In this novel work, we discuss the effect of neodymium doping concentration on PbS thin films coated on glass substrates by a simple nebulizer spray pyrolysis method. The XRD analysis indicated ...that all the prepared PbS and PbS:Nd films possess polycrystalline simple cubic crystal structure along (200) preferential orientation and the estimated crystallites size tapered from 21 to 18 nm with growing Nd concentration. It is detected that Raman spectra of all films shows four characteristic mode at 186 cm
−1
, 281 cm
−1
, 326 cm
−1
, and 472 cm
−1
certify the formation of PbS thin films. The micrographs obtained from scanning electron microscope indicated uniform particle on the surface of the films. Energy dispersive spectroscopy and mapping analyses confirmed the elemental composition. From the linear optical study by UV–Visible spectrometer exposed the absorption level of all the PbS:Nd films was constantly maintained in the whole visible and IR spectrum which is better for optical device fabrication. The rising of Nd content showed enhancement in band-gap as 2.13 to 2.41 eV.
I–V
characteristics of all the prepared films were done under dark and illumination conditions. Photosensitivity of the PbS films is enhanced after Nd doping, which result in enhancement of photo current. The results suggest that the proposed strategy can be applied to prepare high-performance photosensitivity thin films.
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.
The structural and phase analysis of Li@ZnO nanostructures (NSs) were tested by X-ray diffraction (XRD) and transmission electron microscopy (TEM). TEM exhibits the mixture of nanoflakes and ...nanoparticles at 1 wt% Li, and spherical shaped nanoparticles at 7 wt%, respectively. TEM images show the nanoflakes with thickness (12–37 nm) and diameter of nanoparticles (38–63 nm) at 1 wt%, and size of nanoparticles with 34–84 nm at 7 wt%, respectively. Raman spectra exhibit the two major modes at 107 and 446 cm
−1
were credited to longitudinal phonon modes. The optical bandgaps of 3.277–3.289 eV were evaluated from the optical spectra on basis of Kubelka–Munk function F(R) using Tauc’s relation. Red shift in absorption coefficient with wavelength indicates the optical bandgap decreased with increasing Li contents above 3 wt%. The photocatalytic activity of pristine and Li@ZnO NSs were investigated in the photodegradation of organic dye methylene green (MG) solution under UV irradiation. The photocatalytic study showed significant activity improvement in the Li-doped ZnO. The sample with 7 wt% Li-doped ZnO exhibited 6.1 times higher activity compared to neat ZnO sample.
The preparation of SnS, CdS, SnS
2
and ZnO thin films by nebulizer spray method, and their characterization is reported. The size of crystallites, dislocation density, texture coefficient and strain ...were estimated using XRD data. SEM study revealed good surface morphology of films. Optical properties of deposited SnS, CdS, SnS
2
and ZnO films were estimated using the optical absorption measurements. The calculated optical energy gaps of CdS, SnS
2
, ZnO and SnS films were, respectively, found as 2.45, 2.41, 3.2 and 1.45 eV. Hall effect measurements exhibited p-type conductivity for SnS and n-type conductivity for CdS, SnS
2
, ZnO thin films. The grown SnS thin films showed resistivity and carrier concentration as 0.0689 Ωcm and 1.04 × 10
19
cm
− 3
, respectively. Heterojunction solar cells of FTO/CdS/SnS, FTO/SnS
2
/SnS, and FTO/ZnO/SnS were also fabricated and their properties studied. The fabricated FTO/ZnO/SnS heterojunction solar cell presented a superior performance with conversion efficiency (0.96%) greater than other structures.
Graphene quantum dots (GQDs) have become one of the potential materials in several applications. Recently, functionalization of GQDs with various functional groups is one of the hot spots of ...research. Chitosan (CS) biopolymer is used in functionalizing GQDs in order to enhance its mechanical properties. Molecular modeling with different levels including molecular dynamics; Quantum Mechanics as well Quantitative Structure Activity Relationship are widely applied to study emerging materials such as GQDs. As a computational case study, two interaction probabilities are proposed. Physical interaction mechanism through OH and NH
2
of CS is most probable to occur. Feasibility of utilizing the functionalized GQD is studied in interacting with ibuprofen. The resultant structure seems to be stable and highly reactive. This ensures the feasibility of the usage of GQDs in biological applications after some modifications.
The rare earth element, i.e., praseodymium (Pr) co-doped aluminium zinc oxide (AZO) thin films is coated on a well-cleaned glass substrate by facile and cost-effective nebulizer spray technique. The ...Pr co-doping concentrations varied from 0 to 1.5% with the AZO structure in the steps of 0.5%. The structural analysis was characterized by X-ray diffraction (XRD), showing that all the diffracted peaks exhibit polycrystalline hexagonal wurtzite structure and the size of the crystallites is abridged with increasing Pr doping level due to lattice defects. In Raman analysis, the existence of high mode peak
E
2
at 437 cm
−1
; confirmed ZnO wurtzite structure. From the morphological study, it is clearly visualized that the film possesses spherical shaped grains which were uniformly distributed without any pinholes and voids. The surface roughness of the films was increased considerably from 22 to 39 nm on growing Pr doping from 0 to 1.5% as seen using atomic force microscope. Energy dispersive X-ray analysis and elemental mapping images clearly showed the subsistence of Al, Zn, O and Pr elements in Pr:AZO film. The prepared films exposed good transmittance range between 84 and 90% and the optical band gap was found to be 3.28 eV for initial Pr (0.5%) doping concentration. The PL spectra clearly showed that a high intense emission peak observed at 390 nm are associated with NBE which indicates that the film has good optical quality. Hall measurement revealed that the prepared film, i.e., 1.5% Pr-doped AZO film has low resistivity and high carrier concentration which is perfectly suit for optoelectronic device applications.
