Scanning Nanoelectrochemistry and Nanoelectrical Liquid Imaging with Nanoelectrode Probe

Transcription

1 Scanning Nanoelectrochemistry and Nanoelectrical Liquid Imaging with Nanoelectrode Probe Teddy Huang, PhD Sr. Applications Scientist, Bruker Nano Surfaces,

2 Outline Overview Nanoelectrode Probe r ~ 25 nm h ~ 250 nm Pt AFM-SECM PeakForce SECM Force Volume SECM Contact Mode SECM Tapping Mode SECM SiO 2 Nanoelectrical Measurements in Liquid Conductive AFM PFM: Nano-Electromechanics Kelvin Probe Force Microscopy Conclusion 2

3 Success from Collaboration Nanoelectrode Probe Scanning Nano-Electrochemistry Nanoelectrical Measurements in Liquid r ~ 25 nm h ~ 250 nm Pt Applications PeakForce SECM PF-TUNA in Liquid Solar Fuels Surface Chemistry Battery Force Volume SECM PFM in Liquid Collaborators JCAP/Caltech Universität Bayreuth (Germany) CCI Solar University of Oregon University of Leeds (UK) Brown University General Motors R&D Fujian Normal University (China) Stanford University Industrial Companies in China East China Normal University SiO 2 3

4 Some Publications Nellist et al. Nature Energy 2017, accepted Jiang et al. ChemSusChem 2017, DOI: /cssc Nellist et al. Nanotechnology 2017, 28, Huang et al. Bruker Application Note 2017 Huang et al. Microscopy Today 2016, 24, 18 4

5 Nanoelectrode Probe 5

6 Active Tip for SECM (local EC studies) & Electrical Characterization in Liquid r ~ 25 nm h ~ 250 nm Pt 1 mm SiO 2 Probe Batch (wafer) manufactured Exposed tip height: ~ 250 nm End tip radius: ~ 25nm k = 1.5 N/m, f = 65 khz Package Fully isolated, encapsulated in two parts glass Easy to handle, robust ESD protection Chemical resistant (ph 1-13 & battery solution) Nellist et al. Nanotechnology 2017, 28,

7 Current (pa) High Electrochemical Performance [Fe(CN) 6 ] 4-/3-50 CVs 5 mm [Ru(NH 3 ) 6 ] 3+ Potential (V vs Ag/AgCl) Robust for handling and electrochemistry: [Ru(NH 3 ) 6 ] 2+/3+ : 4 rinse-and-dry cycles, 5 min amperometry, and 29 CVs 2 hr i-t curve [Fe(CN) 6 ] 3+/4+ : 50 CVs and 2 hr amperometry sub-pa noise level Nellist et al. Nanotechnology 2017, 28,

8 High Spatial Sensitivity e 10 mm 5 [Ru(NH 3 ) 6 ] 3+ [Ru(NH 3 ) 6 ] 2+ Hynek et. al. InTech, 2014, DOI: /57203 < 100 nm diffusion layer Force Curve 0 Approach Curves Current vs tip-sample distance Inactive/active area: negative/positive feedbacks Kinetic quantification: shape vs. surface activity Consistent with simulation No leakage current Line: Experiment Symbols: Simulation Changes mostly occur within 150 nm High spatial sensitivity Consistent with diffusion layer structure Nellist et al. Nanotechnology 2017, 28,

9 PeakForce Scanning Electrochemical Microscopy 9

10 Scanning Electrochemical Microscopy (SECM) A tiny electrode brings electrochemistry to micro- or nano-scale Local EC characterizes active site, diffusion, ionic transport, permeability, etc. Resolutions are primarily defined by the probe electrode dimension E + ΔV vs Ref O + e R Sample R O + e E vs Ref 10

11 SECM Applications Mauzeroll et. al., Chem. Rev. 2016, 116,

12 PeakForce Tapping Probe is sinusoidally modulated at 1~2 khz: No cantilever tuning required. Low and stable force, < 50 pn. Automatic image optimization. Contact High imaging force Tapping Rely on resonance F SP A SP Quantitative NanoMechanics (QNM). Simultaneous nanoelectric capture. PeakForce Tapping Precise force control F 0 F peak PF-QNM PF-TUNA Electrics Time Z position Separation Time 12

13 PeakForce Tapping: Application Examples Embedded CNT on P3HT lamellar SAM on Au Electrochemistry Leclere et al. Nanoscale, 2012, 4, 2705 Microscopy Today 2016, 24, 18 DNA Small 2014, 10, 3257 Live E. Coli cells 13

14 PeakForce SECM Simultaneously multimodal imaging: Topography, mechanics, conductivity, electrochemistry, etc. Scanning NanoEC Interleaved Scan Lift Height Electrochemistry PeakForce AFM Nellist et al. Nanotechnology 2017, 28,

15 PeakForce SECM Hardware AFM scanner Strain-released module Probe Boot Resistor selector Probe holder Probe connection EC cell Temperature control (RT to 65 o C) Low noise electronics, limited only by potentiostat Operation inside a glovebox Robust ESD protection Compatible with glovebox operation Wide range of chemical compatibility Huang et al. Microscopy Today 2016, 24, 18 15

