Name: Concurrent Quantitative Conductivity and Mechanical Properties Measurements of Organic Photovoltaic Materials using AFM (Video) | JoVE Journal
Uploaded: 2013-01-23T13:00:00.000+00:00
Duration: 8 min 59 s
Description: Discover concurrent conductivity and mechanical measurements of organic photovoltaic materials using atomic force microscopy. This protocol enables sub-100 nm resolution analysis of fullerene polymer blends for solar cell optimization.

ai_agent_IP

ai_agent

maintenance

instantTrialDurationMinutes

isBiopharma

enableNewMyJoveSectionDesign

educationFeatures

seoMetaApi

ai_copilot_institution_blacklist

ai_chat_institution_blacklist

freeAccessWindow

ssoRoleCapture

scheduledMaintenanceBanner

joveLabsFeatures

disable_autoplay_for_bots

extended_trial_duration

5 minutes

playerTrialDesktop

MPN is grateful to the Director's Fellowship Program for financial support. MPN wants to thank Yu-Chih Tseng for help with development of the protocol for solar cell processing. This work was performed at the Center for Nanoscale Materials, a U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences User Facility under Contract No. DE-AC02-06CH11357.

1. Signal Acquisition
<ol class="lalpha">
 <li>Install sample (polymer solar cell without cathode (ITO/PEDOT:PSS/P3HT:PC61BM)) into a commercial Multimode AFM (Veeco, Santa Barbara, CA) equipped with Nanoscope-V controller.</li>
 <li>Install conductive AFM probe into Multimode AFM probe holder.</li>
 <li>Create electrical connection between the AFM probe, sample and voltage source.</li>
 <li>Route current amplifier output (current signal), Multimode AFM deflection output (force signal), Multimode AFM sample height output (distance signal) into a digital acquisition card (NI-PCI-6115 DAQ). The gain on Femto DLPCA-200 current amplifier is 1 nA/V at 50 kHz bandwidth.</li>
 <li>Apply 6V bias between AFM probe and ITO electrode.</li>
 <li>Run Multimode AFM in PeakForceTM mode collecting topography signal: peak force set point of 30 nN, a support oscillation amplitude of 300 nm, a support oscillation frequency of 2 kHz, a scan rate of 1 Hz, and a resolution of 512 by 512 pixels.</li>
 <li>Collect signals listed in section d by LabView/MATLAB control concurrently with acquisition of topography signal (step e).</li>
</ol>
2. Data Analysis Step 1: Generation of Pull-off Force, Contact Stiffness, and Current Maps
<ol class="lalpha">
 <li>Read time-stamped current, force and distance signals into MATLAB.</li>
 <li>Create 2,000 force - distance, and force - current curves for the first scan line. Number of curves is a function of support oscillation frequency and scan rate.</li>
 <li>From each force - distance curve, determine contact stiffness and pull-off-force during withdrawal of the AFM probe (Figure 1).</li>
 <li>From each force - current curve, determine the average current while the AFM probe is in contact with the surface during withdraw (Figure 1).</li>
 <li>Interpolate 2,000 equally spaced contact stiffness, pull-off-force, and current points by 512 points to match resolution of topography signal. The first scan line for contact stiffness, pull-off-force, and current maps is done.</li>
 <li>Create contact stiffness, pull-off-force, and current maps by repeating steps b through e 512 times. Results are shown in Figure 2.</li>
</ol>
3. Data Analysis Step 2: Elimination of Contact-area Artifacts
<ol class="lalpha">
 <li>Use equation (1) and (2) to obtain Young's Modulus (EMATERIAL) and resistance (ρ) of the material at each point of the scan:20 
 <img alt="Mechanical properties equations, material strength analysis, formulae, educational research use." fo:content-width="2.853in" fo:src="/files/ftp_upload/50293/50293eq1highres.jpg" src="/files/ftp_upload/50293/50293eq1.jpg" data-altupdatedat="1787630408000" data-alt="Equation 1"> 
 using FADH = FPULL - 8 nN (adhesion due to water meniscus between the AFM and the surface),20 contact stiffness (k), and current (I) maps; probing voltage (V), film thickness (L), and adhesion energy (w = γPROBE + γMATERIAL - γPROBE-MATERIAL, where γPROBE - surface energy of probe material, γMATERIAL - surface energy of sample material, and γPROBE-MATERIAL - interfacial energy of sample material and probe material).20</li>
</ol>

