Mn-doped titania thin films prepared by spin coating

TiO₂ thin films doped with ≤7 mol% Mn (metal basis) were deposited on F-doped SnO₂-coated (FTO) glass substrates by spin coating. The structural, morphological, and optical properties of the films were investigated by glancing angle X-ray diffraction (GAXRD), laser Raman microspectroscopy, field emission scanning electron microscopy (FESEM), and ultraviolet–visible spectroscopy (UV–VIS). Mn doping of TiO₂ (anatase) extended the optical absorption edge to longer wavelengths (lower photon energies) significantly lowering the band gap from 3.32 eV (undoped) to 2.90 (7 mol% Mn). The absorption edges of all films were sharp and the transparencies in the visible region were in the range 60–75%. All of the films were homogeneous, fully dense, and essentially crack-free.     

Green synthesis of novel lanthanum doped copper oxide nanoparticles for photocatalytic application: Correlation between experiment and COMSOL simulation

Treatment of waste water via photocatalysis is one of the most effective, economical and environment friendly process. In this study, green method (leaf extract of Citrus Medica Linn.) is used to synthesize pure and lanthanum (La)-(1,2 & 3 wt%) doped copper oxide nanoparticles (CuO-NPs). Different characterization techniques such as XRD, SEM, EDS, UV/VIS, PL and FTIR are utilized to investigate their physical, chemical, optical and structural properties. The synthesized material is used as photocatalyst for degradation of methylene blue (MB) dye. Interestingly, the La doped CuO-NPs have exhibited unique results. Variation in dopant concentration reduces the particle size (40.82 ± 0.04 nm to 31.89 ± 0.02 nm) and band gap of material shifts towards visible region (3.03 eV–2.71 eV). During photocatalysis, doping reduces the electron-hole pair recombination rate which makes it a potential photocatalyst. Maximum degradation efficiency of 84% is observed in 150 min for 2% La doped CuO-NPs which reveals that 2% La doping is optimal. Further increase in dopant concentration increases band gap, therefore, degradation efficiency drops to 75%. Simulation of this work is carried out using COMSOL Multiphysics 5.3a Licensed version. A 2D model is constructed and CuO-NPs is considered as photocatalyst in order to correlate simulated and experimental photocatalytic degradation of MB and rhodamine B (RhB) dye. Comparative analysis of rate constants revealed that the trend given by simulation is very close to the experimental observations.     

Boron-doped hydrogenated amorphous carbon films grown by surface-wave mode microwave plasma chemical vapor deposition

We report the effects of boron (B) doping on optical and structural properties of the hydrogenated amorphous carbon thin films grown by surface-wave mode microwave plasma (SW-MWP) chemical vapor deposition (CVD) on n-type silicon and quartz substrates at room temperature. Argon and acetylene were used as a carrier and carbon source gases respectively. Analytical methods such as X-ray photoelectron spectroscopy (XPS), Nanopics 2100/NPX200 surface profiler, JASCO V-570 UV/VIS/NIR spectroscopy, Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy were employed to investigate the properties of the films. Low atomic concentration of B (0.08 at.%) was found in the doped film. The optical band gap of the undoped film was 2.6 eV and it decreased to 1.9 eV for the B-doped film. Structural property shows the crystalline structure of the film and it has changed after incorporating B as a dopant. The structural modifications of the films leading to being more graphite in nature were confirmed by the Raman and FT-IR characterization.     

