increased from 54.7 to 76.6 kA/m with maximum saturation magnetization, Ms = 61 emug–1 for 0.10 Er content. The squareness ratios were found to be less than 0.5, which indicates the single-domain nature of our particles. The blocking temperature measured from field cooled-zero field cooled curves is TB > 350 K for all the samples, which is much higher than the room temperature (300 K). The enhancement of saturation magnetization and coercivity has been explained based on the crystallite size, anisotropy constant, and cation distribution. Thus, the structural and magnetic properties of CoFe2O4 nanoparticles (NPs) can be tuned by Er incorporation and these NPs can be applied in different soft magnetic devices.

Optimization of the luminescence and structural properties of Er-doped ZnO nanostructures: effect of dopant concentration and excitation wavelength

The present study reports the effect of Er doping on the structural, morphological, and optical properties of ZnO nanostructures. ZnO: Er nanorods with different doping concentrations were successfully synthesized via a hydrothermal method. X-ray diffraction and Energy-dispersive X-ray spectroscopy analyses suggest the successful incorporation of Er into the wurtzite structure of ZnO; A secondary phase of Er2O3 appears when the Er concentration exceeds 2.5 wt%. The optical band-gap of ZnO was determined from the analysis of ultraviolet–visible spectra, and a decrease of the band gap is emphasized with increasing Er concentration. Photoluminescence spectra display a strong and broad deep-level emission band, which intensified with increasing Er concentration. The current work provides more details about the excitation wavelength effect on the luminescence of pure and Er-doped ZnO materials, finding that the visible photoluminescence emission intensity could be controlled by adjusting the Er concentration as well as the excitation wavelength; better luminescence was obtained with high Er concentration and high excitation wavelength. Moreover, the DFT calculations support the experimental results and confirm that the presence of oxygen vacancies has an effect on the structural and electronic properties of ZnO. Hence, the research findings of this work could provide an experimental and theoretical reference that may motivate future research on the study of ZnO-based optoelectronic applications.

Consequences of doping Er3+ and Yb3+ ions on the thermoluminescence dosimetry performance of the BaO-ZnO-LiF-B2O3-Sm2O3 glass system

The consequences of doping Er3+ and Yb3+ ions on the thermoluminescence (TL) dosimetry performance of the BaO-ZnO-LiF-B2O3-Sm2O3 glass system were examined for the first time. The incorporation of Er3+ and Yb3+ ions were found to be highly detrimental to the TL intensity, sensitivity, and trap density of the Sm3+ doped glass. Although Sm3+ ions enhanced the integrated TL intensity of the host glass by two thousand times, Sm3+-Er3+ and Sm3+-Yb3+ combinations functioned like activator-quencher systems. Contrary, the problem of anomalous loss of 50% signal after a storage week of the Sm3+ doped glass was effectively countered by doping Er3+ (2% loss) and Yb3+ (8% loss) ions. From the trap parameters, the elimination of some shallow traps and deepening of some existing ones was reasoned for minimizing fading. Even if the Er3+ and Yb3+ ions adversely affected the TL intensity of the Sm3+ glass, they greatly improved the stability. The observations indicate that the TL dosimetry performance of a glass system can be suitably tuned by the doping/co-doping of rare-earth ions.

Feasibility of Emission-Enhanced CsPbCl3 Quantum Dots Co-Doped with Mn2+ and Er3+ as Luminescent Downshifting Layers in Crystalline Silicon Solar Modules

In order to enhance the photoelectric conversion efficiencies of crystalline silicon (c-Si) solar cells, CsPbCl3 quantum dots (QDs) codoped with Mn2+ and Er3+ (CsPbCl3:Mn2+, Er3+ QDs) were mixed with ethylene–(vinyl acetate) (EVA) to form a film which was used as a luminescent down-shifting (LDS) layer. The LDS layer effectively improved the low utilization of near-ultraviolet light of c-Si solar cells. These CsPbCl3:Mn2+,Er3+ QDs were synthesized via a conventional high-temperature injection method. Mn2+ is the luminescence center, and the incorporation of Er3+ greatly enhances the luminescence intensity of Mn2+. The absolute photoluminescence quantum yield of the QDs dispersed in toluene reached 79.5% when the QDs were synthesized under the optimum conditions, that is, an injection temperature of 180 °C and Pb:Mn:Er preparation molar ratios of 6:4:4. The EVA film embedded with QDs at the optimum concentration (0.9 wt %) was used as an LDS layer for c-Si solar module. The short-circuit current (ISC) and the photoelectric conversion efficiency (η) were increased by 3.42% and 4.02%, respectively, owing to the LDS layer. Moreover, a luminescent solar concentrator (LSC) which was another application of luminescent materials was also demonstrated. For LSC, the relative changes in ISC and η by using the QDs-dispersed EVA film were +14.9% and +18.0%, respectively. These results indicate a feasible application of luminescent downshifting films in solar modules.

