Comparison of fresh and aged lithium iron phosphate cathodes using a tailored electrochemical strain microscopy technique

• Matthias Simolka,
• Hanno Kaess and
• Kaspar Andreas Friedrich

Beilstein J. Nanotechnol. 2020, 11, 583–596, doi:10.3762/bjnano.11.46

• solid electrolyte interface (SEI) on graphite anodes and HOPG [14][15][16], Li metal [17] and on cathode materials [18][19] as well as the changes in particle size during ageing [19][20]. Other AFM modes used for the analysis of ageing are, for example, Kelvin probe force microscopy (KPFM) and

Implementation of data-cube pump–probe KPFM on organic solar cells

• Benjamin Grévin,
• Olivier Bardagot and
• Renaud Demadrille

Beilstein J. Nanotechnol. 2020, 11, 323–337, doi:10.3762/bjnano.11.24

• Benjamin Grevin Olivier Bardagot Renaud Demadrille Univ. Grenoble Alpes, CNRS, CEA, IRIG-SyMMES, 38000 Grenoble, France 10.3762/bjnano.11.24 Abstract An implementation of pump–probe Kelvin probe force microscopy (pp-KPFM) is reported that enables recording the time-resolved surface potential in

• PTB7 and PC71BM is subsequently investigated by recording point-spectroscopy curves as a function of the optical power at the cathode and by mapping 2D time-resolved images of the surface photovoltage of the bare organic active layer. Keywords: bulk heterojunctions; Kelvin probe force microscopy (KPFM

• the development of new time-resolved extensions of electrostatic force microscopy (EFM) and Kelvin probe force microscopy (KPFM). Time-resolved EFM (trEFM) has been used to map photoinduced charging rates (i.e., the time needed to reach an electrostatic equilibrium after illumination) in organic donor

Kelvin probe force microscopy work function characterization of transition metal oxide crystals under ongoing reduction and oxidation

• Dominik Wrana,
• Karol Cieślik,
• Wojciech Belza,
• Christian Rodenbücher,
• Krzysztof Szot and
• Franciszek Krok

Beilstein J. Nanotechnol. 2019, 10, 1596–1607, doi:10.3762/bjnano.10.155

• future energy production and storage. As the majority of applications involve the use of heterostructures, the most suitable characterization technique is Kelvin probe force microscopy (KPFM), which provides excellent energetic and lateral resolution. In this paper, we demonstrate precise

• . Keywords: Kelvin probe force microscopy (KPFM); reduction and oxidation; SrTiO3; TiO nanowires; TiO/SrTiO3 heterostructure; transition metal oxides; work function; Introduction Transition metal oxides are viewed today as some of the most promising materials in various fields, ranging from (photo)catalysis

• energetic resolution, Kelvin probe force microscopy (KPFM, also known as scanning Kelvin probe microscopy, SKPM) is the tool of choice for the precise measurement of the WF across oxide heterostructures, which is a technique that has not been fully exploited to date. In recent years, KPFM has proved to be

Kelvin probe force microscopy of the nanoscale electrical surface potential barrier of metal/semiconductor interfaces in ambient atmosphere

• Petr Knotek,
• Tomáš Plecháček,
• Jan Smolík,
• Petr Kutálek,
• Filip Dvořák,
• Milan Vlček,
• Jiří Navrátil and
• Čestmír Drašar

Beilstein J. Nanotechnol. 2019, 10, 1401–1411, doi:10.3762/bjnano.10.138

• nanosheets through the reaction with the Bi2Se3. The Schottky barrier formed by the 1D and 2D nanoinclusions was characterized by means of atomic force microscopy (AFM). We used Kelvin probe force microscopy (KPFM) in ambient atmosphere at the nanoscale and compared the results to those of ultraviolet

• revealed that long-time exposure (tens of seconds) to the electrical field leads to deep oxidation and the formation of perturbations greater than 1 µm in height, which hinder the I–V measurements. Keywords: Kelvin probe atomic force microscope; nanoinclusion; Schottky barrier; thermoelectric materials

• material [19][20][21]; ii) by mapping of the different surface contact potential values by Kelvin probe force microscopy (KPFM) in the semicontact mode [19][22][23][24][25], or iii) by measuring the differences in thermal conductivity by scanning thermal microscopy (SThM) [19][20][26]. Shape, size

