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- 实验方案
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Template‐Assisted Formation of High‐Quality α‐Phase HC(NH <sub/>2</sub> ) <sub/>2</sub> PbI <sub/>3</sub> Perovskite Solar Cells
摘要： Formamidinium (FA) lead halide (α-FAPbI3) perovskites are promising materials for photovoltaic applications because of their excellent light harvesting capability (absorption edge 840 nm) and long carrier diffusion length. However, it is extremely difficult to prepare a pure α-FAPbI3 phase because of its easy transformation into a nondesirable δ-FAPbI3 phase. In the present study, a “perovskite” template (MAPbI3-FAI-PbI2-DMSO) structure is used to avoid and suppress the formation of δ-FAPbI3 phases. The perovskite structure is formed via postdeposition involving the treatment of colloidal MAI-PbI2-DMSO film with FAI before annealing. In situ X-ray diffraction in vacuum shows no detectable δ-FAPbI3 phase during the whole synthesis process when the sample is annealed from 100 to 180 °C. This method is found to reduce defects at grain boundaries and enhance the film quality as determined by means of photoluminescence mapping and Kelvin probe force microscopy. The perovskite solar cells (PSCs) fabricated by this method demonstrate a much-enhanced short-circuit current density (Jsc) of 24.99 mA cm?2 and a power conversion efficiency (PCE) of 21.24%, which is the highest efficiency reported for pure FAPbI3, with great stability under 800 h of thermal ageing and 500 h of light soaking in nitrogen.
关键词： perovskite solar cells,high quality,pure phase,template-assisted,highest efficiency
更新于2025-09-11 14:15:04
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Orientation-selective edge enhancement of phase objects
摘要： We present a method for the orientation-selective enhancement of the first derivatives ?i.e. the edges? of a pure phase object. The proposed method is based on the transport-of-intensity equation (TIE). The TIE contains a term proportional to the scalar product of the phase gradient and an intensity gradient, which plays the role of amplifying factor of the first derivatives. We will show that if the intensity gradient is implemented in the optical setup as a moving amplitude mask with a relatively sharp border ?or eventually, a digital shifting mask displayed in a liquid crystal display? it is possible to generate a synthetic image of the phase object with enhanced edges. The proposed technique is potentially useful in biological and biomedical research. Validation experiments and preliminary qualitative results illustrating the generation of synthetic images with enhanced edges are presented.
关键词： Transport-of-intensity equation,TIE,Edge enhancement of pure phase objects
更新于2025-09-10 09:29:36