In order to establish a new method for measuring the dimensions of coarse aggregates, five different-size flat and elongated (F&E) coarse aggregates were glued into two specimens by epoxy resin, respectively, and ...In order to establish a new method for measuring the dimensions of coarse aggregates, five different-size flat and elongated (F&E) coarse aggregates were glued into two specimens by epoxy resin, respectively, and slice images were obtained by X-ray CT, then the aggregates were extracted by the fuzzy c-means clustering algorithm. Attributions of the particle on different cross-sections were determined by the ‘overlap area method’. And unified three-dimensional Cartesian coordinate system was established based on continuous slice images. The coefficient values of spherical harmonics descriptor representing particles surface profile were gained, then each scanned particle was represented by 60×120 discrete points conformably with spherical harmonics descriptor. The chord length and direction angles were determined by the calculation. With the major axis (L) and orthogonal axis (W and T), the calculated results were compared with those measured by caliper. It is concluded that the new L, W, and T dimension measuring method is able to take the place of the present manual measurement.展开更多
Quantum confinement effect（QCE）, an essential physical phenomenon of semiconductors when the size becomes comparable to the exciton Bohr radius, typically results in quite different physical properties of low-dimens...Quantum confinement effect（QCE）, an essential physical phenomenon of semiconductors when the size becomes comparable to the exciton Bohr radius, typically results in quite different physical properties of low-dimensional materials from their bulk counterparts and can be exploited to enhance the device performance in various optoelectronic applications. Here, taking Cs Pb Br3 as an example, we reported QCE in all-inorganic halide perovskite in two-dimensional（2D） nanoplates. Blue shifts in optical absorption and photoluminescence spectra were found to be stronger in thinner nanoplates than that in thicker nanoplates, whose thickness lowered below -7 nm. The exciton binding energy results showed similar trend as that obtained for the optical absorption and photoluminescence. Meanwile, the function of integrated intensity and full width at half maximum and temperature also showed similar results, further supporting our conclusions. The results displayed the QCE in all-inorganic halide perovskite nanoplates and helped to design the all-inorganic halide perovskites with desired optical properties.展开更多
基金Project(51038004) supported by the National Natural Science Foundation of ChinaProject(2009318000078) supported by the Western China Communications Construction and Technology Program, China
文摘In order to establish a new method for measuring the dimensions of coarse aggregates, five different-size flat and elongated (F&E) coarse aggregates were glued into two specimens by epoxy resin, respectively, and slice images were obtained by X-ray CT, then the aggregates were extracted by the fuzzy c-means clustering algorithm. Attributions of the particle on different cross-sections were determined by the ‘overlap area method’. And unified three-dimensional Cartesian coordinate system was established based on continuous slice images. The coefficient values of spherical harmonics descriptor representing particles surface profile were gained, then each scanned particle was represented by 60×120 discrete points conformably with spherical harmonics descriptor. The chord length and direction angles were determined by the calculation. With the major axis (L) and orthogonal axis (W and T), the calculated results were compared with those measured by caliper. It is concluded that the new L, W, and T dimension measuring method is able to take the place of the present manual measurement.
基金supported by the National Basic Research Program of China (2014CB931702)the National Key Research and Development Program of China (2016YFB0401701)+5 种基金the National Natural Science Foundation of China (NSFC 51572128 and 21403109)NSFC-RGC (5151101197)the Natural Science Foundation of Jiangsu Province (BK20160827)China Postdoctoral Science Foundation (2016M590455)the Fundamental Research Funds for the Central Universities (30915012205 and 30916015106)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘Quantum confinement effect（QCE）, an essential physical phenomenon of semiconductors when the size becomes comparable to the exciton Bohr radius, typically results in quite different physical properties of low-dimensional materials from their bulk counterparts and can be exploited to enhance the device performance in various optoelectronic applications. Here, taking Cs Pb Br3 as an example, we reported QCE in all-inorganic halide perovskite in two-dimensional（2D） nanoplates. Blue shifts in optical absorption and photoluminescence spectra were found to be stronger in thinner nanoplates than that in thicker nanoplates, whose thickness lowered below -7 nm. The exciton binding energy results showed similar trend as that obtained for the optical absorption and photoluminescence. Meanwile, the function of integrated intensity and full width at half maximum and temperature also showed similar results, further supporting our conclusions. The results displayed the QCE in all-inorganic halide perovskite nanoplates and helped to design the all-inorganic halide perovskites with desired optical properties.
