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Electric field assisted spray coated lead free bismuth iodide perovskite thin film for solar cell application
摘要： Solution-processed Methylammonium iodo bismuthate (MBI) perovskite solar cell is fabricated by spray technique with changed applied voltages from 0 to 1000 V during the deposition of MBI thin film. The morphology and surface roughness of MBI films are influenced significantly by the electric field during film deposition. It is attributed to improve the atomization of spray droplets due to process of coulomb fission. The surface roughness of MBI film is reduced from 39 to 19 nm with increased applied voltages during the deposition from 0 V and 1000 V, respectively. A strong absorption band is observed ～500 nm for all MBI films. The MBI perovskite solar cell is showed enhancement in the efficiency with the maximum current density 2.33 mA/cm2 at 1000 V applied voltage during the deposition. The improvement in photovoltaic characteristics with applied voltage during the film deposition is attributed to the formation of more uniform film with improved surface morphology and roughness, resulting in efficient electron transfer and reduced recombination of charge carrier at grain boundaries.
关键词： Methyl ammonium bismuth (III) iodide,Spray deposition,Perovskite solar cell,Electric filed,Lead free perovskite
更新于2025-11-21 11:18:25
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Uniform Cs2SnI6 Thin Films for Lead-Free and Stable Perovskite Optoelectronics via Hybrid Deposition Approaches
摘要： Herein, we synthesized uniform Cs2SnI6 films by two kinds of hybrid deposition methods by considering volume expansion involved during phase transformations. First, oblique thermal evaporation for CsI followed by SnI4 spin-coating resulted in uniform Cs2SnI6 films free of impurity phases. The rapid expansion (within 10 s of spin-coating) from CsI to Cs2SnI6 (ΔV = 106%) was accommodated by porous CsI films inhibiting crack formation. Excess SnI4 on the Cs2SnI6 after spin-coating was effectively removed by toluene washing without any damages to Cs2SnI6, and optimum deposition parameters were suggested in terms of carrier mobility. Second, annealing CsI with SnI4 vapor at 250 °C and post-annealing in the SnI4 and I2 vapor at 300 °C produced Cs2SnI6 film with complete coverage. The slow reaction (70 min for a complete conversion) provided sufficient time for complete diffusion of SnI4 into CsI without crack formation even with compact CsI. The nonradiative recombination path in Cs2SnI6 was suppressed by post-annealing in the SnI4- and I2-atmosphere, as confirmed from the enhanced photoluminescence.
关键词： Lead-free perovskite,Cs2SnI6,Electrical mobility,Oblique thermal deposition
更新于2025-09-23 15:23:52
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Tin halide perovskite films made of highly oriented 2D crystals enable more efficient and stable lead-free perovskite solar cells
摘要： Low toxicity and an ideal energy bandgap make 2D Ruddlesden-Popper tin-based halide perovskites a promising photovoltaic material. However, the disordered crystal orientation and the oxidation of Sn2+ to Sn4+ still need to be addressed. Here, we demonstrate that the annealing of FASnI3 assisted by phenyl ethyl ammonium chloride enables the formation of more ordered 2D tin-based perovskite crystals oriented vertically. We use in-situ synchrotron-based grazing incident X-ray diffraction (GIXRD) to correlate the higher crystal orientation to the better device performance. We measured a maximum power conversion efficiency of >9%. Furthermore, we demonstrate that the phenyl ethyl ammonium chloride acts as a barrier layer at the surface of the crystals protecting the tin from the oxidation. Hence, this work paves the way for more efficient and stable lead-free perovskite solar cells.
关键词： phenyl ethyl ammonium chloride,photovoltaic material,crystal orientation,lead-free perovskite solar cells,oxidation of Sn2+,2D Ruddlesden-Popper tin-based halide perovskites,power conversion efficiency
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Room Temperature Synthesis of Lead-Free Sn/Ge-Based Perovskite Quantum Dots
摘要： Metal halide perovskites have received remarkable attention as photovoltaic (PV) devices. These have already achieved power conversion efficiency higher than 23% rivaling that of silicon-based PV. However, these outstanding efficiencies can only be acquired with lead-based perovskites and the devices are chemically unstable in air and moisture. Therefore, the key to the widespread deployment of perovskite-based solar cell will come down to address their “toxicity” and instability problems. We have taken the challenge to replace lead with other nontoxic or less toxic elements, e.g., Sn, and Ge. We have synthesized Cs(Sn,Ge)X3 (X=I, Br, and Cl) quantum dots (QDs) using room temperature process. The XRD data showed that the synthesized QDs were yellow hexagonal phase, which was further confirmed by the hexagonal shape of the TEM images of the crystals.
