Realizing Large-Area Arrays of Semiconducting Fullerene

Subscriber access provided by READING UNIV

Communication

Realizing Large-Area Arrays of Semiconducting Fullerene Nanostructures with Direct Laser Interference Patterning Jenny Enevold, Christian Larsen, Johan Zakrisson, Magnus Andersson, and Ludvig Edman Nano Lett., Just Accepted Manuscript • DOI: 10.1021/acs.nanolett.7b04568 • Publication Date (Web): 12 Dec 2017 Downloaded from http://pubs.acs.org on December 13, 2017

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

Nano Letters is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Nano Letters

Realizing Large-Area Arrays of Semiconducting Fullerene Nanostructures with Direct Laser Interference Patterning Jenny Enevold, Christian Larsen, Johan Zakrisson, Magnus Andersson, Ludvig Edman*

The Organic Photonics and Electronics Group, Department of Physics, Umeå University, SE-90187 Umeå, Sweden Abstract We present a laser-interference patterning method for the facile fabrication of large-area and highcontrast arrays of semiconducting fullerene nanostructures, which does not rely on a tedious application of sacrificial photoresists or photomasks. A solution-deposited phenyl-C61-butyric acid methyl ester (PCBM) fullerene thin film is exposed to a spatially modulated illumination intensity, as realized by two-beam laser interference. The PCBM molecules exposed to strong intensity are photochemically transformed into a low-solubility dimeric state, so that the non-transformed PCBM molecules can be removed in a subsequent solution-based development step. Following brief exposure to green laser light (λ = 532 nm, t = 5 s, p = 0.17 W cm-2) in the designed two-beam interference setup, and a 1-min development in a tuned acetone:chloroform solution, we realize welldefined and ordered PCBM nanostripe patterns with a FWHM line width of ~200 nm and a repetition rate of ~2.900 lines mm-1 over a large area of 1 cm2. We demonstrate that a desired high contrast is effectuated by that the PCBM-dimer transformation rate is dependent on the square of the illumination intensity. The semiconducting functionality of the patterned fullerene is verified in a field-effect transistor experiment, where a typical PCBM nanostripe featured an electron mobility of 5.3 × 10−3 cm2 V-1 s-1 and an on/off ratio of 3 × 103. Keywords: Semiconducting nanostructure, Mask- and resist-free patterning, Laser interference lithography, Fullerenes, Phenyl-C61-butyric acid methyl ester (PCBM), High contrast. * corresponding author: e-mail address: [email protected] TOC figure

1

ACS Paragon Plus Environment

Nano Letters 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 2 of 14

Main text The serendipitous discovery of a new carbon allotrope in the form of a family of distinct nano-sized hollow structures was rewarded with the 1996 Nobel Prize in Chemistry.1 These fascinating carbonbased molecules are termed fullerenes, and the most common and well-known fullerene is the spherical C60 with its striking structural resemblance of a soccer ball. Fullerenes are semiconductors with interesting and novel chemical and physical properties, such as superconductivity2,

3

and

opportunity for both endohedral and exohedral doping,4, 5 and they have as such found applications in a wide variety of fields including cancer treatment,6 imaging contrast agents,7 and photovoltaics.8-12 For several applications, it is required or desired to endow the fullerene molecule with solubilizing units in order to allow for transport in a liquid medium or for facile processing from solution.13, 14 A common high-solubility version of C60 is phenyl-C61-butyric acid methyl ester (PCBM), and its chemical structure is displayed in the left part of Figure 1(a). C60 can be transformed into covalently connected dimeric, oligomeric and polymeric structures during exposure to strong light15 (or high pressure)16-19; and it was also recently demonstrated that PCBM can react photo-chemically and form dimers,20 as schematically depicted in the right part of Figure 1(a). To date, this light-induced transformation of fullerenes has been utilized for the fabrication of macroscopic patterns and associated electronic devices,20-22 and for the rationalization of temporal changes in performance of fullerene-based bulk-heterojunction photovoltaic devices.9, 2331

