- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Controlling Homogenous Spherulitic Crystallization for High‐Efficiency Planar Perovskite Solar Cells Fabricated under Ambient High‐Humidity Conditions
摘要： The influence of precursor solution properties, fabrication environment, and antisolvent properties on the microstructural evolution of perovskite films is reported. First, the impact of fabrication environment on the morphology of methyl ammonium lead iodide (MAPbI3) perovskite films with various Lewis-base additives is reported. Second, the influence of antisolvent properties on perovskite film microstructure is investigated using antisolvents ranging from nonpolar heptane to highly polar water. This study shows an ambient environment that accelerates crystal growth at the expense of nucleation and introduces anisotropies in crystal morphology. The use of antisolvents enhances nucleation but also influences ambient moisture interaction with the precursor solution, resulting in different crystal morphology (shape, size, dispersity) in different antisolvents. Crystal morphology, in turn, dictates film quality. A homogenous spherulitic crystallization results in pinhole-free films with similar microstructure irrespective of processing environment. This study further demonstrates propyl acetate, an environmentally benign antisolvent, which can induce spherulitic crystallization under ambient environment (52% relative humidity, 25 °C). With this, planar perovskite solar cells with ≈17.78% stabilized power conversion efficiency are achieved. Finally, a simple precipitation test and in situ crystallization imaging under an optical microscope that can enable a facile a priori screening of antisolvents is shown.
关键词： perovskite,spherulite,planar,crystallization,ambient
更新于2025-09-19 17:13:59
-
Controlled nanoa??crystallization of IR frequencya??doubling Cd <sub/>4</sub> GeS <sub/>6</sub> crystal in chalcogenide glass
摘要： Crystallization of IR frequency-doubling nanocrystals in chalcogenide glasses is a promising approach to achieve novel nonlinear optical materials. However, controllable glass crystallization remains challenging. In this study, IR-transparent chalcogenide glass-ceramics containing novel Cd4GeS6 IR frequency-doubling na- nocrystals (about 60-80?nm) are fabricated through controlled nano-crystallization. Nanocrystalline structure of the Cd4GeS6 nano-crystallized glass-ceramics is inves- tigated in detail through X-ray diffractometer, field emission scanning electron mi- croscope, and Raman scattering techniques. The structural similarity of [Cd4GeS6] polyhedron in the network structure of as-prepared glass is found to be responsible for the nucleation of Cd4GeS6 crystal. A unique microstructure of Cd4GeS6 nanocrys- tals embedded GeS2 phase-separated structure is discovered in samples thermally treated at high temperatures (370°C and 380°C). This study would not only shed more light on glass crystallization mechanism but also provide a feasible approach for the design and fabrication of new IR frequency-doubling materials through glass crystallization.
关键词： Cd4GeS6,microstructure,glass-ceramics,chalcogenide glasses,crystallization
更新于2025-09-19 17:13:59
-
Evolving Crystal Morphology of Potassium Chloride Controlled by Optical Trapping
摘要： Dynamic morphology evolution of potassium chloride (KCl) crystal was demonstrated by surface optical trapping with a focused continuous-wave near-infrared laser. Optical trapping at an air/solution interface triggered the crystallization, and then the dynamic change in crystal morphology was observed in real time. We observed three different crystal morphologies of needle, rectangle, and cubic at the early stage of crystallization. As the laser power increases, the probability of generation of a cubic crystal increases, especially upon the irradiation with linear polarization. We also found laser-polarization-dependent morphology evolution by the continuous irradiation to the generated crystals. Upon linearly-polarized laser irradiation, the stepwise morphology evolutions from needle, rectangle, and eventually to cubic, which is an equilibrium shape of KCl crystal. While, circularly-polarized laser irradiation only induced morphology evolution from needle to rectangle, without morphology change into cubic, because the rectangle crystal was dissolved while crystal rotating. It was made possible to observe such a unique morphological evolution due to the spatiotemporal controllability of our crystallization method. The dynamics and mechanism of these intriguing phenomena are discussed from the perspective of a dense cluster domain formed by optical trapping before nucleation.
关键词： laser polarization,potassium chloride,crystal morphology,optical trapping,surface crystallization
更新于2025-09-19 17:13:59
-
Iodine-assisted Antisolvent Engineering for Stable Perovskite Solar Cells with Efficiency >21.3 %
摘要： The quality of the photoactive film is a significant factor in determining the power conversion efficiency (PCE) and the stability of perovskite solar cells (PSCs). We report a simple upgraded antisolvent washing treatment using iodine modulation, which significantly improves the MAPbI3 films with high crystallinity and chemical uniformity. A detailed model for improving the mechanism is proposed to describe how the upgraded antisolvent enhances both the perovskite crystallization and passivates the under-coordinated Pb2+ dangling bond. PSCs fabricated with the FTO/TiO2/MAPbI3/Spiro-OMeTAD/Ag architecture used high quality films with less defective surfaces, present a PCE of 21.33 %, retaining 91 % of its initial value in ambient without any encapsulation after 30 days. These results provide insight into the surface defect passivation process achieved by halide ions balance while providing a simple and efficient process that can be extensively used to fabricate high-quality perovskite films.