Imaging the surface potential at the steps on the rutile TiO₂(110) surface by Kelvin probe force microscopy

• Masato Miyazaki,
• Huan Fei Wen,
• Quanzhen Zhang,
• Yuuki Adachi,
• Jan Brndiar,
• Ivan Štich,
• Yan Jun Li and
• Yasuhiro Sugawara

Beilstein J. Nanotechnol. 2019, 10, 1228–1236, doi:10.3762/bjnano.10.122

• ) surface with O2 exposure using Kelvin probe force microscopy. A drop in contact potential difference was observed at the steps, indicating that the work function locally decreased. Moreover, for the first time, we found that the drop in contact potential difference at a <1−11> step was larger than that at

• steps in the catalytic reaction. Keywords: catalyst; Kelvin probe force microscopy; Smoluchowski effect; step; titanium dioxide; Introduction Titanium dioxide (TiO2) has attracted considerable interest for its promising applications as a photocatalyst and as catalyst support, as well as in gas sensors

• observed with a lateral resolution of several nanometers by Kelvin probe force microscopy (KPFM) [29][30]. However, the dependence of surface potential on direction and structure of steps such as [001], and has not yet been clarified. In scanning tunneling microscopy (STM) [31] studies, three typical

Comparing a porphyrin- and a coumarin-based dye adsorbed on NiO(001)

• Sara Freund,
• Antoine Hinaut,
• Nathalie Marinakis,
• Edwin C. Constable,
• Ernst Meyer,
• Catherine E. Housecroft and
• Thilo Glatzel

Beilstein J. Nanotechnol. 2019, 10, 874–881, doi:10.3762/bjnano.10.88

• Kelvin probe force microscopy measurements. Keywords: coumarin; Kelvin probe force microscopy; metal oxide; molecular resolution; nickel oxide (NiO); non-contact atomic force microscopy; porphyrin; Introduction With regard to its use in dye-sensitized solar cells (DSSCs), the wide-bandgap n-type

• investigated by Kelvin probe force microscopy (KPFM) [25]. This technique is used to observe and quantify the contact potential difference (CPD) changes between the metal oxide surface and the molecular layers and to determine the corresponding dipole moments. Results and Discussion Atomically clean NiO

• ≈ 165 kHz, quality factor Qf1 ≈ 30000) with compensated contact potential difference. Kelvin probe force microscopy was performed in frequency-modulation mode using a voltage modulation applied together with the dc compensation voltage to the sample (Vac = 800 mV and fac = 1 kHz or 250 Hz). (a

Novel reversibly switchable wettability of superhydrophobic–superhydrophilic surfaces induced by charge injection and heating

• Xiangdong Ye,
• Junwen Hou and
• Dongbao Cai

Beilstein J. Nanotechnol. 2019, 10, 840–847, doi:10.3762/bjnano.10.84

• Dongwen) was used for wettability modification of the silica surfaces. An S3000 scanning electron microscope (SEM, Japan Hitachi Group) and a Kelvin probe force microscope (Bruker Dimension Icon, Brook) with a SCM-PIT probe (Pt/Ir coated tips, 2.8 N/m, 75 kHz, Pt/Ir reflective coating) were used for

• (compared to Figure 2b). Therefore, we conclude that the change in coating wettability was not induced by the surface morphology. To establish the reason for the wettability change, Kelvin probe force microscopy was used to detect the surface potential of the electrode contact area and the electrode non

• principle of Kelvin probe force microscopy, in the uncharged area, the surface potentials fluctuate significantly and result in random data, whereas in the charged area, the surface potentials remain steady. As we have known, the electrowetting phenomenon caused by electric-field-driven solid–liquid

Review of time-resolved non-contact electrostatic force microscopy techniques with applications to ionic transport measurements

• Aaron Mascaro,
• Yoichi Miyahara,
• Tyler Enright,
• Omur E. Dagdeviren and
• Peter Grütter

Beilstein J. Nanotechnol. 2019, 10, 617–633, doi:10.3762/bjnano.10.62

• -domain EFM to measure ionic transport [7][12], time-resolved electrochemical strain microscopy (ESM) to measure ionic transport [8][13], various time-resolved Kelvin probe force microscopy (KPFM) techniques that utilize either optical pump-probe or advanced signal processing to measure time-resolved