<ol><li>Chen, W., Nikiforov, M. P., Darling, S. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Morphology+characterization+in+organic+and+hybrid+solar+cells%5BTitle%5D)+AND+%22Energy+Environ.+Sci%22%5BJournal%5D)">Morphology characterization in organic and hybrid solar cells.</a> Energy Environ. Sci. , (2012).</li>
<li>Dupont, S. R., Oliver, M., Krebs, F. C., Dauskardt, R. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Interlayer+adhesion+in+roll-to-roll+processed+flexible+inverted+polymer+solar+cells%5BTitle%5D)+AND+%22Sol.+Energy%22%5BJournal%5D)">Interlayer adhesion in roll-to-roll processed flexible inverted polymer solar cells.</a> Sol. Energy. 97, 171-175 (2012).</li>
<li>Green, M. A., Emery, K., Hishikawa, Y., Warta, W., Dunlop, E. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Solar+cell+efficiency+tables+%28version+39%29%5BTitle%5D)+AND+%22Progress+in+Photovoltaics%22%5BJournal%5D)">Solar cell efficiency tables (version 39).</a> Progress in Photovoltaics. 20 (1), 12-20 (2012).</li>
<li>Krebs, F. C., Gevorgyan, S. A., Alstrup, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+roll-to-roll+process+to+flexible+polymer+solar+cells%3A+model+studies%2C+manufacture+and+operational+stability+studies%5BTitle%5D)+AND+%22Journal+of+Materials+Chemistry%22%5BJournal%5D)">A roll-to-roll process to flexible polymer solar cells: model studies, manufacture and operational stability studies.</a> Journal of Materials Chemistry. 19 (30), 5442-5451 (2009).</li>
<li>Binnig, G., Quate, C. F., Gerber, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Atomic+Force+Microscope%5BTitle%5D)+AND+%22Physical+Review+Letters%22%5BJournal%5D)">Atomic Force Microscope.</a> Physical Review Letters. 56 (9), 930-933 (1986).</li>
<li>Hurley, D. C., Kopycinska-Muller, M., Kos, A. B., Geiss, R. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Nanoscale+elastic-property+measurements+and+mapping+using+atomic+force+acoustic+microscopy+methods%5BTitle%5D)+AND+%22Measurement+Science+%26+Technology%22%5BJournal%5D)">Nanoscale elastic-property measurements and mapping using atomic force acoustic microscopy methods.</a> Measurement Science & Technology. 16 (11), 2167-2172 (2005).</li>
<li>Jesse, S., Nikiforov, M. P., Germinario, L. T., Kalinin, S. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Local+thermomechanical+characterization+of+phase+transitions+using+band+excitation+atomic+force+acoustic+microscopy+with+heated+probe%5BTitle%5D)+AND+%22Applied+Physics+Letters%22%5BJournal%5D)">Local thermomechanical characterization of phase transitions using band excitation atomic force acoustic microscopy with heated probe.</a> Applied Physics Letters. 93 (7), (2008).</li>
<li>Nikiforov, M. P., Gam, S., Jesse, S., Composto, R. J., Kalinin, S. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Morphology+Mapping+of+Phase-Separated+Polymer+Films+Using+Nanothermal+Analysis%5BTitle%5D)+AND+%22Macromolecules%22%5BJournal%5D)">Morphology Mapping of Phase-Separated Polymer Films Using Nanothermal Analysis.</a> Macromolecules. 43 (16), 6724-6730 (2010).</li>
<li>Nikiforov, M. P., Jesse, S., Morozovska, A. N., Eliseev, E. A., Germinario, L. T., Kalinin, S. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Probing+the+temperature+dependence+of+the+mechanical+properties+of+polymers+at+the+nanoscale+with+band+excitation+thermal+scanning+probe+microscopy%5BTitle%5D)+AND+%22Nanotechnology%22%5BJournal%5D)">Probing the temperature dependence of the mechanical properties of polymers at the nanoscale with band excitation thermal scanning probe microscopy.</a> Nanotechnology. 20 (39), (2009).</li>
<li>Rabe, U., Amelio, S., Kopycinska, M., Hirsekorn, S., Kempf, M., Goken, M., Arnold, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Imaging+and+measurement+of+local+mechanical+material+properties+by+atomic+force+acoustic+microscopy%5BTitle%5D)+AND+%22Surface+and+Interface+Analysis%22%5BJournal%5D)">Imaging and measurement of local mechanical material properties by atomic force acoustic microscopy.</a> Surface and Interface Analysis. 33 (2), 65-70 (2002).</li>
