black phosphorene (BP) carries a stellar set of physical properties such as conveniently tunable bandgap and extremely high ambiopolar carrier mobility for optoelectronic devices. Herein, we report, for the first time, the judicious design and positioning of BP with tailored thickness as dual-functional nanomaterials to concurrently enhance carrier extraction at both electron transport layer (ETL)/perovskite and perovskite/hole transport layer (HTL) interfaces for high-efficiency and stable perovskite solar cells (PSCs). The synergy of favorable band energy alignment and concerted cascade interfacial carrier extraction, rendered by concurrent positioning of BP, delivered a progressively enhanced power conversion efficiency (PCE) of 19.83% from 16.95% (BP-free). Investigation into interfacial engineering further reveals enhanced light absorption and reduced trap density for improved photovoltaic performance with BP incorporation. This work demonstrates the appealing characteristic of rational implementation of BP as dualfunctional transport material for a diversity of optoelectronic devices, including photodetectors, sensors, light-emitting diodes, etc.

The Guadalupian–Lopingian boundary stratotype at Penglaitan, and the nearby Tieqiao section, near Laibin, South China, record a series of major environmental changes within the Jiangnan Basin during a Mid-Permian biotic crisis. The sequence-stratigraphic, petrographic and palaeontological record of these sections has been studied and the associated strontium isotopic fluctuations have been assayed. Mass extinction of fusulinid foraminifers is most clearly associated in time with onset of volcanism and a relative sea-level fall that led to the establishment of mid-ramp conditions (Laibin Limestone) in settings that were previously dominated by radiolarian mudstones. The regression also coincides with a low point of 87 Sr/ 86 Sr ratios. The lowstand deposits contain mafic scoriaceous grains that record pyroclastic volcanism probably centred in the Emeishan flood basalt province 800 km to the west of Laibin. Thus, unusually violent eruptions associated with flood basalts in this province may have contributed to the environmental stresses responsible for the extinction event. Subsequent environmental changes included transgression, spread of dysoxic waters, indicated by populations of small pyrite framboids, and a major negative C-isotope excursion. All these phenomena have been previously related to the end-Guadalupian extinction but they in fact post-date the crisis because a post-extinction fauna of foraminifers is encountered at this time.

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