• . One example of this is in time-resolved Kelvin probe force microscopy (KPFM) experiments that measure the surface photovoltage of a sample as a function of time after a light source is pulsed. This was first implemented by Takihara et al. to measure the photovoltage dynamics of a sample at time scales

Nitrous oxide as an effective AFM tip functionalization: a comparative study

• Taras Chutora,
• Bruno de la Torre,
• Pingo Mutombo,
• Jack Hellerstedt,
• Jaromír Kopeček,
• Pavel Jelínek and
• Martin Švec

Beilstein J. Nanotechnol. 2019, 10, 315–321, doi:10.3762/bjnano.10.30

• spectroscopy measurements, i.e., the interaction energy toward different atomic species in force spectroscopy, the contact potential difference in Kelvin probe force microscopy (KPFM) [9][29] and vibrational levels of inelastic tunneling spectroscopy (IETS) [30][31]. A particular termination of the tip may be

Scanning probe microscopy for energy-related materials

• Rüdiger Berger,
• Benjamin Grévin,
• Philippe Leclère and
• Yi Zhang

Beilstein J. Nanotechnol. 2019, 10, 132–134, doi:10.3762/bjnano.10.12

• microscopy (cAFM) and Kelvin probe force microscopy (KPFM) are the major methods that enable the study of the movement of charge carriers and their pathways [1]. We note that the KPFM method is rapidly becoming a tool capable of time-resolved studies. In this context, Yann Almadori and co-workers discuss the

Apparent tunneling barrier height and local work function of atomic arrays

• Neda Noei,
• Alexander Weismann and
• Richard Berndt

Beilstein J. Nanotechnol. 2018, 9, 3048–3052, doi:10.3762/bjnano.9.283

• ][16]. Atomic steps are a well-known example of a structure that affects the local work function Φ. The spill-out of electrons from a planar crystal surface creates a dipole layer that increases Φ [17][18]. Steps modify the spill-out and thus reduce Φ [19] as observed by Kelvin probe measurements [20

In situ characterization of nanoscale contaminations adsorbed in air using atomic force microscopy

• Jesús S. Lacasa,
• Lisa Almonte and
• Jaime Colchero

Beilstein J. Nanotechnol. 2018, 9, 2925–2935, doi:10.3762/bjnano.9.271

• to access the state of contamination of real surfaces under ambient conditions using advanced atomic force microscopy techniques. Keywords: atomic force microscopy; cantilever; contact potential; electrostatic forces; force spectroscopy; Hamaker constant; Kelvin probe microscopy; surface

• where the flat part of the cantilever chip has been analyzed in (true) nc-DAFM using Kelvin probe microscopy (KPM) to measure the contact potential. The three analyzed samples correspond to the surface of platinum-films evaporated onto silicon cantilevers, but with three different state of contamination

• kHz. Further details of how DAFM and Kelvin probe microscopy (KPM) [14] are implemented in our experiments is described elsewhere [42][50][51][52]. WSxM software was used for image processing [56]. Typically, a plane filter was applied to topography images; no filter is applied to the electrostatic

A scanning probe microscopy study of nanostructured TiO₂/poly(3-hexylthiophene) hybrid heterojunctions for photovoltaic applications

• Laurie Letertre,
• Roland Roche,
• Olivier Douhéret,
• Hailu G. Kassa,
• Denis Mariolle,
• Nicolas Chevalier,
• Łukasz Borowik,
• Philippe Dumas,
• Benjamin Grévin,
• Roberto Lazzaroni and
• Philippe Leclère

Beilstein J. Nanotechnol. 2018, 9, 2087–2096, doi:10.3762/bjnano.9.197

• photovoltaic process and the correlation to the nanoscale morphology. A down-shift of the vacuum level of the TiO2 surface upon grafting was measured by Kelvin probe force microscopy (KPFM), evidencing the formation of a dipole at the TiO2/P3HT-COOH interface. Upon in situ illumination, a positive photovoltage

• theoretical and material design perspective. Keywords: hybrid heterojunctions; hybrid photovoltaic; Kelvin probe force microscopy; photoconductive-AFM; photo-KPFM; poly(3-hexylthiophene); TiO2; Introduction Over the past decades, a large range of photovoltaic (PV) technologies have been developed for the

