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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
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Highly Efficient CsPbBr3 Planar Perovskite Solar Cells via Additive Engineering with NH4SCN
摘要： Improving stability is a major aspect of the commercial application of perovskite solar cells (PSCs). The all inorganic CsPbBr3 perovskite material has been proven to have excellent stability. However, the CsPbBr3 film has a small range of light absorption and a serious charge recombination at the interface or inside the device, so that the power conversion efficiency is still lower than that of the organic-inorganic hybrid one. Here, we successfully fabricate high quality CsPbBr3 film via additive engineering with NH4SCN. By incorporating NH4+ and pseudo-halide ion SCN? into precursor solution, a smooth and dense CsPbBr3 film with good crystallinity and low trap state density can be obtained. At the same time, the results of a series of photoluminescence and electrochemical analyses including electrical impedance spectroscopy, space-charge limited current method, Mott-Schottky data, and so on, reveal that the NH4SCN additive can greatly reduce trap state density of the CsPbBr3 film, and also effectively inhibit interface recombination and promote charge transport in the CsPbBr3 planar PSC. Finally, the CsPbBr3 planar PSC prepared with molar ratio of 1.5 % NH4SCN achieves a champion efficiency of 8.47 %, higher than the pure one (7.12 %).
关键词： Additive engineer,Planar perovskite solar cells,CsPbBr3,Photovoltaic performance,NH4SCN
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting - Atlanta, GA, USA (2019.7.7-2019.7.12)] 2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting - Empty Substrate Integrated Waveguide Planar Slot Antenna Array for 5G Wireless Systems
摘要： This paper introduces a planar 4 × 4 slot antenna array based on Empty Substrate Integrated Waveguide at 28 GHz. The proposed antenna offers reduced weight and fabrication cost as well as relatively feasible integration with planar electronic components. The proposed antenna suggests an operating bandwidth of 7.8% (i.e. 27.1-29.3 GHz) suitable to fulfill demands of 5th Generation (5G) networks with high gain performance of 17.2 dBi and with reduced sidelobes level in the H-plan.
关键词： antenna,millimeter-wave,5G,planar,array
更新于2025-09-16 10:30:52
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Circularly Polarized T-Shaped Slot Waveguide Array Antenna for Satellite Communications
摘要： A novel circularly polarized (CP) waveguide slot array for satellite communications is proposed. The antenna features a unique feeding network and a unit cell that consists of a pair of simple T-shaped waveguide slots. The proposed configuration not only eliminates grating lobes, which are often seen in conventional waveguide slot arrays, but also simplifies the fabrication process without any sacrifice in the performance, while also allowing scalability. A prototype 6×8 array antenna is designed at 29.5 GHz, and fabricated by dip brazing. A high gain of 21.9 dBi and a -10 dB impedance bandwidth of 1 GHz are achieved, with an axial ratio of 1.3 dB without any grating lobes. The measured results are in very good agreement with the simulated results.
关键词： circular polarization,antenna arrays,Slot antennas,waveguide antennas,planar arrays
更新于2025-09-16 10:30:52
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Performance data of CH3NH3PbI3 Inverted Planar Perovskite Solar Cells via Ammonium Halide Additives
摘要： The data provided in this data set is the study of organic-inorganic hybrid perovskite solar cells fabricated through incorporating the small amounts of ammonium halide NH4X (X=F, Cl, Br, I) additives into a CH3NH3PbI3 (MAPbI3) perovskite solution and is published as “High-Performance CH3NH3PbI3 Inverted Planar Perovskite Solar Cells via Ammonium Halide Additives”, available in Journal of Industrial and Engineering Chemistry [1]. A compact and uniform perovskite absorber layer with large perovskite crystalline grains, is realized by simply incorporating small amounts of additives into precursor solutions, and utilizing the anti-solvent engineering technique to control the nucleation and growth of perovskite crystal, turning out the enhanced device efficiency (NH4F: 14.88 ± 0.33 %, NH4Cl: 16.63 ± 0.21 %, NH4Br: 16.64 ± 0.35 %, and NH4I: 17.28 ± 0.15 %) compared to that of a reference MAPbI3 device (Ref.: 12.95 ± 0.48 %). In addition, this simple technique of ammonium halide addition to precursor solutions increase the device reproducibility as well as long term stability.
关键词： perovskite grain size,inverted planar structure,CH3NH3PbI3 perovskite,ammonium halide additives,anti-solvent engineering
更新于2025-09-16 10:30:52
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Synergic effect of Zinc (Zn) precursors on the microstructural, optical and electrical properties of Zinc oxide thin films for solar cell applications
摘要： Zinc oxide (ZnO) nanoparticles, with their inimitable characteristics such as easy synthesis, high selectivity and enhanced cytotoxicity are becoming progressively important candidate in modern applications. In this study, we have systematically investigated the effect of fabrication conditions on the morphological, structural, optical and electrical properties of zinc oxide (ZnO) thin films. It was observed that the change in Zn-precursor leads to the growth of grains structure observed with the change in the Zn precursor medium. The presence of ZnO hexagonal structure wurtzite was confirmed with the help of non-destructive X-ray Diffraction (XRD) analysis. Scanning Electron Microscopy (SEM) showed that the islands of nano-grains started to nucleate into highly stressed, uniform and roughly compact morphology of the ZnO grains structures of the crack-free thin films. The as-fabricated ZnO thin films comprised of micro and nanoparticles grains structures. The electrical properties measurement revealed the decrease in the average resistivity with the change in Zn-precursor solution of the as-fabricated ZnO thin films. The UV–Vis. Spectroscopy showed the optical absorption spectra of the ZnO thin films have maximum transmittance in the visible region i.e. 80%. Such kind of films characteristics are very important for solar spectra. It was observed that the change in Zn precursor solution has impact on the transmittance properties of the ZnO thin films. This study highlights an environment friendly, low cost and facile roots for the fabrication of ZnO thin films for probable use in solar cells applications.
