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Impact of CsI concentration, relative humidity, and annealing temperature on lead-free Cs2SnI6 perovskites: Toward visible light photodetectors application
摘要： Physical, electrical, and photodetection properties of stable, lead-free Cs2SnI6 (CSI) perovskite thin films prepared on thermally oxidized Si (SiO2, 100 nm) substrates via direct solution spin coating process are reported. XRD, XPS, and EDS analysis reveal that initial CsI rich-concentration, higher RH% levels (>40%) have an impact on phase formation of CSI films. The porous, sub-lm sized rods of fabricated CSI films are confirmed by FEG-SEM analysis. Contact resistance (Rc) and sheet resistance (Rsh) for CSI films, annealed at 150 (cid:1)C, are decreased up to 37% and 85%, respectively, as compared with those of films processed at 75 (cid:1)C. The photoresponsivity (6 mA/W) and specific detectivity (2.00 (cid:1) 109 Jones) for two-terminal CSI photodetectors are achieved with annealing condition of 100℃ and at a bias voltage of 1 V as well. The preliminary photodetection properties for CSI devices processed at low temperatures indicate that they can be potentially applicable to a flexible, visible light photodetector.
关键词： Electrical and photodetection properties,RH% levels,CsI concentration,Annealing temperature,Structural
更新于2025-09-23 15:19:57
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C-doping into h-BN at low annealing temperature by alkaline earth metal borate for photoredox activity
摘要： BCN (boron carbon nitride) nanosheets are promising photocatalyst materials for solar fuel production by visible light-driven water splitting and CO2 reduction due to their tunable band gap and unique properties. C-doping into h-BN by thermal annealing makes possible the preparation of BCN nanosheets with photocatalytic activity under visible light irradiation, but it generally requires a very high temperature (>1250 °C) from the thermodynamic viewpoint. Here, we report a new method to prepare BCN nanosheets with visible light-photocatalytic activity at lower annealing temperature (1000 °C) than equilibrium by adding alkaline earth metal compounds. BCN nanosheets formed in borate melt show a clear layered structure, tunable bandgap and photocatalytic activity for water splitting and CO2 reduction under visible light illumination. This provides a direction for doping other elements into h-BN at low annealing temperature by alkaline earth metal borates.
关键词： h-BN,low annealing temperature,BCN nanosheets,water splitting,CO2 reduction,C-doping,photoredox activity,alkaline earth metal borate
更新于2025-09-19 17:15:36
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N-Doped Graphene Quantum Dots Supported by Carbon Nanotubes Grown on Carbon Clothes for Lithium Storage
摘要： Graphite has been widely used as an anode material for commercial lithium-ion battery applications because of its excellent stability and low cost. However, graphite-based anodes need to improve the energy storage capacities to meet the increasing power demands of next-generation technologies. Here, we have developed a class of novel and ?exible electrode materials that consist of N-doped graphene quantum dots supported by carbon nanotubes grown on carbon cloth (denoted as CC/CNT@N-GQD). Such architecture synergistically combines the advantages of three dimensions/one dimension substrates and zero dimension N-GQDs. It greatly improves the electron/ion transport kinetics of N-GQDs, resulting in attractive electrochemical performance in terms of high reversible capacity and excellent rate capability. Moreover, the annealing temperature plays an important role in the control of N-doping types of CC/CNT@N-GQD. CC/CNT@N-GQD anodes annealed at 500 °C have a high content of pyridinic N, exhibiting a very excellent rate capability and cycling stability, as exempli?ed by a capacity of 2.88 mAh cm?2 at 4 mA cm?2 and a reversible capacity of 3.63 mAh cm?2 after 150 cycles at 0.19 mA cm?2.
关键词： carbon nanotubes,carbon cloth,lithium storage,annealing temperature,pyridinic N,N-doped graphene quantum dots
更新于2025-09-19 17:13:59
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The effect of annealing conditions: temperature, time, ramping rate and atmosphere on nanocrystal Cu2ZnSnS4 (CZTS) thin film solar cell properties
摘要： Cu2ZnSnS4 (CZTS) nanoparticles were fabricated successfully using the hot injection method; CZTS films were deposited by spin coating of nanocrystal ink. The aim of this work is to study the effect of annealing parameters: temperature, time, ramping rate and atmosphere on CZTS thin film structure and optical properties. XRD, Raman Spectroscopy, SEM, EDX mapping are used to analyse the films and they demonstrate the increase in quality and improvement in the crystallinity of CZTS and the homogeneity of elements which is one of the important factors for CZTS thin film solar cells. The crystallinity, structure and chemical composition of CZTS thin films increased and improved under annealing in H2S+N2 atmosphere which demonstrated that annealing at 500 oC for 1 h with a ramping rate of 10 oC/min under H2S+N2 atmosphere is a suitable condition for the fabrication of CZTS thin films used in solar cell devices.