• photoconductive-AFM (PC-AFM) and photo-assisted Kelvin probe force microscopy (photo-KPFM) to follow the photovoltaic response, i.e., photocurrent and photovoltage, respectively, at the nanoscale under illumination, in order to understand the local physical processes taking place during the photoconversion of

Numerical analysis of single-point spectroscopy curves used in photo-carrier dynamics measurements by Kelvin probe force microscopy under frequency-modulated excitation

• Pablo A. Fernández Garrillo,
• Benjamin Grévin and
• Łukasz Borowik

Beilstein J. Nanotechnol. 2018, 9, 1834–1843, doi:10.3762/bjnano.9.175

• nanostructure and photo-transport mechanisms has become of crucial importance for the development of many emerging photovoltaic technologies. In this context, Kelvin probe force microscopy under frequency-modulated excitation has emerged as a useful technique for probing photo-carrier dynamics and gaining

• probe force microscopy under frequency-modulated excitation over a silicon nanocrystal solar cell, as well as against results obtained by intensity-modulated scanning Kelvin probe microscopy over a polymer/fullerene bulk heterojunction device. Moreover, we show how this simulation routine can complement

• experimental results as additional information about the photo-carrier dynamics of the sample can be gained via the numerical analysis. Keywords: carrier dynamics; carrier lifetime; carrier recombination; Kelvin probe force microscopy; nanostructured photovoltaics; numerical simulations; photo-carrier

Know your full potential: Quantitative Kelvin probe force microscopy on nanoscale electrical devices

• Amelie Axt,
• Ilka M. Hermes,
• Victor W. Bergmann,
• Niklas Tausendpfund and
• Stefan A. L. Weber

Beilstein J. Nanotechnol. 2018, 9, 1809–1819, doi:10.3762/bjnano.9.172

• investigate the influence of the operation method in Kelvin probe force microscopy (KPFM) on the measured potential distribution. KPFM is widely used to map the nanoscale potential distribution in operating devices, e.g., in thin film transistors or on cross sections of functional solar cells. Quantitative

• mode; AM off resonance; AM second eigenmode; cross section; crosstalk; field effect transistor; FM-KPFM; frequency modulation heterodyne; frequency modulation sideband; quantitative Kelvin probe force microscopy; solar cells; Introduction In this study, we compare the most commonly used amplitude

• modulation (AM) and frequency modulation (FM) Kelvin probe force microscopy (KPFM) methods under ambient conditions to investigate how these methods can measure quantitative variations in the local contact potential difference (CPD). KPFM is a scanning force microsopcy (SFM) method that correlates the local

Direct AFM-based nanoscale mapping and tomography of open-circuit voltages for photovoltaics

• Katherine Atamanuk,
• Justin Luria and
• Bryan D. Huey

Beilstein J. Nanotechnol. 2018, 9, 1802–1808, doi:10.3762/bjnano.9.171

• . To simultaneously map VOC directly, the topography is tracked in the same manner, but a secondary PID loop is also configured to continually adjust the sample bias in order to maintain a photocurrent of zero. This is akin to Kelvin probe microscopy or scanning surface potential microscopy, in which a

Multimodal noncontact atomic force microscopy and Kelvin probe force microscopy investigations of organolead tribromide perovskite single crystals

• Yann Almadori,
• David Moerman,
• Jaume Llacer Martinez,
• Philippe Leclère and
• Benjamin Grévin

Beilstein J. Nanotechnol. 2018, 9, 1695–1704, doi:10.3762/bjnano.9.161

• du Parc 20, B7000 Mons, Belgium 10.3762/bjnano.9.161 Abstract In this work, methylammonium lead tribromide (MAPbBr3) single crystals are studied by noncontact atomic force microscopy (nc-AFM) and Kelvin probe force microscopy (KPFM). We demonstrate that the surface photovoltage and crystal

• . Keywords: carrier lifetime; ion migration; Kelvin probe force microscopy (KPFM); noncontact atomic force microscopy (nc-AFM); organic–inorganic hybrid perovskites; photostriction; single crystals; surface photovoltage (SPV); time-resolved surface photovoltage; Introduction Organic–inorganic hybrid

• conversion efficiencies exceeding 20% and several kinds of optoelectronic devices, including efficient light-emitting diodes [3], laser devices [4] and high-gain photodetectors [5]. Recently, Kelvin probe force microscopy (KPFM) has been used to investigate the impact of grain boundaries (GBs) on the