In this work, we have coated 0, 1, 3, and 5 wt% of Erbium (Er)-doped tin oxide (SnO
2
) films on glass using a simple nebulizer spray pyrolysis method to make an ammonia vapor sensor with remarkable ...sensitivity. X-ray diffraction, Atomic force microscopy, Ultraviolet–visible spectroscopy and photoluminescence methods were employed to inspect the thin-film samples. Room-temperature ammonia vapor sensing was performed by a computer connected to the homemade gas-sensing system. The results obtained show that Er doping in SnO
2
films gradually decreased the crystallite size with an increase of the surface area improving the sensing property of the vapor. A minimum optical band gap (i.e., 3.23 eV) is achieved for 5 wt% Er-doped film. The fabricated Er-doped SnO
2
gas sensor showed response/recovery time highly dependent on dopant concentration. The Er concentration of 5 wt% doped SnO
2
thin film showed maximum sensitivity of 91%, fast response, and recovery time of 29 and 7 s, respectively, due to high surface to volume ratio.
Graphic abstract
Cadmium oxide (CdO) thin films doped with different yttrium (Y) concentrations have been prepared by the cost-effective spin coating technique. The effect of Y doping on structural, morphological, ...linear, and nonlinear optical properties of the as-prepared CdO thin films is studied. The AFM morphology of the thin films revealed grain size increase with the increase in the percentage of Y doping. From the optical properties, it is found that the films are highly transparent and the optical band gap spreads over the range of 2.3–2.8 eV. The Y doping drastically suppresses the linear and nonlinear optical properties.
Highlights
Yttrium (Y)-doped CdO nanostructured thin films have been prepared by the cost-effective spin-coating technique.
AFM morphology reveals the grain size with increase in percentage of Y doping.
Optical band gap spreads over the range of 2.3–2.8 eV while optical properties get suppressed with Y.
Herein, we report the one pot synthesis of pure and Cd2+ (= 0.97 Å) doped PbI2 (Pb2+ = 0.133 Å) nanostructures by simple chemical route at room temperature. The structural phase confirmation was done ...by X-ray diffraction and FT-Raman analyses. Using X-ray data various parameters such as lattice constants, crystallinity, crystallite size, lattice strain, dislocation density etc. were determined. The calculated crystallite size using Scherer's rule was found to be in the range of 50–56 nm. The morphology of synthesized product was studied by SEM that confirms the formation of single crystalline nanosheets (NSs) and nanoplates (NPs). PL spectra shows an noticeable enhancement in emission intensity with Cd doping and a blue and green emission band is observed at ∼470 and 525 nm with more or less shifting, which makes it applicable for blue and green LEDs devices. The enhancement in dielectric constant was observed due to doping. The total ac electrical conductivity of PbI2 was found to be enriched due to doping. The radiation activity in terms of linear absorption coefficient was tested using Americium (214Am) radioactive sources and found to be enhanced by Cd2+ doping. The prepared nanostructures are found to be highly sensitive to 214Am 59.5 KeV γ-ray. The simple synthesis route with enhanced properties of Cd2+ doped PbI2 will be key for future electro-optical and radiation detection applications.
Display omitted
•Facile one pot synthesis of Cd2+ doped PbI2 nanostructures are reported first time.•EDX/SEM elemental mapping confirm the homogeneous doping of Cd in PbI2.•Nanoplates, hexagonal nanosheets morphology was confirmed through SEM.•Enrichment in dielectric constant and ac electrical conductivity was fund due to Cd doping.•Enhancement in PL intensity and radiation absorption ability was found in Cd doped PbI2.
Fabrication of highly sensitive p-type-based UV photoconductor with less expense is of utmost importance for next-generation optoelectronic applications. In the current study, high-purity pristine ...and metallic elements of Aluminum (Al), Gallium (Ga), and Indium (In)-doped NiO thin films were successfully grown on glass substrate at 475 ºC via a cost-effective nebulizer spray pyrolysis route. The effect of trivalent metallic elements on physicochemical characteristics was studied elaborately. XRD examination shows that the doped metal impurity element improved the NiO thin film’s crystallinity and was found to be high for Al impurity. The captured FE-SEM images declared the formation of nanograins and the dopant introduction has altered the size of the grain. Optical data prove the enhanced absorption in the UV region and narrowing bandgap energy. The PL spectrum (λ
exc
= 325 nm) exhibits a stout luminescent center at 478 nm and five weak luminescent centers at 387, 415, 437, 450, and 521 nm, respectively. All the doped NiO thin films show exceptional UV photodetection ability. However, compared with the other two dopants of Ga and In, the NiO thin film doped with Al shows outstanding responsivity (40 × 10
− 2
A/W), detectivity (14 × 10
9
Jones), and external quantum efficiency (94%).