Influence of erbium (Er) dopant on the enhanced optical properties of electrochemically deposited zinc oxide (ZnO) films for high-performance photovoltaic systems

Undoped and Er doped ZnO thin film materials have been successfully synthesized using the electrochemically deposited (ECD) technique. SEM results of the undoped and Er/ZnO (at 0.1, 0.2, 0.3 mol%) thin-film materials deposited on FTO substrate reveal the presence of crystallite of various sizes. The morphological and structural properties of the films were investigated using SEM and XRD techniques. XRD results of all the films show peaks at crystal plane (100), (111), and (112) with a prominent preferred orientation along the (100) plane. The optical energy band gap of ZnO was observed to decrease from 1.32 eV to 1.25 eV as a result of the addition of Er as the dopant. The absorbance of undoped and Er/ZnO (at 0.1, 0.2, 0.3 mol%) reveals that all thin-film materials exhibited high absorbance values in the UV–Vis region which dropped drastically as they move towards the NIR region. It was observed that the incorporation of Er in the undoped ZnO led to a notable rise in the absorbance value which indicates that Er doping greatly improved the light absorption of the ZnO thereby making it a good photovoltaic material.

Effect of erbium doping on phase composition, mechanical and thermal properties of ZrO2-based ceramics

ErxTi0.1Zr0.9–xO2–1.5x (x = 0.04, 0.05, 0.06, 0.07, 0.08) ceramics were synthesized by a solid-state reaction method. The influence of the Er3+ addition on the phase composition, Vickers hardness, fracture toughness, and thermal conductivity of this ceramic material was investigated. The X-ray diffraction results reveal that the c-ZrO2 content increases from 1.85 vol% to 33.89 vol%, and the percentage of t-ZrO2 decreases from 98.15 vol% to 66.11 vol% with the increase in Er3+ content from 4 mol% to 8 mol%. Moreover, the addition of Er3+ is beneficial to the volume expansion of the unit cell. At the same time, the incorporation of Er3+ weakens the coordination of oxygen ions around the metal cations, resulting in a corresponding decrease in the tetragonality of the t-ZrO2. The Vickers hardness and fracture toughness of the ErxTi0.1Zr0.9–xO2–1.5x ceramics show increasing and decreasing trends, respectively. The thermal conductivity has a significant decline due to point defects caused by the Er3+ doping. The 8ETZ ceramic exhibits the highest Vickers hardness (12.7 GPa), the lowest fracture toughness (7.6 MPa⋅m1/2), and the lowest average thermal conductivity (1.85 W/(m·K)) in the temperature range of 200–1000 °C. All of the above properties are higher than those of the Y2O3-stabilized ZrO2 ceramic.

A multifunctional antibacterial coating on bone implants for osteosarcoma therapy and enhanced osteointegration

After prosthesisreplacement for thetreatmentofbonetumors, incomplete removal of tumor cells is the main challenge. Moreover, combating implant-associated infection and simultaneously promoting osseointegration are highly demanded for orthopedic implants and therefore, a multifunctional coating that produces tumor therapeutic effects, antibacterial activity, and osteogenesis at the same time is of clinical significance. Herein, a phototherapy platform composed of rare-earth elements - doped titanium dioxide nano-shovel/quercetin/L-arginine (TiO2@UCN/Qr/LA) on titanium bone implant is fabricated. The stable nano-shovel structure prepared by a hydrothermal method improves the photothermal conversion ability of titanium. Incorporation of Yb and Er enhances the upconversion capability, thereby facilitating generation of reactive oxygen species (ROS) during exposure to near-infrared II (NIR-II) light. Furthermore, under the action of ROS, L-arginine is catalyzed to release nitric oxide (NO)freeradicals. In vitro and in vivo experiments indicate that the combined actions of ROS, quercetin, and NO not only inhibit bone tumor growth at a temperature of 48 ℃, but also eliminate Staphylococcus aureus biofilms on the Ti implants at a mild temperature of 45 ℃ upon illumination with a 1,060 nm laser. Moreover, TiO2@UCN/Qr/LA promotes angiogenesis and osteogenic differentiation, reduces inflammation, and accelerates formation of new bone tissues.

