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The perovskite single crystals (PSC) produced by solution‐processed metallic ions doping have a thick p–n junction (greater than 10 µm). Meanwhile, to achieve high responsivity, the carrier drift length (µτE) has to be larger than the dimensions of the detector. If the p–n junction is quite thick, a high bias voltage is required. For the practical application of photodiode, it is imperative to find a means to generate a thin p–n junction. A productive technique is suggested for forming a thin p–n junction by diffusing metallic ions, resulting in a longer drift length of the carrier than the depletion width. Thinner p–n junction leads to reduced dark current density (0.5 µA cm−2), low trap density (5.71 × 108 cm−3), high mobility (417 cm2 V−1 s−1), and hence increased responsivity (77.69 A W−1) for 30 µW cm−2 UV illumination under a low applied voltage of −15 V. A quick response time with a rise/fall duration of 22 ms/30 ms under 0 V and long‐term stability for over 3 months in ambient airis achieved. To comprehend the performance with the thinner p–n junction‐based photodiodes, the results under UV–Vis illumination are examined and compared. The outcomes hint at a method that holds promise for producing efficient photodiodes. [ABSTRACT FROM AUTHOR]

Low‐cost and efficient large‐scale triboelectric nanogenerator (TENG) is considered as the new scheme for distributed mechanical conversion or renewable energy utilization. An extremely popular all‐inorganic lead‐free double perovskite Cs2AgBiBr6 (CABB) has emerged as extraordinary potential material in triboelectric semiconductors' substitution, overcoming high‐impedance limitations associated with organic‐polymer‐insulator based materials. In this study, assembled by the certified available positive frictional material CABB, TENG with sandwiched structure of ITO/compact‐TiO2/mesoporous‐TiO2/CABB – the poly‐tetra‐fluoroethylene/Al exhibits appropriate performance on environmental stability and output capacity for which structure can impede charges decay. Fabrication process comparison shows that as an inexpensive large‐scale functional films preparation method, sprayed CABB TENG with brilliant relative dielectric constant and work function difference possess more distinguished output characteristics. This is confirmed by higher open‐circuit voltage of 105 V, larger short‐current density of 2.45 mA m−2 at 0.25 Hz motion parameter, and more abundant output power density of 0.76 W m−2 under 10 Hz. Further study confirms that both higher frequency and larger contact‐area are conducive to total output power, while terminal charging speed is inversely or positively proportional with capacitance or mechanical frequency. Final physical display effect of sprayed CABB TENG lights up at least 53 commercial yellow‐LEDs, holding decent energy conversion ability. [ABSTRACT FROM AUTHOR]

With the deepening of the global division of labor, it is of great practical significance to study the impact of agricultural global value chain (GVC) on the ecological footprint. Based on the data of trade in value added provided by the OECD, this study adopts the dynamic panel model and moderating effect model to systematically examine the impact of agricultural GVC on ecological footprint and the moderating effect of environmental regulation. Empirical results show that upgrading the position of agricultural GVC significantly reduces the ecological footprint. Further, the effect of agricultural GVC on ecological footprint is more pronounced in middle‐ and low‐income countries than in high‐income countries. The mechanism test using the moderating effect model proves that there is a positive moderating effect of environmental regulation on the relationship between agricultural GVC and ecological footprint. The findings disclose the environmental effect behind upgrading the position of agricultural GVC and offer certain enlightenment from the perspective of environmental regulation for a country to participate in the agricultural GVC, alleviate the pressure on the ecological footprint and ultimately achieve sustainable development. [ABSTRACT FROM AUTHOR]

Narrowband photodetection provides important information in a specific wavelength range. Specially, the use of nonoptical‐filter narrowband photodetectors based on MAPbX3 (MA = CH3NH3; X = Cl, Br, I) perovskites is reported of great potential. However, current MAPbX3‐based narrowband photodetectors have to sacrifice their photocurrent and response speed to achieve an acceptable spectral rejection ratio. In this work, a new type of heterojunction photodetector (hetero‐PD) with a structure of (n‐type doped MAPbCl3)/(intrinsic MAPbBr2.5Cl0.5)/(n‐type doped MAPbBr3) via epitaxial growth is demonstrated as a narrowband photodetector. Through optical bandgap engineering, photons with different wavelength can be absorbed in different layers. Owing to the n–i–n energy band structure, most external bias would apply on a tiny region near the n–i heterojunction. Besides, the energy barriers in the heterojunctions can block holes from injection and collection, resulting in low‐noise electron‐only hetero‐PDs. By sufficiently suppressing the background noise from short‐wavelength photons, hetero‐PDs are capable of achieving a high spectral rejection ratio of 98.1% under an electrical field of 8 V cm−1. Moreover, hetero‐PDs exhibit a high external quantum efficiency value of 45%, a narrow full width at half‐maximum of 13 nm, and a response time of 1.35 µs. [ABSTRACT FROM AUTHOR]

The ion migrations in lead halide perovskite (LHP)‐based devices are complex processes due to the generation of charges and migration multipaths. The migrating ions are generated mainly from element defects and dislocation defects, and transport along paths of element vacancies and grain boundaries. In this regard, it is of interest to investigate the different influences of the two defect types and paths. Herein, the current–voltage hysteresis and X‐ray photoelectron spectra of almost‐dislocation‐free LHP single crystals (LHPSCs) with different halide components are investigated. The ions cannot migrate in iodine‐based LHPSCs. A decrease in halide vacancy content in a bromine–chlorine‐based perovskite single crystal can effectively limit the ion migration. This study provides useful insights to understand the different dominant factors determining the ion migration in LHPs. [ABSTRACT FROM AUTHOR]