Cenozoic tectono-sedimentary characteristics and extension model of the Northwest Sub-basin,South China Sea

Based on the interpretations of three seismic profiles and one wide-angle seismic profile across the Northwest Sub-basin,South China Sea.stratigraphic sequences,deformation characteristics and an extension model for this sub-basin have been worked out.Three tectonic-stratigraphic units are determined.Detailed analyses of extension show that the event occurred mainly during the Paleogene and resulted in the formation of half-grabens or grabens distributed symmetrically around the spreading center.Sediments are characterized by chaotic and discontinuous reflectors,indicating clastic sediments. Farther to the southwest,the sub-basin features mainly continental rifting instead of sea-floor spreading. The rifting would have been controlled by the shape of the massif and developed just along the northern edge of the Zhongsha-Xisha Block,rather than joined the Xisha Trough.After 25 Ma.a southward ridge jump triggered the opening of the Southwest Sub-basin.The NW-directed stress caused by the sea-floor spreading of the Northwest Sub-basin may have prevented the continuous opening of the sub-basin.After that the Northwest Sub-basin experienced thermal cooling and exhibited broad subsidence.The deep crustal structure shown by the velocity model from a wide-angle seismic profile is also symmetrical around the spreading center,which indicates that the Northwest Sub-basin might have opened in a pure shear model.

Surfactant-assisted doctor-blading-printed FAPbBr3 films for efficient semitransparent perovskite solar cells

Organic-inorganic hybrid perovskite solar cells have generated wide interest due to the rapid development of their photovoltaic conversion effciencies.However,the majority of the reported devices have been fabricated via spin coating with a device areaof<1 cm2.In this study,we fabricated a wide-bandgap formamidi-nium lead bromide(FAPbBr3)film using a cost-effective,high-yielding doctor-blade-coating process.The effects of different surfactants,such as I-α-phosphatidylcholine,polyoxyethylene sorbitan monooleate,sodium lauryl sulfonate,and hexadecyl trimethyl ammonium bromide,were studied during the printing process.Accompanying the optimization of the blading temperature,crystal sizes of over 10μm and large-area perovskite films of5cm×5 cm were obtained using this method.The printed FAPbBr3 solar cells exhibited a short-circuit current density of 8.22 mA/cm2,an open-circuit voltage of 1.175 V,and an efficiency of 7.29%.Subsequently,we replaced the gold with silver nanowires as the top electrode to prepare a semitransparent perovskite solar cell with an average transmittance(400-800 nm)of 25.42%,achieving a high-power efficiency of 5.11%.This study demonstrates efficient doctor-blading printing for preparing large-area FAPbBr3 films that possess high potential for applications in building integrated photovoltaics.