Impacts of Surface Depletion on the Plasmonic Properties of Doped Semiconductor Nanocrystals

Degenerately doped semiconductor nanocrystals (NCs) exhibit a localized surface plasmon resonance (LSPR) in the infrared range of the electromagnetic spectrum. Unlike metals, semiconductor NCs offer tunable LSPR characteristics enabled by doping, or via electrochemical or photochemical charging. Tuning plasmonic properties through carrier density modulation suggests potential applications in smart optoelectronics, catalysis, and sensing. Here, we elucidate fundamental aspects of LSPR modulation through dynamic carrier density tuning in Sn-doped Indium Oxide NCs. Monodisperse Sn-doped Indium Oxide NCs with various doping level and sizes were synthesized and assembled in uniform films. NC films were then charged in an in situ electrochemical cell and the LSPR modulation spectra were monitored. Based on spectral shifts and intensity modulation of the LSPR, combined with optical modeling, it was found that often-neglected semiconductor properties, specifically band structure modification due to doping and surface states, strongly affect LSPR modulation. Fermi level pinning by surface defect states creates a surface depletion layer that alters the LSPR properties; it determines the extent of LSPR frequency modulation, diminishes the expected near field enhancement, and strongly reduces sensitivity of the LSPR to the surroundings

Additional file 2: Table S1. of Genome-wide identification and characterization of SnRK2 gene family in cotton (Gossypium hirsutum L.)

FPKM values under abiotic stresses. (XLSX 17 kb

Additional file 4: Table S3. of Genome-wide identification and characterization of SnRK2 gene family in cotton (Gossypium hirsutum L.)

List of the primers used for quantitative real-time PCR in this study. (XLSX 10 kb

Additional file 1: Figure S1. of Genome-wide identification and characterization of SnRK2 gene family in cotton (Gossypium hirsutum L.)

Details of conserved motifs detected among members of the GhSnRK2 protein family by MEME. (TIFF 1466 kb

Additional file 3: Table S2. of Genome-wide identification and characterization of SnRK2 gene family in cotton (Gossypium hirsutum L.)

Gene accession number and samples information of transcriptome data used in our research. (XLSX 10 kb

<i>AtWuschel</i> Promotes Formation of the Embryogenic Callus in <i>Gossypium hirsutum</i>

<div><p>Upland cotton (<i>Gossypium hirsutum</i>) is one of the most recalcitrant species for <i>in vitro</i> plant regeneration through somatic embryogenesis. Callus from only a few cultivars can produce embryogenic callus (EC), but the mechanism is not well elucidated. Here we screened a cultivar, CRI24, with high efficiency of EC produce. The expression of genes relevant to EC production was analyzed between the materials easy to or difficult to produce EC. Quantitative PCR showed that CRI24, which had a 100% EC differentiation rate, had the highest expression of the genes <i>GhLEC1</i>, <i>GhLEC2</i>, and <i>GhFUS3</i>. Three other cultivars, CRI12, CRI41, and Lu28 that formed few ECs expressed these genes only at low levels. Each of the genes involved in auxin transport (<i>GhPIN7</i>) and signaling (<i>GhSHY2</i>) was most highly expressed in CRI24, with low levels in the other three cultivars. WUSCHEL (WUS) is a homeodomain transcription factor that promotes the vegetative-to-embryogenic transition. We thus obtained the calli that ectopically expressed <i>Arabidopsis thaliana Wus</i> (<i>AtWus</i>) in <i>G. hirsutum</i> cultivar CRI12, with a consequent increase of 47.75% in EC differentiation rate compared with 0.61% for the control. Ectopic expression of <i>AtWus</i> in CRI12 resulted in upregulation of <i>GhPIN7</i>, <i>GhSHY2</i>, <i>GhLEC1</i>, <i>GhLEC2</i>, and <i>GhFUS3</i>. <i>AtWus</i> may therefore increase the differentiation potential of cotton callus by triggering the auxin transport and signaling pathways.</p></div

AtWus overexpression results in abnormal development of somatic embryos.

<p><b>A:</b> Many abnormal somatic embryos were produced in 35S:WUS lines, and the somatic embryos were inflated and lacked cotyledons. <b>B:</b> Formation of normal somatic embryos in CK lines at different stages. Scanning electron microscopy: Holistic perspective of somatic embryos in 35S:WUS lines (<b>C</b>) and CK lines (<b>D</b>). <b>E</b>–<b>J:</b> Normal somatic embryos at different stages. <b>E</b>, <b>F:</b> globular embryo. <b>G:</b> heart-shape embryo. <b>H</b>–<b>J:</b> cotyledonary embryo. <b>K</b>–<b>P:</b> Abnormal somatic embryos having various appearance. <b>O:</b> leaf-like embryo. <b>P:</b> multiple-cotyledon embryo. Bar in <b>A</b> or <b>B,</b> 1 cm.</p

Analysis of gene expression in the non-transgenic calli of the four cultivars.

<p>Analysis of gene expression in the non-transgenic calli of the four cultivars.</p

<i>AtWus</i> expression in calli of CRI12.

<p><i>AtWus</i> expression in calli of CRI12.</p

Somatic embryo weight in CRI12.

*<p>p<0.05.</p