Context
The improvement of new organic flavone-based donor-spacer-acceptor (D-π-A) type dye molecules of the 3-(4-hydroxypiperidin-2-yloxy)-7-hydroxy-2-(3,4-dihydroxyphenyl)-4H-chromen-4-one (D1), ...7-hydroxy-2-(3,4-dihydroxyphenyl)-3-(piperidin-4-yloxy)-4H-chromen-4-one (D2), and 3-((2-aminopyridin-4-yloxy)methoxy)-7-hydroxy-2-(3,4-dihydroxyphenyl)-4H-chromen-4-one (D3) were successfully designed and synthesized for dye-sensitized solar cells (DSSCs).
Methods
Here, we discuss the synthesis of flavone compounds as well as their photophysical and electrochemical characterization. Using the Gaussian 09w software, the electronic structures and apsorption spectra have been calculated at the B3LYP, B3PW91, CAM-B3LYP, MPW1PW91, PBEPBE, and ωB97XD theory with the 6-311G(d,p) basis sets.
Results
The computed values of the D2 molecule ground state optimized HOMOs-LUMOs energy is well positioned for advantageous charge transfer (CT) into the semiconducting material (TiO
2
) as well as the electron injection process. With a high power conversion efficiency (PCE) of 3.46% (
V
OC
= 0.718 V,
J
SC
= 7.07 mA cm
−2
, and
FF
= 0.68), the D2 compound also demonstrated good photovoltaic (PV) properties.
Conclusion
These findings unequivocally demonstrate that altering the D-π-A metal-free organic material electron-withdrawing capacity is a useful strategy for enhancing the optical and electrical characteristics of the organic PV system.
The influence of nickel (Ni) doping concentrations on structural, optical, electrical and diode properties of molybdenum trioxide (MoO
3
) thin films has been studied systematically. Ni-doped MoO
3
...films and diodes were prepared for various doping concentrations of Ni such as 0, 3, 6 and 9 wt.% by jet nebulizer spray (JNS) pyrolysis technique. The structural properties of Ni-doped MoO
3
films were analyzed by X-ray diffraction (XRD) pattern and scanning electron microscopy (SEM). The prepared films were exhibited in the orthorhombic crystal structure and sub-microsized plate-like surface morphology. The energy-dispersive X-ray spectroscopy (EDX) analysis confirmed the presence of Ni, Mo and O elements in the prepared films. Ultraviolet–visible (UV–vis) analysis results showed that the absorbance decreases with the increasing of Ni doping concentration and the minimum band gap energy (
E
g
= 2.25) was obtained for 9 wt.% Ni-doped MoO
3
film. From current–voltage (
I
–
V
) characterization, the conductivity is increased by increasing the Ni doping concentration in MoO
3
thin films. The diode measurements were performed in darkness and under light illumination of a halogen lamp. The methods of
I
–
V
, Cheung’s and Norde were used to calculate the diode parameters of ideality factor (
n
), barrier height (Φ
b
) and sheet resistance (
R
s
). Also, the light ON/OFF switching response of the fabricated n-NiMoO
3
/p-Si diodes was analyzed.
In the present article, the pure and different concentrations as 1, 2, 3, and 5 wt.% Mn-doped ZnO (Mn:ZnO) nanoparticles were synthesized by combustion route. XRD of the prepared samples were fitted ...using the Lorentz function and the obtained data files were used to calculate the crystallite size. The crystallite sizes were found to be 25.3 nm, 34.6 nm, 31.1 nm, 32.5 nm, and 33.3 nm for pure, 1 wt.%, 2 wt.%, 3 wt.%, and 5 wt.% Mn-doped ZnO NPs, respectively. The agglomerated spherical shape morphology with different particles sizes of pure and 1, 3, and 5 wt.% Mn:ZnO NPs were observed by scanning electron microscopy (SEM). The vibrational phonon modes observed at 99–100, 326–331, 435–438, 573–585, 676-681, and 1142–1151 cm
−1
were attributed to the presence of intrinsic defects in the samples. The optical band gaps 3.280, 3.218, 3.103, 3.024, and 2.922 eV of pure, 1 wt. %, 2 wt.%, 3 wt.%, and 5 wt.% Mn-doped ZnO NPs were obtained using Kubelka–Munk function, respectively. PL emission spectra exhibit the peaks at 354, 451, 469, 482, 492, and 560 nm under 325 nm excitation wavelength, while emission peaks observed at 389, 451, 468–474, 492, and 557 nm under 350 nm excitation wavelength. The dielectric constant and dielectric losses of the prepared NPs were observed in the range 27.6–23.4 and 29–14, respectively. The greater values of capacitance and impedance of the prepared samples were recorded as 27.3–17.3 (pF) and 2.75 (MΩ)-273 (Ω) over the entire range of the logarithmic frequency. The obtained results of Mn:ZnO nanoparticles were found suitable for the potential applications in optoelectronic devices.
