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Electron Transport Improvement of Perovskite Solar Cell via ZIF-8 Derived Porous Carbon Skeleton
摘要： To improve electron transport rate of perovskite solar cell, ZIF-8 derived porous carbon skeleton layer is prepared by carbonizing the ZIF-8 thin film on conducting glass as the electron transport skeleton of perovskite solar cell. Polyvinyl pyrrolidone is added during the synthesis of ZIF-8 to reduce the particle size of ZIF-8 and decrease the carbonization temperature below 600°C. The porous structure of ZIF-8 is mainly reserved at the optimized carbonization temperature. Then TiO2 nanoparticles are deposited on the surface of porous carbon skeleton to form an electron transport layer of perovskite solar cell with the structure of FTO/ZIF-8 derived porous carbon layer/TiO2/Perovskite/Spiro-OMeTAD/Au. Due to the good conductivity of the ZIF-8 derived porous carbon skeleton, the photogenerated electron transport rate of perovskite solar cell is increased. At the same time, the porous structure of ZIF-8 derived carbon layer increases the contact area between the perovskite layer and the TiO2 layer to favor separation of photogenerated charges. Therefore, the light-to-electric conversion efficiency of CH3NH3PbI3 perovskite solar cell is enhanced from 14.25% to 17.32%.
关键词： Electron transport,Increase of contact area,Porous carbon skeleton,Good conductivity,Polyvinyl pyrrolidone,Perovskite solar cell,Metal organic frameworks
更新于2025-11-14 17:04:02
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Cu/Sb Codoping for Tuning Carrier Concentration and Thermoelectric Performance of GeTe-Based Alloys with Ultralow Lattice Thermal Conductivity
摘要： Pristine GeTe shows promising thermoelectric performance but is limited by the high carrier concentration (nH) from Ge vacancies and thermal conductivity. Herein, Cu/Sb was chosen as codopants to suppress the high nH and to decrease thermal conductivity. In this condition, a promising zT of ～1.62 under 773 K was acquired in the Ge0.85Te(CuSb)0.075 system proposed in this paper/work. Results show that as the dopant concentration increases, the power factor rises due to the reduction of the nH to ～1 × 1020 cm?3. Apart from this, the total thermal conductivity also declines from ～7.4 W m?1 K?1 to ～1.59 W m?1 K?1 originating from an ultralow lattice thermal conductivity, in which the multiscatter mechanism from grain boundaries and point defect disperses the frequency phonons di?erently. The ?ndings in this paper combine thermal and electronic strategies and lay the foundation to develop Pb-free thermoelectric materials.
关键词： multiscatter mechanism,Cu/Sb codoped GeTe,thermoelectric materials,ultralow lattice thermal conductivity,zT value,carrier concentration,Seebeck coefficient
更新于2025-11-14 17:03:37
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Complex impedance, FT-Raman, and photoluminescence spectroscopic studies of pure and L-phenylalanine doped ammonium dihydrogen phosphate single crystals: the correlation with hydrogen bonding defect
摘要： Ammonium dihydrogen phosphate (ADP) is an important nonlinear optical (NLO) material used for electro-optical applications. The aromatic side chain contained dopant like L-phenylalanine causes defect in ADP. The pure and L-phenylalanine doped ADP crystals are grown using slow solvent evaporation technique at room temperature. The Powder XRD spectra suggest tetragonal crystal system and slit shifting of peak. The FT-Raman shows strong absorption peak at 922 cm?1 due to v1 group symmetry of P - OH for all grown crystals without shifting indicating the single phase nature of all the crystals. The photoluminescence study suggests the presence of defects in doped crystals compared to the pure one due to increase of Stokes shift and vibrational energy relaxation phenomena. The dielectric constant and dielectric loss have shown the usual behavior with respect to frequency and temperature. The calculated electro-optic coefficient is found to be in accordance with dielectric constant. The protonic conduction is prevailing for electric transport, and from Jonscher’s plot, the correlation barrier hopping (CBH) is confirmed. The Nyquist plot and modulus spectra of pure ADP show the presence of grain and grain boundary while the same plots for L-phenylalanine doped ADP show the presence of grain only. The stretch exponent exhibits non-Debye-type relaxation.