关键词： Annealing temperature,CZTS,Cu2ZnSnS4,Annealing time,Thin film solar PV,Annealing atmosphere,Annealing ramping rate
更新于2025-09-16 10:30:52
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Controlled sol–gel synthesis of oxygen sensing CdO?:?ZnO hexagonal particles for different annealing temperatures
摘要： CdO : ZnO hexagonal particles were synthesized by a sol–gel precipitation method at di?erent annealing temperatures. A mixed crystal phase of cubic and wurtzite structures was observed from X-ray di?raction patterns. The micrographs showed hexagonal shapes of the CdO : ZnO nanocomposites particles. The energy dispersive X-ray spectroscopy mapping images showed a uniform distribution of the Cd and Zn. The CdO : ZnO nanocomposite pallet annealed at 550 (cid:1)C has an electrical resistance of 0.366 kU at room temperature. The nanocomposites showed an excellent sensing response against oxygen gas with a sensing response of 47% at 200 (cid:1)C for the CdO : ZnO particles annealed at 550 (cid:1)C. The sensor response and recovery times were found to be 43s and 45s, respectively. The sensor response was due to the sorption of oxygen ions on the surfaces of the CdO : ZnO hexagonal particles.
关键词： sol–gel,annealing temperature,hexagonal particles,oxygen sensing,CdO : ZnO
更新于2025-09-16 10:30:52
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Investigation of the structural, optical, elastic and electrical properties of spinel LiZn <sub/>2</sub> Fe <sub/>3</sub> O <sub/>8</sub> nanoparticles annealed at two distinct temperatures
摘要： Nanoparticles of Li0.5ZnFe1.5O4 (LiZn2Fe3O8) with the spinel structure were prepared by a sol–gel auto-combustion method at two different annealing temperatures. X-ray diffractograms and Rietveld refinement confirmed the formation of the spinel structure. The morphology was analyzed by electron microscopy, which showed that the grains were composed of different crystallites. Elastic properties were determined from infrared spectroscopy. It was found that the elastic parameters increased with the increase in annealing temperatures. The band gap depends on the annealing temperature and it decreased on increasing the particle size. The conductivity of the specimen annealed at 500 °C followed either the Jonscher's model or Drude's model depending on the temperature range. This conductivity decreased when the annealing temperature was raised by 600 °C. AC conductivity was found to be controlled by the hopping model. A single relaxation phenomenon was evidenced for each sample from impedance analysis. The Nyquist diagram proved that the samples were simultaneously capacitive and resistive and also supported the presence of multiple relaxation times.
关键词： annealing temperature,spinel,conductivity,LiZn2Fe3O8,impedance analysis,band gap,elastic properties,sol–gel auto-combustion
更新于2025-09-16 10:30:52
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Impact of post annealing and hydrogen implantation on functional properties of Cu2O thin films for photovoltaic applications
摘要： Polycrystalline cuprous oxide (Cu2O) thin films were sputtered, annealed (900 ?C rapid thermal annealing) and subsequently implanted with various hydrogen ion (H+) doses from 5E13 to 2E15 cm-2 with a low acceleration energy of 36 keV at room temperature to tailor the functional properties of the thin films for solar cell application. The annealed and H+ implanted Cu2O thin films were post annealed at low temperatures from 100 ?C to 600 ?C in an inert atmosphere to promote hydrogen passivation of prevalent intrinsic acceptors and tune the carrier concentration for optimum performance as an absorption layer in a heterojunction solar cell. The H+ incorporation and post annealing tuned the structural, optical and electrical properties of annealed polycrystalline Cu2O thin films. The results show an enhancement of the excitonic feature around ~2.0 eV with H+ dose. The normalized photoluminescence (PL) area around ~1.7 eV was drastically enhanced with increasing H+ doses compared to excitonic and copper vacancy related area. The normalized total PL quantum efficiency shows an enhancement in yield with elevated H+ doses by two orders of magnitude. The hole concentration decreases down to ~1013 cm-3, while hole mobility and resistivity increase to ~27 cm2/Vs and ~2.4 k?cm, respectively, as the H+ implantation goes from lower to higher doses. In addition, the post annealing and H+ incorporation lead to a change in the energy level of the major acceptor from 0.21 eV to 0.27 eV above the valence band maximum. By following the qualitative (PL analysis) and quantitative (Hall data) outcomes, we can conclude that H+ implantation and post annealing likely indicates the passivation of both acceptor defects and compensating donor defects.