Improved Photodetection Performance of Nanostructured CdS films Based Photodetectors Via Novel Er Doping

This work reports the fabrication of Er@CdS films with 0, 1, 3, 5 wt% Er contents incorporated in CdS via spray pyrolysis route. The films were developed successfully with hexagonal structure and preferred growth orientation along (002) plane and crystallites sizes were found in the range 8–13 nm. Raman spectra showed the 1LO and 2LO vibrational bands centered at 300 cm−1 and 600 cm−1; respectively which confirms the synthesis of pure CdS. The optical band gaps of the films were found in range of 2.38–2.41 eV. A clear reduction in the band gap values is observed as with the incorporation of Er in the CdS matrix. In addition, Er@CdS thin films were utilized to construct a high performance photodetector (PD). The fabricated device shows enhanced visible light photodetection in comparison with the pure CdS films based device. The rise and decay time were detected in the range of 0.079–0.32 s and 0.099–0.32 s, respectively. Noticeable enhancements in responsivity (R) and the external quantum efficiency (EQE) were recorded, reaching maximum values as high as 4.95 A/W and 1150% for 3 wt% Er-doped films. This improvement in the PD performance may be due to the reduction in the defects and sulfur vacancies as a result of Er incorporation in the CdS matrix.

Synthesis of bismuth ferrite nanopowder doped with erbium ions

The potential for the practical application of bismuth ferrite (BFO) in information storage, microelectronic, and spintronic devices and in medical sensors of various purpose is limited by the presence of a spin cycloid. Its destruction, including destruction due to doping with rare earth elements and the transfer of BFO to a nanoscale state, contributes to the occurrence of ferromagnetism and the manifestation of the magnetoelectric effect. The study was aimed at the synthesis of bismuth ferrite nanopowder doped with erbium ions.By spray pyrolysis at a temperature of 760 °C, we synthesised BFO samples with a nominal degree of doping with erbium ions from 0.05 to 0.20. The data of X-ray diffraction analysis show that there is a small amount of Bi25FeO39 and Bi2Fe4O9 in the doped samples.The shift of the BFO reflections on diffraction patterns towards larger 2q angles is representative of the incorporation of erbium ions into the crystal lattice of BiFeO3. The morphological characteristics of the samples were determined using transmission electron microscopy. According to the data of electron probe X-Ray microanalysis, the real composition of the doped ErxBi1-xFeO3 samples is very close to the nominal.The particles of ErxBi1-xFeO3 powders synthesised by spray pyrolysis have a nearly spherical shape, the particle-size distribution is in the range of 5–300 nm, the predominant number of particles have a size in the range of 50-200 nm, and the agglomeration is weak. The decrease in the crystal lattice parameters and the unit cell volume of ErxBi1-xFeO3 and an increase in the degree of doping with erbium ions confirm the incorporation of Er3+ into the BFO crystal lattice to the bismuth position.

Luminescent Erbium-Doped Silicon Thin Films for Advanced Anti-Counterfeit Labels.

The never-ending struggle against counterfeit demands the constant development of security labels and their fabrication methods. This study demonstrates a novel type of security label based on downconversion photoluminescence from erbium-doped silicon. For fabrication of these labels, a femtosecond laser is applied to selectively irradiate a double-layered Er/Si thin film, which is accomplished by Er incorporation into a silicon matrix and silicon-layer crystallization. The study of laser-induced heating demonstrates that it creates optically active erbium centers in silicon, providing stable and enhanced photoluminescence at 1530 nm. Such a technique is utilized to create two types of anti-counterfeiting labels. The first type is realized by the single-step direct laser writing of luminescent areas and detected by optical microscopy as holes in the film forming the desired image. The second type, with a higher degree of security, is realized by adding other fabrication steps, including the chemical etching of the Er layer and laser writing of additional non-luminescent holes over an initially recorded image. During laser excitation at 525 nm of luminescent holes of the labels, a photoluminescent picture repeating desired data can be seen. The proposed labels are easily scalable and perspective for labeling of goods, securities, and luxuryitems.

Understanding up and down-conversion luminescence for Er3+/Yb3+ co-doped SiO2-SnO2 glass-ceramics

Er3+/Yb3+ co-doped SiO2-SnO2 glass-ceramics bulks were synthesized using the sol-gel method. High-resolution transmission electron microscopy images, x-ray diffraction, and energy-dispersive x-ray spectroscopy mapping confirm that 5 nm SnO2 crystals were homogeneously dispersed in the silica matrix. The incorporation of Er3+ and Yb3+ ions in SnO2 was also confirmed by X-ray photoelectron spectroscopy. This analysis shows Er3+ and Yb3+ ions locate in SnO2 nanocrystal and amorphous silica sites. Er3+/Yb3+ co-doped SiO2-SnO2 glass-ceramics behave as both down and up-conversion luminescent materials. Efficient energy transfers from Yb3+ ion sensitizers to Er3+ activators cause remarkable 5-fold Er3+ emission enhancement at 1.55 µm. We also propose a mechanism for down and up-conversion processes.