关键词： solar cell,nanoparticle,photoluminescence,doping,Lead-free perovskite
更新于2025-09-23 15:21:01
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Nucleation-controlled growth of superior lead-free perovskite Cs3Bi2I9 single-crystals for high-performance X-ray detection
摘要： The organic-inorganic hybrid lead halide perovskites have emerged as a series of star materials for solar cells, lasers and detectors. However, the issues raised by the toxic lead element and marginal stability due to the volatile organic components have severely limited their potential applications. In this work, we develop a nucleation-controlled solution method to grow large size high-quality Cs3Bi2I9 perovskite single crystals (PSCs). Using the technique, we harvest some centimeter-sized single crystals and achieved high device performance. We ?nd that X-ray detectors based on PSCs exhibit high sensitivity of 1652.3 μC Gyair?1 cm?2 and very low detectable dose rate of 130 nGyair s?1, both desired in medical diagnostics. In addition, its outstanding thermal stability inspires us to develop a high temperature X-ray detector with stable response at up to 100 °C. Furthermore, PSCs exhibit high X-ray imaging capability thanks to its negligible signal drifting and extremely high stability.
关键词： nucleation-controlled growth,high sensitivity,X-ray detection,lead-free,perovskite single crystals
更新于2025-09-23 15:21:01
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Boosted efficiency of conductive metal oxide-free pervoskite solar cells using poly[3-(4-methylamincarboxylbutyl)thiophene] buffer layers
摘要： Owing to low work functions of transparent anodes and poor contact issues at interfaces, the p-i-n conductive metal oxide (CMO)-free perovskite solar cells (PVSCs) commonly suffered from a limited power conversion efficiency. Herein, we reported an efficient CMO-free PVSC using poly[3-(4-methylamincarboxylbutyl)thiophene] (P3CT-N) modified poly(3,4-ethylenedioxylenethiophene):poly(styrenesulfonate) (PEDOT:PSS) anodes. The contact angle between PEDOT:PSS anodes and P3CT-N buffer layers tended to be 0o for an intimate contact. Meanwhile, the work function of the PEDOT:PSS anodes coated with P3CT-N is as high as -5.11 eV, which substantially accounted for the raised ability of hole transport. All the parameters (i.e., open-circuit voltage, short-circuit current density and fill factor) were improved simultaneously. As a result, the efficiency of the CMO-free solar cells was significantly improved from 4.63% to 13.13%. Our results indicate that P3CT-N is suitable to the highly conductive but hydrophobic PEDOT:PSS anodes for making high-efficiency CMO-free PVSCs.
关键词： work function,CMO-free,perovskite solar cells,PEDOT:PSS,P3CT-N
更新于2025-09-23 15:21:01
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RbF modified FTO electrode enable energy-level matching for efficient electron transport layer-free perovskite solar cells
摘要： The development of highly efficient electron transport layer free perovskite solar cells (ETL-free PSCs) with simplified and economical device configurations can significantly motivate the commercialization of PSCs. However, the performance of ETL-free PSCs has been hampered by the sluggish charge extraction and severe charge carrier recombination due to the energy-level mismatch at the interface of the perovskite and the transparent conductive electrode FTO (fluorine doped tin-oxide). In this study, this issue is well solved by modifying the FTO surface with a simple, low-cost and non-toxic rubidium fluoride (RbF) interlayer. An interfacial dipole layer is formed on the FTO surface by inserting a RbF layer, which tunes the work function of FTO, eliminates the electron transport barrier and optimizes the energy-level alignment at the FTO/perovskite interface, thereby enhancing the charge transfer and suppressing the carrier recombination. Consequently, the rigid ETL-free PSCs with RbF layer yield high efficiencies of up to 18.79%, higher than that of ETL-free devices on bare FTO (16.03%). By virtue of the low-temperature processability, a superior PCE of 15.7% has been achieved by flexible ETL-free PSCs fabricated on RbF modified plastic substrate. This study provides a simple, efficient and environmentally friendly approach to modify the FTO electrode for fabricating ETL-free PSCs, which contribute to promote the design of advanced interface materials for simplified and high-performance perovskite photovoltaics.
