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Pre-crystallisation applied in sequential deposition approaches to improve the photovoltaic performance of perovskite solar cells
摘要： The fabrication process for perovskite films is critical for their microstructure and photo-electrical properties. In this study, a pre-preparation step for perovskite crystal particles with a conventional two step spin-coating method was introduced for improving the quality of the prepared perovskite films. By adding CH3NH3I into the PbI2 precursor solution and performing anti-solvent extraction during the preparation process, a small amount of perovskite crystal particles was produced in the PbI2 layers. We demonstrated that the pre-preparation of perovskite crystal particles enhanced the grain size and coverage of the perovskite films due to modification of the surface morphology and crystallisation of the PbI2 layers. Furthermore, after optimisation, the crystal size in the perovskite films reached almost 3 μm, which tremendously enhanced the generation and transportation of photo-generated carriers in photo-voltaic devices. Under illumination, the fill factor (FF) and short circuit current density (Jsc) of the corresponding devices increased, and the photoelectric conversion efficiency (PCE) was enhanced from 11.7% to 17.5%. Further, the stability of the devices in dark humid air was improved. Our results demonstrate that pre-preparing the perovskite crystal particles is useful for the fabrication of high-quality perovskite films. This approach can also be applied to devices based on perovskite films with other compositions.
关键词： Solvent engineering,sequential,solar cells,Crystallization,perovskite,deposition
更新于2025-09-12 10:27:22
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4-Aminoethyl Pyridine as a Bifunctional Spacer Cation for Efficient and Stable 2D Ruddlesden-Popper Perovskite Solar Cells
摘要： Two-dimensional (2D) Ruddlesden?Popper (RP) perovskites are attractive due to their appealing environmental stability. We demonstrate herein a spacer cation, 4-aminoethyl pyridine (4-AEP), for preparation of 2D RP perovskite films. The 4-AEP can not only act as a spacer cation, but also coordinate with the Pb2+ ions in PbI2 with the nitrogen atom on the pyridine ring. High-quality 2D RP perovskite films can thus be formed as the coordination interaction retards the crystallization rate of the 2D RP perovskites. As a result, the solar cell employing the (4-AEP)2MAn?1PbnI3n+1 (n=5) 2D perovskite achieves a power conversion efficiency (PCE) of 11.68% with good air stability, which is much better than the phenylethylamine spacer cation at the same conditions (PCE = 7.95%). This work provides a new idea for designing novel spacer cations towards efficient and stable 2D RP perovskite solar cells.
关键词： Two-dimensional perovskite,pyridine,spacer cation,perovskite solar cells,crystallization regulation
更新于2025-09-12 10:27:22
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Acetate based Crystallization Kinetics Modulation of CsPbI2Br for Improved Photovoltaic Performance
摘要： Inorganic CsPbI2Br perovskite has emerged to be a promising candidate for photovoltaic materials, while developing additives engineering strategies to address the issues of defects induced crystalline phase transformation from photoactive perovskite phase to non-perovskite phase has been a challenge to achieve their outstanding optoelectronic properties and thermal stability. In this work, we demonstrate an effective acetate mediation strategy for significantly retarding the crystallization process and thus the phase transformation, which leads to much improved optoelectronic performance of the solar cells. It was demonstrated that the addition of acetate like Cobalt(II) acetate (Co(Ac)2) or zinc acetate (Zn(Ac)2) could lead to significantly retarded crystallization process of perovskite films, as well as the formation of the flat, dense and defect-less perovskite film. We propose that the perovskite crystal grows up following the ostwald ripening mechanism at 270 ℃ annealing temperature, during which the acetate in the perovskite film would be squeezed from boundaries by grains growing cause the acetate cannot through the crystalline. Based on the proposed strategy of crystallization kinetics modulation with acetate, the photon conversion efficiency (PCE) of champion device with that acetate modified perovskite film can reach as high as 15.04%, and superb fill factor of 80.46%. We thus believe that our work could provide an effective alternative for the designing of high performance inorganic CsPbI2Br perovskite solar cells.