The synthesis and large-sized single crystals of pure and Mg
2+
-doped zinc (tris) thiourea sulfate has been developed using slow evaporation methods at 300 K. The size of the grown crystal for pure, ...2% Mg and 5% Mg-doped ZTS is found to be ~ 15 mm × 17 mm, ~ 20 mm × 18 mm, and 22 mm × 10 mm, respectively. The crystal structural and vibrational modes are identified by powder X-ray diffraction, FT-IR and FT-Raman analyses. The grown crystal with 5% Mg doping possesses higher optical transparency (67%). Optical energy band gap is found ~ 4.36 eV for 2% Mg and ~ 4.41 eV for 5% Mg-doped crystals. Enhancement in PL intensity of UV band was observed due to doping. The third-order nonlinear susceptibility,
χ
3
is found to be enhanced due to doping which is in the order of 10
−3
esu. DSC study confirms that the 5% MgZTS crystals possess higher thermal stability than pure as well as 2% MgZTS. Furthermore, the dielectric study confirms that the grown crystals possess low defects. The microhardness is also found to be enhanced due to doping. All the properties of ZTS are found to be enhanced by Mg doping and make it more suitable for optoelectronic and nonlinear applications compared to pure.
Cd and Na co-doped ZnO nanostructured thin films with different doping concentrations were prepared using a sol-gel spin coating technique on glass substrates. The effect of doping with Cd and 1, 2 ...and 3 wt % Na on the structural, morphological, optical and UV detection properties of the nanostructured ZnO thin films was investigated. The grown co-doped nanostructured thin films exhibit wurtzite structure with preferential growth along the (002) plane. The change in the doping concentration was found to have a considerable effect on the grain size of the prepared films as well as their morphology. A variation in the band gap of the co-doped nanostructured thin films was also observed with changing the doping concentration. The band gap was found to vary in the range from 3.27 to 3.24 eV with increasing Na concentrations. The UV detection performance of the co-doped ZnO nanostructured thin films based UV detector was also investigated and found to strongly depend on the dopants concentrations with an obvious correlation with the variation in the films band gap. The findings of the current study show that a good control of the optical properties and the UV detection performance of the ZnO nanostructured thin films can be achieved through co-doing with Cd and Na with increased potential for their uses in high performance opto-electronic devices.
•High quality ZnO nanostructured thin films co-doped with Cd and Na were prepared using sol-gel method.•The effect of co-doping with Cd and Na on the optical properties and the UV-detection performance of the films is reported.•Cd and Na co-doping significantly improves the UV detection performance of ZnO films based devices.•Co-doping with Cd & Na could be an effective route to improve the performance of ZnO based opto-electronic applications.
Thin films of Tb-doped CdO were grown on FTO substrates using the sol–gel-spin coater technique. XRD studies confirmed the polycrystalline cubic growth of the films with a (200) preferential ...orientation. XRD analysis was used to estimate the crystallite sizes, dislocation density, and microstrain values, and found that they are highly dependent on the doping percentage. Homogeneous distributions of the nano-gains were observed from the AFM studies. Energy-dispersive spectroscopy and mapping analyses were used for the uniform elemental composition confirmation. All the films displayed high transmission reaching nearly 80% in the visible spectrum and the effect of Tb doping was very clear by corresponding systematic increase in intensities. The direct band-gap values were estimated from the Tauc plots and are found to be highly tunable based on the doping percentage, which was varying between 2.79 and 2.91 eV. The refractive index and extinction coefficient values are lies between 1.8 and 2.5 and 0.44 to 0.82. The
χ
(
1
)
values are found to be varying between of 0.05 to 0.45 within the range 1–4 eV. This suggests all the linear and nonlinear optical properties of the present samples can be tailored for the various applications by the doping.
In this study, the newly designed organic dyes (CBS1-CBS3) were designed by the donor (D), π-linkers (π) and acceptor (A) to forming the D-π-A structure. Besides, the screened efficient spacer dye ...sensitizers were simulated by the density functional theory (DFT) and time-dependent DFT (TD-DFT) methods for dye-sensitized solar cell (DSSC) application. First, the optical absorption peak of CB1 dye was analyzed by the different exchange–correlation (XC) and long-range corrected (LC) functionals with 6-31G(d) basis set. As a result of functional, TD-CAM-B3LYP method nearly well matched with the literature data of CB1. The computational outcomes were shown that the highest occupied molecular orbitals (HOMOs) and lowest unoccupied MOs (LUMOs) of the CBS1-CBS3 dyes confirmed useful response on the electron injection (
Δ
G
inject
) and dye regeneration (
Δ
G
reg
). Therefore, the short-circuit current density (
J
SC
) key factors of the light harvesting efficiency (
LHE
),
Δ
G
inject
and
Δ
G
reg
in CBS1-CBS3 dye derivatives were superior performance of the DSSCs. In addition to the highest vertical dipole moment (
µ
normal
) and open circuit photovoltage (
e
V
OC
) of the planned dyes were better performance for DSSCs. Hence, it benefits to higher efficiency. The present theoretical investigation results demonstrate that all the D-π-A dyes may be capable sensitizers for DSSC application.