关键词： power conversion efficiency,defect passivation,perovskite solar cells,antisolvent engineering,crystallization
更新于2025-09-19 17:13:59
-
Synthesis of Lithography Free Micro-Nano Electron Field Emitters Using Pulsed KrF Laser Assisted Metal Induced Crystallization of Thin Silicon Films
摘要： Hydrogenated amorphous thin silicon films (a-Si:H) deposited on metal coated glass substrates were investigated to analyze the effect of a novel processing technique called Laser Assisted Metal Induced Crystallization (LAMIC) on their electron field emission (FE) properties. Post-surface characterization of the processed films showed increased surface roughness and the presence of uniformly spaced “island-like” micro-nano structures on the surface of metal coated backplane samples. Best FE results were obtained from samples sputtered with a thin layer of Aluminum (Al) on top and cross laser annealed at 190 mJ/cm2 (y-axis) and 100 mJ/cm2 (x-axis). FE measurements indicate a low turn-on electric field of less than 16 V/mm with emission currents in the order of 10?6 A. FE results were found to be particularly dependent on the laser fluence and the surface morphology exhibited very high discharge resistance. Oxidation of the films was observed to deteriorate their FE characteristics, thereby increasing the emission threshold to 36 V/mm. Diode configured field emission display prototypes are fabricated to exemplify their potential as cold cathode emitters.
关键词： excimer laser crystallization,electron field emission,metal induced crystallization,micro-nano emitters,Hydrogenated amorphous silicon
更新于2025-09-16 10:30:52
-
Rapid Layer‐Specific Annealing Enabled by Ultraviolet LED with Estimation of Crystallization Energy for High‐Performance Perovskite Solar Cells
摘要： A rapid layer-specific annealing on perovskite active layer enabled by ultraviolet (UV) light-emitting diode (LED) is demonstrated and efficiency close to 19% is achieved in a simple planar inverted structure ITO/PEDOT:PSS/MAPbI3/PC71BM/Al without any device engineering. These results demonstrate that if the UV dosage is well managed, UV light is capable of annealing perovskite into high-quality film rather than simply damaging it. Different in principle from other photonic treatment techniques that can heat up and damage underlying films, the UV-LED-annealing method enables layer-specific annealing because LED light source is able to provide a specific UV wavelength for maximum light absorption of target film. Moreover, the layer-specific photonic treatment allows accurate estimation of the crystallization energy required to form perovskite film at device quality level.
关键词： UV LED,crystallization energy,perovskites,layer-specific annealing,solar cells
更新于2025-09-16 10:30:52
-
Glass (Selected Properties and Crystallization) || 9. Crystallization of Undercooled Liquids: Results of Molecular Dynamics Simulations
摘要： The present contribution is devoted to molecular dynamics (MD) simulations modeling of the kinetics of spontaneous crystal nucleation in under-cooled one-component Lennard-Jones liquids and detailed comparison with the basic assumptions and results of classical nucleation theory (CNT). In the MD-computations the following spectrum of properties of the respective nucleating systems under consideration is determined: nucleation rate, J, diffusion coefficient of the crystal clusters in cluster size space, D, non-equilibrium Zeldovich factor, Z, size of the critical crystal nucleus, n?, pressure inside the critical crystal nucleus, p?. Based on these data, the interfacial energy density of the critical crystal nucleus is determined. Simultaneously, the interfacial energy density is computed by molecular dynamics methods for the planar interface liquid-crystal. It is found that for typical sizes of the critical nuclei in the range of 0.7–1.0 nm the value of the effective specific interfacial energy differs from that of the planar interface by less than 15 %. A comparison of the molecular dynamics results with the classical nucleation theory shows that for the considered case of crystallization of one-component liquids MD simulation results are in good agreement with the classical nucleation theory not only with respect to the final result, the nucleation frequency, but also with respect to the parameters D, Z, n?. Consequently, the results of molecular dynamics simulations of crystallization in one-component liquids demonstrate the validity of the basic assumptions and the final results of CNT for this particular case of phase formation.