Here, we demonstrate that it is possible to realize well-ordered and high-contrast fullerene patterns with semiconducting function also on the nano-scale. For this end, we design and employ a twobeam laser interference setup to photo-chemically establish a one-dimensional PCBM dimer stripe pattern with a feature size of ~200 nm within a solution-processed large-area film, and then develop this pattern by washing the exposed film in a tuned developer solution. It is notable that the resulting well-resolved nano-sized features are repeated over the entire film area of 1 cm2, and that the fabricated PCBM-dimer nanostripes are n-type semiconductors, as manifested in a measured electron mobility of 5.3 × 10−3 cm2 V-1 s-1 and an on/off ratio of 3 × 103 when implemented in a field-effect transistor device.

2


Page 3 of 14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Nano Letters

Figure 1. (a) (left) The chemical structure of the PCBM fullerene, and (right) the photochemical transformation of two neighboring PCBM molecules to the dimeric state during exposure to (green laser) light. The double bonds in the PCBM molecular structure are omitted for clarity. (b) A schematic presentation of the two-beam laser interference setup, as employed for the formation of a nanostripe pattern in a fullerene film on a substrate (the sample). (c) An SEM image of the PCBM nanostripe pattern on a Si substrate. The inset at the bottom shows a lower-magnification cross-sectional SEM demonstrating the regularity of the nanostripe pattern. (d) Photographs of a patterned PCBM film recorded at different illumination angles. The color variation from dark red (upper right image), over orange, yellow and green, to blue (lower right image) is an indicator of the repeatability of the nanostripe pattern over the entire substrate area. A thin PCBM film was deposited from chlorobenzene solution on a Si substrate (see Experimental section for details), and the dry film subsequently patterned with the facile two-step exposure/development procedure. The exposure setup is schematically depicted in Figure 1(b). The desired spatially modulated light intensity profile is created by: first expanding the single laser beam with a beam expander, then splitting it into two equal-intensity coherent beams with a beam splitter, and finally allowing the two coherent beams to interfere at the surface of the film to be patterned (“the sample”) with the aid of an assembly of mirrors.

3


Nano Letters 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

With the two beams being incident in a plane perpendicular to the sample surface and featuring the same angle θ with respect to the surface normal, the light intensity will feature a sinusoidal variation between zero and the double of the intensity of the original laser light incident on the beam splitter. The distance between two neighboring intensity maxima (Л) is given by

where λ is the laser wavelength.32 By using a green laser featuring a wavelength of λ = 532 nm and setting θ = 45°, the intensity maxima will be separated by Л = 376 nm. The exposed PCBM film was developed by immersion into an acetone:chloroform developer solution (volume ratio = 7:1), which had been tuned to selectively remove the non-exposed monomeric PCBM while leaving the exposed and dimerized PCBM intact. After systematic testing, we were able to identify a preferred set of process parameters constituting a laser power intensity of 0.17 W cm-2, an exposure time of ~5 s, and a development time of ~1 min, but other exposure settings, such as ramping from 0 to 2.8 W cm-2 during 5 s, were also found to be functional. Figure 1(c) is an SEM image of a patterned PCBM film on a Si substrate, which reveals well-resolved PCBM nanostripes separated by bare substrate regions where all PCBM material has been removed. The peak-to-peak distance for this specific pattern was Л ≈ 350 nm, i.e. slightly smaller than the value predicted by Equation (1), which implies that the angle of incidence with respect to the surface normal was slightly larger than θ = 45° in the presented experiment. This corresponds to a repetition rate of ~2.900 lines mm-1, and the cross-sectional SEM in the inset in Figure 1(c) demonstrates that the pattern remains effectively perfect over a larger distance of ~50 repeat units. Figure 1(d) presents photographs of the entire patterned film when illuminated with a point source positioned at different angles. The observed distinct and uniform color change over the entire film area with altered viewing angle, from dark red (largest angle, upper right inset), over orange, yellow and green, to blue (smallest angle, lower right inset), implies that the nanostripe structures are formed in a periodic fashion over the entire PCBM film area of ~1 cm2. It also follows from Equation (1) that a higher pattern resolution can be attained with a shorter wavelength laser, and the employment of, e.g., an ArF excimer laser featuring a wavelength of 193 nm could result in a sub-100 nm peak-to-peak distance and a repetition rate of >10.000 lines mm-1.

