The plasmonic characteristic of core–shell nanomaterials can effectively improve exciton‐generation/dissociation and carrier‐transfer/collection. In this work, a new strategy based on core–shell Au@CdS nanospheres is introduced to passivate perovskite grain boundaries (GBs) and the perovskite/hole transport layer interface via an antisolvent process. These core–shell Au@CdS nanoparticles can trigger heterogeneous nucleation of the perovskite precursor for high‐quality perovskite films through the formation of the intermediate Au@CdS–PbI2 adduct, which can lower the valence band maximum of the 2,2,7,7‐tetrakis(N,N‐di‐p‐methoxyphenyl‐amine)9,9‐spirobifluorene (Spiro‐OMeTAD) for a more favorable energy alignment with the perovskite material. With the help of the localized surface plasmon resonance effect of Au@CdS, holes can easily overcome the barrier at the perovskite/Spiro‐OMeTAD interface (or GBs) through the bridge of the intermediate Au@CdS–PbI2, avoiding the carrier accumulation, and suppress the carrier trap recombination at the Spiro‐OMeTAD/perovskite interface. Consequently, the Au@CdS‐based perovskite solar cell device achieves a high efficiency of over 21%, with excellent stability of ≈90% retention of initial power conversion efficiencies after 45 days storage in dry air.

A fundamental task of the visual system is to extract figure-ground boundaries between images of objects, which in natural scenes are often defined not only by luminance differences but also by "second-order" contrast or texture differences. Responses to contrast modulation (CM) and other second-order stimuli have been extensively studied in human psychophysics, but the neuronal substrates of second-order responses in nonhuman primates remain poorly understood. In this study, we have recorded single neurons in area V2 of macaque monkeys, using both CM patterns as well as conventional luminance modulation (LM) gratings. CM stimuli were constructed from stationary sine wave grating carrier patterns, which were modulated by drifting envelope gratings of a lower spatial frequency. We found approximately one-third of visually responsive V2 neurons responded to CM stimuli with a pronounced selectivity to carrier spatial frequencies, and often orientations, that were clearly outside the neurons' passbands for LM gratings. These neurons were "form-cue invariant" in that their tuning to CM envelope spatial frequency and orientation was very similar to that for LM gratings. Neurons were tuned to carrier spatial frequencies that were typically 2-4 octaves higher than their optimal envelope spatial frequencies, similar to results from human psychophysics. These results are distinct from CM responses arising from surround suppression, but could be understood in terms of a filter-rectify-filter model. Such neurons could provide a functionally useful and explicit representation of segmentation boundaries as well as a plausible neural substrate for human perception of second-order boundaries.

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Interface engineering is critical for achieving high-efficiency and high-stability perovskite solar cells (PSCs). Herein, a new interface engineering approachpoly(ethylene oxide) (PEO) modification of SnO 2 quantum dot (QD) film-to improve electron transport is introduced. It is found that when the PEO film is annealed over its glass-transition temperature, the ether-oxygen unshared electron pair in the PEO film activates to form a crosslinking complex with metal ions at the SnO 2 QD and perovskite interface, which triggers heterogeneous nucleation over the perovskite precursor film and is beneficial for achieving uniform and dense perovskite films. PEO is also shown to passivate the bulk defects of perovskite films and the interface defects between SnO 2 QD and perovskite, which promotes electron-transferring from the perovskite layer to cathode. PSCs based on SnO 2 QD with PEO treatment exhibit an enhanced efficiency, leading to a champion PCE of 20.23%, with good reproducibility and stability.