Magnetic characteristics and optical band alignments of rare earth (Sm+3, Nd+3) doped garnet ferrite nanoparticles (NPs)

Yttrium iron garnet (YIG) nanoparticles (NPs) doped with rare earth (RE) metal ions (Y_2.5Sm_0.5Fe₅O₁₂, Y_2.5Nd_0.5Fe₅O₁₂) were successfully synthesized by sol-gel auto combustion approach. The cubic crystalline structure and morphology of the prepared garnet ferrite NPs were analyzed by X-ray diffractometer (XRD) and field emission scanning electron microscopy (FESEM). The cubic crystalline garnet phase of the synthesized YIG, Sm-YIG and Nd-YIG samples was successfully achieved at 950 °C sintering temperature. The force constant and absorption bands were estimated by using Fourier transform infrared spectroscopy (FTIR). The doping effect of RE metal ions on the chemical states of YIG were examined by x-ray photoelectron microscopy (XPS). The valence band (from 12.63 eV to 13.22 eV), conduction band (from 10.89 eV to 11.34 eV) edges and optical bandgap values of RE doped YIG samples were calculated using UV–Vis spectroscopy and ultraviolet photo electron spectroscopy (UPS). The magnetic analysis of the prepared NPs was studied using vibrating sample magnetometer (VSM). The XPS analysis of RE doped YIG samples exhibit the existence of RE (Sm⁺³, Nd⁺³) contents on the surface of YIG ferrite by decreasing the oxygen lattice in garnet structure. The optical bandgap (from 1.74 eV to 1.88 eV) explains the semiconducting nature of the synthesized NPs. The UPS results confirm the valence band position of YIG doped samples. The saturation magnetization and remanence of RE doped garnet ferrite samples increased from 13.45 to 18.83 emu/g and 4.06–6.53 emu/g, respectively.     

Ultra-rapid microwave-assisted synthesis of gallium doped zinc oxide for enhanced photocurrent generation

Ultra-rapid microwave-assisted hydrothermal synthesis was performed, zinc oxide nanoparticles were fabricated and doped with gallium. Different times (5, 15, and 30 min) and concentrations of doped Ga (1, 3, and 6%) were used to improve their characteristic properties. In addition, the relation between time/dopant was analyzed. The samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, and UV–Vis diffuse reflectance spectroscopy. Photoluminescence (PL) to verify number of defects. SEM analysis showed the formation of nanorods morphology even with a short synthesis time. The X-ray diffractograms and Raman spectra suggest the successful insertion of Ga into the ZnO lattice. The crystallite size obtained by doping was between 36 and 50 nm. The lattice parameters determined by the Rietveld refinement confirmed the formation of a wurtzite hexagonal structure. The band gap range found was 3.12–3.22 eV, which increases the potential of ZnO for optical applications. The presence of defects as result of doping was confirmed by PL. The microstructural changes of the material are enhanced by doping, which causes the photocurrent to increase from 0,002 to 0.012 mA/cm² in doped ZnO. The synthesis time and Ga doping facilitated the production of ZnO nanoparticles with improved properties.     

Synthesis and structural,optical, photocatalytic,and electrochemical properties of undoped and yttrium-doped tetragonal ZrO2 nanoparticles

Template-free undoped and yttrium-doped tetragonal ZrO₂ nanoparticles were successfully synthesized using a hydrothermal technique, and their structural, morphological, optical, and electrochemical properties were characterized. The photocatalytic activity for the dye degradation of the Rhodamine B (RhB) was also studied under UV light irradiation. The tetragonal crystal phase of the nanoparticles was confirmed by XRD analysis. The observed peak shift in XRD patterns confirmed the incorporation of dopant into host lattice. The Yttrium-doped ZrO₂ nanoparticles showed a higher specific surface area and smaller optical band gap (191.5?m²/g and 3.66?eV) than the pristine ZrO₂ nanoparticles (108.6?m²/g and 4.94?eV). The yttrium-doped ZrO₂ nanoparticles exhibited greater photocatalytic activity (~98%) than the pure ZrO₂ nanoparticles within 40?min, due to their high specific surface area and reduced photogenerated charge carrier recombination rate. The Nyquist plot of yttrium-doped sample exhibited lower charge transfer resistance than that of the undoped sample. The photocurrent of the doped sample (28.6?mA/cm²) was ~9 times higher than that of pristine ZrO₂ sample (3.2?mA/cm²). The doped sample showed stable and higher photocurrent density up to 520?s under light illumination.     