Artifacts in time-resolved Kelvin probe force microscopy

• Sascha Sadewasser,
• Nicoleta Nicoara and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2018, 9, 1272–1281, doi:10.3762/bjnano.9.119

• 10.3762/bjnano.9.119 Abstract Kelvin probe force microscopy (KPFM) has been used for the characterization of metals, insulators, and semiconducting materials on the nanometer scale. Especially in semiconductors, the charge dynamics are of high interest. Recently, several techniques for time-resolved

• deflection detection system. Finally, guidelines for avoiding such artifacts are given. Keywords: Kelvin probe force microscopy; time-resolved; Introduction Kelvin probe force microscopy (KPFM) [1] has been widely used for the characterization of metals, insulators, and semiconducting materials on the

• quality factor. The first three (i = 1,2,3) eigenmodes of the cantilever are used. Only the electrostatic forces relevant for electrostatic and Kelvin probe force microscopy are considered according to [2]: Here, Vdc is the applied dc voltage, Vac the ac-detection voltage, fac the frequency of the ac

Electro-optical interfacial effects on a graphene/π-conjugated organic semiconductor hybrid system

• Karolline A. S. Araujo,
• Luiz A. Cury,
• Matheus J. S. Matos,
• Thales F. D. Fernandes,
• Luiz G. Cançado and
• Bernardo R. A. Neves

Beilstein J. Nanotechnol. 2018, 9, 963–974, doi:10.3762/bjnano.9.90

• of the RA SAM, even at room temperature. Additionally, photo-assisted electrical force microscopy, photo-assisted scanning Kelvin probe microscopy and Raman spectroscopy indicate a RA-induced graphene doping and photo-charge generation. Finally, the optical excitation of the RA monolayer generates

• optical response, interface-induced modulation of the electrical properties of the RA–graphene hybrid system were investigated in a series of photo-assisted electric force microscopy (EFM) and scanning Kelvin probe microscopy (SKPM) measurements. Figure 4 shows a scheme of the photo-assisted EFM

• electrostatic force microscopy (EFM) [65][66] and scanning Kelvin probe microscopy (SKPM) [67] experiments were carried out using a white light emitting diode (LED) source. ScanAsyst – Air (bare Si tip), HQ:NSC18/Cr-Au (Au-coated tip) and HQ:CSC37-CrAu (Au-coated tip) cantilevers from Bruker and MikroMasch were

Anchoring of a dye precursor on NiO(001) studied by non-contact atomic force microscopy

• Sara Freund,
• Antoine Hinaut,
• Nathalie Marinakis,
• Edwin C. Constable,
• Ernst Meyer,
• Catherine E. Housecroft and
• Thilo Glatzel

Beilstein J. Nanotechnol. 2018, 9, 242–249, doi:10.3762/bjnano.9.26

• that they are lying flat on the surface in a trans-conformation. Within the limits of our Kelvin probe microscopy setup a charge transfer from NiO to the molecular layer of 0.3 electrons per molecules was observed only in the areas where the molecules are closed packed. Keywords: metal oxide; nickel

• recorded by Kelvin probe force microscopy (KPFM) [68]. The CPD arises from the work function difference between the tip and the substrate and is altered by surface charges or dipoles. The voltage needed to compensate for the electrostatic forces due to this potential difference is measured in KPFM. The CPD

• ), using silicon cantilever (Nanosensors PPP-NCR, stiffness k = 20–30 N/m, resonance frequency f1 around 165 kHz, Qf1 factor around 30000, torsional frequency fTR around 1.5 MHz, and QTR factors around 100000) with compensated contact potential difference (CPD). Kelvin probe force microscopy was performed

Combined scanning probe electronic and thermal characterization of an indium arsenide nanowire

• Tino Wagner,
• Fabian Menges,
• Heike Riel,
• Bernd Gotsmann and
• Andreas Stemmer

Beilstein J. Nanotechnol. 2018, 9, 129–136, doi:10.3762/bjnano.9.15

• spots may put limits on device integration. Therefore, being able to observe profiles of both electronic and thermal device properties at the nanoscale is important. Here, we show measurements by scanning thermal and Kelvin probe force microscopy of the same 60 nm diameter indium arsenide nanowire in

