Epitaxial grown [hk1] oriented 2D/1D Bi2O2S/Sb2S3 heterostructure with significantly enhanced photoelectrochemical performance

Bismuth oxysulfide (Bi2O2S) is a layered material with high carrier mobility, excellent light absorption characteristic and good stability. However, there are few reports about the use of Bi2O2S in photoelectrochemical (PEC) water splitting. In this paper, Bi2O2S nanosheets (NSs) films were prepared on FTO substrates by one-step hydrothermal method, which broke the traditional powder state of Bi2O2S prepared. Based on the high lattice matching between antimony sulfide (Sb2S3) and bismuth sulfide (Bi2S3) obtained from the topological transformation of partial Bi2O2S, Sb2S3 nanorods (NRs) with [hk1] predominant orientation were epitaxially grown on the surface of Bi2O2S to establish a transport channel for rapid carrier migration. Titanium dioxide (TiO2) electron transport layer with oxygen vacancies was introduced into the back to capture and release electrons, further reducing the recombination rate. The photocurrent density of TiO2/Bi2O2S/Sb2S3-annealed photoelectrode at 1.23 V vs. RHE was 4.37 mA/cm2, which was 13.7 times that of monomer Bi2O2S. In addition, the TiO2/Bi2O2S/Sb2S3-annealed photoelectrode had lower charge transfer resistance and the IPCE value up to 48.22%. This study is of great significance for the application of Bi2O2S based photoelectrodes in the field of PEC water splitting.

Neurophysiology goes wild: from exploring sensory coding in sound proof rooms to natural environments

To perform adaptive behaviours, animals have to establish a representation of the physical "outside" world. How these representations are created by sensory systems is a central issue in sensory physiology. This review addresses the history of experimental approaches toward ideas about sensory coding, using the relatively simple auditory system of acoustic insects. I will discuss the empirical evidence in support of Barlow's "efficient coding hypothesis", which argues that the coding properties of neurons undergo specific adaptations that allow insects to detect biologically important acoustic stimuli. This hypothesis opposes the view that the sensory systems of receivers are biased as a result of their phylogeny, which finally determine whether a sound stimulus elicits a behavioural response. Acoustic signals are often transmitted over considerable distances in complex physical environments with high noise levels, resulting in degradation of the temporal pattern of stimuli, unpredictable attenuation, reduced signal-to-noise levels, and degradation of cues used for sound localisation. Thus, a more naturalistic view of sensory coding must be taken, since the signals as broadcast by signallers are rarely equivalent to the effective stimuli encoded by the sensory system of receivers. The consequences of the environmental conditions for sensory coding are discussed.