关键词： Photoluminescence,Protonic conductivity,Impedance spectroscopy,Dihydrogen phosphate,Raman spectroscopy
更新于2025-11-14 15:26:12
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Determination of the Thin-Film Structure of Zwitterion-Doped Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate): A Neutron Reflectivity Study
摘要： Doping poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is known to improve its conductivity, however little is known about the thin film structure of PEDOT:PSS when doped with an asymmetrically charged dopant. In this study, PEDOT:PSS was doped with different concentrations of the zwitterion 3-(N,N Dimethylmyristylammonio)propanesulfonate (DYMAP), and its effect on the bulk structure of the films characterized by neutron reflectivity. The results show that at low doping concentration, the film separates into a quasi bi-layer structure with lower roughness (10%), increased thickness (18%), and lower electrical conductivity compared to the un-doped sample. However when the doping concentration increases the film forms into a homogeneous layer and experiences an enhanced conductivity by more than an order of magnitude, a 20% smoother surface, and a 60% thickness increase relative to the pristine sample. Atomic force microscopy and profilometry measurements confirmed these findings, and AFM height and phase images showed the gradually increasing presence of DYMAP on the film surface as a function of the concentration. Neutron reflectivity also showed that the quasi bi-layer structure of the lowest concentration doped PEDOT:PSS is separated by a graded rather than a well defined interface. Our findings provide an understanding of the layer structure modification for doped PEDOT:PSS films that should be prove important for device applications.
关键词： neutron reflectivity,hole transporting layer,conductivity,film structure,zwitterion,PEDOT:PSS
更新于2025-11-14 15:19:41
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Performance optimization of bi-layer solar steam generation system through tuning porosity of bottom layer
摘要： In recent years, solar steam generation has attracted many attentions due to its potential applications in desalination, etc. In the present work, a bi-layer solar steam generation system is prepared by daubing carbon particles on the sintered sawdust film, which possesses an advantage of adjustable porosities compared to widely used wood. Then, the influence of the porosity on the evaporation performance is explored. The experimental result indicates that: the porosity could significantly affect the water transportation in the film, and the water diffusivity increases almost linearly with the increase of the porosity. The evaporation efficiency increases with the increasing porosity, until the porosity reaches about 0.52 then decrease slowly. The positive effect of the increased water diffusivity and the negative effect of the increased thermal conductivity of the bottom film layer determine that the porosity of 0.52 is optimal for improving the evaporation efficiency. Under a solar light power of 1 kW·m?2, the optimal porosity gives an evaporation efficiency of 77.64%, which is comparable to the best performance of bi-layer systems reported in previous works. The conduction of heat through the bottom layer to the bulk water and the convection heat loss on the top surface contribute 83% to the total heat losses in the system, suggesting that the energy losses of these two modes should be further reduced in the future applications. Considering the accessible materials, easy preparation, low cost and high efficiency, we conclude that the 0.52-porosity system is suitable for being used as an efficient solar steam generation device.
关键词： Solar steam generation,Thermal conductivity,Solar energy,Porous material
更新于2025-11-14 15:14:40
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Synthesis, Conductivity and Impedance Studies on across adjacent ring formed new metallo phthalocyanines
摘要： The synthesis and characterization of Co(II), Zn(II) and Ni(II) phthalocyanines (Pcs) 4, 5 and 6, respectively containing two Bis[2-(4-hydroxyphenyl)-2-propyl]benzene across adjacent ring formed at the peripheral positions are described. The Pcs were synthesized by cyclotetramerization of the previously prepared precursor 4,4’-bis[1,3-propylbenzene-2-p-phenoxy]phthalonitrile (3) with the presence of metal salt in boiling dry DMF under a dry nitrogen atmosphere. Elemental analysis, UV-Vis, FT-IR, MALDI-TOF mass and 1H-NMR spectrometry techniques were used for characterization of 4. DC and ac conductivity and impedance spectra (IS) measurements were performed on the films 5, and 6 between the temperatures 293 - 523 K and frequencies 40-100 kHz. The dc conductivity values were calculated as 2.11x10-10 S/cm, 3.48x10-10 S/cm, and 1.90x10-10 S/cm for the films of 4, 5, and 6 at room temperature. Activation energy values of the films were also calculated. ac conductivity results suggest that dominant charge transport mechanisms can be explained by hopping model depending on temperature and frequency range. From impedance spectra, Cole-Cole plots, the relaxation time in Debye dispersion relation is considered as a distribution of relaxation time values, rather than as a single relaxation time. To elucidate the structural, spectroscopic and bonding properties of the obtained compounds, DFT/TD-DFT calculations were performed.
