in 2D chiral layered hybrid perovskites, such as (R-BPEA) 2 PbI 4 , [9] [(R)-α-(PEA)] 2 PbI 4 , [5] [(R)-β-MPA] 2 PbCl 4 , [10] [(R)-β-MPA] 4 AgBiI 8 . [11] Compared to these monolayered chiral perovskites, multilayered chiral hybrid perovskites possess superior charge transport and congenitally chiroptical activity, emerging as the most promising candidates for CPL detection. [12] From a structural point of view, multilayered 2D chiral hybrid perovskites can be described by the formula (RNH 3 ) 2 A n-1 M n X 3n+1 (n > 1), where R can be the chiral organic cations and n represents the layer number of the perovskite sheets. [13] Obviously, intrinsic chirality is rooted in themselves. Meanwhile, the MX 6 (intra-well) octahedra networks and RNH 3 (barrier) alternating arrangements will form the quantum-confined architectures for the multilayered chiral hybrid perovskites. [14] This unique quantum-well structure endows multilayered perovskites with fascinating semiconductor performance including lower exciton binding energy and enhanced carrier mobility, far outweighing that of monolayered perovskites. [15,16] Despite showing outstanding advantages for CPL detection, multilayered chiral hybrid perovskites are still in their infancy. Therefore, it is eager and challenging to develop other multilayered chiral perovskites.Alternating cations intercalation-type (ACI) perovskites, defined as two different space cations alternating in 2D Multilayered chiral hybrid perovskites are highly desired for highly-sensitive circularly polarized light (CPL) detection rooted in their efficient charge transport and strong chiroptical activity. However, designing multilayered chiral hybrid perovskites remains a huge challenge. Here, through pairing achiral ethylamine (EA)−chiral arylamine in the interlayer space, multilayered chiral alternating cations intercalation-type (ACI) hybrid perovskites (R-/S-PPA) EA 2 Pb 2 Br 7 (PPA = 1-phenylpropylamine) are successfully obtained. Significantly, perovskitizer EA extends the thickness of the quantum well and alternating space cation EA greatly alleviates in-plane tilting distortions of adjacent metal halide octahedra, providing fast channels for in-plane carrier transport. Consequently, single-crystal photodetectors of (R-/S-PPA) EA 2 Pb 2 Br 7 exhibit high circular polarization sensitivity with a large anisotropy factor of 0.3, which falls around the highest value among the layered hybrid perovskites. In addition, a fast responding rate (τ r )of 308 µs and a high CPL-detectivity of 8 × 10 12 Jones are also presented. This work opens up a new perspective to design multilayered chiral hybrid perovskites for highsensitive CPL detection.
In the last decade, two‐dimensional layered materials (2DLMs) have been drawing extensive attentions due to their unique properties, such as absence of surface dangling bonds, thickness‐dependent bandgap, high absorption coefficient, large specific surface area, and so on. But the high‐quality growth and transfer of wafer‐scale 2DLMs films is still a great challenge for the commercialization of pure 2DLMs‐based photodetectors. Conversely, the material growth and device fabrication technologies of three‐dimensional (3D) semiconductors photodetectors tend to be gradually matured. However, the further improvement of the photodetection performance is limited by the difficult heterogeneous integration or the inferior crystal quality via heteroepitaxy. Fortunately, 2D/3D van der Waals heterostructures (vdWH) combine the advantages of the two types of materials simultaneously, which may provide a new platform for developing high‐performance optoelectronic devices. Here, we first discuss the unique advantages of 2D/3D vdWH for the future development of photodetection field and simply introduce the structure categories, working mechanisms, and the typical fabrication methods of 2D/3D vdWH photodetector. Then, we outline the recent progress on 2D/3D vdWH‐based photodetection devices integrating 2DLMs with the traditional 3D semiconductor materials, including Si, Ge, GaAs, AlGaN, SiC, and so on. Finally, we highlight the current challenges and prospects of heterointegrating 2DLMs with traditional 3D semiconductors toward photodetection applications.
Heart disease is one of the major diseases threatening human health. This paper proposed a novel deep neural network model to predict heart disease based on routine clinical data. We adapt the deep residual structure to discover a novel Deep Residual Neural Network (DRNN). In order to verify the effectiveness of DRNN, we performed experiments on Heart Disease UCI. The accuracy reached 95%, which is better than the traditional machine learning methods among Random Forest 83%, Decision Tree 68%, Logistic Regression 87%, KNN 60%, Native Bayes 80%.
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