No abstract

Multi-person pose estimation is an important but challenging problem in computer vision. Although current approaches have achieved significant progress by fusing the multi-scale feature maps, they pay little attention to enhancing the channel-wise and spatial information of the feature maps. In this paper, we propose two novel modules to perform the enhancement of the information for the multi-person pose estimation. First, a Channel Shuffle Module (CSM) is proposed to adopt the channel shuffle operation on the feature maps with different levels, promoting cross-channel information communication among the pyramid feature maps. Second, a Spatial, Channel-wise Attention Residual Bottleneck (SCARB) is designed to boost the original residual unit with attention mechanism, adaptively highlighting the information of the feature maps both in the spatial and channel-wise context. The effectiveness of our proposed modules is evaluated on the COCO keypoint benchmark, and experimental results show that our approach achieves the state-of-the-art results.

Surface defects of perovskite films are the major sources of nonradiative recombination which limit the efficiency and stability of perovskite solar cells. Surface passivation represents one of the most efficient strategies to solve this problem. Herein, for the first time we designed a porphyrin-involved benzene-1,3,5-tricarboxamide dendrimer (Por-BTA) as a multifunctional interface material between the interface of the perovskite and the hole-transporting layer (spiro-OMeTAD) for the surface passivation of perovskite films. The results suggested that Por-BTA not only efficiently passivated the perovskite surface defects via the coordination of the exposed Pb2+ with the carbonyl unit and basic sites of pyrrole units in Por-BTA but also improved the interface contact and the charge transfer between the perovskite and spiro-OMeTAD ascribed to the strong intermolecular π–π stacking of Por-BTA. It was shown that the PSC devices with the Por-BTA treatment exhibited improved power conversion efficiency with the champion of 22.30% achieved (21.30% for the control devices), which is mainly attributed to the increased short-circuit current density and fill factor. Interestingly, the stability of moisture for the Por-BTA-treated device was also enhanced compared to those without the Por-BTA treatment. This work presents a promising direction toward the design of multifunctional organic molecules as the interface materials to improve the cell performance of PSCs.

It is an effective strategy to improve the performance of quasi-two-dimensional (Q-2D) perovskite solar cells (PSCs) by introducing fluoro-substituted aromatic alkylammonium spacer cations into the active layer. Herein, the influence of the benzylammonium (BA) and the x-fluorobenzylammonium (xFBA) cation, in which x stands for the substitution position of the benzene ring (o, ortho; m, meta; p, para), on the crystal orientation, phase distribution, film morphology of the Q-2D (n = 5) perovskite films, and the corresponding device performance is systematically evaluated. The result suggests that compared with BA and oFBA, mFBA and pFBA have a larger dipole moment, forming a dense perovskite film with gradient structures where the n = 1 2D perovskite mainly exists at the top of the film and the large n-phase perovskite exists at the bottom of the film. Encouragingly, the (pFBA)2MA4Pb5I16 (MA = CH3NH3 +)-based perovskite solar cells achieve the highest efficiency of 17.12%, with an open-circuit voltage of 1.175 V, a short-circuit current density of 18.50 mA cm–2, and a fill factor of 78.78%, which is significantly higher than those of BA (14.07%)-, oFBA (12.89%)-, and mFBA (14.67%)-based PSCs. Furthermore, pFBA-based devices also exhibit the best stability compared to the other three devices.