The shifting pattern of CO2 source sink in a subtropical urbanizing lightly eutrophic lake.

Globally, numerous freshwater lakes exist, and rapid urbanization has impacted carbon biogeochemical cycling at the interface where water meets air in these bodies. However, there is still a limited understanding of CO2 absorption/emission in eutrophic urbanizing lakes. This study therefore involved biweekly in-situ monitoring to evaluate fluctuations in the partial pressure (pCO2) and flux (fCO2) of CO2 and associated parameters from January to September 2020 (7:00-17:00 CST) in an urbanizing lake in southwestern China. Our study revealed that during the daylight hours of the 11 sampling days, both pCO2 and fCO2 consistently demonstrated decreasing trends from the early morning period to the late afternoon period, with notable increases on May 7th and August 15th, respectively. Interestingly, unlike our previous findings, an nonsignificant difference (p > 0.05) in mean pCO2 and fCO2 was observed between the morning period and the afternoon period (n = 22). Furthermore, the mean pCO2 in January (~105 µatm; n = 4) and April (133-212 µatm; n = 8) was below the typical atmospheric CO2 level (C-sink), while that in the other months surpassed 410 µatm (C-source), although the average values (n = 44) of pCO2 and fCO2 were 960 ± 841 µatm and 57 ± 85 mmol m-2 h-1, respectively. Moreover, the pCO2 concentration was significantly greater in summer (May to August, locally reaching 1087 µatm) than in spring (January to April at 112 µatm), indicating a seasonal shift between the C-sink (spring) and the C-source (summer). In addition, a significant positive correlation in pCO2/fCO2 with chlorophyll-a/nitrate but a negative correlation in dissolved oxygen and total phosphorus were recorded, suggesting that photosynthesis and respiration were identified as the main drivers of CO2 absorption/emissions, while changes in nitrate and phosphorus may be attributed to urbanization. Overall, our investigations indicated that this lightly eutrophic lake demonstrated a distinct shifting pattern of CO2 source-sink variability at daily and seasonal scales.

Microstructure-Assisted Wafer-Scale Fabrication of Perovskite Microlaser Arrays.

All inorganic lead halide perovskites exhibit fascinating optical and optoelectronic characteristics for on-chip lasing, but the lack of precise control of wafer-scale fabrication for perovskite microstructure arrays restricts their potential applications in on-chip-integrated devices. In this work, a microstructure-template assisted crystallization method is demonstrated via a designed chemical vapor deposition process, achieving the controllable fabrication of homogeneous perovskite micro-hemispheroid (PeMH) arrays spanning the entire surface area of a 4-inch wafer. Benefiting from the low-loss whispering gallery resonance and plasmon-enhanced light-matter interactions in well-confined hybrid cavities, this CsPbX3/Ag (X = Cl, Br) plasmonic microlasers exhibit quite low thresholds below 10 µJ cm-2. Interestingly, these thresholds can be efficiently modulated through the manipulation of plasmonic resonance and electromagnetic field mode in PeMHs owning various diameters. This strategy not only provides a valuable methodology for the large-scale fabrication of perovskite microstructures but also endorses the potential of all-inorganic perovskite nanostructures as promising candidates for on-chip-integrated light sources.

Multifunctional Optoelectronic Synapses Based on Arrayed MoS2 Monolayers Emulating Human Association Memory.

Optoelectronic synaptic devices integrating light-perception and signal-storage functions hold great potential in neuromorphic computing for visual information processing, as well as complex brain-like learning, memorizing, and reasoning. Herein, the successful growth of MoS2 monolayer arrays assisted by gold nanorods guided precursor nucleation is demonstrated. Optical, spectral, and morphology characterizations of MoS2 prove that arrayed flakes are homogeneous monolayers, and they are further fabricated as optoelectronic devices showing featured photocurrent loops and stable optical responses. Typical synaptic behaviors of photo-induced short-term potentiation, long-term potentiation, and paired pulse facilitation are recorded under different light stimulations of 450, 532, and 633 nm lasers at various excitation powers. A visual sensing system consisting of 5 × 6 pixels is constructed to simulate the light-sensing image mapped by forgetting curves in real time. Moreover, the system presents the ability of utilizing associated images to restore vague and incomplete memories, which successfully mimics human intelligent behaviors of association memory and logical reasoning. The work emulates the brain-like artificial intelligence using arrayed 2D semiconductors, which paves an avenue to achieve smart retina and complex brain-like system.

All-inorganic lead halide perovskite nanocrystals applied in advanced display devices.

Advanced display devices are in greater demand due to their large color gamut, high color purity, ultrahigh visual resolution, and small size pixels. All-inorganic lead halide perovskite (AILHP) nanocrystals (NCs) possess inherent advantages such as narrow emission width, saturated color, and flexible integration, and have been developed as functional films, light sources, backlight components, and display panels. However, some drawbacks still restrict the practical application of advanced display devices based on AILHP NCs, including working stability, large-scale synthesis, and cost. In this review, we focus on AILHP NCs, review the recent progress in materials synthesis, stability improvement, patterning techniques, and device application. We also highlight the important role of materials systems in creating advanced display devices, followed by the challenges and opportunities in industrial processes. This review provides beneficial inspiration for the future development of AILHP NCs in colorful and white backlight, as well as high resolution full-color displays.