Search

Kesterite Cu2ZnSn(S,Se)4 (CZTSSe) is one of the most promising materials for photovoltaics. CZTSSe solar cells have achieved an efficiency of 15.1%, yet further improvements have been challenging. Defects in light-absorbing layers have indelible effects on the performance of kesterite solar cells. In the development of CZTSSe solar cells, a good understanding and effective engineering of the defects in CZTSSe absorbers have been demonstrated to be crucial factors for the fabrication of high-efficiency CZTSSe solar cells. Some effective defect passivation strategies have successfully been applied to reduce defects in CZTSSe absorbers to improve film quality and device properties. Defect characterization techniques also play an important role in clarifying the mechanism of defect passivation in CZTSSe solar cells, allowing the development of more prospective passivation strategies. This review summarizes the types of defects in CZTSSe absorbers and the mechanisms for their formation, as well as their impact on the device performance. Furthermore, commonly used defect passivation strategies and advanced measurements of defects were precisely reviewed, aiming to provide powerful guidelines for further commercialization and applications of CZTSSe solar cells. [ABSTRACT FROM AUTHOR]

It has been validated that enhancing crystallinity and passivating the deep‐level defect are critical for improving the device performance of kesterite Cu2ZnSn(S,Se)4 (CZTSSe) solar cells. Coordination chemistry interactions within the Cu‐Zn‐Sn‐S precursor solution play a crucial role in the management of structural defects and the crystallization kinetics of CZTSSe thin films. Therefore, regulating the coordination environment of anion and cation in the precursor solution to control the formation process of precursor films is a major challenge at present. Herein, a synergetic crystallization modulation and defect passivation method is developed using P2S5 as an additive in the CZTS precursor solution to optimize the coordination structure and improve the crystallization process. The alignment of theoretical assessments with experimental observations confirms the ability of the P2S5 molecule to coordinate with the metal cation sites of CZTS precursor films, especially more liable to the Zn2+, effectively passivating the Zn‐related defects, thereby significantly reducing the defect density in CZTSSe absorbers. As a result, the device with a power conversion efficiency of 14.36% has been achieved. This work provides an unprecedented strategy for fabricating high‐quality thin films by anion‐coordinate regulation and a novel route for realizing efficient CZTSSe solar cells. [ABSTRACT FROM AUTHOR]

Inadequate vascularization is a major challenge in tissue engineering and can lead to the failure of tissue defect repair. Currently, the use of nanomaterials has emerged as a critical strategy for tissue engineering. Nanoparticles can be utilized as additives in composite materials to enhance the development of bone tissue engineering. Niobium (Nb), a transition metal element with notable biocompatibility, has potential in angiogenesis. However, the effect of Nb nanoparticles (a form of niobium in the nanoparticle state) on endothelial cell behavior remains unclear. This study focused on the effect of Nb nanoparticles on the differentiation of tip cells and its in-depth regulatory mechanism. Our results revealed that Nb nanoparticles promoted angiogenesis at an early stage and increased bone regeneration in calvarial bone defects. In addition, Nb nanoparticles activated tip cell differentiation and thereby promoted cell migration and tube formation. Furthermore, we verified that Nb nanoparticles promoted endothelial tip cell formation by activating YAP. Nb nanoparticles regulates YAP through the newly identified upstream regulatory molecules FOXA1 and PAK4. When FOXA1 or PAK4 was inhibited, YAP expression and tip cell activation were inhibited. Thus, Nb nanoparticles promoted angiogenesis by activating endothelial tip cells, and the FOXA1-PAK4-YAP signaling cascade regulated this process. The insights garnered from this study suggest a strategy for tissue engineering and lay a theoretical foundation for the expanded application of Nb nanoparticles in this field. [ABSTRACT FROM AUTHOR]

Agropastoralism has prevailed in Inner Asia since the Bronze Age. It is an optimal subsistence strategy of inhabitants for adaptation to arid marginal environment. However, previous studies paid little attention to different development trajectories of this mixed economy within similar habitat. The Turpan and Hami Basins, located in eastern Tianshan Mountains of Xinjiang, are two typical desert oases with extremely dry climate, providing us with an appropriate region to investigate the issue. In present study, radiocarbon dates (n = 154) of eight typical sites in these two basins were reviewed and used to reconstruct the prehistoric chronology sequence prior to Han Dynasty (2200 cal BP). Then the data of botanical and faunal remains and stable isotope analyses (n = 159) of human diets from these sites were also reviewed for reliably revealing the subsistence economy pattern. Combining the time scale with multiple biological proxies, results show that, from the Bronze Age to early Iron Age, inhabitant subsistence in the Turpan Basin was dominated by livestock herding and supplemented by low-investment cereal crop cultivation, while the agriculture in Turpan Basin has developed significantly by the later period of Subeixi Culture. In contrast, agriculture-based economy was continuously developed in the Hami oases. Although the climate is very dry in both basins, temperature in warm seasons is much higher in the Turpan Basin. Besides thermal condition, size, range and convenient availability of highland pasture located at the southern flank of the Tianshan Mountains, are main driving factors leading to differentiated development trajectories of agropastoralism. Apart from that, cultural factors like economy, culture and technology communication along with population migration also impact local subsistence economy pattern. [ABSTRACT FROM AUTHOR]