Growth of van der Waals Halide Perovskites within the Interlayer Spacings of Mica

Two-dimensional hybrid organic–inorganic perovskites (2D-HOIPs) have been extensively researched for use in solar cells as well as optoelectronic devices over the past few years. Controllable growth of single-crystalline 2D-HOIP thin films has been regarded as a key component for the development of high-performance end devices. Here, we report a solution-based method for the growth of 2D-HOIPs using muscovite mica as a van der Waals substrate that yields millimeter-scale perovskite flakes. Interestingly, the grown 2D-HOIP flakes lie embedded within the interlayer spacings of muscovite mica. We find that such 2D-HOIP flakes buried in mica demonstrate enhanced photostability in comparison to conventional 2D-HOIP flakes. Such liquid-phase growth in the interlayer spacings of van der Waals substrates opens a new avenue for developing novel material structures for designing optoelectronic devices

Table_1_Influence of carbon emission trading policy on residents' health in China.XLSX

Residents' health is the basic condition for economic and social development. At present, China's environmental pollution problem is becoming increasingly serious, which not only hinders sustainable economic and social development, but also poses a major threat to public health. Therefore, based on the carbon emissions trading policy implemented in China, this paper explores this policy's impact on residents' health using the DID model and illustrates the moderating effect of environmental pollution. The results show that (1) carbon emissions trading policies can promote the improvement of residents' health; (2) the effect is stronger for western regions and provinces with smaller population sizes after taking control variables into consideration; and (3) environmental pollution has a significant moderating effect on the relationship between carbon emissions trading and residents' health. This research serves as an important reference for expanding the scope of the policy pilot, reducing pollutant emissions, and improving the health of the population.</p

Island-like Nanoporous Gold: Smaller Island Generates Stronger Surface-Enhanced Raman Scattering

The surface-enhanced Raman scattering properties of nanoporous gold prepared by the dealloying technique have been investigated for many years.The relatively low enhancement factor and the poor uniformity of existing conventional or advanced nanoporous gold structures are still the main factors that limit their wide application as Raman enhancement substrates. Here, we report island-like nanoporous gold (INPG) fabricated by simply controlling the composition of the dealloying precursor.This nanostructure can generate ∼10 times higher enhancement factor (above 10⁷) with ∼4 times lower gold consumption than conventional nanoporous gold. The dimensions of the gold islands can be controlled by the composition of the precursor. The enhancement factor can therefore be controlled by the gold island dimensions, which suggests an effective approach to fabricate better Raman enhancement substrates. Furthermore, INPG exhibits excellent Raman enhancement uniformity and reproducibility with the relative standard deviations of only 2.5% and 6.5%, which originate from the extremely homogeneous structure of INPG at both the microscale and macroscale. The excellent surface-enhanced Raman scattering properties make INPG a potential surface-enhanced Raman scattering substrate