Cyclohexanone

The electroluminescent organic semiconductor Super Yellow (PDY-132, Merck, GER) was dissolved in cyclohexanone (purity > 99.5%, Sigma Aldrich, USA) in a concentration of either 8 or 10 g·l⁻¹. The KCF₃SO₃ (Merck, GER) salt and the hydroxyl-capped trimethylolpropane ethoxylate (TMPE-OH, M_W = 450 g·mol⁻¹, Merck, GER) ion transporter were separately dissolved in cyclohexanone in a 10 g·l⁻¹ concentration. KCF₃SO₃ and TMPE-OH were dried under vacuum at 80 °C for 12 h before dissolution, while the other chemicals were used as received.
The master solutions were stirred on a magnetic hot plate at 70 °C for 1 day, and thereafter blended in a Super Yellow:TMPE-OH:KCF₃SO₃ mass ratio of 1:0.1:0.03. The doping solution was thereafter added in a number of different concentrations for the formulation of the active-material inks. These inks are solely distinguished by the concentration of r-BV⁰, which is herein quantified by the mass ratio between r-BV⁰ and Super Yellow. The inks for the electron-transport measurements were prepared in an identical manner, but with the TMPE-OH and KCF₃SO₃ master solutions excluded. All of the ink preparation and device fabrication processes were performed in a pair of interconnected N₂-filled glove boxes ([O₂] < 1 ppm, [H₂O] < 1 ppm).

PSf with number-averaged molecular weight M_n = 22 kg mol⁻¹ (Sigma-Aldrich) is dissolved in cyclohexanone (Sigma-Aldrich, puriss p.a. >99.5%). Psf films are made with a thickness of h ≈ 400 nm. These films are annealed at 220 °C for 12 h. The re-annealing after contact angle measurement is done at 220 °C for 15 min. Poly(Bisphenol-A Carbonate) (PC) with M_n = 22 kg mol−1 (Polymer Source Inc.) and polydispersity index of 1.9 is dissolved in chloroform (Fisher Scientific, Optima grade). PC films are made with a thickness of h ≈ 1200 nm. These films are annealed at 170 °C for 12 h. The re-annealing after contact angle measurement is done at 175 °C for 15 min. SIS triblock copolymer (Sigma-Aldrich) with a 14% styrene content is dissolved in toluene (Fisher Scientific, Optima grade). These films are made with a thickness of h ≈ 1300 nm and annealed at 110 °C for 10 min. Elastollan TPU 1185A (BASF) is dissolved in cyclohexanone (Sigma-Aldrich, puriss p.a. >99.5%). These films are made with a thickness of h ≈ 250 nm and annealed at 100 °C for 90 min. PVS elastomer is made by mixing base and catalyst (RTV EC00 Translucid) at a 1:1 ratio. These films are made with thicknesses on the order of several hundred microns.

To monitor the performance of the GC-MS operating conditions, an external standard (ES) solution was added at the start and end of each GC-MS sample run. The ES was comprised of 1-butanol, dimethyl disulfide, butyl acetate, cyclohexanone, and benzaldehyde (Merck, Ireland) at 10 mg L⁻¹ with 2-phenyl-D5-ethanol (Merck, Arklow, Co., Wicklow, Ireland) added at 5 mg L⁻¹ in ultra-pure water. For the HS-SPME technique, 10 µL of ES was added to the sample in a 20 mL amber La-Pha-Pack HS vial with magnetic screw caps and a silicone/polytetraflurorethylene septa (Apex Scientific Ltd., Maynooth, Ireland); see details in Section 2.3.1. The ES (10 µL) was also added to the TD tube containing the sample extract for both TD and HiSorb (HS-HiSorb and DI-HiSorb), the details of which are described in Section 2.3.2 and Section 2.3.3. To monitor the performance of each extraction procedure, an internal standard (IS) of 2-phenyl-D5-ethanol and 4-methyl-2-pentanol (Merck, Arklow, Co., Wicklow, Ireland) at 20 mg L⁻¹ in ultra-pure water, was added (50 µL) to each WMP sample prior to extraction.