[3]-Radialene-based dopant CN6-CP studied herein, with its reduction potential of +0.8 versus Fc/Fc+ and the lowest unoccupied molecular orbital level of -5.87 eV, is the strongest molecular p-dopant reported in the open literature, so far. The efficient p-doping of the donor-acceptor dithienyl-diketopyrrolopyrrole-based copolymer having the highest unoccupied molecular orbital level of -5.49 eV is achieved. The doped films exhibit electrical conductivities up to 70 S cm(-1) .

Thermally activated delayed fluorescence (TADF)‐type compounds have great potential as emitter molecules in organic light‐emitting diodes, allowing for electrofluorescence with 100% internal quantum efficiency. In small molecules, TADF is achieved through the formation of intramolecular charge‐transfer states. The only design limitation is the requirement that donor and acceptor entities spatially decouple the highest occupied and lowest unoccupied molecular orbitals, respectively, to minimize exchange splitting. The development of polymeric TADF emitters, on the contrary, has seen comparably small progress and those are typically built up from monomeric units that show promising TADF properties in small molecule studies beforehand. By contrast, herein, a way to achieve TADF properties in cyclic oligomers and polymers composed of non‐TADF building blocks is shown. Due to a strongly decreased energy splitting of the polymer with respect to the individual repeating unit between the lowest singlet and triplet excited state (ΔEST) and a sufficiently high radiative decay rate kSr, a highly efficient TADF polymer with up to 71% photoluminescence quantum yield is obtained. For the first time, an encouraging method is provided for producing highly efficient TADF oligomers and polymers from solely non‐TADF units via induced conjugation, opening a new design strategy exclusive for polymers.

Herein we present a molecular doping of a high mobility diketopyrrolopyrrole−dithienylthieno[3,2-b]thiophene donor−acceptor copolymer poly[3,6-thiophene], PDPP(6-DO) 2 TT, with the electron-deficient compound hexafluorotetracyanonaphthoquinodimethane (F6TCNNQ). Despite a slightly negative HOMO donor −LUMO acceptor offset of −0.12 eV which may suggest a reduced driving force for the charge transfer (CT), a partial charge CT was experimentally observed in PDPP(6-DO) 2 TT:F6TCNNQ by absorption, vibrational, and electron paramagnetic resonance spectroscopies and predicted by density functional theory calculations. Despite the modest CT, PDPP(6-DO) 2 TT:F6TCNNQ films possess unexpectedly high conductivities up to 2 S/cm (comparable with the conductivities of the benchmark doped polymer system P3HT:F4TCNQ having a large positive offset). The observation of the high conductivity in doped PDPP(6-DO) 2 TT films can be explained by a high hole mobility in PDPP(6-DO) 2 TT blends which compensates a lowered (relatively to P3HT:F4TCNQ) concentration of free charge carriers. We also show that F6TCNNQ-doped P3HT, the system which has not been reported so far to the best of our knowledge, exhibits a conductivity up to 7 S/cm, which exceeds the conductivity of the benchmark P3HT:F4TCNQ system.

Matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) and MALDI MS imaging are ubiquitous analytical methods in medical, pharmaceutical, biological, and environmental research. Currently, there is a strong interest in the investigation of low molecular weight compounds (LMWCs), especially to trace and understand metabolic pathways, requiring the development of new matrix systems that have favorable optical properties and a high ionization efficiency and that are MALDI silent in the LMWC area. In this paper, five conjugated polymers, poly{[ N, N'-bis(2-octyldodecyl)-naphtalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]- alt-5,5'(2,2'-bithiophene)} (PNDI(T2)), poly(3-dodecylthiophene-2,5-diyl) (P3DDT), poly{[2,3-bis(3-octyloxyphenyl)quinoxaline-5,8-diyl]- alt-(thiophene-2,5-diyl)} (PTQ1), poly{[ N, N'-bis(2-octyldodecyl)-isoindigo-5,5'-diyl] -alt-5,5'(2,2'-bithiophene)} (PII(T2)), and poly(9,9-di- n-octylfluorenyl-2,7-diyl) (P9OFl) are investigated as matrices. The polymers have a strong optical absorption, are solution processable, and can be coated into thin films, allowing a vast reduction in the amount of matrix used. All investigated polymers function as matrices in both positive and negative mode MALDI, classifying them as rare dual-mode matrices, and show a very good analyte ionization ability in both modes. PNDI(T2), P3DDT, PTQ1, and PII(T2) are MALDI silent in the full measurement range (> m/ z = 150k), except at high laser intensities. In MALDI MS experiments of single analytes and a complex biological sample, the performance of the polymers was found to be as good as two commonly used matrices (2,5-DHB for positive and 9AA for negative mode measurements). The detection limit of two standard analytes was determined as being below 164 pmol for reserpine and below 245 pmol for cholic acid. Additionally P3DDT was used successfully in first MALDI MS imaging experiments allowing the visualization of the tissue morphology of rat brain sections.

The N-type semiconducting polymer, P(NDI2OD-T2), with different molecular weights (MW=23, 72, and 250 kg/mol) was used for the fabrication of field-effect transistors (FETs) with different semiconductor layer thicknesses. FETs with semiconductor layer thicknesses from ∼15 to 50 nm exhibit similar electron mobilities (μ's) of 0.2-0.45 cm2 V(-1) s(-1). Reduction of the active film thickness led to decreased μ values; however, FETs with ∼2 and ∼5 nm thick P(NDI2OD-T2) films still exhibit substantial μ's of 0.01-0.02 and ∼10(-4) cm2 V(-1) s(-1), respectively. Interestingly, the lowest molecular weight sample (P-23, MW≈23 kg/mol, polydispersity index (PDI)=1.9) exhibited higher μ than the highest molecular weight sample (P-250, MW≈250 kg/mol, PDI=2.3) measured for thicker devices (15-50 nm). This is rather unusual behavior because typically charge carrier mobility increases with MW where improved grain-to-grain connectivity usually enhances transport events. We attribute this result to the high crystallinity of the lowest MW sample, as confirmed by differential scanning calorimetry and X-ray diffraction studies, which may (over)compensate for other effects.