4


Page 4 of 14

Page 5 of 14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Nano Letters

Figure 2. (a) Side-view SEM image of two representative patterned PCBM nanostripes on a Si substrate. The red line presents the modelled spatial distribution of PCBM dimers for the longest exposure time (i.e., peak dimer fraction = 99 %). (b) The modelled PCBM-dimer concentration profile at bi-excited dimerization. The arrow indicates increasing time, and the data are presented for a peak dimer fraction of 30 % (shortest exposure time, blue triangles), 64 % (black diamonds), and 99 % (longest exposure time, solid red line). The side-view SEM image in Figure 2(a), and the atomic force microscopy (AFM) image in Figure S1 in the Supporting Information, reveals a sharp transition (i.e. a high contrast) between the PCBMdimer nanostripe region and the bare substrate. We further find that the width of the bare-substrate region is ~15 % of the width of the nanostripe. In order to rationalize these observations, we begin by considering the fundamentals of the PCBM dimerization reaction. It has been debated whether an intermolecular fullerene bond (Fig. 1a, right part) will form following the photo-excitation of only one of the two neighboring fullerene molecules (as implied by the “mono-molecular” excited dimerization model)33 or if both neighboring molecules must be excited in order for the bond to form (as dictated by the “bi-molecular” excited dimerization model)34. A distinguishing observable is that the mono-molecular scenario results in an initial dimer formation

5


Nano Letters 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

rate that is linearly dependent on the illumination intensity, whereas the latter bi-molecular case mandates an initial dimer formation rate that is dependent on the square of the illumination intensity. We performed numerical simulation to shed light on this issue, and the results for the bi-molecular model are presented in Figure 2(b). At short times, we find that the spatial variation of the dimer concentration follows a sinusoidal-squared distribution, which is expected with a sinusoidal illumination intensity. At longer exposure times, the number of reaction-available PCBM monomers will diminish when the number of PCBM dimers increases, and this saturation effect is apparent for the longest exposure time (the red line) in the form a flattened peak shape, a high contrast, and a significantly sized region where the number of dimers is very small. We included the longest-exposure-time data as the solid red line in Figure 2(a), and the agreement between the modelled and experimental results are striking. The only minor deviation is observed at the nanostripe edges, where the model predicts a larger number of PCBM-dimers than is observed. It is however highly plausible that this deviation can be rationalized by that a small fraction of PCBM dimers immersed in a majority matrix of PCBM monomers will be removed by the developer solution during the development step. More importantly is that the simulation based on the monoexcited model (data not shown) invariably failed to replicate the experimental data, since, e.g., the corresponding longest-exposure time data displayed a less sharp and a much smaller bare region than what is observed experimentally. A similar good agreement between the measured AFM data and the simulated data is presented in Fig. S1, with the minor difference being that the simulated data corresponded to 85 % peak-dimer fraction in response to a shorter exposure time. The presented data thus yield support for that the photochemical formation of PCBM dimers is a biexcited molecular reaction, and importantly that this results in that the pattern contrast, as desired for many applications, is high. We also emphasize that the bi-excited process is distinctly distinguished from the “two-photon process” utilized in high-contrast photoresist materials.35 In the former case, it is two neighboring molecules that must be singly excited for a reaction to take place, whereas in the latter case it is a single molecular entity that must be excited by two photons in order to reach the reactive state.36 The probability of this double-excitation event is typically low, which is why the twophoton reaction process is dependent on a very strong light intensity.37