Perovskite solar cells (PSCs) have a great potential for commercialization due to their chemical versatility and tunable energy bands, [1] low-cost solution process, [2] and large-scale compatibility with flexible substrates. [3] During the past decade, we have witnessed a sharp increase in the record power conversion efficiencies (PCEs) from %3% to the most recently certified value of 25.5%, [4] comparable with that of silicon solar cells. Multiple strategies have been developed for raising the performance of PSCs, including the design and crystal growth of perovskite absorber, innovation of device architecture, defect passivation, and interface engineering. [4a,5] Among them, interface engineering stands out as an effective approach to control carrier dynamics and minimize carrier recombination within the PSCs. [6] The imperfect interface is a major limiting factor of the performance of PSCs. [7] Therefore, an optimal interface engineering can balance the charge generation, recombination, transportation, and extraction processes. [8] PSCs with an n-i-p architecture are usually termed as the conventional structure. Normally, the mobility of hole is lower than that of electron. The equilibrium between hole and electron-transport plays a key role in determining the device performance, which is closely related to the balanced charge extraction [9] and perfect interfacial band alignment. [10] Although many researchers have recently focused on optimizing

It is well known that, in humans, contrast sensitivity training at high spatial frequency (SF) not only leads to contrast sensitivity improvement, but also results in an improvement in visual acuity as assessed with gratings (direct effect) or letters (transfer effect). However, the underlying neural mechanisms of this high spatial frequency training improvement remain to be elucidated. In the present study, we examined four properties of neurons in primary visual cortex (area 17) of adult cats that exhibited significantly improved acuity after contrast sensitivity training with a high spatial frequency grating and those of untrained control cats. We found no difference in neuronal contrast sensitivity or tuning width (Width) between the trained and untrained cats. However, the trained cats showed a displacement of the cells’ optimal spatial frequency (OSF) to higher spatial frequencies as well as a larger neuronal signal-to-noise ratio (SNR). Furthermore, both the neuronal differences in OSF and SNR were significantly correlated with the improvement of acuity measured behaviorally. These results suggest that striate neurons might mediate the perceptual learning-induced improvement for high spatial frequency stimuli by an alteration in their spatial frequency representation and by an increased SNR.

Aging-related declines in vision can decrease well-being of the elderly. Concerning early sensory changes as in the primary visual cortex, physiological and behavioral reports seem contradictory. Neurophysiological studies on orientation tuning properties suggested that neuronal changes might come from decreased cortical local inhibition. However, behavioral results either showed no clear deficits in orientation processing in older adults, or proposed stronger surround suppression. Through psychophysical experiments and computational modeling, we resolved these discrepancies by suggesting that lateral inhibition increased in older adults while neuronal orientation tuning widths, related to local inhibition, stayed globally intact across age. We confirmed this later result by re-analyzing published neurophysiological data, which showed no systematic tuning width changes, but instead displayed a higher neuronal noise with aging. These results suggest a stronger lateral inhibition and mixed effects on local inhibition during aging, revealing a more complex picture of age-related effects in the central visual system than people previously thought.

Among the serious consequences of alcohol abuse is the reduced ability to process visual information. Diminished vision from excessive consumption of alcohol has been implicated in industrial, home, and automobile accidents. Alcohol is also generally recognized as an inhibitor in the brain by potentiating GABA-ergic transmission. In this study, we focused on visual motion processing and explored whether moderate alcohol intoxication induced changes in inhibitory mediated motion repulsion in a centersurround configuration. We conducted a double-blind, placebo-controlled, within-subjects study on the effect of alcohol on visual motion repulsion. Each subject underwent three experimental conditions (no alcohol, placebo and moderate alcohol) on separate days. The order of the placebo and moderate alcohol conditions was counterbalanced. The results showed that the effects of the surround context on the perception of the center motion direction were similar in both the sober (no alcohol) and placebo conditions. However, contextual modulations were significantly stronger during intoxication compared to both the sober and placebo conditions. These results demonstrate that moderate alcohol consumption is associated with altered neural function in visual cortical areas and that motion repulsion deficits might reflect the inhibitory effects of alcohol on the central nervous system. Acute alcohol consumption disturbs cognitive, attentional, motor, and perceptual functions in a dose-dependent manner. Negative effects occur with a small to moderate blood alcohol concentration (BAC) of approximately 0.4-0.5 mg/ml [1][2][3]