16 PeakForce SECM Multimodal imaging at 15 nm lift height Si 3 N 4 Pt 25 nm depth Si 3 N 4 15 nm 25 nm 40 nm 60 nm 4.5 nn 9 nn 4.5 nn 150 nm 400 nm 0.3 na 7~10 na 0.3 na Si 3 N 4 Pt Si 3 N 4 Contact Current 290 pa 495 pa 290 pa SECM Current Lift height-dependent current. Changes mostly occur within 100 nm lift height. Confirm the compact structure of the diffusion layer. 16

17 Defects on HOPG Electrode Topography 900 nm x 600 nm 0.4 nm step 800 nm r ~ 25 nm Adhesion Topography 250 nm 4 nn difference 800 nm Modulus Adhesion SECM Conductivity Electrochemistry 2~5 pa higher 55 pa difference 800 nm Nellist et al. Nanotechnology 2017, 28,

18 PeakForce SECM Pt/p + -Si for Catalysis Topography Contact Current SECM Current Settings: 10 mm [Ru(NH 3 ) 6 ] 3+, 0.1M KCl Tip potential: -0.4 V vs AgQRE Sample potential: -0.1 V vs AgQRE Peak force: 700 pn; Scan rate: 0.2 Hz; Lift height: 100 nm; PeakForce Tapping is required to measure these loosely attached particles Contact current measures interfacial conductivity SECM current measures electrochemical activity Jiang et al. ChemSusChem, 2017 DOI: /cssc

19 Force Volume Scanning Electrochemical Microscopy 19

20 Kinetic Quantification of Surface Reaction Si 3 N 4 Pt 3 µm Inhomogeneous conductivity 3 µm Inhomogeneous electrochemical activity 3 µm Approach curves of distinct characteristics 20

21 Force Volume Quantitative mechanical mapping modes FastForce Force Volume: Volume156Hz 1Hz Separation Linear ramping to collect the complete force curve from every tap Multiple property maps calculated Multiple ramp data channels acquired Ramp and hold functionality 21

22 Force Volume SECM Topography Approach Curves Force Curves 0.75 Hz ramp rate on Z 62.5 nm / pixel Array of approach curves for improved EC quantification. EC activity in function of distance to sample surface, in every pixel (mapping). Correlated topography, nanomechanics and nanoelectrics 22

23 Force Volume SECM Insulating Flake on Au Substrate Sample Courtesy: Liming Zhang, J. Tyler Meffordd, Andrew Akbashev, and William Chueh, Stanford University Oxide Au 23

24 Tip Current (na) Force Volume SECM Density Plot Density plot shows which EC activities are most commonly present Two distinct areas are differentiated by the two density plots Sample Courtesy: Liming Zhang, J. Tyler Meffordd, Andrew Akbashev, and William Chueh, Stanford University Au Oxide 11/15/2017 Bruker Confidential 24

25 Tip Current (pa) Tip Current (na) Force (nn) Ramp and Hold with FV-SECM On Pt, positive feedback and electrically connected with the Pt electrode Pt Si 3 N 4 On nitride, negative feedback and electrically disconnected with the Pt electrode Pt Si 3 N 4 25

26 Nanoelectrode AFM probes enable the in-operando measurement of surface electrochemical potentials during oxygen evolution catalysis planar Fe 2 O 3 CoPi CoPi on planar photoelectro- Fe 2 O 3 1 µm deposition 1 µm Spatially resolved photovoltage! Catalytst voltage (V tip ) identical whether on ITO or illuminated hematite Holes transfer from hematite to CoPi, where water oxidation occurs Nellist, M. R.; Laskowski, F. A. L.; Qiu, J.; Sivula, K.; Hamann, T.W.; Boettcher, S.W. Potential-sensing electrochemical atomic force microscopy enables in-operando analysis of electrocatalysis during (photo)electrochemical water splitting. Accepted, Nat. Energy.

27 Nanoelectrical Measurements in Liquid 27

28 AFM Nanoelectrical Measurements Bruker provides a versatile array of electrical techniques for a multitude of applications. Conductivity/Resistivity C-AFM, TUNA, PeakForce-TUNA, SSRM Electric Field EFM Charge EFM, SCM Surface Potential / Work Function KPFM, PeakForce KPFM Carrier Density SCM, SSRM, smim, PeakForce-sMIM Piezoelectricity PFM 11/15/2017 Bruker 28

29 PeakForce Nanoelectrical Measurements For previously AFM-inaccessible, delicate samples and adds correlated nanomechanical data Improve tip lifetime with hard samples Decrease sample wear with soft samples Improve resolution due to sharper tips & less sample damage Electrics Time PeakForce TUNA (A) topography, (B) current, and (C) adhesion maps reveal the influence of an embedded nanotube on P3HT lamellar ordering and current pathways. Image size 500 nm. Leclere et al. Nanoscale, 2012, 4, /15/2017 Bruker 29