关键词： Acetate,CsPbI2Br,All-inorganic perovskite solar cell,Photo-conversion efficiency,Crystallization kinetics
更新于2025-09-12 10:27:22
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Large-Scale Growth of Ultrathin Low-Dimensional Perovskite Nanosheets for High-Detectivity Photodetectors
摘要： Low-dimensional organic-inorganic hybrid perovskites have demonstrated to be promising semiconductor materials due to their unique optoelectronic properties, however, the controllable growth of high-quality ultrathin 2D perovskites with large lateral dimension still faces great challenges. Herein, we report the controllable growth of large-scale ultrathin 2D (C6H5(CH2)3NH3)3Pb2I7 ((PPA)3Pb2I7) perovskite nanosheets (NSs) using a facile antisolvent-assisted crystallization approach under mild condition. As a result, the well-defined regular-shaped (PPA)3Pb2I7 NSs, with the largest lateral size over 100 micrometers, have been successfully synthesized, which is more than several ten times larger than that of other 2D perovskites NSs previously reported. Moreover, the thickness of the achieved 2D perovskite NSs can be well-tuned by altering the concentration of the precursor solution, with the smallest thickness down to ~4.7 nm. More importantly, the photodetectors based on the high-quality (PPA)3Pb2I7 perovskites exhibit fascinating performance, including an extremely low dark current (~1.5 pA), fast response/recovery rate (~850/780 μs) and high detectivity (~1.2×1010 Jones). This work provides a simple and promising strategy to controllably grow large-scale and ultrathin 2D perovskite NSs for low-cost and high-performance optoelectronic devices.
关键词： low-dimensional perovskite,antisolvent-assisted crystallization approach,large size,photodetectors,ultrathin,nanosheets
更新于2025-09-12 10:27:22
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Effect of annealing temperature on silicon-based MoS <sub/>x</sub> thin film solar cells
摘要： A suitable annealing temperature was found by adopting the sol–gel method to prepare silicon-based molybdenum sulfide film heterojunction solar cells. As shown by the results, a change in the efficiency of the solar cells, which was attributed to the fact that as the annealing temperature rises, the degree of crystallization of the film increases continuously, the degree of order of the crystal particles goes up first and then goes down, and the temperature change affects the proportion of Mo in different valence states. By comparison, it was found that when the temperature reached 500 °C, the degree of order of the film was raised and the film was in the initial zone from the amorphous to the microcrystal phase change and the proportion of Mo 6+ was relatively large, increasing the conversion efficiency of the device power to 7.55% and laying a good basis for preparing high-performance solar batteries made in the two-dimensional materials. When the annealing temperature continues to rise, the intergranular defects increase, and the overall degree of order of the film decreases. Furthermore, the highly crystalline thin films and the improvement in the device efficiency can be controlled if we obtained the relationship between the annealing temperature and the layers of the two-dimensional materials.
关键词： annealing temperature,solar cells,crystallization,sol–gel method,silicon-based MoSx thin film
更新于2025-09-12 10:27:22
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High-performance p-channel thin-film transistors with lightly doped n-type excimer-laser-crystallized germanium films
摘要： High-performance polycrystalline-germanium (poly-Ge) thin-film transistors (TFTs) fabricated with lightly doped Ge thin films by excimer laser crystallization (ELC) and counter doping (CD) have been demonstrated. High-quality n-type Ge thin films with a grain size as large as 1 μm were fabricated by ELC in the super lateral-growth regime and CD at a dose of 1 × 1013 cm?2 or higher. Consequently, a superior field-effect mobility of 271 cm2 V?1 s?1 and a high on/off current ratio of 2.7 × 103 have been obtained for p-channel Ge TFTs with the channel width and length of both 0.5 μm fabricated by ELC at 300 mJ/cm2 and CD at a dose of 1 × 1013 cm?2. The effects of ELC conditions and CD dose on the electrical characteristics of p-channel Ge TFTs were also investigated.
关键词： field-effect mobility,excimer laser crystallization,thin-film transistors,polycrystalline-germanium,counter doping
更新于2025-09-11 14:15:04
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Modulating Crystallization in Semitransparent Perovskite Films Using Submicrometer Spongelike Polymer Colloid Particles to Improve Solar Cell Performance
摘要： Semitransparent perovskite solar cells (PSCs) have excellent potential for solar window applications. A major challenge exists, however, in achieving uniform coverage for thin perovskite films. Unfortunately, uncontrolled pinhole formation is a common problem for such films that obstructs development, especially for large area devices. In this study, we used very small (submicrometer) swellable polymer colloid particles (microgels) as additives to prepare uniform thin CH3NH3PbI3 (MAPI) perovskite films. Microgels (MGs) are good film-formers and promoted formation of semitransparent (ST) perovskite films with improved coverage. The MGs act as colloidal sponges and delayed release of perovskite precursors, thereby delaying perovskite crystallization. The ST films prepared using MGs had fewer pinholes compared to the MG-free control films. X-ray photoelectron spectroscopy showed evidence of Pb coordination by the MGs and they were shown to passivate MAPI. Remarkably, the submicrometer MGs used in this study decreased light scattering for the ST films. Planar devices constructed using a 10 nm ST film with an average visible transmittance of 46.8% gave an average power conversion efficiency (PCE) of 7.69%, which compares favorably to literature values. The average PCE increased to 9.62% upon inclusion of a thin meso-TiO2 layer. These PCE values are significantly higher than that achieved for the MG-free ST control (4.93%). The MGs and approaches used here are scalable and should apply to other ST perovskite films, solar cells, and, potentially, tandem devices.