<li>Nikiforov, M. P., Zerweck, U., Milde, P., Loppacher, C., Park, T. -H., Uyeda, H. T., Therien, M. J., Eng, L., Bonnell, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+effect+of+molecular+orientation+on+the+potential+of+porphyrin-metal+contacts%5BTitle%5D)+AND+%22Nano+Letters%22%5BJournal%5D)">The effect of molecular orientation on the potential of porphyrin-metal contacts.</a> Nano Letters. 8 (1), 110-113 (2008).</li>
<li>Nikiforov, M. N., Brukman, M. J., Bonnell, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((High-resolution+characterization+of+defects+in+oxide+thin+films%5BTitle%5D)+AND+%22Applied+Physics+Letters%22%5BJournal%5D)">High-resolution characterization of defects in oxide thin films.</a> Applied Physics Letters. 93 (18), (2008).</li>
<li>Kalinin, S. V., Karapetian, E., Kachanov, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Nanoelectromechanics+of+piezoresponse+force+microscopy%5BTitle%5D)+AND+%22Physical+Review+B%22%5BJournal%5D)">Nanoelectromechanics of piezoresponse force microscopy.</a> Physical Review B. 70 (18), (2004).</li>
<li>Kolosov, O., Gruverman, A., Hatano, J., Takahashi, K., Tokumoto, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Nanoscale+Visualization+and+Control+of+Ferroelectric+Domains+by+Atomic-Force+Microscopy%5BTitle%5D)+AND+%22Physical+Review+Letters%22%5BJournal%5D)">Nanoscale Visualization and Control of Ferroelectric Domains by Atomic-Force Microscopy.</a> Physical Review Letters. 74 (21), 4309-4312 (1995).</li>
<li>Nikiforov, M. P., Thompson, G. L., Reukov, V. V., Jesse, S., Guo, S., Rodriguez, B. J., Seal, K., Vertegel, A. A., Kalinin, S. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Double-Layer+Mediated+Electromechanical+Response+of+Amyloid+Fibrils+in+Liquid+Environment%5BTitle%5D)+AND+%22Acs+Nano%22%5BJournal%5D)">Double-Layer Mediated Electromechanical Response of Amyloid Fibrils in Liquid Environment.</a> Acs Nano. 4 (2), 689-698 (2010).</li>
<li>Botiz, I., Darling, S. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Optoelectronics+using+block+copolymers%5BTitle%5D)+AND+%22Materials+Today%22%5BJournal%5D)">Optoelectronics using block copolymers.</a> Materials Today. 13 (5), 42-51 (2010).</li>
<li>Brabec, C. J., Heeney, M., McCulloch, I., Nelson, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Influence+of+blend+microstructure+on+bulk+heterojunction+organic+photovoltaic+performance%5BTitle%5D)+AND+%22Chemical+Society+Reviews%22%5BJournal%5D)">Influence of blend microstructure on bulk heterojunction organic photovoltaic performance.</a> Chemical Society Reviews. 40 (3), 1185-1199 (2011).</li>
<li>Karagiannidis, P. G., Kassavetis, S., Pitsalidis, C., Logothetidis, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Thermal+annealing+effect+on+the+nanomechanical+properties+and+structure+of+P3HT%3A+PCBM+thin+films%5BTitle%5D)+AND+%22Thin+Solid+Films%22%5BJournal%5D)">Thermal annealing effect on the nanomechanical properties and structure of P3HT: PCBM thin films.</a> Thin Solid Films. 519 (12), 4105-4109 (2011).</li>
<li>Sweers, K., vander Werf, K., Bennink, M., Subramaniam, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Nanomechanical+properties+of+alpha-synuclein+amyloid+fibrils%3A+a+comparative+study+by+nanoindentation%2C+harmonic+force+microscopy%2C+and+Peakforce+QNM%5BTitle%5D)+AND+%22Nanoscale+Research+Letters%22%5BJournal%5D)">Nanomechanical properties of alpha-synuclein amyloid fibrils: a comparative study by nanoindentation, harmonic force microscopy, and Peakforce QNM.</a> Nanoscale Research Letters. 6, (2011).</li>
<li>Nikiforov, M. P., Darling, S. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Improved+conductive+atomic+force+microscopy+measurements+on+organic+photovoltaic+materials+via+mitigation+of+contact+area+uncertainty%5BTitle%5D)+AND+%22Progress+in+Photovoltaics%3A+Research+and+Applications%22%5BJournal%5D)">Improved conductive atomic force microscopy measurements on organic photovoltaic materials via mitigation of contact area uncertainty.</a> Progress in Photovoltaics: Research and Applications. , (2012).</li>
