BiVO₄/WO₃/SnO₂ Double-Heterojunction Photoanode with Enhanced Charge Separation and Visible-Transparency for Bias-Free Solar Water-Splitting with a Perovskite Solar Cell

Coupling dissimilar oxides in heterostructures allows the engineering of interfacial, optical, charge separation/transport and transfer properties of photoanodes for photoelectrochemical (PEC) water splitting. Here, we demonstrate a double-heterojunction concept based on a BiVO₄/WO₃/SnO₂ triple-layer planar heterojunction (TPH) photoanode, which shows simultaneous improvements in the charge transport (∼93% at 1.23 V vs RHE) and transmittance at longer wavelengths (>500 nm). The TPH photoanode was prepared by a facile solution method: a porous SnO₂ film was first deposited on a fluorine-doped tin oxide (FTO)/glass substrate followed by WO₃ deposition, leading to the formation of a double layer of dense WO₃ and a WO₃/SnO₂ mixture at the bottom. Subsequently, a BiVO₄ nanoparticle film was deposited by spin coating. Importantly, the WO₃/(WO₃+SnO₂) composite bottom layer forms a disordered heterojunction, enabling intimate contact, lower interfacial resistance, and efficient charge transport/transfer. In addition, the top BiVO₄/WO₃ heterojunction layer improves light absorption and charge separation. The resultant TPH photoanode shows greatly improved internal quantum efficiency (∼80%) and PEC water oxidation performance (∼3.1 mA/cm² at 1.23 V vs RHE) compared to the previously reported BiVO₄/WO₃ photoanodes. The PEC performance was further improved by a reactive-ion etching treatment and CoO_<i>x</i> electrocatalyst deposition. Finally, we demonstrated a bias-free and stable solar water-splitting by constructing a tandem PEC device with a perovskite solar cell (STH ∼3.5%)

Effects of genetic variants of <i>ST8SIA2</i> and <i>NCAM1</i> genes on seasonal mood changes and circadian preference in the general population

<p><i>ST8SIA2</i> and <i>NCAM1</i> are functionally related genes forming polysialic acid (PSA) - neural cell adhesion molecule (NCAM) complex in suprachiasmatic nucleus (SCN), the regulating site of circadian biological rhythm. In this study, the relationship of <i>ST8SIA2</i> and <i>NCAM1</i> with circadian and seasonal rhythms of human behavior was explored. Subjects were 261 healthy Korean adults who were free of any history of clinically significant psychiatric symptoms. The phenotypes were circadian preference and seasonal change of mood and behavior (seasonality) measured by the Composite Scale of Morningness and the Seasonal Pattern Assessment Questionnaire, respectively. Thirty-four single nucleotide polymorphisms (SNPs) across the <i>ST8SIA2</i> region and 15 SNPs of <i>NCAM1</i> were analyzed. A nominally significant association with seasonality and circadian preference was observed in 21 variants of both genes. After corrections for multiple testing, associations of 8 SNPs of <i>ST8SIA2</i> and 2 SNPs of <i>NCAM1</i> with seasonality remained significant. Some of these SNPs were also associated with psychiatric disorders in previous studies. This study demonstrated a meaningful and/or suggestive evidence of association between behavioral phenotypes reflecting human biological rhythm and two interplaying genes involved in the plasticity of SCN’s neuronal network.</p

Characteristics of the 34 <i>ST8SIA2</i> tag SNPs.

<p>SNP, single nucleotide polymorphism; MAF, minor allele frequency</p><p>^a Minor allele frequency based on the control group data</p><p>Characteristics of the 34 <i>ST8SIA2</i> tag SNPs.</p

SNPs associated with either schizophrenia or bipolar disorder with nominally significant <i>p-</i>values (<0.05).

<p>BD-I, bipolar I disorder; BD-II, bipolar II disorder; OR, odds ratio; CI, confidence interval</p><p>* <i>p</i> < 0.05</p><p>** corrected <i>p</i> < 0.05</p><p>^a Nominal <i>p</i>-value by logistic regression with age and sex covariates.</p><p>^<b>b</b> The inheritance model with the least Akaike Information Criterion was accepted as the best fitting model.</p><p>SNPs associated with either schizophrenia or bipolar disorder with nominally significant <i>p-</i>values (<0.05).</p

Demographic characteristics of the subjects.

<p>BD-I, bipolar I disorder; BD-II, bipolar II disorder</p><p>^a After post-hoc analysis, BD-II group was older than the other groups and the control group was younger than the other groups. More males were in the schizophrenia group than in the BD-1 and control groups, and the BD-II group had more females than the other groups.</p><p>Demographic characteristics of the subjects.</p

Relative positions of the <i>ST8SIA2</i> single nucleotide polymorphisms (SNPs) analyzed in the current study and previous studies reporting positive associations with schizophrenia or bipolar disorder.

<p>BD-I, bipolar I disorder; BD, bipolar disorder. Relative positions of the exons are displayed in the left column. Colored area is the covered area of the gene in the corresponding study. Box with bold outline indicates high linkage disequilibrium block (D’> 0.9) generated by Haploview v4.0 (<a href="http://www.broad.mit.edu/mpg/haploview" target="_blank">http://www.broad.mit.edu/mpg/haploview</a>) using the control group data of the current study (<i>n</i> = 502). SNPs with red letter indicate a significant association with nominal <i>p</i>-values < 0.05.</p

Sociodemographic profiles of the 817 subjects.

<p>Sociodemographic profiles of the 817 subjects.</p

Comparison of types of trauma experienced between MDD with any binge eating (ABE), frequent binge eating (FBE), and without binge eating (BE) groups.

<p>Comparison of types of trauma experienced between MDD with any binge eating (ABE), frequent binge eating (FBE), and without binge eating (BE) groups.</p

Logistic regression analyses to determine factors associated with suicide attempt.

<p>Logistic regression analyses to determine factors associated with suicide attempt.</p

Comparison of depression symptoms, comorbid psychiatric conditions and suicide-related behavior between MDD with any binge eating (ABE), frequent binge eating (FBE), and without binge eating (BE) groups.

<p>Comparison of depression symptoms, comorbid psychiatric conditions and suicide-related behavior between MDD with any binge eating (ABE), frequent binge eating (FBE), and without binge eating (BE) groups.</p