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Showing papers on "Crystallization published in 2022"


Journal ArticleDOI
TL;DR: In this paper , a multifunctional interfacial material, biguanide hydrochloride (BGCl), is introduced between tin oxide (SnO2 ) and perovskite to enhance electron extraction, as well as the crystal growth of the perovsite.
Abstract: Interfacial modification, which serves multiple roles, is vital for the fabrication of efficient and stable perovskite solar cells. Here, a multifunctional interfacial material, biguanide hydrochloride (BGCl), is introduced between tin oxide (SnO2 ) and perovskite to enhance electron extraction, as well as the crystal growth of the perovskite. The BGCl can chemically link to the SnO2 through Lewis coordination/electrostatic coupling and help to anchor the PbI2 . Better energetic alignment, reduced interfacial defects, and homogeneous perovskite crystallites are achieved, yielding an impressive certified power conversion efficiency (PCE) of 24.4%, with an open-circuit voltage of 1.19 V and a drastically improved fill factor of 82.4%. More importantly, the unencapsulated device maintains 95% of its initial PCE after aging for over 500 h at 20 °C and 30% relative humidity in ambient conditions. These results suggest that the incorporation of BGCl is a promising strategy to modify the interface and control the crystallization of the perovskite, toward the attainment of highly efficient and stable perovskite solar cells as well as other perovskite-based electronics.

137 citations


Journal ArticleDOI
01 Mar 2022-Joule
TL;DR: In this paper , a dual-functional additive consisting of organic ammonium cation and dithiocarbamate anion was developed to regulate the crystallization and defects of the FA-Cs perovskite film.

63 citations


Journal ArticleDOI
TL;DR: In this paper , the impact of adding MoO3 to the glasses on their shielding ability was investigated, and the lower value of the (MFP) sample has been detected at a higher MoO 3 concentration and it is good radiation attenuation glasses.
Abstract: The glass system 42.5P2O5–42.5B2O3–( $$15-x$$ ) Li2O– $$x$$ MoO3 $$x$$ = $$(0, 2.5,5.10 \;{\text{and}}\;15$$ ), was fabricated using a melt-quenching technique. Optical features are examined depending on measuring the absorption and transmission of the prepared glasses. The energy gap ( $$E_{{{\text{opt}}}}$$ ), increases from 2.23 to 2.49 e.V. Urbach ( $$E_{u}$$ ), decreases from 0.513 to 0.5 e.V. Basicity, polarizability, electronegativity, and some physical constants are determined. The temperature of the glass transition Tg, increases from 493 to 532 °C, the temperature of onset glass crystallization Tc increases from 493 to 532 °C and the temperature of the crystallization Tp increases from 606 to 636 °C. Radiation shielding properties have been examined by Phy-X / PSD. The impact of adding MoO3 to the glasses on their shielding ability was investigated. The lower value of the (MFP) sample has been detected at a higher MoO3 concentration and it is good radiation attenuation glasses. For radiation protection applications, the investigational glasses had superior characteristics.

59 citations


Journal ArticleDOI
TL;DR: A comprehensive review of polyvinyl alcohol (PVA) hydrogels prepared by the freezing/thawing (F-T) process is presented in this paper , where the authors discuss their preparation, gelation mechanisms, handling of physical/mechanical properties, physicochemical characteristics, and various applications.

59 citations


Journal ArticleDOI
TL;DR: In this paper , a low-temperature method for incorporating up to eight metallic elements into one single-phase sub-nanometer ribbon was proposed to achieve the thinnest HEA metal materials in the world.
Abstract: High-entropy alloys (HEAs) are attracting intensive attention due to their broad compositional tunability and interesting catalytic properties. However, precisely shaping the HEAs into suprathin low-dimensional nanostructures for achieving diverse applications remains an enormous challenge owing to their intrinsic thermodynamic instability. Herein we propose a new and general low-temperature method for incorporating up to eight metallic elements into one single-phase subnanometer ribbon to achieve the thinnest HEA metal materials in the world. We experimentally demonstrate that synthetic processes for suprathin HEA subnanometer ribbons (SNRs) include (1) different metal atom nucleation via galvanic exchange reaction between different metal precursors and Ag nanowire template, (2) co-reduction of different metal precursors on nanowire template, and (3) the removal of the inner Ag core. Density functional theory (DFT) calculations reveal that the crystallization and stabilization of HEA SNRs strongly depend on the "highly dynamic" Ag from the template, and the crystallization levels of HEA subnanometer ribbons are closely correlated with the concentration of Pt and Pd. We demonstrate that the present synthetic method enables the flexible control of components and concentrations in HEAs SNRs for achieving a library of HEA SNRs and also superior electrocatalytic properties. The well-designed HEA SNRs show great improvement in catalyzing the oxygen reduction reaction of fuel cells and also high discharge capacity, low charge overpotential, and excellent durability for Li-O2 batteries. DFT calculations reveal the superior electrochemical performances are attributed to the strong reduction capability from high-concentration reductive elements in HEAs, while the other elements guarantee the site-to-site efficient electron transfer.