<li>Li, H. -C., Rao, K. K., Jeng, J. -Y., Hsiao, Y. -J., Guo, T. -F., Jeng, Y. -R., Wen, T. -C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Nano-scale+mechanical+properties+of+polymer%2Ffullerene+bulk+hetero-junction+films+and+their+influence+on+photovoltaic+cells%5BTitle%5D)+AND+%22Solar+Energy+Materials+and+Solar+Cells%22%5BJournal%5D)">Nano-scale mechanical properties of polymer/fullerene bulk hetero-junction films and their influence on photovoltaic cells.</a> Solar Energy Materials and Solar Cells. 95 (11), 2976-2980 (2011).</li>
<li>Mueller, C., Goffri, S., Breiby, D. W., Andreasen, J. W., Chanzy, H. D., Janssen, R. A. J., Nielsen, M. M., Radano, C. P., Sirringhaus, H., Smith, P., Stingelin-Stutzmann, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Tough%2C+semiconducting+polyethylene-poly%283-hexylthiophene%29+diblock+copolymers%5BTitle%5D)+AND+%22Advanced+Functional+Materials%22%5BJournal%5D)">Tough, semiconducting polyethylene-poly(3-hexylthiophene) diblock copolymers.</a> Advanced Functional Materials. 17 (15), 2674-2679 (2007).</li>
<li>Kuila, B. K., Nandi, A. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Physical%2C+mechanical%2C+and+conductivity+properties+of+poly%283-hexylthiophene%29-montmorillonite+clay+nanocomposites+produced+by+the+solvent+casting+method%5BTitle%5D)+AND+%22Macromolecules%22%5BJournal%5D)">Physical, mechanical, and conductivity properties of poly(3-hexylthiophene)-montmorillonite clay nanocomposites produced by the solvent casting method.</a> Macromolecules. 37 (23), 8577-8584 (2004).</li>
<li>O'Connor, B., Chan, E. P., Chan, C., Conrad, B. R., Richter, L. J., Kline, R. J., Heeney, M., McCulloch, I., Soles, C. L., DeLongchamp, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Correlations+between+Mechanical+and+Electrical+Properties+of+Polythiophenes%5BTitle%5D)+AND+%22Acs+Nano%22%5BJournal%5D)">Correlations between Mechanical and Electrical Properties of Polythiophenes.</a> Acs Nano. 4 (12), 7538-7544 (2010).</li>
<li>Tahk, D., Lee, H. H., Khang, D. -Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Elastic+Moduli+of+Organic+Electronic+Materials+by+the+Buckling+Method%5BTitle%5D)+AND+%22Macromolecules%22%5BJournal%5D)">Elastic Moduli of Organic Electronic Materials by the Buckling Method.</a> Macromolecules. 42 (18), 7079-7083 (2009).</li>
<li>Kuila, B. K., Nandi, A. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Structural+hierarchy+in+melt-processed+poly%283-hexyl+thiophene%29-montmorillonite+clay+nanocomposites%3A+Novel+physical%2C+mechanical%2C+optical%2C+and+conductivity+properties%5BTitle%5D)+AND+%22Journal+of+Physical+Chemistry+B%22%5BJournal%5D)">Structural hierarchy in melt-processed poly(3-hexyl thiophene)-montmorillonite clay nanocomposites: Novel physical, mechanical, optical, and conductivity properties.</a> Journal of Physical Chemistry B. 110 (4), 1621-1631 (2006).</li>
<li>Nikiforov, M. P., Darling, S. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Improved+conductive+atomic+force+microscopy+measurements+on+organic+photovoltaic+materials+via+mitigation+of+contact+area+uncertainty%5BTitle%5D)+AND+%22Progress+in+Photovoltaics%3A+Research+and+Applications%22%5BJournal%5D)">Improved conductive atomic force microscopy measurements on organic photovoltaic materials via mitigation of contact area uncertainty.</a> Progress in Photovoltaics: Research and Applications. , In Press (2012).</li>
<li>Kim, J. Y., Frisbie, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Correlation+of+Phase+Behavior+and+Charge+Transport+in+Conjugated+Polymer%2FFullerene+Blends%5BTitle%5D)+AND+%22Journal+of+Physical+Chemistry+C%22%5BJournal%5D)">Correlation of Phase Behavior and Charge Transport in Conjugated Polymer/Fullerene Blends.</a> Journal of Physical Chemistry C. 112 (45), 17726-17736 (2008).</li>
<li>Bange, S., Kuksov, A., Neher, D., Vollmer, A., Koch, N., Ludemann, A., Heun, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+role+of+poly%283%2C4-ethylenedioxythiophene%29%3Apoly%28styrenesulphonate%29+as+a+hole+injection+layer+in+a+blue-emitting+polymer+light-emitting+diode%5BTitle%5D)+AND+%22Journal+of+Applied+Physics%22%5BJournal%5D)">The role of poly(3,4-ethylenedioxythiophene):poly(styrenesulphonate) as a hole injection layer in a blue-emitting polymer light-emitting diode.</a> Journal of Applied Physics. 104 (10), (2008).</li>
</ol>

