Supplementary Information for
Luminescent LineArt by Direct-Write Patterning
Erik Mattias Lindh1, Andreas Sandström1,2, Mats Roland Andersson3 and Ludvig Edman1,2
1 The Organic Photonics and Electronics Group, Umeå University, Umeå, Sweden
2 LunaLEC AB, Umeå, Sweden
3 Future Industries Institute, University of South Australia, Mawson Lakes, SA 5095, Australia
Correspondence: L Edman, Email:
The ITO-coated glass substrates were sequentially ultrasonicated in acetone and isopropylalcohol, dried in an oven at 120 °C for ≥12h, and exposed to UV-ozone for 15 min before device fabrication. Additionally investigated electroluminescent (EL) compounds included: poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV, LT-S931, Luminescence Technology Corp., Taiwan), Polymer Blue (Livilux SPB 02T, Merck GmbH, Germany), and Polymer Red (Livilux SPR-001 L05, Merck GmbH, Germany). The EL compounds were separately dissolved in toluene at a concentration of 10 g l-1.KCF3SO3 (Sigma-Aldrich) was dried under vacuum at 50 °C for ≥24h before use. Other investigated salts included LiCF3SO3 (Sigma-Aldrich), LiN(CF3SO2)2 (Sigma-Aldrich), and combinations thereof. The salts were separately dissolved in cyclohexanone and blended with the ion-transporting material poly(ethylene-oxide) (PEO, MW= 5∙106 g mol-1, Aldrich) in a
{PEO:salt} = {4:1} mass ratio.
Figure S1. Current density as a function of time for the patterned line-art device featured in Fig. 3. The device was driven by a constant voltage of 6 V.
The temporal evolution of the current density for a line-art device driven at 6 V is presented in
Figure S1. Photographs were recorded with a digital single-lens reflex camera (60D, Canon, Japan), equipped with a macro lens (Macro 150 mm F2.8 EX DG HSM, Sigma, Japan). The film thicknesses were measured with a stylus profilometer (Dektak XT, Bruker, US). The optical micrographs were recorded using an optical microscope (BX51, Olympus) equipped with a 20× magnification lens and a camera in place of the ocular. The micrographs were analyzed using a script (MATLAB R2014b, Image Processing Toolbox, TheMathworks Inc., US) following the procedure described below:
1)A list of images, together with their corresponding timestamps, was loaded into the script. A manually specified region encircling one emissive edge was considered for all images in the list.
2)The edge region for each such RGB image was converted using a luminous grey conversion scheme, followed by a black and white conversion at a threshold value of 0.61 ([0,1]), using the MATLAB image analysis toolbox built-in function im2bw.
3)The width of the emissive line was determined by calculating the number of non-zero pixels for every pixel row in the image and correcting for any tilt of the groove. The number of pixels for each row was thereafter converted to an actual width (in µm) using the number of pixels/µm as provided by the micrograph collection software.
4)The sets of linewidth data were used to obtain the arithmetic mean value and standard deviation for each image (or time) with the zero-width data points being removed.
As observed by the naked eye, the full length of the emissive lines emitted light, although the emission width and intensity varied along the length of the line. Due to limitations in the light collection of the microscope and the dynamic range of the camera detector, parts of the images were either oversaturated or perceived as dark. The threshold setting (0.61) for black and white conversion was chosen to achieve a good agreement between the linewidth output of the script and what was perceived by directly observing the images. This approach resulted in a few zero linewidth rows, but because those rows were artifacts from light collection and image analysis, they were discarded from the analysis. A Lilliefors test (lillietest, 5%, MATLAB, R2014b, Statistical Toolbox, The Mathworks Inc., US) revealed that the emission linewidth data sets featured a normal distribution, which allowed for the use of arithmetic mean and standard deviation as statistical measures.
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