关键词： Density functional theory,Conductivity,Electrical characterization,Impedance spectra,Metallophthalocyanine,Hopping
更新于2025-09-23 15:23:52
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Novel solid polymer electrolyte based on PMMA:CH3COOLi effect of salt concentration on optical and conductivity studies
摘要： Novel solid polymer electrolyte (SPE) films based on poly(methyl methacrylate) (PMMA) and lithium acetate (CH3COOLi) with different weight ratios of PMMA:CH3COOLi wt% (60:40, 70:30, 80:20 wt%) were prepared by solution casting technique. XRD analysis confirmed the amorphous nature of Li–PMMA SPE films. FTIR analysis revealed the structural changes in polymer by complexation with Li salt. From the optical absorbance studies, the value of lowest energy band gap was found to be 3.06 eV for the composition, PMMA:CH3COOLi (60:40 wt%). From AC impedance studies, the highest value of ionic conductivity 8.21 × 10?5 S/cm at 303 K for the SPE film PMMA:CH3COOLi (60:40 wt%) is observed compared to the reported literature. From the results of Li–PMMA SPE film with high ionic conductivity, it is a promising material for the application of solid-state battery.
关键词： Band gap,Ionic conductivity,Dielectric measurements,Li–PMMA SPE
更新于2025-09-23 15:23:52
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Seed Free Growth of Aligned ZnO Nanowire Arrays on AZO Substrate
摘要： In the absence of commonly used seed layer, we can still successfully synthesized aligned ZnO nanowire arrays by the hydrothermal method. By using aluminum-doped zinc oxide (AZO) glass as a substrate, high-density and vertically aligned ZnO nanowires were synthesized directly on the substrate in the absence of the ZnO seed layer. The current-voltage curve indicated that the sample grown on AZO glass substrate in the absence of seed layer possesses better conductivity than that synthesized on FTO glass substrate with ZnO seed layer. Thus, a simplified, seed-free and low-cost experimental protocol was reported here for large-scale production of high quality ZnO nanowire arrays with promoted conductivity.
关键词： conductivity,ZnO nanowire arrays,seed layer free,AZO substrate
更新于2025-09-23 15:23:52
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Facile preparation of stable reactive silver ink for highly conductive and flexible electrodes
摘要： Stability of conductive ink and mechanical ?exibility of conductive pattern are essential for ?exible printed electronics. In this work, we reported a stable reactive silver ink for the facile fabrication of ?exible electrodes. The ink was mainly composed of silver-isopropanolamine (IPA) complex, formic acid reductant, and hydroxyethyl cellulose (HEC) adhesive agent, and it displayed good chemical stability. The ?exible electrodes on polyimide (PI) substrates were achieved by mask-printing and thermal sintering of the ink, and the e?ects of sintering parameters and HEC adhesive agent content on the electrical and ?exible properties and microstructure evolutions of silver layer were systematically investigated. Consequently, the silver layer sintered at 110 °C yields low electrical resistivity of 12.1 μΩ·cm, which is only eight times higher than that of bulk silver. Furthermore, the sintered silver layer still presents excellent ?exibility and low relative resistances after the bending, twisting, and folding tests. These results demonstrate that the stable reactive silver ink provides a promising and low cost opportunity for low temperature design and fabrication of high performance ?exible printed electronics.
关键词： Reactive silver ink,High conductivity,Silver layer,Flexibility,Printed electronics
更新于2025-09-23 15:23:52
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Elastic, electronic and thermoelectric properties of Sr3MN (M?= Sb, Bi) under pressure
摘要： We have performed first-principles calculations to study the structural, elastic, electronic and thermoelectric properties of Sr3MN (M = Sb, Bi) under pressure. The optimized lattice parameters are in good agreement with the available experimental and theoretical measurements. Brittle to ductile transition occurs at 15 GPa and the hardness of both compounds decreases with the increase of pressure. The band gap slightly reduces with pressure and both compounds exhibit semiconducting nature for TB-mBJ potential. The density of states increases slightly at the Fermi level. The inclusion of the spin-orbit coupling effect reduces the band gap of Sr3BiN. The calculated Seebeck coefficient for Sr3SbN and Sr3BiN at 15 GPa and 600 K are 257 and 142 μV/K, respectively. The calculated lattice thermal conductivity of both compounds decreases with the increase of pressure, as phonon scattering increased. The predicted thermoelectric figure of merit (ZT) for Sr3SbN and Sr3BiN at 15 GPa and 600 K are 0.71 and 0.63, respectively. The obtained thermoelectric properties at high pressure making them suitable for thermoelectric device applications.
关键词： Lattice thermal conductivity,Pressure effect,Thermoelectric properties,Electronic properties,Elastic properties
更新于2025-09-23 15:23:52