关键词： molecular dynamics simulations,nucleation rate,critical crystal nucleus,Lennard-Jones liquids,classical nucleation theory,interfacial energy density,crystallization,undercooled liquids
更新于2025-09-16 10:30:52
-
Crystallization tailoring of cesium/formamidinium double-cation perovskite for efficient and highly stable solar cells
摘要： Achieving high-quality perovskite crystal films is a critical prerequisite in boosting solar cell efficiency and improving the device stability, but the delicate control of nucleation and growth of the perovskite film remains limited success. Herein, a facile but effective strategy has been developed to finely tailor the crystallization of thermally stable cesium/formamidinium (Cs/FA) based perovskite via partially replacing PbI2 with PbCl2 in the precursor solution. The incorporation of chlorine into the perovskite crystal lattice derived from PbCl2 changes the crystallization process and improves the crystal quality, which further results in the formation of larger crystal grains compared to the control sample. The larger crystal grains with high crystallinity lead to reduced grain boundaries, suppressed non-radiative recombination, and enhanced photoluminescence lifetimes. Under the optimized conditions, the methylammonium free perovskite solar cells (PSCs) delivers a champion power conversion efficiency (PCE) of 21.30% with an open-circuit voltage as high as 1.18 V, which is one of the highest efficiencies for Cs/FA based PSCs up to now. Importantly, the unencapsulated PSC devices retain more than 95% and 81% of their original PCEs even after (over one year) storage under ambient conditions or 2000 h’s thermal aging at 85 oC in a nitrogen atmosphere, respectively.
关键词： Stability,Perovskite solar cells,Crystal quality,Crystallization tailoring
更新于2025-09-16 10:30:52
-
Chiral Reduced-Dimensional Perovskite for Efficient Flexible Circularly Polarized Light Photodetector
摘要： Advancements in exploring new chiral perovskites are highly demanded to improve the circular polarized light (CPL) detection efficiency to date. Reduced-dimensional (quasi-2D) perovskites thus emerged as the most promising candidates due to its appealing characteristics. We herein reported new chiral quasi-2D perovskite single crystals (SCs) synthesis, and investigate their CPL detecting capability for the first time. We proved quasi-2D chiral perovskites, [(R)-β-MPA]2MAPb2I7 ((R)-β-MPA = (R)-(+)-β-methylphenethylamine, MA = methylammonium), do possess intrinsic chirality and have the capability to distinguish different polarization states of CPL photons. Corresponding quasi-2D perovskite SCs CPL photodetector exhibit excellent detection performance. In particular, our device responsivity is almost one order of magnitude higher than the best reported 2D perovskite CPL detectors to date. On this basis, we carefully modulate the film’s crystallization dynamics to facilitate its carrier transport. We prove that parallelly oriented perovskite films with homogeneous energy landscape are crucial to maximize the device’s carrier collection efficiency. The obtained responsivity and linear dynamic range (LDR) of this flexible chiral quasi-2D perovskite thin-film photodetector are comparable with the best reported results to date. The photodetector also exhibits superior mechanical flexibility and durability, representing one of the most sensitive and robust CPL photodetector to date.
关键词： circular polarized light,photodetector,reduced-dimensional perovskites,chiral perovskite,crystallization dynamics
更新于2025-09-16 10:30:52
-
Regulated Crystallization of Efficient and Stable Tin-based Perovskite Solar Cells via Self-sealing Polymer
摘要： Tin-based perovskite solar cells (PVSCs) have emerged as the most promising lead-free perovskite materials owing to their superior optoelectronic properties. However, the deficiency of accurate control for the tin-based perovskite crystallization process increases the possibility of unexpected perovskite film morphology and defects, resulting in inferior power conversion efficiency (PCE). Meanwhile, the poor environmental stability of tin-based perovskite film hinders its further development. In this work, a unique polymer [poly(ethylene-co-vinyl acetate) (EVA)] is introduced into anti-solvent during spin coating of formamidinium tin tri-iodide (FASnI3) precursor solution. The C=O groups contained in EVA have a powerful Lewis acid-base complexation with uncoordinated tin atoms in perovskite grains, which can greatly improve grain size, optimize grain orientation and decrease surface defects of FASnI3 films. This strategy offers an impressive PCE of 7.72% with favorable reproducibility. More importantly, the PVSCs devices based on FASnI3-EVA absorber have a self-encapsulation effect, which exhibits distinguished moisture and oxygen barrier property, thereby retaining 62.4% of the original efficiency value after aging for 48 h in air environment with humidity of 60%. Such convenient strategy provides a new inspiration for the establishment of stable and high performance tin-based PVSCs.
关键词： environmental stability,self-encapsulation,poly(ethylene-co-vinyl acetate),crystallization,tin-based perovskite solar cells
更新于2025-09-16 10:30:52