Electronic Supplementary Material (ESI) for Journal of Materials Chemistry A. This journal is The Royal Society of Chemistry 2017 Electronic Supplementary Information (ESI) for Fabrication of a One-dimensional Tube-in-tube Polypyrrole/Tin oxide Structure for Highly Sensitive DMMP Sensor Applications Jaemoon Jun, Jun Seop Lee, Dong Hoon Shin, Jungkyun Oh, Wooyoung Kim, Wonjoo Na, and Jyongsik Jang * School of Chemical and Biological Engineering, College of Engineering, Seoul National University (SNU), 599 Gwanangno, Gwanak-gu, Seoul, 151-742 (Korea). Fax: +82-2-888-7295; Tel: 82-2-880-8348; e-mail: jsjang@plaza.snu.ac.kr 1
Fig. S1. (a, c) Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images of the SnO 2 fibers. (b, d) TEM and SEM images of the SnO 2 tubes. 2
Fig. S2. Transmission electron microscopy (TEM) images of the PPy@SnO 2 tube in tube by conducting the VDP step at different temperature (a)60 C and (b)100 C. 3
Fig. S3. TEM image of the morphology of the PPY coated SnO 2 tube structure after VDP method in ambient state. 4
a) b) Fig. S4. (a) Low-and (c) high-resolution FE-SEM images of the tube-in-tube SnO 2. 5
200nm Fig. S5. High-resolution SEM image of the PPy@SnO 2 tube in tube. 6
Intensity (a.u.) C1s N1s Sn3d O1s Fe2p 0 200 400 600 800 1000 1200 Binding energy(ev) Fig. S6.. X-ray photoelectron spectroscopy (XPS) analysis of a fully scanned spectra (0 1200 ev). Fig.S6 shows the overall XPS spectroscopy of the PPy@SnO 2 tube in tube over the range of 0-1200eV; carbon, nitrogen, oxygen, tin, and iron atoms were present. Based on the XPS peak, it is considered that the small quantities of iron atom originated from FeCl3 solution is still exist. 7
(a) (b) (c) C N (d) (e) (f) Sn O Fe Fig. S7. EDS dot mapping of PPy@SnO 2 tube in tube surface components indicating (a)overall SEM image, (b)carbon, (c)nitrogen, (d)tin, (e)oxygen and (f)iron Fig. S8. EDX spectrum of the PPy@SnO 2 tube in tube surface Table S1. Summarized elemental distribution of the PPy@SnO 2 tube in tube Element Weight% Atomic% C K 5.42 14.30 N K 5.64 12.77 O K 27.71 54.94 Al K 0.31 0.36 Cl K 1.50 1.35 Fe K 2.15 1.22 Sn L 51.54 13.77 Sb L 3.66 0.95 Pt M 2.07 0.34 8
(a) (b) (c) Adsorbed (cm 3 g -1 STP) 50 40 30 20 10 0 0.0 0.2 0.4 0.6 0.8 1.0 Adsorbed (cm 3 g -1 STP) 70 60 50 40 30 20 10 0 0.0 0.2 0.4 0.6 0.8 1.0 Relative pressure (P/P0) Relative pressure (P/P0) Adsorbed (cm 3 g -1 STP) 120 100 80 60 40 20 0 0.0 0.2 0.4 0.6 0.8 1.0 Relative pressure (P/P0) Fig. S9. Nitrogen adsorption desorption isotherm curves of (a) Fiber, (b) Tube, and (c) Tube-in-tube. 9
(a) (b) 2 μm 25 μm Fig. S10. (a) Low- and (b) high-resolution optical microscopy images of the interdigitated array (IDA) electrode. 10
0.50 Current (ma) 0.25 0.00-0.25 PPy@SnO 2 tube in tube -0.50-0.10-0.05 0.00 0.05 0.10 Voltage (V) Fig. S11. Current voltage (I V) curve of the tube-in-tube PPy@SnO 2 sensor electrode. 11
Fig. S12. Molecular structures of (a) dimethyl methylphosphonate (DMMP) and (b) polypyrrole (PPy). (c) Schematic diagram describing the effect of hydrogen bonding on PPy. 12
a) b) hole P-type P-type DMMP Depletion region n-type - - - - - + + + + + e - e - e - e - e - e - e - e - e - e - e - e - n-type e - e - DMMP Depletion region - - - - - - - - - - + + + + + e - e - e - e - e - e - e - e - e - e - e - e - e - e - Fig. S13. Schematic diagram of the formation of a p-n junction. 13
Fig. S14. SEM image of the PPy@SnO 2 nanoparticles. 14
Fig. S15. Real-time monitoring of PPy@SnO 2 having different one-dimensional (1D) structures after sequential exposure to DMMP. 10 8 R/R 0 (%) 6 4 2 0.1 ppb 1 ppb 10 ppb 0.1 ppm 1 ppm 0 0 200 400 600 800 100012001400 Time (s) Fig. S16. Real-time responses of the PPy@SnO 2 nanoparticles upon periodic exposure to dimethyl methylphosphonate(dmmp); 0.1 ppb to 1 ppm. 15
R/R 0 (%) 14 12 10 8 6 4 2 0 PPy@SnO 2 tube in tube PPy@SnO 2 tube PPy@SnO 2 fiber 0 200 400 600 800 1000 Concentration (ppb) Fig. S17. Changes in sensitivity as a function of DMMP concentration calculated from the real-time responses. 10 8 Sens i t i v i t y di st r i but i on R/R 0 (%) 6 4 2 0 Fiber tube tube in tube Fig. S18. Variation and comparison of the sensitivity parameter. These parameters were evaluated from 10 devices fabricated at 1 ppm 16