Structural,morphological and photocatalytic properties of Bi–Mg–Cu ferrites: Influence of the Bi: Fe ratio

Rhodamine B (RhB) dye is an exceedingly dangerous pollutant. So, this study described an effective synthesis of pure and Bi³⁺ doped Mg–Cu nanophotocatalysts (MCBF) to facilitate the disposal of this harmful pollutant. We studied their structural, morphological, optical, and photocatalytic degradation characteristics. The XRD results of all the prepared photocatalysts confirmed their spinel structure without any impurities. Three justifications for why the lattice parameters of these nanoferrites have a peculiar behavior. The crystallite size has unsteadied behavior; within the range of 29.75–44.87 nm, as determined by the Williamson-Hall approach. The lattice parameter has a distinctive behavior; decrement from 8.3168 Å for MCBF0 to 8.3037 Å for MCBF2 and increment for the nanoferrites MCBF3 (8.3448 Å) and MCBF4 (8.3852 Å) and decreased again for the nanoferrite MCBF5 (8.3448 Å). The STEM graphs demonstrated the agglomeration of nanosized, spherical, and homogeneous-shaped particles. The optical band energy of all the MCBF nanoferrites was in the visible light range of 2.009–2.031 eV. The nanoferrites MCBF0 and MCBF4 have the highest energy gap (2.031 eV), whereas the nanoferrite MCBF5 has the lowest (2.009 eV). Although the modification of the energy gap of MCBF nanoferrites by Bi doping was not large, the photocatalytic activity of MCBF nanophotocatalysts was improved by substituting bismuth ions. In particular, MCBF5, with the highest bismuth content, gave the supreme RhB degradation of 95.81%, with a higher ratio of 245.39% than the pure Mg–Cu ferrite sample. The MCBF5 catalyst showed excellent stability under visible light irradiation across all cycles, 95.81, 95.64, 95.28, 95.04, and 94.89%. Therefore, Mg_0·5Cu_0·5Bi_0·1Fe_1·9O₄ nanoferrite is a suitable option for RhB degradation under sunlight and may function as a likely catalyst in wastewater purification.     

Role of Mn doping on magnetic properties of multiferroic NiCr2O4 nanoparticles

The structural and magnetic properties of Mn doped Nickel Chromite (Ni_1-xMn_xCr₂O_4, x = 0, 0.2, 0.3, 0.4, 0.6, 0.8) nanoparticles (NPs) were studied in detail. The X-ray diffraction analysis affirms normal spinel structure for all the samples and average crystallite size was found in the range 31–58 nm. The spinel structure of these nanoparticles was also confirmed by Fourier transform infrared spectroscopy which revealed the formation of tetrahedral and octahedral vibrational bands in the range 607 -628 cm^?1 and 486 - 491 cm^?1, respectively. Transmission electron microscopy images depicts less agglomerated and non-spherical shaped NPs. The temperature dependent zero field cooled and field cooled magnetic measurements revealed a paramagnetic to ferrimagnetic transition T_c at 87 K for NiCr₂O₄ NPs, which is shifted to low temperatures by Mn doping. This effect was attributed to cationic distributions between adjacent sites produced by Mn doping. M ? H loops of Ni_1-xMn_xCr₂O₄ NPs revealed enhanced saturation magnetization with increase in Mn doping which is attributed to a large magnetic moment of Mn ions. Ni_1-xMn_xCr₂O₄ (x = 0.6 and 0.8) NPs show steps in their M ? H loops because of exchange interactions between two sites of these NPs.     