• operation. The observed temperature along the wire is substantially elevated near the contacts and deviates from the bell-shaped temperature profile one would expect from homogeneous heating. Voltage profiles acquired by Kelvin probe force microscopy not only allow us to determine the electrical nanowire

• . Keywords: contact resistance; Kelvin probe force microscopy (KFM); nanowire; scanning thermal microscopy (SThM); self-heating; Introduction Electronic and thermal properties of nanoscale devices are innately coupled. The charge carriers in most conductors release energy by scattering at defects or phonons

Analysis and modification of defective surface aggregates on PCDTBT:PCBM solar cell blends using combined Kelvin probe, conductive and bimodal atomic force microscopy

• Hanaul Noh,
• Alfredo J. Diaz and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2017, 8, 579–589, doi:10.3762/bjnano.8.62

• modification of unidentified surface aggregates. The aggregates are characterized electrically by Kelvin probe force microscopy and conductive atomic force microscopy (C-AFM), whereby the correlation between local electrical potential and current confirms a defective charge transport. Bimodal AFM modification

• confirms that the aggregates exist on top of the solar cell structure, and is used to remove them and to reveal the underlying active layer. The systematic analysis of the surface aggregates suggests that the structure consists of PCBM molecules. Keywords: conductive atomic force microscopy; Kelvin probe

• of PSCs [15], thus providing insights into the operating mechanism of PSCs. Among all the available modes of AFM, conductive AFM (C-AFM) and Kelvin probe force microscopy (KPFM) are the most widely used for PSC research, since the measured current and electrical potential can reveal local charge

Noise in NC-AFM measurements with significant tip–sample interaction

• Jannis Lübbe,
• Matthias Temmen,
• Philipp Rahe and
• Michael Reichling

Beilstein J. Nanotechnol. 2016, 7, 1885–1904, doi:10.3762/bjnano.7.181

• frequency shift noise in the presence of tip–sample forces [12]. Ultimately, the noise in the frequency shift signal determines the base performance of all downstream processing such as the topography signal or the Kelvin probe force signal [13]. Here, we use the formalism derived by Polesel-Maris et al

Scanning probe microscopy studies on the adsorption of selected molecular dyes on titania

• Jakub S. Prauzner-Bechcicki,
• Lukasz Zajac,
• Piotr Olszowski,
• Res Jöhr,
• Antoine Hinaut,
• Thilo Glatzel,
• Bartosz Such,
• Ernst Meyer and
• Marek Szymonski

Beilstein J. Nanotechnol. 2016, 7, 1642–1653, doi:10.3762/bjnano.7.156

• results, the next step should be aimed on monitoring the influence of the oxygen vacancies density on the averaged level alignment between a semiconducting substrate and a full organic layer. Another method used to understand the molecule-substrate interactions is Kelvin probe force microscopy (KPFM

• microscopies, it is indispensable to use other techniques such as Kelvin probe force microscopy, which allows measuring the local work function with high resolution. Such a measurement may shed some light on fundamental processes taking place in an organic DSSC upon photon absorption. Quite often, in

High-resolution noncontact AFM and Kelvin probe force microscopy investigations of self-assembled photovoltaic donor–acceptor dyads

• Benjamin Grévin,
• Pierre-Olivier Schwartz,
• Laure Biniek,
• Martin Brinkmann,
• Nicolas Leclerc,
• Elena Zaborova and
• Stéphane Méry

Beilstein J. Nanotechnol. 2016, 7, 799–808, doi:10.3762/bjnano.7.71

• dyads are used as model nanostructured heterojunctions for local investigations by noncontact atomic force microscopy (nc-AFM) and Kelvin probe force microscopy (KPFM). With the aim to probe the photo-induced charge carrier generation, thin films deposited on transparent indium tin oxide substrates are

• elementary building block level. Keywords: donor–acceptor co-oligomers; donor–acceptor lamellae; donor–acceptor-ordered bulk heterojunction; Kelvin probe force microscopy (KPFM); noncontact atomic force microscopy (nc-AFM); organic photovoltaics; surface photo-voltage (SPV); Introduction Nowadays, with

• ) materials, arranged in interpenetrated networks at the 10 nm scale to efficiently separate the excitons into free charges at the D–A interface. In the past decade, several studies demonstrated that Kelvin probe force microscopy (KPFM) can be powerfully combined with atomic force microscopy (AFM) to