6


Page 6 of 14

Page 7 of 14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Nano Letters

Figure 3. (a) Schematic of the field-effect transistor structure, with a section of the PCBM-nanostripe active material indicated by the black square. (b) SEM images of an array of PCBM nanostripes aligned between the source and drain electrodes in the field-effect transistor. (c) Output data from the PCBM-nanostripe FET recorded at a sweep rate of 4 V s-1 and with the source-gate voltages identified in the upper left corner. (d) Transfer data from a PCBMnanostripe FET recorded at a source-drain voltage of +60 V. The PCBM film was patterned by a 5 s laserinterference exposure at p = 0.17 W cm-2 followed by a solution development for 70 s. The transistor-channel length and width was 12.5 µm and 1 mm, respectively. An interesting and important question is whether the fabricated PCBM nanostripes are semiconducting and as such can be utilized in electronic applications. To answer this question, we fabricated field-effect transistors (FETs) comprising the patterned PCBM film as the active material. Figure 3(a) presents a schematic of the employed bottom-gate/top-electrode FET architecture, and details on its structure and fabrication are available in the experimental section. Figure 3(b) is a SEM image depicting a one-dimensional array of well-aligned 200-nm wide PCBM nanostripes bridging 7


Nano Letters 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

the source and drain electrodes in an efficient manner. The higher magnification SEM image in the inset demonstrates that the nanostripes form a continuous path between the electrodes, and that the contact between different stripes is effectively non-existent. In this context, we want to emphasize that the attainment of this well-defined morphology is directly dependent on the selection of “appropriate” exposure/development process parameters, e.g., plaser = 0.17 W cm-2, texposure = 5 s, tdevelopment = 70 s. In our setup, we found that a longer exposure time than 5 s often resulted in a blurring of the pattern features, presumably because of minor external vibrations; see Figure S2. We further observed that a too high laser exposure intensity could create irregular cracks in the patterned films, which we tentatively assign to volume changes induced by the resulting higher temperature during the high-intensity exposure; see Figure S3. We measured 63 independent PCBM-nanostripe transistors with a channel length of 12.5 µm and a channel width of 1 mm, and typical output and transfer data are presented in Figures 3(c) and 3(d), respectively. The well-behaved transistor characteristics, with gate-modulated drain-source current and distinct current saturation when the drain-source voltage exceeds the gate-source voltage, demonstrate that the PCBM-dimer nanostripes, as desired, feature n-type semiconducting function. More specifically, we find that it is possible to modulate the electron current by a factor of 3×103, and by fitting the classical transistor equations to the measured data, we extract a high average electron mobility of 2.4(±2.0) × 10-3 cm2 V-1 s-1, with the peak value being 5.3 × 10-3 cm2 V-1 s-1. We note that this mobility is comparable, within an order of magnitude, to previously published values on pristine spin-coated PCBM films.38-46 This calculation was done under the assumption that 67 % of the channel area was covered by active nanostripes, and that the nanostripes are oriented in a perpendicular direction to the electrode edges. These assumptions will most probably result in a slight underestimation of the true electron mobility. To summarize, we introduce a direct laser interference patterning method for the realization of welldefined and ordered semiconducting fullerene nanostructures over large areas. We emphasize that the patterning method is not only easily scalable,47 but also practical, economical and highly faulttolerant as it does not rely on the use of neither a photomask, stamp nor a photoresist. We further demonstrate that the constituent photochemical transformation of the PCBM fullerenes into covalently connected dimer structures originates in a bi-excited process, which has the consequence that the realized fullerene patterns exhibit a desired high contrast. To the best of our knowledge, this is the pioneering demonstration of a high-throughput patterning of semiconducting structures on the

8


Page 8 of 14

Page 9 of 14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Nano Letters

nanoscale that do not rely on the employment of a sacrificial photoresist material or a difficult-toadjust and expensive template or stamp. We finally anticipate that our results can be utilized for the development of large arrays of nanosized organic transistors and for the realization of vertical organic heterojunction structures from solution.

