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Air-stable hybrid perovskite solar cell by sequential vapor deposition in a single reactor
摘要： Here we demonstrate a facile two-step low-pressure vapor deposition of methyl-ammonium lead iodide (MAPbI3) perovskite films in a single reactor. Continuous, poly-crystalline lead iodide (PbI2) films were deposited in the first step and successfully converted to high quality perovskite films in the second step during exposure of PbI2 films to methyl-ammonium iodide (MAI) vapor. A complete conversion was realized after 90 minutes of exposure with an average grain size of 3.70 ± 1.80 μm. The perovskite conversion starts at the PbI2 surface through the intercalation reaction of PbI2 and MAI vapor molecules and progresses towards the PbI2/substrate interface. The coverage and quality of the perovskite thin film is controlled by that of the pre-deposited PbI2 film. The absorbance measurements confirmed air stability of the fully converted perovskite for 21 days, ascribed to its superior morphology and grain size. Finally, a planar single-junction perovskite solar cell with no additives or additional interfacial engineering was fabricated and tested under open-air conditions, yielding a best power conversion efficiency of 11.7%. The solar cell maintains 85% of its performance up to 13 days in open-air with relative humidity up to 80%.
关键词： planar device,Two-step vapor deposition,large grains,intercalation,air-stable
更新于2025-09-23 15:19:57
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Tellurene Photodetector with High Gain and Wide Bandwidth
摘要： Two-dimensional (2D) semiconductors have been extensively explored as a new class of materials with great potential. In particular, black phosphorus (BP) has been considered to be a strong candidate for applications such as high-performance infrared photodetectors. However, the scalability of BP thin film is still a challenge, and its poor stability in the air has hampered the progress of the commercialization of BP devices. Herein, we report the use of hydrothermal-synthesized and air-stable 2D tellurene nanoflakes for broadband and ultrasensitive photodetection. The tellurene nanoflakes show high hole mobilities up to 458 cm2/V·s at ambient conditions, and the tellurene photodetector presents peak extrinsic responsivity of 383 A/W, 19.2 mA/W, and 18.9 mA/W at 520 nm, 1.55 μm, and 3.39 μm light wavelength, respectively. Due to the photogating effect, high gains up to 1.9 ×103 and 3.15×104 are obtained at 520 nm and 3.39 μm wavelength, respectively. At the communication wavelength of 1.55μm, the tellurene photodetector exhibits an exceptionally high anisotropic behavior, and a large bandwidth of 37 MHz is obtained. The photodetection performance at different wavelength is further supported by the corresponding quantum molecular dynamics (QMD) simulations. Our approach has demonstrated the air-stable tellurene photodetectors that fully cover the short-wave infrared band with ultrafast photoresponse.
关键词： air-stable,two-dimensional (2D),wide bandwidth,tellurene,photodetector,high gain
更新于2025-09-12 10:27:22
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Water Soluble and Bright Luminescent Cesium Lead Bromide Perovskite Quantum Dot-Polymer Composites for Tumor-Derived Exosomes Imaging
摘要： Cesium-lead-halide perovskite quantum dots (PQDs), are a highly promising class of next-generation optical material for bio-imaging applications. Herein, we present a nanocomposite strategy for the design of water soluble, highly luminescence CsPbBr3 PQD nanocomposites without modifying the crystal symmetry and photoluminescence (PL) property. Water soluble PQDs are reproducibly synthesized via encapsulating CsPbBr3 PQDs with polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (PS-PEB-PS) and poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol (PEG-PPG-PEG). In the reported design, the polystyrene triblock polymers strongly interact with the hydrophobic parts of PQDs and the water-soluble PEG moiety acts as protection layer to effectively prevent degradation of PQDs in water. Outer shell PEG layer also helps to develop biocompatible PQDs. Reported data indicate that encapsulating CsPbBr3 PQDs with polymer helps to improve the photoluminescence quantum yield (PLQY) from 83% to 88%, which may be due to decrease in the surface defects after the effective polymer coating. Experimental data show that PL intensity from CsPbBr3 PQD nanocomposites remain unchanged even after 30 days of exposure in air. Similarly, reported data indicate that nanocomposites retain their luminescence properties in water for first 8 days and then decreases slowly to 60% of its initial PL intensity after one month. On the other hand, the PL emission for the PQD without polymer encapsulation is completely quenched within few hours. Exosomes are highly promising avenue for accessing tumor type and stage and to monitor cancer treatment response. Reported data reveal that anti-CD63 antibody attached PQD nanocomposites are capable of tracking of triple negative MDA-MB-231 breast tumor derived exosomes via binding using anti- CD63 antibody and selective green luminescence imaging using PQD nanocomposites.
关键词： selective imaging of exosomes,Triple negative breast tumor derived exosomes,water soluble perovskite nanocomposites,Air stable CsPbBr3 quantum dots,Green luminescence imaging
更新于2025-09-11 14:15:04
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Baking soda: an ultra-cheap and air stable electron injection layer for organic electronic devices
摘要： To realize high performance printed organic optoelectronic devices, the development of air-stable, cheap, and solution-processable electron injection layers (EILs) is urgently required to avoid the use of a low work-function metal electrode with poor air stability. We report sodium bicarbonate (baking soda, NaHCO3) as an efficient, low-cost, air-stable, and environmentally friendly EIL material in various printed organic electronic devices including organic solar cells (OSCs), organic light-emitting diodes (OLEDs), organic photodiodes (OPDs) and n-channel organic thin film transistors (OFETs). UV photoelectron spectroscopy results indicated that the work-function of various common electrodes used for organic devices such as ITO, Au, Al and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) decreased significantly by more than 1 eV following deposition of a thin NaHCO3 film. The performance and stability of these organic devices improved by around 15% overall with ultra-cheap, air stable EILs. In particular, high performance OSCs based on PTB7:PC71BM with a power conversion efficiency of 8.40% and solution processed OLEDs based on PVK:PBD:Ir(ppy)3 with light emitting efficiencies of 68.5 cd A?1 and 20 lm A?1 were achieved by applying a NaHCO3 interlayer.
关键词： air-stable,sodium bicarbonate,organic electronic devices,electron injection layers,baking soda,low-cost,solution-processable
更新于2025-09-04 15:30:14