51 citations


Journal ArticleDOI
TL;DR: In this paper , a simple and effective universal anion modification strategy to increase the photovoltaic performance of perovskite solar cells was implemented through incorporating a series of guanidinium salts containing different anions.

48 citations


Journal ArticleDOI
TL;DR: In this article , aerosol-assisted crystallization (AAC) was used to obtain phase-stable α-FAPbI3 p-i-n solar cells, which demonstrates increases of both power conversion efficiency and operational stability compared to devices fabricated using 150 °C annealed films.
Abstract: Formamidinium lead triiodide (FAPbI3 ) is attractive for photovoltaic devices due to its optimal bandgap at around 1.45 eV and improved thermal stability compared with methylammonium-based perovskites. Crystallization of phase-pure α-FAPbI3 conventionally requires high-temperature thermal annealing at 150 °C whilst the obtained α-FAPbI3 is metastable at room temperature. Here, aerosol-assisted crystallization (AAC) is reported, which converts yellow δ-FAPbI3 into black α-FAPbI3 at only 100 °C using precursor solutions containing only lead iodide and formamidinium iodide with no chemical additives. The obtained α-FAPbI3 exhibits remarkably enhanced stability compared to the 150 °C annealed counterparts, in combination with improvements in film crystallinity and photoluminescence yield. Using X-ray diffraction, X-ray scattering, and density functional theory simulation, it is identified that relaxation of residual tensile strains, achieved through the lower annealing temperature and post-crystallization crystal growth during AAC, is the key factor that facilitates the formation of phase-stable α-FAPbI3 . This overcomes the strain-induced lattice expansion that is known to cause the metastability of α-FAPbI3 . Accordingly, pure FAPbI3 p-i-n solar cells are reported, facilitated by the low-temperature (≤100 °C) AAC processing, which demonstrates increases of both power conversion efficiency and operational stability compared to devices fabricated using 150 °C annealed films.

47 citations



Journal ArticleDOI
TL;DR: In this paper , the degradation of halide perovskites upon water exposure has been intensively studied, resulting in chemical insights into key processes, including hydration, phase transformation, decomposition, and dissolution.
Abstract: Halide perovskites are considered to be next-generation semiconductor materials with bright prospects to advance the technology of photonics and optoelectronics. Because of the intrinsic ionic feature, the interactions between perovskites and water induce serious stability issues, which has been one of the fundamental problems hindering the practical application of perovskites. The degradation of halide perovskites upon water exposure has been intensively studied, resulting in chemical insights into key processes, including hydration, phase transformation, decomposition, and dissolution. In this Perspective, we try to illustrate what happens when halide perovskites meet with water. We summarize the research progress regarding the understanding of these processes and discuss the principle of strategy design toward improved stability against water. In addition to the instability-related interactions, we also discuss the aqueous solution of perovskite precursors for fabricating perovskite-based functional materials. Hopefully, this Perspective can inspire more fundamental studies on the interactions between perovskites and water, such as spectroscopy and simulation, crystal structure and material characterizations, and solution chemistry and crystallization.

44 citations


Journal ArticleDOI
TL;DR: In this article , a facile and effective ethyl alcohol cosolvent strategy is demonstrated with the incorporation of EtOH into perovskite ink for highperformance room-temperature blade-coated perovsite solar cells (PSCs) and modules.
Abstract: Manipulating the perovskite solidification process, including nucleation and crystal growth, plays a critical role in controlling film morphology and thus affects the resultant device performance. In this work, a facile and effective ethyl alcohol (EtOH) cosolvent strategy is demonstrated with the incorporation of EtOH into perovskite ink for high‐performance room‐temperature blade‐coated perovskite solar cells (PSCs) and modules. Systematic real‐time perovskite crystallization studies uncover the delicate perovskite structural evolutions and phase‐transition pathway. Time‐resolved X‐ray diffraction and density functional theory calculations both demonstrate that EtOH in the mixed‐solvent system significantly promotes the formation of an FA‐based precursor solvate (FA2PbBr4·DMSO) during the trace‐solvent‐assisted transition process, which finely regulates the balance between nucleation and crystal growth to guarantee high‐quality perovskite films. This strategy efficiently suppresses nonradiative recombination and improves efficiencies in both 1.54 (23.19%) and 1.60 eV (22.51%) perovskite systems, which represents one of the highest records for blade‐coated PSCs in both small‐area devices and minimodules. An excellent VOC deficit as low as 335 mV in the 1.54 eV perovskite system, coincident with the measured nonradiative recombination loss of only 77 mV, is achieved. More importantly, significantly enhanced device stability is another signature of this approach.

