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Understanding the effect of solvent additive in polymeric thin film: turning a bilayer in a bulk heterojunction like photovoltaic device
摘要： Here we report the effect of an additive solvent, the 1,8-diiodooctane (DIO) on the performance of a bilayer organic photovoltaic (OPV) device which active layer comprises the poly[2,7-(9,9-bis(2 ethylhexyl)-dibenzosilole)-alt-4,7-bis(thiophen-2-yl)benzo-2,1,3-thiadiazole] (PSiF-DBT) as the electron donor material and C60 as the electron acceptor material. We observed that when the donor layer was treated with 1% of DIO the power conversion efficiency (PCE) of the device increase 138.4% in relation to the device with a non-treated donor layer and 21.3% in relation to the device containing a donor layer submitted to a thermal annealed. The main effects that lead to this increase in PCE are the large interfacial area between donor and acceptor materials and the improved conductivity at low voltages. The increase in polymer surface roughness leads to a more effective PSiF-DBT/C60 interface for exciton dissociation. This effect, as well as the increase in the conductivity, raised the short circuit current density (JSC) to 13.89 mA/cm2 and PCE to 4.84%. Our conclusions are supported by morphological analysis, chemical cross-sectional evaluations with advanced microscopy techniques, charge mobility measurements as well as by theoretical simulations of the devices in which the changes on the donor/acceptor interfacial area were considered. The outcomes suggest that, solvent additives could be an alternative treatment to replace the thermal annealing which imposes further difficulties to perform the lab-to-manufacturing upscaling.
关键词： solvent additive,PSiF-DBT,exciton dissociation,1,8-diiodooctane,C60,organic photovoltaic,power conversion efficiency
更新于2025-09-23 15:21:01
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Green Solution Bathing Process for Efficient Large-area Planar Perovskite Solar Cells
摘要： Perovskite solar cells (PSCs) towards practical application relies on high efficiency, long lifetime, low toxicity and device upscaling. To realize large-area PSCs, a green solution bathing strategy is delivered to prepare high-performance PSCs. By utilizing 2-pentanol as a green solvent and formamidinium chloride (FACl) as a solute in the green solution bathing, perovskite films with enlarged grain sizes, improved crystallinity and alleviated defect state density were obtained, resulting in the enhancement in the power conversion efficiency of PSCs. Coupled with 2-pentanol and FACl, a champion efficiency of 21.03% for small cells (0.103 cm2) and over 18% for large size (1.00 cm2) were obtained based on the GSB process, which can outperform its counterpart made from commonly-used anti-solvent dropping method. In addition, a large perovskite film (5 cm × 5 cm) with obvious mirror effect was successfully prepared. Our innovative approach paves the way to promote device upscaling of PSCs via environment-friendly technique.
关键词： 2-pentanol,green solvent,large-area,solution bathing,perovskite solar cells,FACl
更新于2025-09-23 15:21:01
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Roll-to-Roll Slot-Die Coated P-I-N Perovskite Solar Cells Using Acetonitrile Based Single Step Perovskite Solvent System
摘要： Roll-to-roll coating of all active layers is demonstrated for a P-I-N perovskite solar cell stack, using a single step perovskite ink with an acetonitrile solvent system and flexible plastic substrate. A slot-die coating roll-to-roll process (with a common coating speed for all layers) is developed by using appropriate length meniscus guides as part of the coating head for each ink rheology. High performance devices are demonstrated with four roll-to-roll slot-die coated layers and evaporated top electrode. The drying conditions of the perovskite layer are optimized and found to be critical to achieving good performance. Multi solvent blend systems for the electron collection layer are developed that are more industrially compatible than the commonly used chlorobenzene solvent system and make use of a gradient of solvent volatilities to give both good macro film formation and rapid drying. A stabilised power conversion efficiency of 12.2% is demonstrated, that is the highest reported to date for devices with all layers other than the top electrode deposited roll-to-roll. This work demonstrates the feasibility of a roll-to-roll fabrication process for perovskite solar cells that could be transferred to a fully inline roll-to-roll process with all coating and drying stages made sequentially on one line running at a common coating speed and further demonstrates the potential to produce high efficiency photovoltaics using roll-to-roll fabrication methods.
关键词： Stabilised power conversion efficiency,Perovskite solar cells,Slot-die coating,Roll-to-roll,Acetonitrile solvent system
更新于2025-09-23 15:21:01
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Tailoring Component Interaction for Aira??Processed Efficient and Stable Alla??Inorganic Perovskite Photovoltaic
摘要： All-inorganic lead halide perovskites with potential stability improvement is promising candidate for optoelectronic applications. However, fundamental questions remain over the component interaction in the perovskite precursor solution due to the limitation of the most commonly used solvents of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). Here, we report a simple and very effective interaction tailoring strategy for all-inorganic CsPbI3-xBrx perovskites by involving ionic liquid solvent methylammonium acetate (MAAc). We found that C=O has strong interaction with lead (Pb2+) and the N-H…I hydrogen bonds formation are observed. The interaction enables the stable perovskite precursor solution and allows the high-quality production of pinhole-free, large grain size, and flat all-inorganic perovskite films by retarding the crystallization. With a one-step, without the necessity for antisolvent treatment, air-processing approach regardless of humidity, the corresponding photovoltaic cell exhibits a high efficiency of 17.10% along with long operation stability over 1500 h under continuous light illumination.