No conflicts of interest declared.

Recent breakthroughs in power conversion efficiency (PCE) of organic photovoltaic (OPV) cells (pushing 10% at the cell level)3 in concert with compliance with high-throughput and low-cost manufacturing processes4 have brought a spotlight onto OPV technology as a possible solution for the challenge of inexpensive manufacturing of large-area solar cells. OPV materials are inherently inhomogeneous at the nanometer scale. Nanoscale inhomogeneity of OPV materials and performance of photovoltaic devices are intimately connected. Thus, understanding inhomogeneity in composition as well as electrical properties of OPV materials is of paramount importance for moving OPV technology forward. Atomic force microscopy (AFM) has been developed as a tool for high-resolution measurements of surface topography since 1986.5 Nowadays, techniques for materials properties (Young's modulus,6-10 work function,11 conductivity,12 electromechanics,13-15 etc.) measurements are attracting increasing attention. In the case of OPV materials, correlation of local phase composition and electrical properties holds promise for revealing better understanding of the inner workings of organic solar cells.1, 16-17 AFM-based techniques are capable of high-resolution phase attribution8 as well as electrical properties mapping in polymeric materials. Thus, in principle, correlation of polymer phase composition (through mechanical measurements)18 and electrical properties is possible using AFM-based techniques. Many AFM-based techniques for measurements of mechanical and electrical properties of materials use the assumption of constant area of contact between the AFM probe and the surface. This assumption often fails, which results in strong correlation among surface topography and mechanical/electrical properties. Recently, a new AFM-based technique for high-throughput measurements of mechanical properties (PeakForce)19 was introduced. PeakForce TUNA (variation of the PeakForce method) provides a platform for concurrent measurements of mechanical and electrical properties of the sample. However, the PeakForce TUNA method produces mechanical and electrical property maps, which usually are strongly correlated because of unaccounted variability of contact during measurements. In this paper, we present an experimental protocol for removing correlations associated with varying contact radius while maintaining accurate measurements of the mechanical and electrical properties using AFM. Implementation of the protocol results in quantitative measurements of materials' resistance and Young's Modulus.