39 citations


Journal ArticleDOI
TL;DR: In this article , a model of boroxine 2D dynamic covalent polymer is characterized using in situ scanning tunnelling microscopy to reveal both qualitative and quantitative details of the nucleation-elongation processes in real time and under ambient conditions.
Abstract: The quality of crystalline two-dimensional (2D) polymers1-6 is intimately related to the elusive polymerization and crystallization processes. Understanding the mechanism of such processes at the (sub)molecular level is crucial to improve predictive synthesis and to tailor material properties for applications in catalysis7-10 and (opto)electronics11,12, among others13-18. We characterize a model boroxine 2D dynamic covalent polymer, by using in situ scanning tunnelling microscopy, to unveil both qualitative and quantitative details of the nucleation-elongation processes in real time and under ambient conditions. Sequential data analysis enables observation of the amorphous-to-crystalline transition, the time-dependent evolution of nuclei, the existence of 'non-classical' crystallization pathways and, importantly, the experimental determination of essential crystallization parameters with excellent accuracy, including critical nucleus size, nucleation rate and growth rate. The experimental data have been further rationalized by atomistic computer models, which, taken together, provide a detailed picture of the dynamic on-surface polymerization process. Furthermore, we show how 2D crystal growth can be affected by abnormal grain growth. This finding provides support for the use of abnormal grain growth (a typical phenomenon in metallic and ceramic systems) to convert a polycrystalline structure into a single crystal in organic and 2D material systems.


Journal ArticleDOI
TL;DR: In this article , Ge incorporation is found to be able to modify crystallization growth of CsPb1−xGexI3 films and reduce annealing temperature and treatment time by lowering C sPbI3 formation energy.
Abstract: Aiming at stable CsPbI3 perovskite solar cells, Ge incorporated for the first time into DMAPbI3‐based precursor systems. Ge incorporation is found to be able to modify crystallization growth of CsPb1−xGexI3 films and reduce annealing temperature and treatment time by lowering CsPbI3 formation energy. The champion power conversion efficiency (PCE) of 19.52% is achieved with a certified PCE of 18.8%, which is the highest performance of CsPbI3 PSCs with alien element‐doping. In addition, in situ formation of GeO2 can passivate the grain boundary and surface defects, thus significantly improving the moisture resistance of the perovskite film and related devices. Excellent operational stability is achieved with no PCE degradation over 3000 h at a fixed bias voltage of 0.85 V under continuous white LED (6500 K) illumination and a nitrogen atmosphere. This work demonstrates that Ge‐incorporation is a promising way to stabilize CsPbI3 perovskite solar cells by simultaneously improving perovskite crystallinity and passivating the grain boundary and interfacial defects.

Journal ArticleDOI
TL;DR: Recently, all-inorganic CsPbX3 perovskite solar cells have stimulated enormous research interests due to their numerous merits including superior thermal and light stability and become one of the most prominent research topics as mentioned in this paper .
Abstract: Recently, all-inorganic CsPbX3 perovskite solar cells have stimulated enormous research interests due to their numerous merits including superior thermal and light stability and become one of the most prominent research...

Journal ArticleDOI
TL;DR: In this article , the atomic-level structure of biomacromolecules-metal-organic frameworks (BMOFs) was identified using differential phase contrast-scanning transmission electron microscopy, cryo-electron microscopy and x-ray absorption fine structure techniques.
Abstract: Crystallization of biomacromolecules-metal-organic frameworks (BMOFs) allows for orderly assemble of symbiotic hybrids with desirable biological and chemical functions in one voxel. The structure-activity relationship of this symbiotic crystal, however, is still blurred. Here, we directly identify the atomic-level structure of BMOFs, using the integrated differential phase contrast-scanning transmission electron microscopy, cryo-electron microscopy and x-ray absorption fine structure techniques. We discover an obvious difference in the nanoarchitecture of BMOFs under different crystallization pathways that was previously not seen. In addition, we find the nanoarchitecture significantly affects the bioactivity of the BMOFs. This work gives an important insight into the structure-activity relationship of BMOFs synthesized in different scenarios, and may act as a guide to engineer next-generation materials with excellent biological and chemical functions.