关键词： Spray pyrolysis,grain structure,ZnO,planar architecture
更新于2025-09-16 10:30:52
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Rapid screening and quantification of multi-class antibiotic pollutants in water using a planar waveguide immunosensor
摘要： Rapid screening and quantification of multi-class antibiotic pollutants in water using a planar waveguide immunosensor
关键词： immunosensor,antibiotics,planar waveguide,detection,water
更新于2025-09-16 10:30:52
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Fast objective coupled planar illumination microscopy
摘要： Among optical imaging techniques light sheet fluorescence microscopy is one of the most attractive for capturing high-speed biological dynamics unfolding in three dimensions. The technique is potentially millions of times faster than point-scanning techniques such as two-photon microscopy. However light sheet microscopes are limited by volume scanning rate and/or camera speed. We present speed-optimized Objective Coupled Planar Illumination (OCPI) microscopy, a fast light sheet technique that avoids compromising image quality or photon efficiency. Our fast scan system supports 40 Hz imaging of 700 μm-thick volumes if camera speed is sufficient. We also address the camera speed limitation by introducing Distributed Planar Imaging (DPI), a scaleable technique that parallelizes image acquisition across cameras. Finally, we demonstrate fast calcium imaging of the larval zebrafish brain and find a heartbeat-induced artifact, removable when the imaging rate exceeds 15 Hz. These advances extend the reach of fluorescence microscopy for monitoring fast processes in large volumes.
关键词： Distributed Planar Imaging,calcium imaging,light sheet fluorescence microscopy,zebrafish brain,OCPI microscopy
更新于2025-09-16 10:30:52
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Flat concentrator photovoltaic system for automotive applications
摘要： In this paper, we present a novel design and an optical simulation of a ?at concentrator photovoltaic (CPV) system for electric vehicle application. The sunlight concentration component is comprised of a planar waveguide integrated dichroic mirror-coated cone prisms and a mirror-coated lens array. Sunlight re?ects ?rstly at the mirror-coated lens array and then strikes the cone prism of the planar waveguide. The prisms are coated by the dichroic mirrors to divide the solar spectrum into two bands. The low-energy band is transmitted and reaches the GaInAsP/GaInAs dual-junction solar cells. The mid-energy band is re?ected at the prism surface and coupled inside the waveguide. The exit port of the waveguide is attached with GaInP/GaAs dual-junction solar cells. The simulation results demonstrated a maximum electricity conversion e?ciency of 32.88% at the high con- centration ratio. The system thickness is 35 mm, which is as thin as the conventional ?at photovoltaic panel and system allow for a lateral sun-tracking mechanism. This is suitable for installation on the vehicle's roof. The results showed that the presented ?at CPV system is a new approach for a highly e?cient application of solar energy to the electrical vehicle.
关键词： Automotive application,Photovoltaic system,Flat concentrator photovoltaic (CPV),Lateral sun-tracking,Planar waveguide
更新于2025-09-16 10:30:52
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Investigating the Role of Reduced Graphene Oxide as a Universal Additive in Planar Perovskite Solar Cells
摘要： In this work we present the effects of the incorporation of reduced graphene oxide (rGO) nanoflakes into the titania compact layer, the methylammonium lead iodide (CH3NH3PbI3) absorber and the Spiro-MeOTAD hole transporter which are typical components of a planar perovskite solar cell (PSC). The addition of rGO within the TiO2 electron transport layer (ETL) offers fast electron transport rates toward the anode and favors the growth of large, uniform perovskite crystals. When added in MAPbI3, rGO further increases the perovskite grains size and creates a more homogenous and smooth film with enhanced crystallinity, thus improving the power conversion efficiency (PCE) of the corresponding PSC. On the contrary, its presence in Spiro-MeOTAD is detrimental for the cells performance. For the first time in the literature a graphene derivative favors the performance of a MAPbI3–based PSC when incorporated as an additive in both the ETL and the perovskite absorber. As a result, we obtained devices with optimized electrical characteristics, resulting to stabilized 13.6% PCE, outperforming by 20% the reference (rGO-free) ones. Moreover, the presence of rGO offered additional stability to the solar cells which retained 40% of their initial PCE after 50 days of storage in mildly humid, dark environment.
关键词： Reduced graphene oxide,Lead acetate,Planar perovskite solar cells,MAPbI3 absorber,Titania compact layer
更新于2025-09-16 10:30:52