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Deposition of orientation-controlled thick (K,Na)NbO<sub>3</sub> films on metal substrates by repeated hydrothermal deposition technique
摘要： (K,Na)NbO3 thick films were grown at 240°C on Ni-based metal substrates by repeated hydrothermal method. The metal substrates were covered with two types of buffer layers; SrRuO3/LaNiO3 and SrRuO3. Film thickness monotonically increased with increasing number of deposition cycles. The 27 μm-thick film was obtained on the metal substrate with SrRuO3/LaNiO3 by four cycles. The obtained films tended to show {100}c orientation and their degree of orientation increased with increasing number of deposition cycles. Films deposited on SrRuO3/LaNiO3-covered metal substrates showed more highly {100}c orientation compared with those on SrRuO3-covered metal substrates. Remnant polarization and coercive field measured at 5 kHz were 12 μC/cm2 and 70 kV/cm, while their effective values of piezoelectric coefficient (d33) was 35–40 pm/V for both films. These properties remained unchanged irrespective of a number of deposition cycles despite the orientation change of films. These results show that repeated hydrothermal deposition technique is one of the effective ways to prepare thick (K,Na)NbO3 films on metal substrates.
关键词： Metal substrate,Lead-free (K,Na)NbO3 film,Orientation control,Ferroelectric and piezoelectric properties,Hydrothermal,synthesize
更新于2025-09-12 10:27:22
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Single-Source Vapor-Deposited Cs2AgBiBr6 Thin Films for Lead-Free Perovskite Solar Cells
摘要： Lead-free double perovskites have been considered as a potential environmentally friendly photovoltaic material for substituting the hybrid lead halide perovskites due to their high stability and nontoxicity. Here, lead-free double perovskite Cs2AgBiBr6 films are initially fabricated by single-source evaporation deposition under high vacuum condition. X-ray diffraction and scanning electron microscopy characterization show that the high crystallinity, flat, and pinhole-free double perovskite Cs2AgBiBr6 films were obtained after post-annealing at 300°C for 15 min. By changing the annealing temperature, annealing time, and film thickness, perovskite Cs2AgBiBr6 solar cells with planar heterojunction structure of FTO/TiO2/Cs2AgBiBr6/Spiro-OMeTAD/Ag achieve an encouraging power conversion efficiency of 0.70%. Our preliminary work opens a feasible approach for preparing high-quality double perovskite Cs2AgBiBr6 films wielding considerable potential for photovoltaic application.
关键词： perovskite solar cell,lead-free,thin film,single-source vapor deposition
更新于2025-09-12 10:27:22
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Effect of Different Bonding Materials on Flip-Chip LED Filament Properties
摘要： This article researches the effect of Sn-based solder alloys on flip-chip light-emitting diode LED (FC-LED) filament properties. SEM images, shearing force, steady-state voltage, blue light luminous flux, and junction temperature were examined to demonstrate the difference between two types of FC-LED filaments welded with two solders. The microstructure surface of Sn90Sb10 filament solder joints was smoother and had fewer voids and cracks compared with that of SAC0307 filament solder joints, which indicates that the Sn90Sb10 filaments had a higher shearing force than the SAC0307 filaments; moreover, the average shearing force was beyond 200 gf (standard shearing force). The steady-state voltage and junction temperature of the Sn90Sb10 solder-welded FC-LED filament were lower, and the Sn90Sb10 filament had a relatively higher blue light luminous flux. If high reliability of the solder joints and better photoelectric properties of the filaments are required, this Sn90Sb10 solder is the best bonding material for FC-LED filament welding.
关键词： reliability,lead-free solder,photoelectric properties,FC-LED filament
更新于2025-09-12 10:27:22
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Surface optimization by poly(α-methylstyrene) as additive in the antisolution to enhance lead-free Sn-based perovskite solar cells
摘要： Surface quality of the perovskite layer plays an important role in the determination of the device performance. This study presents an e?ective method to optimize the surface morphology for the lead-free formamidinium tin iodide (FASnI3) perovskite solar cells. Poly(α-methylstyrene) (PAMS) was applied as polymer additive into the diethyl ether at di?erent blend concentration. The addition of PAMS can apparently reduce the pinholes at the surface of the FASnI3 ?lm without ruining the interior crystallinity of the bulk FASnI3 layer. Therefore the non-radiative carrier traps can be e?ectively suppressed. The surface of the FAsnI3 ?lm becomes more hydrophobic which facilitates the consequent spin-coating of the acceptor material solution. The modi?cation of FASnI3 ?lm’s wettability is favorable of the photo-induced carriers’ extraction and transportation. As a result, the power conversion e?ciency of the PAMS-modi?ed devices is greatly improved.
关键词： Polymer additive,Antisolution,Lead-free,Perovskite,Solar cells,Poly(α-methylstyrene)
更新于2025-09-12 10:27:22
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First-Principles Screening of Lead-Free Mixed-Anion Perovskites for Photovoltaics
摘要： Organic-inorganic hybrid lead perovskites have made rapid progress in photovoltaic fields. However, the toxicity and poor long-term stability of these materials still limit their further commercial application. Herein, we proposed a system of lead-free mixed-anion perovskites in which a chalcogen element is incorporated into the perovskite octahedrons to improve the system stability. We performed first-principles calculations of the bandgaps of 192 lead-free mixed-anion perovskites belonging to the class of ABX'X"2, where A=Cs+, CH3NH3+, and HC(NH2)2+; B=Ga3+, In3+, Sb3+, Bi3+; X'= O2-, S2-, Se2-, and Te2-, and X"= F-, Cl-, Br-, and I-. The bandgap shows a linear relationship with the average anion electronegativity. The contribution of anions to the band edge states is related to electron affinity and structure parameters. Considering multiple factors forming perovskites, we screened out a promising candidate, CsInOBr2, with a suitable bandgap (1.3 eV) for application in photovoltaics.