关键词： ETL-Free Perovskite Solar Cells,Interface Dipole,Energy-Level Matching,Aqueous Processing
更新于2025-09-23 15:21:01
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Reducing photovoltage loss at anode contact of methylammonium-free inverted perovskite solar cells by conjugated polyelectrolyte doping
摘要： The efficiency of perovskite solar cells (PSCs) developed rapidly in recent years, but the stability still lagged behind. Ion migration effect, especially from the small methylammonium (MA) cations, is a main factor for stability issues and MA-free perovskite is one appreciated pathway to suppress ion migration. In this work, we reveal there is a much lower valence band maximum (VBM) of -5.8 eV for the most studied MA-free perovskite of FA0.83Cs0.17PbI2.7Br0.3, which is much different from traditional perovskite and the huge energy level mismatch between perovskite and hole transport layer (HTL) is a main factor to limit the device performance of MA-free PSCs. It is found doping with conjugated polyelectrolyte of poly[(9,9-bis(3’-((N,N-dimethyl)-N-ethylammonium)-propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)](PFN-Br) in perovskite can significantly promote anode contact and result in better device performance as well as stability of FA0.83Cs0.17PbI2.7Br0.3 based MA-free PSCs in inverted planar structure. The PFN-Br arise the energy position of VBM of perovskite and results in well-matched energy levels between perovskite and HTL of poly[bis(4-phenyl) (2,4,6-trimethylphenyl) amine (PTAA). Carrier extraction and transportation are highly encouraged at the surface of PTAA / perovskite, and the corresponding interface recombination is effectively suppressed. As a result, a 60mV increased VOC is achieved, which promotes champion device efficiency to 20.32%. At the same time, the efficient device displays a significant stability under continuous illumination and bias at MPP conditions, which could remain 80% of its initial power conversion efficiency (PCE) under continuous operation under one sun illumination over 500 hours.
关键词： PFN-Br doping,MA-free perovskite,device stability,energy level alignment,perovskite solar cells
更新于2025-09-23 15:19:57
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Refractory plasmonics enabling 20% efficient lead-free perovskite solar cells
摘要： Core-shell refractory plasmonic nanoparticles are used as excellent nanoantennas to improve the efficiency of lead-free perovskite solar cells (PSCs). SiO2 is used as the shell coating due to its high refractive index and low extinction coefficient, enabling the control over the sunlight directivity. An optoelectronic model is developed using 3D finite element method (FEM) as implemented in COMSOL Multiphysics to calculate the optical and electrical parameters of plain and ZrN/SiO2-modified PSCs. For a fair comparison, ZrN-decorated PSCs are also simulated. While the decoration with ZrN nanoparticles boosts the power conversion efficiency (PCE) of the PSC from 12.9% to 17%, the use of ZrN/SiO2 core/shell nanoparticles shows an unprecedented enhancement in the PCE to reach 20%. The enhancement in the PCE is discussed in details.
关键词： lead-free perovskite solar cells,refractory plasmonics,ZrN/SiO2 core/shell nanoparticles,power conversion efficiency,optoelectronic modeling
更新于2025-09-23 15:19:57
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Dependence of material properties and photovoltaic performance of triple cation tin perovskites on the iodide to bromide ratio
摘要： In this work, the influence of a partial introduction of bromide (x = 0–0.33) into MA0.75FA0.15PEA0.1Sn(BrxI1?x)3 (MA: methylammonium, FA: formamidinium, PEA: phenylethylammonium) triple cation tin perovskite on the material properties and photovoltaic performance is investigated and characterized. The introduction of bromide shifts the optical band gap of the perovskite films from 1.29 eV for the iodide-based perovskite to 1.50 eV for the perovskite with a bromide content of x = 0.33. X-ray diffraction measurements reveal that the size of the unit cell is also gradually reduced based on the incorporation of bromide. Regarding the photovoltaic performance of the perovskite films, it is shown that already small amounts of bromide (x = 0.08) in the perovskite system increase the open circuit voltage, short circuit current density and fill factor. The maximum power conversion efficiency of 4.63% was obtained with a bromide content of x = 0.25, which can be ascribed to the formation of homogeneous thin films in combination with higher values of the open circuit voltage. Upon introduction of a higher amount of bromide (x = 0.33), the perovskite absorber layers form pinholes, thus reducing the overall device performance.
关键词： Semiconductors,Solar cell,Material science,Lead-free perovskite
更新于2025-09-19 17:13:59