关键词： Post annealing temperature,H+ doses,Thin films,Hall effect,Cu2O,Photoluminescence
更新于2025-09-16 10:30:52
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Dielectric and electrical properties of annealed ZnS thin films. The appearance of the OLPT conduction mechanism in chalcogenides
摘要： The annealing temperature (Ta) dependence of the structural, morphological, electrical and dielectric properties of ZnS thin films was investigated. In this work, we consider the as-deposited and annealed ZnS thin films at different temperatures. The as-deposited films were amorphous in nature. However, the films annealed at Ta ≥ 673 K, exhibited a hexagonal structure with (002) preferential orientation. The post annealing caused an improvement in crystallinity. The best one was observed at Ta = 723 K. Grain size increased from 7 nm to 25 nm as annealing temperature was increased from 673 K to 723 K. The surface of annealed samples is homogenous and uniform and the rms roughness is dependent on the annealing temperature: it increases with temperature within the range 5–50 nm. The film electrical conductance is found to be dependent on frequency measurement and annealing temperature: the dc conductance exhibits semi-conductor behavior for all ZnS films over the explored range of temperature and the conductance was found to enhance with increasing annealing temperature up to 623 K. In addition, it was observed that the highest conductance and lowest activation energy of ZnS films were obtained at an annealing temperature of 623 K. The mechanism of alternating current ac conductance can be reasonably explained in terms of the overlapping-large polaron tunnelling (OLPT) model for samples annealed at 623 K and 673 K. To our knowledge, this conduction mechanism was rarely found in chalcogenide materials. A significant change of Nyquist plot with annealing temperature was noted permitting the correlation between the microstructure and its electrical properties. The impedance analysis investigated that the relaxation process is well pronounced for the both annealed films at 623 K and 673 K. The dielectric behavior was associated to the polarization effect, an improvement on the dielectric constant 30 and dielectric loss 300 with annealing was noticed.
关键词： electrical properties,dielectric properties,annealing temperature,OLPT conduction mechanism,ZnS thin films
更新于2025-09-16 10:30:52
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Investigating the impact of thermal annealing on the photovoltaic performance of chemical bath deposited SnO2/p-Si heterojunction solar cells
摘要： The current work investigates the impact of annealing temperature on the optoelectronic properties of SnO2 thin films grown by chemical bath deposition (CBD) method. The as-grown SnO2 films, on p-Si substrate, are annealed at 200 °C and 400 °C for 10 min in Ar ambient for investigating the impact of such annealing on the performance of SnO2/p-Si heterojunction solar cells. The growth of a uniform SnO2 film on Si surface has been confirmed from SEM studies and the chemical composition and optical properties of the as-grown and annealed films are investigated in detail by employing XRD and ellipsometric measurements. Absorption coefficient of the samples is observed to vary in the range of 24 × 105 – 60 × 105/m, at its band gap (3.0 eV). The current–voltage characteristics under both dark and illuminated conditions suggest superior voltaic performance of the 200 °C annealed SnO2 film. The short-circuit current density, open-circuit voltage and fill-factor are obtained to be 0.45 mA/cm2, 5.41 mA/cm2 and 0.4 V, 0.34 V and 13%, 8% respectively for as-grown and 200 °C annealed samples. The maximum power conservation efficiency (η) of 4.9% is obtained for the 200 °C annealed sample. Thus, the study indicates the potential of CBD-grown SnO2 film for photovoltaic applications.
关键词： Optoelectronic properties,Heterojunction solar cells,Chemical bath deposition,Annealing temperature,SnO2 thin films
更新于2025-09-12 10:27:22
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Effect of annealing temperature on silicon-based MoS <sub/>x</sub> thin film solar cells
摘要： A suitable annealing temperature was found by adopting the sol–gel method to prepare silicon-based molybdenum sulfide film heterojunction solar cells. As shown by the results, a change in the efficiency of the solar cells, which was attributed to the fact that as the annealing temperature rises, the degree of crystallization of the film increases continuously, the degree of order of the crystal particles goes up first and then goes down, and the temperature change affects the proportion of Mo in different valence states. By comparison, it was found that when the temperature reached 500 °C, the degree of order of the film was raised and the film was in the initial zone from the amorphous to the microcrystal phase change and the proportion of Mo 6+ was relatively large, increasing the conversion efficiency of the device power to 7.55% and laying a good basis for preparing high-performance solar batteries made in the two-dimensional materials. When the annealing temperature continues to rise, the intergranular defects increase, and the overall degree of order of the film decreases. Furthermore, the highly crystalline thin films and the improvement in the device efficiency can be controlled if we obtained the relationship between the annealing temperature and the layers of the two-dimensional materials.
关键词： annealing temperature,solar cells,crystallization,sol–gel method,silicon-based MoSx thin film
更新于2025-09-12 10:27:22