Journal ArticleDOI
TL;DR: In this paper , the atomic-level structure of biomacromolecules-metal-organic frameworks (BMOFs) was identified using differential phase contrast-scanning transmission electron microscopy, cryo-electron microscopy and x-ray absorption fine structure techniques.
Abstract: Crystallization of biomacromolecules-metal-organic frameworks (BMOFs) allows for orderly assemble of symbiotic hybrids with desirable biological and chemical functions in one voxel. The structure-activity relationship of this symbiotic crystal, however, is still blurred. Here, we directly identify the atomic-level structure of BMOFs, using the integrated differential phase contrast-scanning transmission electron microscopy, cryo-electron microscopy and x-ray absorption fine structure techniques. We discover an obvious difference in the nanoarchitecture of BMOFs under different crystallization pathways that was previously not seen. In addition, we find the nanoarchitecture significantly affects the bioactivity of the BMOFs. This work gives an important insight into the structure-activity relationship of BMOFs synthesized in different scenarios, and may act as a guide to engineer next-generation materials with excellent biological and chemical functions.

Journal ArticleDOI
Yihui Wu, Qi Wang, Yuting Chen, Wu Qiu, Qiang Peng 
TL;DR: In this article , a new ammonium salt of 2-amidinopyrimidine hydrochloride (APC) was proposed to improve the performance of perovskite solar cells.
Abstract: The film quality of light absorber is the key factor that limits the efficiency and stability of perovskite solar cells (PSCs). Herein, a new ammonium salt of 2-amidinopyrimidine hydrochloride (APC)...


Journal ArticleDOI
TL;DR: In this paper , a zwitterion-functionalized tin(IV) oxide (SnO2) is introduced as the electron-transport layer (ETL) to induce the crystallization of high-quality black-phase FAPbI3.
Abstract: Black‐phase formamidinium lead iodide (FAPbI3) with narrow bandgap and high thermal stability has emerged as the most promising candidate for highly efficient and stable perovskite photovoltaics. In order to overcome the intrinsic difficulty of black‐phase crystallization and to eliminate the lead iodide (PbI2) residue, most sequential deposition methods of FAPbI3‐based perovskite will introduce external ions like methylammonium (MA+), cesium (Cs+), and bromide (Br–) ions to the perovskite structure. Here a zwitterion‐functionalized tin(IV) oxide (SnO2) is introduced as the electron‐transport layer (ETL) to induce the crystallization of high‐quality black‐phase FAPbI3. The SnO2 ETL treated with the zwitterion of formamidine sulfinic acid (FSA) can help rearrange the stack direction, orientation, and distribution of residual PbI2 in the perovskite layer, which reduces the side effect of the residual PbI2. Besides, the FSA functionalization also modifies SnO2 ETL to suppress deep‐level defects at the perovskite/SnO2 interface. As a result, the FSA–FAPbI3‐based perovskite solar cells (PSCs) exhibit an excellent power conversion efficiency of up to 24.1% with 1000 h long‐term operational stability. These findings provide a new interface engineering strategy on the sequential fabrication of black‐phase FAPbI3 PSCs with improved optoelectronic performance.

Journal ArticleDOI
TL;DR: In this paper , a downward homogenized crystallization strategy was proposed for suppressing the initial vertical halide phase separation during perovskite crystallization and reducing open-circuit voltage (Voc) loss.
Abstract: Mixed-halide perovskite has an irreplaceable role as wide-bandgap absorber in multi-junction tandem solar cells. However, large open-circuit voltage (Voc) loss due to non-uniform halide distribution and compromised device stability due to photo-induced halide segregation has significantly limited the applications. Here, it is introduced 4-(2-aminoethyl)-benzenesulfonyl fluoride hydrochloride (ABF) with multifunctional groups (sulfonyl, ammonium, and fluoride) to the mixed-halide precursor to demonstrate a downward homogenized crystallization strategy for suppressing the initial vertical halide phase separation during perovskite crystallization and reducing Voc loss. Furthermore, fluoride with strong electronegativity effectively fixes anions and cations, while sulfonyl and ammonium are used to passivate positive charged (halide vacancies) and negative charged (FA/MA vacancies) defects, respectively, thereby reducing the generation of ion vacancies that lead to subsequent photo-induced halide segregation. As a result, the 1.63 and 1.68 eV wide-bandgap perovskite solar cells with inverted structures exhibit the champion power conversion efficiency (PCE) of 21.76% and 20.11% with Voc of 1.18 and 1.21 V, respectively. Most importantly, the optimized devices without encapsulation preserve 86% of initial efficiency after 240 h of continuous illumination under AM 1.5G, showing excellent light stability. Thus, the homogenized crystallization strategy provides highly efficient performance and stability for future tandem solar cell applications.