<table><tbody><tr><td>Plextronics inks</td><td>Plexcore</td><td>PV 1000</td><td></td></tr><tr><td>ITO-coated glass substrates</td><td>Delta Technologies, Inc</td><td></td><td>25 Ohms/sq</td></tr><tr><td>30 MHz synthesized function generator</td><td>Stanfor Research Systems</td><td>DS345</td><td></td></tr><tr><td>Current amplifier</td><td>Femto</td><td>DLPCA-200</td><td></td></tr><tr><td>Multimode AFM</td><td>Veeco, Santa Barbara, CA</td><td></td><td>equipped with Nanoscope-V controller</td></tr><tr><td>DAQ card</td><td>National Instruments</td><td>NI-PCI-6115</td><td></td></tr><tr><td>Metal Pt probes</td><td>RMNano</td><td>12Pt3008</td><td></td></tr><tr><td>MATLAB software</td><td>Mathworks</td><td></td><td></td></tr><tr><td>LabView software</td><td>National Instruments</td><td></td><td></td></tr></tbody></table>

concurrent quantitative conductivity and mechanical properties measurements of organic photovoltaic materials using afm

Concurrent Quantitative Conductivity and Mechanical Properties Measurements of Organic Photovoltaic Materials using AFM

Organic photovoltaic (OPV) materials are inherently inhomogeneous at the nanometer scale. Nanoscale inhomogeneity of OPV materials affects performance of photovoltaic devices. Thus, understanding of spatial variations in composition as well as electrical properties of OPV materials is of paramount importance for moving PV technology forward.1,2 In this paper, we describe a protocol for quantitative measurements of electrical and mechanical properties of OPV materials with sub-100 nm resolution. Currently, materials properties measurements performed using commercially available AFM-based techniques (PeakForce, conductive AFM) generally provide only qualitative information. The values for resistance as well as Young's modulus measured using our method on the prototypical ITO/PEDOT:PSS/P3HT:PC61BM system correspond well with literature data. The P3HT:PC61BM blend separates onto PC61BM-rich and P3HT-rich domains. Mechanical properties of PC61BM-rich and P3HT-rich domains are different, which allows for domain attribution on the surface of the film. Importantly, combining mechanical and electrical data allows for correlation of the domain structure on the surface of the film with electrical properties variation measured through the thickness of the film.

Young's modulus and resistivity maps (Figure 3) present typical results of the measurements described above. Mechanical and electrical properties of the ITO/PEDOT:PSS/P3HT:PC61BM stack were measured at negative (-10 V) and positive (+6 V) voltages applied to the AFM probe. Imaging artifacts, associated with electrostatic interaction between the AFM probe and the sample, are a common problem for quantitative measurements of functional properties using AFM. The similarity of Young's modul...

Organic photovoltaic (OPV) materials are inherently inhomogeneous at the nanometer scale. Nanoscale inhomogeneity of OPV materials affects performance of photovoltaic devices. In this paper, we describe a protocol for quantitative measurements of electrical and mechanical properties of OPV materials with sub-100 nm resolution.

Organic photovoltaic  (OPV) materials are inherently inhomogeneous at the nanometer scale. Nanoscale  inhomogeneity of OPV materials affects performance ...

The overall aim of the following experiment is to understand conductivity mechanisms in phase separated fullerene polymer blends through correlation of morphology with electrical performance. Morphology and electrical properties of polymer blends are two primary factors that control their performance inside organic solar cells. Correlation of morphology with electrical performance of the samples is achieved by concurrent measurements of mechanical and electrical properties of the sample using an atomic force microscope with a home-built controller and data acquisition system.This is used to collect spatially resolved data about distance dependence of force between the A FM probe and the sample surface, as well as distance dependence of current between the A FM probe and the sample as a second step, perform automatic analysis of the force distance and current distance curves collected at each point of the scan. This produces high resolution maps of contact, stiffness, pull off force and current. Next, apply an approximate contact mechanics model to execute a mathematical conversion of contact, stiffness and current data in order to obtain young's modulus and resistance of the sample

concurrent-quantitative-conductivity-mechanical-properties

Research

JoVE Journal

Engineering

This paper demonstrates a protocol to characterize the mechanical properties of living cells by means of microindentation using an Atomic Force Microscope (AFM).