Experimental PCBM (≥99.5%, Solenne) was dissolved in chlorobenzene (99.8%, anhydrous, Sigma-Aldrich) in a 20 g l-1 concentration, and the solution was stirred at T = 333 K for 5 h. The PCBM solution was filtered (pore size = 0.45 µm, Puradisc 25 TF, VWR) and thereafter spin-coated on carefully cleaned SiO2/p-Si substrate (SiO2 thickness = 200 nm). The spin-coating was done in two consecutive steps: (i) speed = 800 rpm, acceleration = 100 rpm s-1, t = 60 s; (ii) speed = 2000 rpm, acceleration = 100 rpm s-1, t = 60 s. This resulted in a PCBM film thickness of 100 nm. We executed these procedures in a N2-filled glove box ([O2] ≤ 0.5 ppm, [H2O] ≤ 1 ppm). The PCBM-coated substrate was then transferred to a vacuum oven for drying at T = 353 K and p < 10−3 mbar for 12 h, before being introduced into an air-tight box filled with dry N2 gas and equipped with a quartz window for optical manipulation. The output beam from a green laser (λ = 532 nm, coherence length = 19 m, Verdi V-18 diode laser, Coherent) was expanded by a beam expander, divided into two beams of equal intensity by a beam splitter, where after an assembly of mirrors and lenses allowed the two beams to hit the surface of the PCBM film in a plane perpendicular to the sample surface and featuring the same angle θ with respect to the surface normal. This resulted in the formation of a light interference pattern in the plane of the PCBM film, where the distance between two neighboring intensity maxima is given by Equation (1) in the main text. The average exposure intensity of the PCBM film was controlled by the laser output, which was varied between 0.17 - 2.8 W cm-2. The exposure time was controlled by a manual shutter, and was set to 5 s in the presented experiments, with the exception of Figs. S2-S3 in the Supporting Information. The two-beam laser interference setup is schematically depicted in Figure 1(b). The development of the exposed PCBM film was effectuated by immersing the entire substrate in a carefully tuned chloroform:acetone (volume ratio = 1:7) developer solution, which selectively removed the non-exposed PCBM regions. The development time was selected to be ~1 min

9


Nano Letters 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 10 of 14

following optimization studies. The patterned PCBM film was dried for 12 h in the vacuum oven at p < 10−3 mbar and T = 295 K. The samples were thereafter transferred into the N2-filled glove box for storage before further characterization. The SEM imaging (Zeiss MERLIN, accelerating voltage = 4 kV) was performed on the surface of the PCBM-nanostripe covered SiO2/Si substrates. The samples for the high-resolution crosssectional SEM images (Zeiss LEO, accelerating voltage = 3 kV, Figure 1c; accelerating voltage = 2 kV, Figure 2a) were prepared by manually cleaving the PCBM-nanostripe substrates after scratching the Si back side with a diamond scribe. The modelling is based on two sets of rate equations, as derived and presented in detail in our previous work,34 which describe the mono-excited and bi-excited dimerization processes, respectively. The resulting partial differential equation systems were solved numerically using the Matlab function ode45 (relative error tolerance = 1×10-5, absolute tolerance = 1×10-6) to obtain the dimerization fraction as a function of exposure intensity and time. The substrates for the FET measurements comprised a 200 nm thick thermally grown SiO2 layer (the dielectric) on a p-type doped Si wafer (the gate electrode). The PCBM was spin-coated on the SiO2 surface, and the dry PCBM film subsequently patterned using the above described exposure/development procedure. The exposure intensity and time were 0.17 W cm-2 and 5 s, respectively, while the development time was 1 min. Source and drain electrodes (Au, thickness = 70 nm) were thermally evaporated (Univex 350G, Leybold, p < 5 × 10-6 mbar) on top of the patterned PCBM film through a shadow mask, which was aligned so that the PCBM nanostripes were perpendicular to the electrode edges. The source and drain electrodes defined a channel length (LG) of 12.5 µm and a channel width (WD) of 1 mm. The source electrode was grounded during all transistor measurements. The electron mobility (µe) was derived by fitting the equation (2)