关键词： photovoltaic,component interaction,all-inorganic perovskites,stability,ionic liquid solvent
更新于2025-09-23 15:21:01
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General Synthesis Principles for Ruddlesden-Popper Hybrid Perovskite Halides from a Dynamic Equilibrium
摘要： Two-dimensional (2D) Ruddlesden-Popper hybrid perovskites are a homologous series of compounds with the formula A’2An–1BnX3n+1 (A’ = bulky organic cation; A = small organic cation; B = Pb2+ or Sn2+, X = Cl–, Br–, I–; n is an integer) composed of inorganic octahedra layers separated by organic spacer cations. The octahedral layer thickness is modified by the stoichiometry of the A site cation, but limited methods exist for controlled and discriminating synthesis for all compositions. We report a general synthesis method and its principles that yield phase-pure 2D hybrid perovskites; the chemistry operates within a dynamic equilibrium established by the molar solubility of the compounds within the homologous series. A solvent-antisolvent (HI-acetic acid) pair and the common-ion effect provide selective control over the molar solubility to precipitate phase-pure compounds, as is supported by simple and predictive calculations. Here, this approach is demonstrated in detail with A’ = n-butylammonium, A = methylammonium, and n ≤ 3 and is applied to the synthesis and discovery of materials with other bulky ammonium cations (e.g., iso-butylammonium and benzylammonium).
关键词： dynamic equilibrium,Ruddlesden-Popper,molar solubility,common-ion effect,hybrid perovskites,solvent-antisolvent,synthesis
更新于2025-09-23 15:21:01
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Chiral Helical Polymer Nanomaterials with Tunable Morphology: Prepared with Chiral Solvent To Induce Helix-Sense-Selective Precipitation Polymerization
摘要： We report an unprecedented strategy for using achiral monomer to construct chiral helical polymer nanomaterials with tunable morphology—helix-sense-selective precipitation polymerization induced by a chiral solvent (HSSPP-CS). CHCl3, chiral α-pinene, and an alkanol were employed to constitute a solvent mixture for performing HSSPP-CS. (R)- or (S)-α-pinene worked as chiral source and transferred its chirality to the resulting helical polyacetylenes derived from achiral monomer in the course of polymerization, thereby forming chiral helical polymers and endowing the nanomaterials thereof with optical activity. Simply changing solvent composition provided chiral polymer products varying in morphology from fibrous to rod-like and finally to spherical morphology. This is the first report dealing with chirality transfer from chiral solvent to induce helix-sense-selective precipitation polymerizations. The study establishes a straightforward and effective alternative for making use of achiral monomers to construct chiral helical polymer nanomaterials with diverse morphology.
关键词： tunable morphology,chiral solvent,achiral monomer,chiral helical polymer nanomaterials,helix-sense-selective precipitation polymerization
更新于2025-09-23 15:21:01
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Effect of Dye Extraction Solvent on the Photovoltaic Performance of Tecoma stans-Sensitized Solar Cells
摘要： The use of natural dyes as photosensitizers has several advantages including their easy extraction and their biodegradable, nontoxic, and environmentally friendly nature, which makes them vital for application in dye-sensitized solar cells (DSSC). In the present work, we study the effects of extraction solvent on the photovoltaic performance of a natural dye sensitizer for TiO2-based DSSC. Extracts of Tecoma stans flowers in two different solvents, ethanol and ethanol–water mixture, were used as the dye sensitizer for extending the spectral sensitivity of TiO2. The optical properties of the dye extracts were studied by their UV–visible absorption spectra. Fourier transform infrared spectra revealed the presence of anchoring groups and coloring pigments, and nuclear magnetic resonance spectroscopy and mass spectrometry were used to characterize the main constituents of the dye extract. The photovoltaic characteristics of these dye extracts coated on TiO2 were investigated by employing them as DSSC photoanodes. With the dye extracted in ethanol and coated on TiO2, an open-circuit voltage (Voc) of 0.293 V, short-circuit photocurrent density (Jsc) of 0.790 mA/cm2, fill factor (FF) of 0.46, and conversion efficiency (g) of 0.13% were obtained, whereas dye extracted in the ethanol–water mixture revealed Voc of 0.285 V, Jsc of 0.735 mA/cm2, FF of 0.37, and g of 0.09%. The photovoltaic performance of the dye extracts in the two cases underlines the greater effectiveness of ethanol as dye extraction solvent.