Efficient sunlight and UV photocatalytic degradation of Methyl Orange,Methylene Blue and Rhodamine B,using Citrus×paradisi synthesized SnO2 semiconductor nanoparticles

In this work, tin dioxide (SnO2) Nanoparticles (NPs) were synthesized through green synthesis, using Citrus × paradisi extract as a stabilizing (capping). The extract concentrations used were 1, 2 and 4% in relation to the aqueous solution. The resulting SnO2 NPs were used for the degradation of Methyl Orange (MO), Methylene Blue (MB) and Rhodamine B (RhB), under both solar and UV radiation. The NPs were characterized via Attenuated Total Reflectance Infrared Spectroscopy (ATR-IR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM-SAED), the Brunauer-Emmett-Teller (BET) theory, Ultraviolet to Visible spectroscopy (UV–Vis), and Photoluminescence spectroscopy (PL); while the photocatalytic degradation was evaluated using UV-VIS. The results showed that the Citrus × paradisi extract is a good medium for the formation of SnO2 NPs. These NPs presented quasi-spherical morphology, particle sizes of 4–8 nm, with a rutile phase crystalline structure, and with banned gap of 2.69 at 3.28 eV. The NPs had excellent photocatalytic properties under solar radiation, degrading 100% of the OM in 180 min. Furthermore, under UV radiation, 100% degradation of the three dyes was achieved in a short time; 20 min for MO, and 60 min for MB and RhB. Therefore, green synthesis is a feasible medium for the formation of SnO2 NPs with good photocatalytic properties.     

Synthesis of Ni doped barium hexaferrite by microemulsion route to enhance the visible light-driven photocatalytic degradation of crystal violet dye

The pristine and Ni doped BaNi_xFe_12-xO₁₉ (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) NPs have been fabricated via facile microemulsion approach and the impact of dopants was explored based dielectric, optical, structural and the photocatalytic properties of BaNi_xFe_12-xO₁₉ nanoparticles. X-ray diffraction and Raman study confirmed the formation of regular hexagonal geometry with space group P6₃/mmc with crystallite size in 32–50 nm range. Functional groups were identified using FTIR analysis. The remanence (Pr), saturation polarization (Ps) and coercivity (Hc) was explored by P-E loop analysis and the value of Pr and Ps was enhanced with the concentration of dopant. According to PL spectra, highly doped materials had a higher charge separation (e^?- h⁺) and low recombination rate, which resulted in higher photocatalytic degradation activity of fabricated nanomaterials. The optical band gap was found to be 1.78 eV versus undoped (2.60 eV for pristine BaFe₁₂O₁₉). Due to polarizations, the dielectric loss, dielectric constant and tangent loss values were declined, while AC conductivity was enhanced. Photocatalytic performance of doped and undoped samples under visible right irradiation was studied for crystal violet dye. For 100 min exposure to visible light, the highly doped catalyst exhibits 97% degradation versus 60% in case of pristine this is attributed to efficient electron-hole pair separation. Furthermore, quenching effect of different scavengers indicated that hydroxyl radical had a main role, and e^? or h⁺ played a minimal role in CV dye degradation. The enhanced properties due to doping make BaNi_xFe_12-xO₁₉ a potential candidate for photocatalytic applications under visible light irradiation.     

Dopants induced structural and optical anomalies of anisotropic edges of black phosphorous thin films and crystals

A detailed experimental investigation of dopants modified black-phosphorus and methodology to deposit film on glass substrate have been conducted in order to improve the optical properties and wider utility. It was observed that Raman peaks were less intense for film, compared to separately grown black-P crystals. It was also observed that when synthesis duration was reduced to four hours, all Raman peaks became broader. A non-uniform material luminescence with dominance of green luminescence was observed when black-P crystals were irradiated with light of wavelength ~565–575 nm. The sulfur doped black-P illustrated fascinating rod-and-globule like deposits on the parent nano-coral black phosphorous substrate, whereas selenium doped black-P exhibits a localized concentration of Se in the near homogeneous phosphorous coverage. The boron and sulfur doping increased the band gap. In contrast, Se, In, and Ga doping resulted in a significant decrease in band gap energy. Frequency dependent dielectric functions of the anisotropic zig-zag and armchair edges of phosphorene suggest that doping of black –P causes a diminution in the first peak position for the zigzag electric field polarization demonstrating a gradual red shift. The red shift in the first peak position was perceived to be greatest for doping with boron exhibiting a band edge at 0.65 eV and least in the case of doping with sulfur, resulting in a band edge at 1.09 eV.     