where CG represents the gate capacitance, to the transfer data. The on/off ratio was determined at a drain-source voltage of VDS = 60 V and gate-source voltages of VGS = 60 V (on) and VGS = 0 V(off).

10


Page 11 of 14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Nano Letters

Associated content The following is provided as Supporting Information: An AFM image and cross-section profile of a pattern of PCBM nanostripes, and SEM images depicting PCBM nanostripe patterns fabricated using non-optimized exposure parameters.

Acknowledgements The authors acknowledge financial support from the Swedish Foundation for Strategic Research, the Swedish Research Council, the Swedish Energy Agency, Kempestiftelserna, and the Knut and Alice Wallenberg Foundation. Cheng Choo Lee at the Umeå Core Facility Electron Microscopy (UCEM), Victoria Sternhagen at the Ångström Microstructure Laboratory, and Nicolas Boulanger, Mattias Lindh and Petter Lundberg at Umeå University are all gratefully acknowledged for technical assistance.

11


Nano Letters 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

References 1.

Kroto, H. W.; Heath, J. R.; Obrien, S. C.; Curl, R. F.; Smalley, R. E. Nature 1985, 318, (6042), 162163.

2.

Hebard, A. F.; Rosseinsky, M. J.; Haddon, R. C.; Murphy, D. W.; Glarum, S. H.; Palstra, T. T. M.; Ramirez, A. P.; Kortan, A. R. Nature 1991, 350, (6319), 600-601.

3.

Wang, H. H.; Kini, A. M.; Savall, B. M.; Carlson, K. D.; Williams, J. M.; Lathrop, M. W.; Lykke, K. R.; Parker, D. H.; Wurz, P.; Pellin, M. J.; Gruen, D. M.; Welp, U.; Kwok, W. K.; Fleshler, S.; Crabtree, G. W.; Schirber, J. E.; Overmyer, D. L. Inorganic Chemistry 1991, 30, (15), 2962-2963.

4.

Breton, J.; Gonzalezplatas, J.; Girardet, C. J Chem Phys 1993, 99, (5), 4036-4040.

5.

Zhang, R.; Murata, M.; Aharen, T.; Wakamiya, A.; Shimoaka, T.; Hasegawa, T.; Murata, Y. Nat. Chem.

2016, 8, (5), 435-441. 6.

Brown, S. B.; Brown, E. A.; Walker, I. Lancet Oncol. 2004, 5, (8), 497-508.

7.

Lalwani, G.; Sitharaman, B. Nano Life 2013, 03, (03), 1342003.

8.

Sariciftci, N. S.; Smilowitz, L.; Heeger, A. J.; Wudl, F. Science 1992, 258, (5087), 1474-1476.

9.

Burlingame, Q.; Tong, X. R.; Hankett, J.; Slootsky, M.; Chen, Z.; Forrest, S. R. Energy & Environmental Science 2015, 8, (3), 1005-1010.

10. Inasaridze, L. N.; Shames, A. I.; Martynov, I. V.; Li, B.; Mumyatov, A. V.; Susarova, D. K.; Katz, E. A.; Troshin, P. A. J. Mater. Chem. A 2017, 5, (17), 8044-8050. 11. Zhong, Y. F.; Munir, R.; Balawi, A. H.; Sheikh, A. D.; Yu, L. Y.; Tang, M. C.; Hu, H. L.; Laquai, F.; Amassian, A. Acs Energy Letters 2016, 1, (5), 1049-1056. 12. Zhang, H.; Borgschulte, A.; Castro, F. A.; Crockett, R.; Gerecke, A. C.; Deniz, O.; Heier, J.; Jenatsch, S.; Nuesch, F.; Sanchez-Sanchez, C.; Zoladek-Lemanczyk, A.; Hany, R. Adv. Energy Mater. 2015, 5, (2), 9. 13. Andersson, T.; Nilsson, K.; Sundahl, M.; Westman, G.; Wennerstrom, O. J. Chem. Soc.-Chem. Commun.