SmFeO 3 and SmFe 1‐x Er x O 3 based perovskite nanorods for improved oxygen and hydrogen evolution functions

Samarium (Sm) based perovskite nanorod-like structures were processed for electrocatalytic functions involving oxygen and hydrogen evolution reactions. Influence of erbium (Er) ions on the structural and electrocatalytic properties of SmFe1−xErxO3 perovskites were studied under varied alkaline pH (8.5-14) conditions. The rod-like dimensional analysis was obtained through scanning/transmission electron microscopes. Diffraction signals affirmed the presence of samarium oxide (Sm2O3) traces in processed perovskites. X-ray photoelectron spectroscopy data signified the presence of corresponding oxides and determined the valence state of Sm, Er and Fe ions. Er ions were found to boost the production of oxygen and hydrogen molecules. The anodic overpotential values improved from 216 mV to 184 mV, while cathodic overpotential values improved from 231 mV to 213 mV upon Er inclusion. Electrocatalytic results approved SmFe1−xErxO3 as a promising oxygen/hydrogen liberating electrocatalyst with remarkable stability and Tafel slopes that improved from 96 to 77 mV/dec and 78 to 55 mV/dec upon Er incorporation in host perovskite.

Assessment of SnO2-nanocrystal-based luminescent glass-ceramic waveguides for integrated photonics

For integrated photonics, waveguide structures based on rare-earth-activated glasses are potential candidates for implementing compact integrated light sources and amplifiers. However, rare-earth ions (REs) possess low absorption cross-section, and this limits the light emission and amplification efficiency. As long as the REs are involved, there are other phenomena detrimental to their luminescence quantum yield including ion-ion interactions and non-radiative relaxation processes. To solve such problems, photonic glass-ceramics can be strategic solutions. Transparent glass-ceramics combine interesting properties of both amorphous and crystalline phases and offer specific characteristics of capital importance in photonics. More important, photonic glass-ceramics can tailor and enhance the spectroscopic properties of the rare-earth ions depending on their compositions and nature. In this work, we studied SnO2-nanocrystal-based transparent glass-ceramic planar waveguides activated by rare-earths to give solutions for the problems mentioned above and enhance the rare-earth luminescence efficiency for integrated photonics. SiO2–SnO2:Er3+ planar waveguides containing 30 mol% SnO2 nanocrystals were fabricated by sol-gel method and dip-coating technique. The planar waveguides were assessed by various characterization techniques to ensure the applicability of such glass-ceramics for integrated photonics. The experimental assessment of the SiO2–SnO2:Er3+ planar waveguides focused on the key considered photonic characteristics including the structural, morphological, spectroscopic, and especially optical waveguiding properties. The photoluminescence measurements put in evidence the role of SnO2 nanocrystals as efficient Er3+ luminescence sensitizers. Moreover, the incorporation of Er3+ ions in SnO2 nanocrystals was demonstrated to reduce the effect of non-radiative relaxation processes on the luminescence of the Er3+ ions and thus led to higher luminescence efficiency. Majority of the Er3+ ions (97%) was confirmed to be imbedded in the SnO2 nanocrystals. The SiO2–SnO2:Er3+ glass-ceramic planar waveguides have confined propagation modes, step-index profile with high confinement of 82% at 1542 nm and especially, low losses of 0.6 ± 0.2 dB/cm at 1542 nm.

Modification of SnO2 surface oxygen vacancies through Er doping for ultralow NO2 detection

Despite the high prevalence of tin oxide (SnO2) based sensors for detection of numerous toxic gases, they suffer from issues of cross-sensitivity and high operating temperatures. Herein, SnO2 lattice has been modified with highly catalytic erbium (Er) based rare earth metal to address aforementioned issues. Thin films of undoped and 1, 3, 5 wt% Er-doped SnO2 nanoparticles have been deposited by electron beam evaporation technique and influence of Er on structural and optical characteristics of SnO2 films has been investigated for gas sensing applications. The incorporation of Er in SnO2 thin films has been found to tune the concentration of oxygen vacancies, which can enhance the gas sensing parameters. The sensor with an optimized amount of Er (3 wt%) exhibits a maximum sensing response for 1 ppb of NO2 at room temperature (25°C) with improved selectivity and stability against humidity.