关键词： theoretical screening,GLLB-SC methods,photovoltaic materials,lead-free perovskites,bandgap
更新于2025-09-12 10:27:22
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Modeling of a high performance bandgap graded Pb-free HTM-free perovskite solar cell
摘要： In this study, a lead-free nontoxic and hole transport material (HTM)-free perovskite solar cell (PSC) with a novel con?guration of glass/FTO/ZnO/CH3NH3SnI3(cid:1)xBrx/back contact has been modeled and optimized by a solar cell capacitance simulator (SCAPS). The bandgap of CH3NH3SnI3(cid:1)xBrx absorber is tuned in the range of 1.3 eV to 2.15 eV by variation of the Br doping content. To make a comparison, an optimized Pb-based PSC is also modeled. By optimizing the parameters, power conversion ef?ciency (PCE) of 16.30%, open circuit voltage (Voc) of 1.02 V, short circuit current density (Jsc) of 22.23 mA/cm2, and ?ll factor (FF) of 0.72 were obtained. As compare to the reports available in the literature, these results show much improvement and can provide guidelines for production of economic and environmentally friendly PSCs with further ef?ciency enhancement.
关键词： lead-free,perovskite solar cell,SCAPS,bandgap grading,HTM-free
更新于2025-09-11 14:15:04
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Efficient Anti-solvent-free Spin-Coated and Printed Sn-Perovskite Solar Cells with Crystal-Based Precursor Solutions
摘要： The existence of a mass oxidation of Sn2+ that takes place mainly during preparation of precursor solutions and fabrication of films creates a lead-free solar cell of low open-circuit voltage, which leads to low PCE. To reduce the oxidation process, we employed an innovative crystal fabrication method with anti-solvent-free recrystallization technology. As a result, to the best of our knowledge, both spin-coated and printed lead-free solar cells based on FASnI3 achieved the highest 3D-based PCE to date.
关键词： FASnI3,anti-solvent-free method,lead-free solar cells,PCE,single crystals
更新于2025-09-11 14:15:04
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Interface Engineering in Tin Perovskite Solar Cells
摘要： As a rising star of lead-free perovskite solar cells (PCSs), tin-based PSCs have drawn much attention and made promising progress during the past few years. Notably, interfaces in the tin-based PSCs device have great impacts on performance enhancements. In this Review, the authors first demonstrate why the interface is especially crucial for tin-based PSCs device. It is proposed that the engineering of i) interface between perovskite grains in the film and ii) interface within the PSCs device are of great significance on the improvement of device functionality and stability. Then, the up-to-date studies on interface engineering of tin-based PSCs are reviewed, including the following strategies: i) passivation of trap states; ii) modification of interfacial layers; iii) construction of 2D/3D structure. At last, a future perspective and remaining challenges in this field are given, aiming to provide a comprehensive understanding of interfaces in tin-based PSCs and give some new thoughts on interface engineering for efficient PSCs device.
关键词： 2D/3D structure,interfaces,Sn perovskites,lead-free,solar cells
更新于2025-09-11 14:15:04
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Eco-friendly and stable silver bismuth disulphide quantum dot solar cells via methyl acetate purification and modified ligand exchange
摘要： From the point of view of environmentally-friendly, non- or less toxic photovoltaic material and fabrication method are desired by both the academia and industrial community. However, most efficient quantum dot solar cells have been fabricated based on heavy metal and toxic solvent consumption, which could cause serious ecological problems. Quantum dot solar cells were studied and explored based on lead-free active material silver bismuth disulphide, less toxic solvent purification of methyl acetate and lab-developed ligand exchange process. Twice ligand exchanges with tetramethylammonium iodide were applied for every deposited quantum dot layer kept in static. Methanol rinse was applied to the quantum dot film after each ligand exchange process to promote the ligand exchange and clean the organic residuals. Decent power conversion efficiency and good stability were demonstrated for the fabricated silver bismuth disulphide quantum dot solar cells. The best power conversion efficiency of 4.57% was achieved, with open-circuit voltage of 0.445 V, short-circuit current of 18.87 mA/cm2 and fill factor of 54.4%. Over 95% of the original power conversion efficiency was maintained after 150 days both in N2-filled glove box and ambient atmosphere with relative humidity of 30%. This work demonstrated fabrication of quantum dot solar cells based on non- or less-toxic quantum dots and solvent consumption. Which would benefit the development and commercialization of quantum dot solar cell technology.
关键词： low-toxic solvent,silver bismuth disulphide,performance,eco-friendly solar cell,Lead-free quantum dots,ligand exchange
更新于2025-09-11 14:15:04
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Benzodithiophene Hole‐Transporting Materials for Efficient Tin‐Based Perovskite Solar Cells
摘要： Developing efficient interfacial hole transporting materials (HTMs) is crucial for achieving high-performance Pb-free Sn-based halide perovskite solar cells (PSCs). Here, a new series of benzodithiophene (BDT)-based organic small molecules containing tetra- and di-triphenyl amine donors prepared via a straightforward and scalable synthetic route is reported. The thermal, optical, and electrochemical properties of two BDT-based molecules are shown to be structurally and energetically suitable to serve as HTMs for Sn-based PSCs. It is reported here that ethylenediammonium/formamidinium tin iodide solar cells using BDT-based HTMs deliver a champion power conversion efficiency up to 7.59%, outperforming analogous reference solar cells using traditional and expensive HTMs. Thus, these BDT-based molecules are promising candidates as HTMs for the fabrication of high-performance Sn-based PSCs.
关键词： benzodithiophene,tin,perovskite solar cells,triphenylamine,lead-free
更新于2025-09-11 14:15:04