1992, (8), 604-606. 14. Hummelen, J. C.; Knight, B. W.; Lepeq, F.; Wudl, F.; Yao, J.; Wilkins, C. L. J. Org. Chem. 1995, 60, (3), 532-538. 15. Rao, A. M.; Zhou, P.; Wang, K.-A.; Hager, G. T.; Holden, J. M.; Wang, Y.; Lee, W.-T.; Bi, X.-X.; Eklund, P. C.; Cornett, D. S.; Duncan, M. A.; Amster, I. J. Science 1993, 259, (5097), 955-957. 16. Cui, W.; Sun, S. S.; Sundqvist, B.; Wang, S. M.; Liu, B. B. Carbon 2017, 115, 740-745. 17. Yao, M.; Cui, W.; Du, M.; Xiao, J.; Yang, X.; Liu, S.; Liu, R.; Wang, F.; Cui, T.; Sundqvist, B.; Liu, B. Advanced Materials 2015, 27, (26), 3962-3968. 12


Page 12 of 14

Page 13 of 14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Nano Letters

18. Cui, W.; Yao, M.; Liu, S.; Ma, F.; Li, Q.; Liu, R.; Liu, B.; Zou, B.; Cui, T.; Liu, B. Advanced Materials

2014, 26, (42), 7257-7263. 19. Yao, M.; Cui, W.; Xiao, J.; Chen, S.; Cui, J.; Liu, R.; Cui, T.; Zou, B.; Liu, B.; Sundqvist, B. Applied Physics Letters 2013, 103, (7), 071913. 20. Dzwilewski, A.; Wagberg, T.; Edman, L. Journal of the American Chemical Society 2009, 131, (11), 40064011. 21. Dzwilewski, A.; Matyba, P.; Edman, L. J. Phys. Chem. B 2010, 114, (1), 135-140. 22. Larsen, C.; Wang, J.; Edman, L. Thin Solid Films 2012, 520, (7), 3009-3012. 23. Li, Z.; Wong, H. C.; Huang, Z.; Zhong, H.; Tan, C. H.; Tsoi, W. C.; Kim, J. S.; Durrant, J. R.; Cabral, J. T. Nat Commun 2013, 4. 24. Wong, H. C.; Li, Z.; Tan, C. H.; Zhong, H.; Huang, Z.; Bronstein, H.; McCulloch, I.; Cabral, J. T.; Durrant, J. R. ACS Nano 2014, 8, (2), 1297-1308. 25. Distler, A.; Sauermann, T.; Egelhaaf, H.-J.; Rodman, S.; Waller, D.; Cheon, K.-S.; Lee, M.; Guldi, D. M. Adv. Energy Mater. 2014, 4, (1), n/a-n/a. 26. Yan, L. P.; Yi, J. D.; Chen, Q.; Dou, J. Y.; Yang, Y. Z.; Liu, X. G.; Chen, L. W.; Ma, C. Q. J. Mater. Chem. A 2017, 5, (20), 10010-10020. 27. Heumueller, T.; Mateker, W. R.; Distler, A.; Fritze, U. F.; Cheacharoen, R.; Nguyen, W. H.; Biele, M.; Salvador, M.; von Delius, M.; Egelhaaf, H. J.; McGehee, M. D.; Brabec, C. J. Energy & Environmental Science 2016, 9, (1), 247-256. 28. Cardinaletti, I.; Kesters, J.; Bertho, S.; Conings, B.; Piersimoni, F.; D'Haen, J.; Lutsen, L.; Nesladek, M.; Van Mele, B.; Van Assche, G.; Vandewal, K.; Salleo, A.; Vanderzande, D.; Maes, W.; Manca, J. V. Journal of Photonics for Energy 2014, 4, 12. 29. Dominguez, I. F.; Distler, A.; Luer, L. Adv. Energy Mater. 2017, 7, (10), 23. 30. Li, Z.; Wong, H. C.; Huang, Z. G.; Zhong, H. L.; Tan, C. H.; Tsoi, W. C.; Kim, J. S.; Durrant, J. R.; Cabral, J. T. Nature Communications 2013, 4, 7. 31. Tan, C. H.; Wong, H. C.; Li, Z.; Bucknall, D. G.; Durrant, J. R.; Cabral, J. T. Journal of Materials Chemistry C 2015, 3, (37), 9551-9558. 32. Magyar, G.; Mandel, L. Nature 1963, 198, (4877), 255-256. 33. Wang, Y.; Holden, J. M.; Dong, Z.-H.; Bi, X.-X.; Eklund, P. C. Chemical Physics Letters 1993, 211, (4), 341-345. 34. Wang, J.; Enevold, J.; Edman, L. Advanced Functional Materials 2013, 23, (25), 3220-3225. 35. He, G. S.; Tan, L.-S.; Zheng, Q.; Prasad, P. N. Chemical Reviews 2008, 108, (4), 1245-1330. 13


