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Ultraviolet (UV) photodetectors have gained much attention due to their numerous important applications ranging from environmental monitoring to space communication. To date, most p‐NiO/n‐Si heterojunction photodetectors (HPDs) exhibit poor UV responsivity and slow response. This is mainly due to a small valence band offset (ΔEV) at the NiO/Si interface and a high density of dangling bonds at the silicon surface. Herein, an UV HPD consisting of NiO/Al2O3/n‐Si is fabricated using magnetron sputtering technique. The HPD has a large rectification ratio of 2.4 × 105. It also exhibits excellent UV responsivity (R) of 15.8 A/W at −5 V and and detectivity (D*) of 1.14 × 1013 Jones at −4 V, respectively. The excellent performance of the HPD can be attributed to the defect passivation at the interfaces of the heterojunction and the efficient separation of photogenerated carriers by the Al2O3 nanolayer. The external quantum efficiency (EQE) of the HPD as high as 5.4 × 103%, hence implying a large optical gain due to carrier proliferation resulting from impact ionization. Furthermore, the ultrafast response speed with a rise time of 80 µs and a decay time of 184 µs are obtained. [ABSTRACT FROM AUTHOR]

This study employs a regression discontinuity design to systematically examine the governance effect of bike-sharing on urban traffic congestion, utilizing city-level data from Beijing, Shanghai, and Wuhan in China between 2016 and 2018. We discover that the introduction of bike-sharing services significantly mitigates traffic congestion in the short term. Our heterogeneity analysis reveals that the initial deployment of shared bicycles primarily alleviates urban congestion, while additional deployments have a limited impact. Further, mechanism test analysis demonstrates that bike-sharing leads to increased metro ridership in these cities, effectively explaining the reduction in road congestion. This study underscores the pivotal role of bike-sharing services in easing urban traffic congestion and provides vital policy insights for enhancing traffic management strategies in Chinese cities. [ABSTRACT FROM AUTHOR]

In this study, we examine the green innovation effect of investor preference on Chinese listed companies from 2008 to 2020. We observe that investors with environmental protection preferences can significantly increase enterprise green innovation. The baseline conclusions remain robust after we conduct multiple sensitivity tests, such as establishing a shift-share instrumental variable (Bartik IV), using the Heckman's two-step method, changing the regression methods, substituting the core variables, adopting the DID method, and considering investors' ownership. Our analysis shows that the green innovation effect of environmental investors is highly pronounced in companies with a high level of indebtedness and low managerial ability. We verify that environmental investors can improve the green innovation level of enterprises through two potential mechanisms, namely, easing corporate financing constraints and incentivising managers. In addition, political and public attention can strengthen the positive relationship between environmental investors and green innovation. [ABSTRACT FROM AUTHOR]

Natural birnessite‐like minerals are commonly enriched in various transition metals, such as iron (Fe). Though the fates of metals associated with birnessites during mineral transformation in aqueous conditions are thoroughly studied, we determined the Fe behaviors in Fe‐doped hexagonal turbostratic birnessites during mineral evolution in dry state at room temperature for 8 years and upon thermal treatments at temperatures ranging from 323 to 773 K, covering the temperatures in extreme environments such as wildfires. These Fe‐containing birnessites were very stable upon aging in the dry state. Upon thermal treatment, the birnessite sample with a small amount of Fe (≤2.8 wt.%) was transformed to cryptomelane at 573–673 K, while for the sample with ∼5.6 wt.% Fe, the transformation temperature increased to 673–773 K. This indicated that Fe adsorption enhanced the birnessite's thermal stability. Further, there was a linear relationship between the fraction of edge‐sharing Fe–Fe(Mn) pairs and temperature over 298–473 K. This implied the migration of Fe adsorbed on vacancies into birnessite layers and/or increased edge‐sharing of Fe around vacancies from adjacent layers during heating. The average manganese (Mn) valences in the Mn dioxides were almost constant with the increase in temperature when the layer structure was kept, but greatly increased when the tectomanganate was formed. These results provided deep insights into the mechanisms of Mn dioxide mineral transformation and the fates of associated metals under extreme conditions in terrestrial environments. Core Ideas: Birnessite structure remained stable during 8 years of dry aging.Iron (Fe) adsorption enhanced birnessite thermal stability.Heating at 298–473 K promoted the formation of edge‐sharing Fe–Fe(Mn) pairs in the birnessite structure.Fe‐doped birnessite was converted to cryptomelane after heating at 673–773 K.Average manganese valences were almost constant in birnessites but were greatly increased for cryptomelanes. [ABSTRACT FROM AUTHOR]

Lead sulfide colloidal quantum dots (PbS CQDs) are promising optoelectronic materials due to their unique properties, such as tunable band gap and strong absorption, which are of immense interest for application in photodetectors and solar cells. However, the tunable band gap of PbS CQDs would only cover visible short-wave infrared; the ability to detect longer wavelengths, such as mid- and long-wave infrared, is limited because they are restricted by the band gap of the bulk material. In this paper, a novel photodetector based on the synergistic effect of PbS CQDs and bismuth telluride (Bi2Te3) was developed for the detection of a mid-wave infrared band at room temperature. The device demonstrated good performance in the visible-near infrared band (i.e., between 660 and 850 nm) with detectivity of 1.6 × 1010 Jones at room temperature. It also exhibited photoelectric response in the mid-wave infrared band (i.e., between 4.6 and 5.1 μm). The facile fabrication process and excellent performance (with a response of up to 5.1 μm) of the hybrid Bi2Te3/PbS CQDS photodetector are highly attractive for many important applications that require high sensitivity and broadband light detection. [ABSTRACT FROM AUTHOR]