Measuring the Mechanical Properties of Living Cells Using Atomic Force Microscopy

Progress has been made in utilizing spin echo resolved grazing incidence scattering (SERGIS) as a neutron scattering technique to probe the length-scales in irregular samples. Crystallites of [6,6]-phenyl-C61-butyric acid methyl ester have been probed using the SERGIS technique and the results confirmed by optical and atomic force microscopy.

Using Neutron Spin Echo Resolved Grazing Incidence Scattering to Investigate Organic Solar Cell Materials

This experimental protocol describes how atomic force microscopy can be used to measure hardness at the true nanometer scale and to detect single atomistic plasticity events.

Quantitative Hardness Measurement by Instrumented AFM-indentation

In this article, we describe electrochemical, electron paramagnetic resonance, and ultraviolet-visible and near-infrared spectroelectrochemical methods to analyze organic compounds for application in organic electronics.

Using Cyclic Voltammetry, UV-Vis-NIR, and EPR Spectroelectrochemistry to Analyze Organic Compounds

Here, we present atomic force microscopy (AFM), operated as a nano- and micro-indentation tool on cells and tissues. The instrument allows the simultaneous acquisition of 3D surface topography of the sample and its mechanical properties, including cell wall Young's modulus as well as turgor pressure.

Use of Atomic Force Microscopy to Measure Mechanical Properties and Turgor Pressure of Plant Cells and Plant Tissues

Covalent attachment of probe molecules to atomic force microscopy (AFM) cantilever tips is an essential technique for the investigation of their physical properties. This allows us to determine the stretching force, desorption force and length of polymers via AFM-based single molecule force spectroscopy with high reproducibility.

Covalent Attachment of Single Molecules for AFM-based Force Spectroscopy

Atomic force microscopy (AFM) combined with scanning electrochemical microscopy (SECM), namely, AFM-SECM, can be used to simultaneously acquire high-resolution topographical and electrochemical information on material surfaces at nanoscale. Such information is critical to understanding heterogeneous properties (e.g., reactivity, defects, and reaction sites) on local surfaces of nanomaterials, electrodes and biomaterials.

Probing Surface Electrochemical Activity of Nanomaterials using a Hybrid Atomic Force Microscope-Scanning Electrochemical Microscope (AFM-SECM)

Studies of cell wall biomechanics are essential for understanding plant growth and morphogenesis. The following protocol is proposed to investigate thin primary cell walls in the internal tissues of young plant organs using atomic force microscopy.

Characterizing Mechanical Properties of Primary Cell Wall in Living Plant Organs Using Atomic Force Microscopy

Quantifying the contact area and force applied by an atomic force microscope (AFM) probe tip to a sample surface enables nanoscale mechanical property determination. Best practices to implement AFM cantilever-based nanoindentation in air or fluid on soft and hard samples to measure elastic modulus or other nanomechanical properties are discussed.

Atomic Force Microscopy Cantilever-Based Nanoindentation: Mechanical Property Measurements at the Nanoscale in Air and Fluid

The goal of this experiment is to determine and control the size, shape and stability of self-assembled discotic amphiphiles in water. For aqueous based supramolecular polymers such level of control is very difficult. We apply a strategy using both repulsive and attractive interactions. The experimental techniques applied to characterize this system are broadly applicable.

Controlling the Size, Shape and Stability of Supramolecular Polymers in Water

Discover concurrent conductivity and mechanical measurements of organic photovoltaic materials using atomic force microscopy. This protocol enables sub-100 nm resolution analysis of fullerene polymer blends for solar cell optimization.

Concurrent Quantitative Conductivity and Mechanical Properties Measurements of Organic Photovoltaic Materials using AFM

Explore More Videos