Nano Letters 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

36. Maruo, S.; Nakamura, O.; Kawata, S. Opt. Lett. 1997, 22, (2), 132-134. 37. Farsari, M.; Chichkov, B. N. Nat Photon 2009, 3, (8), 450-452. 38. Janasz, L.; Luczak, A.; Marszalek, T.; Dupont, B. G. R.; Jung, J.; Ulanski, J.; Pisula, W. ACS Applied Materials & Interfaces 2017, 9, (24), 20696-20703. 39. Wei, Q.; Tajima, K.; Hashimoto, K. ACS Applied Materials & Interfaces 2009, 1, (9), 1865-1868. 40. Morana, M.; Koers, P.; Waldauf, C.; Koppe, M.; Muehlbacher, D.; Denk, P.; Scharber, M.; Waller, D.; Brabec, C. Advanced Functional Materials 2007, 17, (16), 3274-3283. 41. Rossbauer, S.; Müller, C.; Anthopoulos, T. D. Advanced Functional Materials 2014, 24, (45), 7116-7124. 42. Wang, J.; Larsen, C.; Wågberg, T.; Edman, L. Advanced Functional Materials 2011, 21, (19), 3723-3728. 43. Anthopoulos, T. D.; Tanase, C.; Setayesh, S.; Meijer, E. J.; Hummelen, J. C.; Blom, P. W. M.; de Leeuw, D. M. Adv. Mater. 2004, 16, (23-24), 2174-2179. 44. Chikamatsu, M.; Nagamatsu, S.; Yoshida, Y.; Saito, K.; Yase, K.; Kikuchi, K. Appl. Phys. Lett. 2005, 87, (20), 203504. 45. Takeomi, M.; Wataru, T.; Keiichi, K. Jpn. J. Appl. Phys. 2007, 46, (3L), L256. 46. Seo, J. H.; Gutacker, A.; Walker, B.; Cho, S.; Garcia, A.; Yang, R.; Nguyen, T.-Q.; Heeger, A. J.; Bazan, G. C. Journal of the American Chemical Society 2009, 131, (51), 18220. 47. Xia, D.; Ku, Z.; Lee, S. C.; Brueck, S. R. J. Advanced Materials 2011, 23, (2), 147-179.

14


Page 14 of 14

Realizing Large-Area Arrays of Semiconducting Fullerene

Recommend Documents