Fig. 3
From: Nanoscale membranes that chemically isolate and electronically wire up the abiotic/biotic interface
Spectroscopic characterization of PV3 wire attachment and casting into SiO2. a FT-IR characterization. (1) Absorbance spectrum of TMSA powder in KBr. Scale bar is 0.008. (2) IRRAS of TMSA anchored on Pt/SnO2 (using Pt/SnO2 as reference) at 2 cm−1 resolution, computed as the negative log of a single beam spectrum at p-polarization of a sample, divided by a single beam spectrum at s-polarization. Scale bar is 0.002. (3) Absorbance spectrum of powder of PV3 with the aniline groups attached on both ends of the wire molecule (model for TMSA anchored PV3) in KBr. Scale bar is 0.008. (4) IRRAS of PV3 attached to TMSA on Pt/SnO2 (using SnO2/Pt as reference). PV3 bands highlighted in blue. Scale bar is 0.002. (5) IRRAS of pure SiO2 layer on Pt/SnO2 (using Pt/SnO2 as reference). For clarity, raw spectrum shown in light trace is overlaid by computationally filtered (low bandpass) dark trace. Scale bar is 0.002. (6) IRRAS of SiO2-encapsulated PV3 attached to TMSA on Pt/SnO2 (using Pt/SnO2 as reference). PV3 bands are shaded in black for clarity. Scale bar is 0.002. b XPS spectrum of the N 1s region of (1) Pt/SnO2; (2) TMSA anchored on Pt/SnO2 showing N 1s NH2 peak; and (3) PV3 attached to TMSA on Pt/SnO2 showing overlapping amide and cyano group signals centered at 399.5 eV and the nitro group at 406.2 eV. Two-component deconvolution is shown (see text). Binding energies are aligned with reference to adventitious C 1 s peak at 284.8 eV. CPS counts per second. For completeness, bands for C 1s, O 1s, and Si 2p spectra are shown in Supplementary Fig. 4. c UV-Vis spectra of (1) 0.47 μM PV3 in aqueous solution and (2) difference spectrum of SiO2-encapsulated PV3 on quartz/SnO2 (transmission mode). Reference is pure SiO2 on quartz/SnO2. The gray line is a cubic fit for the background