The presence of carcinogenic dyes in industrial wastewater is a serious problem that hazards the water bodies and nano-catalysts are key members that are used to purify it. Therefore, this work ...investigates the synthesis of tungsten oxide (WO
3
) nanoparticles with various annealing temperatures in the range of 100–600 °C by the co-precipitation method for photocatalysis applications. The improvement in crystallinity of the nanoparticles achieved through annealing temperature and the crystallite size was an increase from 10 to 34 nm. The structural parameters of the prepared samples were characterized using XRD reveals the formation of stable monoclinic structure. FESEM morphological images confirmed the formation of irregularly shaped nanoplates. HRTEM and SAED patterns confirmed the growth of nanocrystalline WO
3
nanoparticles. Parameters like (hkl) planes and interplanar spacing values obtained from HRTEM studies agreed well with the results of XRD. The elemental presence and chemical compositions were confirmed from EDS and XPS studies, respectively. The presence of functional groups has been verified through FTIR spectroscopy studies. Considerable decrements in the energy gap of WO
3
NPs were observed with annealing from 2.89 to 2.61 eV. The defects/oxygen deficiencies were examined through photoluminescence. The photocatalytic performance of WO
3
NPs was assessed by degrading the methylene blue dye. The parameters obtained from Pseudo first-order kinetic studies confirmed that 600 °C annealed WO
3
NPs have higher photocatalytic activity.
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•The stable molecular geometry of LANB has been obtained by B3LYP and CAM-B3LYP level of theory using 6-31G∗ basis set.•The dipole moment of LANB (4.124a.u.) was found to be 3 times ...higher than urea.•The absorption wavelength calculated by TDDFT study was found to be 268nm.•The energy gap (EHOMO–ELUMO) was calculated and found to be 4.3eV.•Total first hyperpolarizability (βtot) of LANB (1.630×10−30esu) was found to be 4 times higher than prototype urea molecule.
In current work, the authors have been applied the density functional theory (DFT) using B3LYP and CAM-B3LYP exchange–correlation functional with 6-31G∗ basis set on l-arginine p-nitrobenzoate monohydrate (LANB) molecule for the first time to optimize its geometry and study the spectroscopic, electronic structure, nonlinear optical properties. Vibrational modes were found in good agreement with experimental reports. The calculated UV spectra by B3LYP/6-31G∗ and CAM-B3LYP/6-31G∗ level of theory shows an electronic transition at ∼268nm (4.63eV) and 264nm (4.70eV) respectively. To explain the charge interaction taking place within the molecule highest occupied molecular orbital and lowest unoccupied molecular orbital were analyzed and their calculated energy gap was found to be 4.3eV with an oscillatory strength 0.3796 at B3LYP/6-31G∗ level of theory. The dipole moment (μtot), average and anisotropy of polarizability (αtot, Δα) and static and total first hyperpolarizability (β0, βtot) values were calculated. The value of μtot and βtot are found to be 4.124D and 1.630×10−30 esu and 4.127D and 1.133×10−30 esu using B3LYP/6-31G∗ and CAM-B3LYP/6-31G∗ functional respectively. The value of βtot is >4 and >3 times higher than prototype urea molecule calculated at both level of theory, respectively. The molecular electrostatic potential (MEP), frontier molecular orbital’s (FMOs), global reactivity descriptors and thermodynamic properties are also calculated and discussed. The properties of LANB calculated at B3LYP are in good correlation with experimental than the CAM-B3LYP level of theory. The obtained results show that LANB molecule can be treated as a good candidate for nonlinear optical devices.
SEM image for 10 wt% Er@NiO, energy gap and dielectric constant variation with Er doping contnt in NiO.
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•First time Er@NiO NPs synthesis was done facilely by flash combustion ...process.•Monophasic cubic structure was confirmed from XRD and Rietveld refinement process.•Crystallite size reduced from 27 to 8 nm and also the grain size with Er doping in NiO.•Reduction in energy gap from 3.50 to 3.17 eV was noticed by Er doping in NiO.•High dielectric constant was noticed i.e. in range of 65–115 at 3 kHz and 18–36 at 3 MHz.
A facile synthesis of erbium doped nickel oxide (Er@NiO) was accomplished via combustion route at 550 °C within 2 h. Cubic phase of all Er@NiO samples was confirmed by X-ray diffraction (XRD) and Rietveld refinement methods. All XRD profiles were fitted well by Rietveld. XRD data was used to determine the values of size, dislocations, strain and the size was reduced from 26 to 8 nm on rising the Er content in NiO. Vibrational spectroscopy also approved the synthesis of NiO without any impurity content at all Er concentrations. The composition of Ni, O and Er was evaluated by EDX and their uniform dispersal in final product was confirmed by SEM e-mapping. Further, SEM study confirms very compact nanostructure of final products and the size reduction was observed by Er content. Kubelka-Munk methodology was employed to attain the bandgap of all Er@NiO NPs and lies between 3.17 and 3.50 eV. The ε' values are lies between 65–115 at 3 kHz and 18–36 at 3 MHz, however, it was higher for 5 wt% Er@NiO NPs compare to other at 3 kHz and lower after 7 kHz. The ac conductivity and conduction behaviour were also inveterate and conferred.