关键词： natural dye,DSSC,rutin and zeaxanthin,Tecoma stans flower,TiO2,extraction solvent
更新于2025-09-23 15:21:01
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Novel report on structural, optical and electrical investigation into brucinium 4-methyl-3-nitrobenzoate 0.5 hydrate single crystal: a promising material for high-power laser, ultrahigh cooling, sensor and detector applications
摘要： A new brucinium 4-methyl-3-nitrobenzoate 0.5 hydrate (B4M3NB0.5H) NLO single crystal was harvested from saturated solution by solvent evaporation method. Crystal system and symmetric type of B4M3NB0.5H compound were analyzed by structure analysis. Linear optical parameters of title compound were discussed in detail by UV–visible analysis. Lifetime values of the molecule were quanti?ed by ?uorescence study, and it con?rms the good crystalline perfection of the grown crystal. The SHG ef?ciency is 5.11 times superior to the KDP material. By utilizing Nd:YAG laser as an input, SLDT measurement of the crystal was done. The grown crystal has good crystalline nature which is analyzed by HRXRD study. Dielectric behavior of B4M3NB0.5H crystal was discussed in detail. With the help of theoretical approach, few of the solid-state parameters were calculated and listed. Piezoelectric charge coef?cient and piezovoltage were calculated to be 4.5 p C/N and 0.0417 p V m/N, respectively. The TGA and DTA spectrum con?rms that the title compound is thermally stable up to 101 °C.
关键词： piezoelectric charge coefficient,brucinium 4-methyl-3-nitrobenzoate,fluorescence study,solvent evaporation method,SHG efficiency,HRXRD study,NLO single crystal,Nd:YAG laser,dielectric behavior,UV–visible analysis,TGA and DTA spectrum
更新于2025-09-23 15:21:01
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Thermionic Emission-Based Interconnecting Layer Featuring Solvent Resistance for Monolithic Tandem Solar Cells with Solution-Processed Perovskites
摘要： All-perovskite tandem cells have been considered a potential candidate for bringing the power conversion efficiency (PCE) beyond the Shockley– Queisser limit of single-junction device while retaining the advantages of earth-abundant materials and solution processability. However, a challenging issue with regard to realizing such solution-processed devices is the fulfillment of complex and coupled requirements of the interconnecting layer (ICL), including solvent resistance to protect underlying perovskite film, high electrical properties for carrier transport and recombination, and high optical transmission. In this work, a new thermionic emission–based ICL with enhanced solvent resistance features is demonstrated. Fundamentally, the thermionic emission plays a critical role in the electron transport process in the ICL, which is confirmed through both experimental and theoretical studies. Besides achieving high optical transmission and electrical properties, the new ICL chemically protects the underlying perovskite film by introducing a fluoride silane– incorporated polyethylenimine ethoxylated hybrid system that also passivates the surface defects to reduce electrical loss. The monolithic all-perovskite tandem cells demonstrate highest PCE of 17.9% (from current density–voltage scan) and the highest steady-state efficiency is 16.1% for a typical device. Consequently, this work contributes to not only understanding the fundamental mechanism of ICLs but also promotes robust and low-cost photovoltaics.
关键词： monolithic all-perovskite tandem solar cells,solvent resistance,interconnecting layer,thermionic emission,defect passivation
更新于2025-09-23 15:21:01
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Controlled crystallinity and morphologies of 2D Ruddlesden-Popper perovskite films grown without anti-solvent for solar cells
摘要： Two-dimensional (2D) Ruddlesden-Popper (RP) perovskite films have attracted considerable attention for the environmentally stable perovskite solar cells. However, there is a big space for improving the film crystallinity and its crystallographic orientation to enhance the efficiency of solar cells. In addition, the assistance of anti-solvent is commonly used to obtain a better crystallinity and orientation of 2D RP perovskite films. Nevertheless, the anti-solvent method produces a lot of volatile organic compounds toxic to human health and is challenging to control. Here, we prepared 2D RP perovskite (PEA)2(MA)4Pb5I16 (n = 5) films with the assistance of methylammonium chloride (MACl) additive via a simple one-step deposition method by avoiding anti-solvent treatment. The MACl additive is believed to induce the formation of an intermediate phase composed of perovskite crystals without annealing, which directly promotes the vertical alignment of 2D RP perovskite films on the substrate. The 2D RP films deposited on the mesoporous TiO2 electron transport layer showed high crystallinity and preferential vertical crystallographic orientation. The resulting devices exhibited a power conversion efficiency of 9.7%, much higher than that of the devices prepared without MACl (0.66%).
关键词： High efficiency,High crystallinity and preferential vertical orientation,Two-dimensional perovskite solar cells,No anti-solvent treatment,MACl additive
更新于2025-09-23 15:21:01