Impact of tailoring of the defect states and the band gap towards extreme photocatalytic performance and photo-induced conductivity in cobalt doped ZnO QD

Due to the advantages of tuning the electronic structure and reducing charge carrier recombination, metal doping into semiconductor metal oxides has been considered an efficient method for enhancing photocatalytic activity and photo-induced conductivity. In this paper, we focus on the effect of cobalt doping on the photocatalytic performance and photo-induced conductivity of ZnO QD. It was found that after Co doping, the photocatalytic activity of ZnO QD was remarkably higher than that of undoped ZnO QD when measured with methylene blue (MB) dye. The study showed that the complete degradation of the dye using 5 mol% cobalt doped ZnO QD occurred in just 6 min, which is 4 times faster than that of undoped ZnO QD. The extent of dye mineralization was supported by chemical oxygen demand (COD) study, which revealed that the dye was almost entirely mineralized. Furthermore, the photoconductivity and photosensitivity of 5 mol% doped Co doped ZnO QD were increased by 20 and 7 times, respectively, over that of undoped ZnO QD. The outstanding boost in photocatalytic activity and photoconductivity is caused by the tunable band gap mediated photo response, which increases light harvesting and thus the generation of a large number of electron hole pairs. Another possible explanation is that sub-energy levels formed between the conduction and valence bands act as a trap for electrons and holes, promoting charge separation by limiting photogenerated charge carrier recombination.     

Blue light emission from barium doped zinc sulfide nanoparticles

ZnS nanoparticles with Ba²⁺doping have been prepared at room temperature through chemical route, namely the chemical precipitation method. The nanostructures of the prepared nanoparticles have been analyzed using X-ray diffraction (XRD) for phase analysis, Field emission scanning electron microscope (FESEM) for the morphological characterization, UV–Vis–NIR spectrophotometer for determining band gap energy and fluorescence spectroscopy for determining the emission wave length. The sizes of as prepared nanoparticles are found to be in 9–10 nm range. FESEM morphology shows the formation of nanostructure of ZnS samples. The value of optical band gap has been found to be in range 4.10–4.63 eV. Room temperature photoluminescence (PL) spectrum of the undoped sample exhibits emission in the blue region with multiple peaks under UV excitation. On the other hand, the Ba²⁺ doped ZnS samples exhibit visible light emissions under the same UV excitation wavelength of 310 nm.     

Structural,optical and photoelectrochemical properties of p type Ni doped CuFeO2 by hydrothermal method

Great efforts have been devoted to delafossite CuFeO₂ for exploring its potential application in solar energy conversion. In this study, the structural, band gap, photoelectrochemical properties of pure and Ni doped delafossite CuFeO₂ powders synthesized by hydrothermal method were investigated. XRD patterns confirm the formation of a majority of 3R and a small amount of 2H mixed delafossite CuFeO₂ crystals. UV-VIS-NIR spectra display gradual narrowing trend of direct band gaps from 3.43 eV to 3.02 eV and indirect band gaps from 1.03 eV to 0.59 eV after Ni doping. The corresponding carrier concentration is promoted from 7.95 × 10¹⁹ to 1.14 × 10²⁰ cm⁻³ together with the anodic shift of flat band potential. The photoresponse performance is enhanced by utilization of Ni doping, mainly due to the evidently narrowed band gap with promoted light absorption ability. The transient decay time of 6% Ni doped CuFeO₂ is evidently prolonged from 5.0s to 11.0s, indicating the lower carrier recombination rate as compared with pure CuFeO₂. The reduced semicircle radius in EIS spectra indicates the smaller charge transfer resistance and higher interfacial carrier transfer efficiency for Ni doped CuFeO₂. In addition, Ni doped CuFeO₂ exhibits slightly enhanced magnetic performance which is very easily to be recycled and beneficial for the potential application in suspended status.     