Journal ArticleDOI
TL;DR: In this paper , the effect of moisture on perovskite crystallization was investigated and controllable moisture treatment for the intermediate perovsite can promote the mass transportation of organic salts, and help them enter the buried bottom of the films.
Abstract: Abstract Understanding the function of moisture on perovskite is challenging since the random environmental moisture strongly disturbs the perovskite structure. Here, we develop various N 2 -protected characterization techniques to comprehensively study the effect of moisture on the efficient cesium, methylammonium, and formamidinium triple-cation perovskite (Cs 0.05 FA 0.75 MA 0.20 )Pb(I 0.96 Br 0.04 ) 3 . In contrast to the secondary measurements, the established air-exposure-free techniques allow us directly monitor the influence of moisture during perovskite crystallization. We find a controllable moisture treatment for the intermediate perovskite can promote the mass transportation of organic salts, and help them enter the buried bottom of the films. This process accelerates the quasi-solid-solid reaction between organic salts and PbI 2 , enables a spatially homogeneous intermediate phase, and translates to high-quality perovskites with much-suppressed defects. Consequently, we obtain a champion device efficiency of approaching 24% with negligible hysteresis. The devices exhibit an average T 80 -lifetime of 852 h (maximum 1210 h) working at the maximum power point.

Journal ArticleDOI
TL;DR: In this article , the authors systematically analyzed the means to control the crystallization behavior of PLA, and summarized the effects of nucleating agents, cross-linking, grafting, and annealing processes on the crystallisation behavior and heat resistance of PLA.

Journal ArticleDOI
TL;DR: In this article , the authors investigated myofibrillar protein denaturation induced by pH changes during freeze-thaw (FT) cycles, and proposed an effective mitigation strategy.

Journal ArticleDOI
TL;DR: In this paper , a green antisolvent of ethyl acetate (EA) with acetylacetone (AA) additive is used to fine-tune perovskite crystallization and passivate defect.


Journal ArticleDOI
TL;DR: In this paper , the authors provide a summary and highlight the in situ studies of crystal nucleation and growth, with a particular emphasis on the state-of-the-art research progress since the year 2016, and include technological advances, atomic-scale observations, substrate-and temperature-dependent nucleation, and the progress achieved in the various materials: metals, alloys, metallic compounds, colloids, and proteins.
Abstract: Nucleation and growth are critical steps in crystallization, which plays an important role in determining crystal structure, size, morphology, and purity. Therefore, understanding the mechanisms of nucleation and growth is crucial to realize the controllable fabrication of crystalline products with desired and reproducible properties. Based on classical models, the initial crystal nucleus is formed by the spontaneous aggregation of ions, atoms, or molecules, and crystal growth is dependent on the monomer's diffusion and the surface reaction. Recently, numerous in situ investigations on crystallization dynamics have uncovered the existence of nonclassical mechanisms. This review provides a summary and highlights the in situ studies of crystal nucleation and growth, with a particular emphasis on the state-of-the-art research progress since the year 2016, and includes technological advances, atomic-scale observations, substrate- and temperature-dependent nucleation and growth, and the progress achieved in the various materials: metals, alloys, metallic compounds, colloids, and proteins. Finally, the forthcoming opportunities and challenges in this fascinating field are discussed.


Journal ArticleDOI
01 Mar 2022-iScience
TL;DR: In this paper , a strategy that promotes acceptor and donor to crystallize separately was proposed, and an interpenetrating network with high crystallinity and proper domain size was obtained, which boosted the power conversion efficiency to 7.59%.

Journal ArticleDOI
TL;DR: In this paper , the effects of the devitrification process on the microstructure evolution and corrosion resistance of arc-sprayed AlFeSi metallic glass coatings were explored.