Research ArticleELECTRONICS

Electronic plants

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Science Advances  20 Nov 2015:
Vol. 1, no. 10, e1501136
DOI: 10.1126/sciadv.1501136
  • Fig. 1 Basic plant physiology and analogy to electronics.

    (A and B) A plant (A), such as a rose, consists of roots, branches, leaves, and flowers similar to (B) electrical circuits with contacts, interconnects, wires, and devices. (C) Cross section of the rose leaf. (D) Vascular system of the rose stem. (E) Chemical structures of PEDOT derivatives used.

  • Fig. 2 Electronically conducting xylem wires.

    (A) Forming PEDOT-S:H wires in the xylem. A cut rose is immersed in PEDOT-S:H aqueous solution, and PEDOT-S:H is taken up and self-organizes along the xylem forming conducting wires. The optical micrographs show the wires 1 and 30 mm above the bottom of the stem (bark and phloem were peeled off to reveal the xylem). (B) Scanning electron microscopy (SEM) image of the cross section of a freeze-dried rose stem showing the xylem (1 to 5) filled with PEDOT-S:H. The inset shows the corresponding optical micrograph, where the filled xylem has the distinctive dark blue color of PEDOT. (C) SEM images (with corresponding micrograph on the left) of the xylem of a freeze-dried stem, which shows a hydrogel-like PEDOT-S structure.

  • Fig. 3 Electrical characterization of xylem wires.

    (A) Schematic of conductivity measurement using Au probes as contacts. (B) I-V characteristics of PEDOT-S xylem wires of different lengths: L1 = 2.15 mm, L2 = 0.9 mm, and L3 = 0.17 mm. The inset shows resistance versus length/area and linear fit, yielding a conductivity of 0.13 S/cm.

  • Fig. 4 Xylem transistors and digital logic.

    (A) Output characteristics of the xylem-OECT. The inset shows the xylem wire as source (S) and drain (D) with gate (G) contacted through the plant tissue. (B) Transfer curve of a typical xylem-OECT for VD = −0.3 V (solid line, linear axis; dashed line, log axis). (C) Temporal response of ID and IG relative to increasing VG. (D) Logical NOR gate constructed along a single xylem wire. The circuit diagram indicates the location of the two xylem-OECTs and external connections (compare with circuit in Fig. 1B). Voltage traces for Vin1, Vin2, and Vout illustrate NOR function. The dashed lines on the Vout plot indicate thresholds for defining logical 0 and 1.

  • Fig. 5 PEDOT-infused leaves.

    (A) Vacuum infiltration. Leaf placed in PEDOT:PSS–NFC solution in a syringe with air removed. The syringe is pulled up, creating negative pressure and causing the gas inside the spongy mesophyll to be expelled. (B) When the syringe returns to standard pressure, PEDOT:PSS–NFC is infused through the stomata, filling the spongy mesophyll between the veins. (C and D) Photograph of the bottom (C) and cross section (D) of a pristine rose leaf before infiltration. (E and F) Photograph of the bottom (E) and cross section (F) of leaf after PEDOT:PSS–NFC infusion.

  • Fig. 6 Electrochromism in PEDOT:PSS–NFC–infused leaf.

    (A and B) Optical micrographs of the infused leaf upon application of (A) +15 V and (B) −15 V. Movie S1 shows a video recording of these results. (C and D) False color map of change in grayscale intensity between application of (C) +15 V and (D) −15 V. Green represents a positive increase in grayscale value (light to dark). (E and F) Grayscale values of pixel intensity along the lines indicated in (C) and (D) showing successive oxidation/reduction gradients. A plot of the change in grayscale intensity over a fixed line showing the change and oxidation/reduction gradations versus distance. a.u., arbitrary unit.

  • Fig. 7 Leaf OECD.

    (A) Visualization of the electric field in the leaf-OECD via the induced electrochromic gradient directions [cf. study by Said et al. (30)]. (B) Electrical schematic representation of n-compartments modeling both electronic and ionic components of the current.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/1/10/e1501136/DC1

    Methods

    Fig. S1. PEDOT-infused and electrochromic leaves on living rose.

    Table S1. Summary of materials attempted for conducting xylem wires.

    Movie S1. Video recording of electrochromism in PEDOT:PSS–NFC–infused rose leaf.

    References (3134)

  • Supplementary Materials

    This PDF file includes:

    • Methods
    • Fig. S1. PEDOT-infused and electrochromic leaves on living rose.
    • Table S1. Summary of materials attempted for conducting xylem wires.
    • Legend for movie S1
    • References (31–34)

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    Other Supplementary Material for this manuscript includes the following:

    • Movie S1 (.mp4 format). Video recording of electrochromism in PEDOT:PSS–NFC–infused rose leaf.

    Files in this Data Supplement:

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