Influence of Mn-doping on the photocatalytic and solar cell efficiency of CuO nanowires

Pristine copper oxide (CuO) and manganese (Mn) doped CuO nanostructures with different ratios were synthesized via wet chemical method. As-prepared materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-rays (EDX), UV–Visible and emission spectroscopy. Further, the doped nanowires were employed in the hybrid solar cells in combination with P3HT and gave better current densities than their corresponding undoped counterparts. The photoactivity of synthesized materials was evaluated by the photocatalytic oxidation of Rhodamine B (RhB). The results showed that the 2% Mn doped CuO photocatalyst is highly photoactive than other corresponding undoped and doped CuO nanowires. The increase in solar cell efficiency and photocatalytic activity of the doped CuO nanowires is solely due to the improvement in the charge separation efficiency in the 2% Mn doped CuO nanowires.     

One dimensional (1-D) signatures of nanopillars and nanowires in niobium doped zinc oxide (NZO) thin films prepared by aerosol assisted chemical vapour deposition (AACVD)

We report for the first time a facile synthesis of niobium (Nb) doped (1-D) ZnO nanopillars and nanowires by aerosol assisted chemical vapour deposition with improved structural and optical properties. The micro structural, vibrational and optical properties of Nb-doped ZnO were investigated by X-ray diffraction (XRD), Raman spectroscopy, Scanning electron microscopy (SEM)/Energy dispersive spectroscopy (EDS) and UV–Vis spectroscopy (UV/VIS). The results presented show that Nb doping and solvent choice can effectively control the growth of ZnO nanostructures as well as their reproducibility. The XRD results revealed that the highest estimated crystallite size of Nb doped ZnO was found to be 4.7 nm from depositions conducted in methanol and 5.4 nm from depositions conducted in toluene for 0.2 M% Nb doping. It is further explored that with an increase of Nb content, ZnO films show poor crystallinity with preferential orientation along the 0 0 2 plane. The change in morphology and local structure of ZnO also led to variations in the vibrational properties of the materials. Upon Nb doping, the A1 (LO) mode of ZnO was found to red shift and broaden, whereas a blue shift was found for the 2A1 (LO), 2E1 (LO) and 2LO vibrational modes. The UV–Visible spectroscopy of Nb doped ZnO revealed that excellent visible transmittance (∼89%) was achievable and witnessed an increase in band gap from 3.3 eV to 3.5 eV with increased Nb doping.     

Piezopotential‐Induced Schottky Behavior of Zn1−xSnO3 Nanowire Arrays and Piezophotocatalytic Applications

This article presents the piezotronic‐ and piezophototronic effect‐enhanced photocatalysis (piezophotocatalysis) of Zn_1?xSnO₃ (ZTO) nanowires fabricated through a two‐step hydrothermal reaction. The highlights of this research include (1) tailoring hydrothermal synthesis parameters to obtain well‐aligned LN‐type single‐crystalline ZTO nanowire arrays; (2) exploring the piezopotential‐driven piezotronic and piezophototronic effects of ZTO nanowires; (3) identifying Schottky barrier height variations; and (4) exploiting synergistic piezophotocatalysis for decomposing methylene blue (MB). Transmission electron microscopy, electron probe energy‐dispersive spectroscopy, and X‐ray photoelectron spectroscopy analyses reveal highly crystalline Zn‐deficient ZTO nanowires. The band gap is estimated to be approximately 3.8 eV. The ZTO nanowires exhibit piezopotential‐modulated piezotronic and piezophototronic effects. The corresponding Schottky barrier height variation is calculated using thermionic emission‐diffusion theory. The calculated photodegradation rate constant k of the sample, under pressure from ultrasonic vibration and a piece of glass, is approximately 1.5 × 10^?2 min^?1, approximately four times higher than that of ZTO nanowires in the absence of stress. The observed synergistic piezophotocatalysis is attributed to (1) band bending of ZTO nanowires; (2) application of alternating ultrasonic vibration; (3) MB mass transfer enhancement; and (4) abundant active reaction sites generated from ZTO nanowire surface sweeping.     