30 Nanoelectrical Liquid Imaging Applications Energy research Bio-electricity Catalysis Sensing Battery Bio-electricity Kumar et al. ACS Appl. Mater. Interfaces, 2017, 9, Lee et al. Adv. Mater. 2014, 26, 4880 Challenges Compatibility: Environment & chemicals Energy/Catalysis Localized signals High S/N Jiang et al. ChemSusChem, 2017 DOI: /cssc

31 Nanoelectrical Liquid Imaging 100 µm Probe and sample are fully immersed in solution High quality, localized signal Fully-insulated but the tip apex Conductive path to minimize stray capacitance High bandwidth, next-to-tip amplifier 11/15/2017 Bruker 31

32 TUNA & PeakForce TUNA in Liquid 32

33 PeakForce TUNA in Liquid (DMC) in Glove Box Si 3 N Pt Si 3 N Sample was in DMC, a solvent for battery research Measurement was done inside a glove box Clearly differentiates exposed Pt on the current map I-V spectra confirms the difference in conductivity Single line data, no averaging Negligible background current at nitride surface Nellist et al. Nanotechnology 2017, 28,

34 PeakForce TUNA in Liquid in 1M KCl Aqueous Solution at High Bias Si 3 N 4 Pt 0.5V 0.5V Si 3 N 4 Pt -0.5V Si 3 N 4 Pt -0.5V Low parasitic currents on Si 3 N 4 : At -0.5V: 1.06 pa At +0.5V: 0.07 pa Low current noise level: ~1 pa 34

35 PeakForce TUNA in Liquid Interfacial Energetics on a Photoelectrode Liquid 120 nm Liquid on SiO pa Air Sample bias: 0.3 V 120 nm -250 pa Semiconductor/Metal Junction in Liquid Sample shows diode behavior in air I-V characteristics in H 2 O totally changes Huang et al. Microscopy Today 2016, 24, 18 35

36 Pt/p + -Si: PeakForce SECM Col 1 vs Col 2 Col 1 vs Col 2: Col 1 vs Col 2: Topography Contact Current SECM Current (na) #3 #2 SECM Current Contact Current (na) Resistive interface: contact current (interfacial conductivity) is correlated with SECM current Conductive interface: EC activity is compared (e.g. #2 vs. #3, higher contact current but lower SECM current) Jiang et al. ChemSusChem, 2017 DOI: /cssc

37 PeakForce KPFM in Liquid 37

38 PeakForce KPFM in Liquid (H 2 O, 1 mm KCl, or DMC) In Air: ~125 mv difference Pt Pt Si 3 N 4 Si 3 N 4 Pt Si 3 N 4 Pt In H 2 O: ~150 mv difference Si 3 N 4 Si 3 N 4 Si 3 N 4 Pt Si 3 N 4 Pt Pt 38

39 Piezoresponse Force Microscopy (PFM) in Liquid 39

40 Web: High-Resolution Electromechanical Imaging of Bio-compatible Ferroelectric Materials in Air, Water and NaCl Electrolyte. Slides contributed from Anyang Cui, East China Normal University. Measurements were in collaboration with Bruker. Cui & Hu et al., manuscript in preparation. Anyang Cui Nanoelectrode from Bruker Air- at contact resonance H 2 O-Off resonance H 2 O - at resonance 0.01 mm NaCl 0.1 mm NaCl 0.5 M NaCl 1 M NaCl Unpublished Results, Manuscript in Preparation

41 Phase Contrast at Contact Resonance Measurements were in collaboration with Cui&Hu et. al. at ECNU in China Sample: PPLN; Electrolyte: NaCl; Image Force: 100 nn Air H 2 O 1 mm 10 mm 2 µm 2 µm 2 µm 2 µm Air H 2 O 1 mm 10 mm H 2 O Air 1 mm 41

42 Conclusion Bruker s new AFM-SECM probe technology improves SECM lateral resolution by orders of magnitude and opens the door to new measurements on individual nanoparticles, -phases, and pores r ~ 25 nm h ~ 250 nm SiO 2 Pt PeakForce SECM enables the highest spatial resolution and multi-modal imaging on soft and fragile samples Force Volume SECM allows for improved kinetic quantification and provides 3D electrochemical mapping, through capturing a complete data cube PeakForce nanoelectrical measurements in liquid provide new capabilities for visualization of electrical processes in solution Huang et al. Microscopy Today 2016, 24, 18 42

43 Copyright Bruker Corporation. All rights reserved. Bruker Confidential 43

44 KPFM Sensitivity Scales with Q/k In Air In di-h 2 O f 0 ~ 62 khz Q ~ 215 f 0 ~ 29 khz Q = 10 In liquid, the sensitivity is about 20x lower (vs. air) with these cantilevers 44

45 Tapping Mode (Z Modulation) Cells were over grown and covered the whole petri dish SECM probe successfully imaged the topography of live cells without sample damages 45

46 Defects on HOPG Electrode Topography Electrochemistry 800 nm 800 nm 46