关键词： Perovskite solar cell,semitransparent,crystallization,average visible transmittance,microgel
更新于2025-09-11 14:15:04
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Structure, crystallization, and dielectric properties of the Al <sub/>2</sub> O <sub/>3</sub> filled CaO–B <sub/>2</sub> O <sub/>3</sub> –SiO <sub/>2</sub> –Al <sub/>2</sub> O <sub/>3</sub> glass composites for LTCC applications
摘要： The glass structures and crystallization behaviors of CaO–B2O3–SiO2 (C1) and CaO–B2O3–SiO2–Al2O3 (C1A03) glasses are investigated. The addition of Al3+ into CaO–B2O3–SiO2 glass acts as a glass former and bonds with the silicon tetrahedron with non-bridged oxygen to form Si–O–Al–O–Si, which increases the Q4 structural unit. The relative dielectric constants for C1 and C1A03 glass systems were all about 7.8–8.4. Compared to the C1 glass, the size and amount of pores decreased for the C1A03, leading to a higher dielectric constant. The C1A03 glass system exhibits better Qxf value than the C1 system due to the decrease in the size and amount of pores. The Qxf value roughly decreased with increasing glass addition for the densified samples. The C1A03 glasses with 50 wt% alumina exhibited the highest dielectric constant (8.4) and Qxf value (3150 GHz) due the maximum densification and highest amount of anorthite were obtained.
关键词： crystallization,dielectric properties,CaO–B2O3–SiO2–Al2O3 glass,LTCC,Al2O3
更新于2025-09-11 14:15:04
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Van der Waals Integration of Bismuth Quantum Dots–Decorated Tellurium Nanotubes (Te@Bi) Heterojunctions and Plasma‐Enhanced Optoelectronic Applications
摘要： Crystallization is relevant to many disciplines, and the control of crystallization of molecules is of importance to a great range of technological applications. It has been well established that a variety of surfaces can serve as possible nucleation sites for heterogeneous crystallization. However, it is still unknown what features of such system may be crucial and whether just a single molecule might serve as a nucleation site for crystallization. Therefore, to probe this question, we have investigated the nucleation of a prototypical multicomponent crystal, clathrate hydrates. As multicomponent crystalline compounds, clathrate hydrates have drawn considerable attention because of their scientific and industrial importance. Clathrate hydrates can occur in several possible structures, where the size of guest molecules and their ability to fit into water cages is a crucial factor. Despite the fact that in most applications, for example in oil?gas pipelines, clathrate hydrates form from gas mixtures that feature a variety of sizes of guest molecules, the possible roles of these species in hydrate formation has remained essentially unexplored. Herein, we investigate the impact of the presence of 2,2-dimethylbutane (DMB) on the nucleation of methane hydrate. Our simulation results provide clear evidence that DMB can serve as a nucleation site and can promote the formation of methane hydrates. The low mobility of the DMB molecule, and the longer residence time and hydrate-like structure of water molecules in its hydration shell appear as important contributors to its behavior. These results demonstrate that the presence of a somewhat larger hydrocarbon in low concentration can significantly impact hydrate nucleation and hence have immediate impact in, for example, flow assurance in oil?gas pipelines. More generally, the results presented herein indicate that single molecules in an otherwise homogeneous solution can promote crystal nucleation by stabilizing early stage structural fluctuations in the liquid.
关键词： crystallization,clathrate hydrates,molecular dynamics simulations,methane hydrate,2,2-dimethylbutane,nucleation
更新于2025-09-11 14:15:04
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Room temperature synthesis of CsPbX3 (X?= Cl, Br, I) perovskite quantum dots by water-induced surface crystallization of glass
摘要： Currently, the mainstream method for preparing perovskite quantum dots in glass is a heat treatment method. Here, a new method for the preparation of CsPbX3 (X ? Cl, Br, I) quantum dots (QDs) by water-induced surface crystallization in tin ?uorophosphates glass has been developed. A plausible water-induced surface crystallization mechanism has been proposed, revealing that water can reduce the non-uniform nucleation barrier to induce crystallization. Through changing the ratio of Cl/Br/I halogen elements in the raw material, a whole-family of CsPbX3 QDs in tin ?uorophosphate glass can be obtained, covering the entire visible band from 414 nm to 713 nm. Besides, the proposed material technology may exert a vital role in the ?eld of anti-counterfeiting technology shortly.
关键词： Surface crystallization,Glass,Water-induced,CsPbX3
更新于2025-09-11 14:15:04