Structural,morphological, and optical properties of W-doped VO2 thin films prepared by sol-gel spin coating method

Thermochromic VO₂ thin films were deposited on soda-lime glass via sol-gel method. Doping was done through adding tungstic acid solution to the vanadium solution precursor. Grazing incidence x-ray diffractometer (GIXRD) results showed that VO₂ and V₆O₁₃ phases were formed together in the heat-treated sample. According to the GIXRD result of the W-doped sample, only VO₂ remained. Field-emission scanning electron microscopy (FESEM) micrographs showed that the VO₂ grain size decreased from about 70 to about 25 nm for undoped film and 2 wt% W-doped films, respectively. Atomic force microscopy (AFM) results showed that the root mean square roughness for the film with 180 nm thickness was about 18 nm, and 2 wt% W-doped film had a smoother surface. Diffuse reflectance spectroscopy (DRS) results showed that the band gap energy for undoped, 1 wt% W- doped, and 2 wt% W-doped VO₂ thin films was 1.7, 1.3, and 0 eV, respectively. Four-point probe resistivity measurements showed a significant decrement, from approximately 1 MΩ at 15°C to <100 Ω at 80°C. Regarding Vis-NIR spectroscopy results, maximum optical transmission for undoped and W-doped films was approximately 75% and 35%, respectively.     

Gradient doping of Cu(I) and Cu(II) in ZnO nanorod photoanode by electrochemical deposition for enhanced photocurrent generation

This study describes the synthesis and characterization of Cu-doped ZnO nanorods (NRs) by an electrochemical method in the presence of two different Cu precursor (Cu⁺² and Cu⁺) in order to improve photocurrent generation. Analyses of the resulting materials by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–Vis and electrochemical photocurrent (ECP) spectroscopy confirm the formation of well-aligned ZnO Würtzite nanostructures in the form of hexagonal rods. For both doping source with a concentration of up to 0.5%, the following changes were observed: a distortion of the ZnO morphology, an increase in transmittance to 96% for ZnO doped with Cu⁺², and a reduction of the energy gap from 3.36 eV to 3.06 and 3.02 eV for ZnO doped with Cu⁺² and Cu⁺, respectively. From photoelectrochemical tests, the photo-current density was improved up to 0.05 mA cm^-2 in the presence of Cu doping, which is twelve times superior to that of undoped ZnO nanorods, which means that the incorporation of Cu+2 or Cu + significantly improves the separation efficiency of photogenerated electron-hole pairs. These results can be considered promising for optoelectronic and photocatalysis applications.     

Effect of silver (Ag) ions irradiation on the structural,optical and photovoltaic properties of Mn doped TiO2 thin films based dye sensitized solar cells

Dye sensitized solar cell (DSSC) is an emerging energy harvesting tool which converts direct sunlight into electrical energy. These cells have much better properties in contrast with silicon based solar cells because of their flexible nature, light weight, low cost, environment friendly nature, and involvement of a simple manufacturing process. Since, a photoanode is the backbone of DSSC, we synthesized a pure and 1% manganese (Mn) doped titanium dioxide (TiO₂) films by sol-gel method which are irradiated with silver (Ag) ions at two different concentrations (2 × 10¹⁴ and 4 × 10¹⁴) ions-cm^?2. X-ray diffraction revealed that Mn doping followed by Ag irradiation transformed TiO₂ from pure anatase to rutile phase. Ultraviolet–visible spectroscopy exposed the reduction in band gap of TiO₂ film during this doping and irradiation process. Therefore, absorption is enhanced with red shift in UV-range. When these films are used as a photoanode in DSSC, 1% Mn doped TiO₂ film exposed with Ag at the concentration of (2 × 10¹⁴) ions-cm^?2 exhibited maximum efficiency of 2.40%.