Datenschutz-Folgenabschätzung: Chancen, Grenzen, Umsetzung

With the European General Data Protection Regulation (GDPR) there will be a legal obligation for controllers to conduct a Data Protection Impact Assessment (DPIA) for the first time. This paper examines the new provisions in detail and examines ways for their implementation. A special focus is on elements which, according to experience, can be problematic and how they can be addressed

Amorphous Thieno[3,2‑<i>b</i>]thiophene and Benzothiadiazole Based Copolymers for Organic Photovoltaics

Three types of amorphous thienothiophene (TT)-benzothiadiazole (BT) based copolymers (<b>PFTTBT</b>) were synthesized by incorporating alkyl-substituted fluorene moieties as a third component in the polymer backbone. Their optical, electrochemical, morphological, and photovoltaic properties were examined by a comparison with those of a crystalline TT-BT derivative (<b>PTTBT14</b>). <b>PTTBT14</b> was reported to have a high hole mobility (0.26 cm²/(V s)) due to the pronounced interchain ordering but poor photovoltaic power conversion efficiency (PCE) of 2.4–2.6% was reported due to excessively strong self-interactions with poor miscibility with fullerene structures. By incorporating fluorene units, the UV–vis spectra showed an increased bandgap (∼1.9 eV) with the disappearance of the packing-originated shoulder peak, and the valence band decreased compared to crystalline <b>PTTBT14</b>. The amorphous <b>PFTTBT</b> polymers showed substantially improved photovoltaic properties compared to <b>PTTBT14</b>, even though they showed poor hole mobility (∼10^–6 cm²/(V s)) and fill factor. The optimal devices were achieved by blending with excess PC₇₁BM (polymer:PC₇₁BM = 1:4 by weight), showing little improvement in the thermal and additive treatments. Under simulated solar illumination of AM 1.5 G, the best PCE of 6.6% was achieved for a <b>PFehTTBT</b>:PC₇₁BM device with an open-circuit voltage of 0.92 V, a short-circuit current of 15.1 mA/cm², and a fill factor of 0.48. These results suggest that it is useful to disrupt partially the interchain organizations of excessively crystalline polymers, enabling fine-control of intermolecular ordering and the morphological properties (i.e., miscibility with fullerene derivatives, etc.) to utilize the advantages of both crystalline and amorphous materials for further improving PCE of polymer solar cells

Semicrystalline D–A Copolymers with Different Chain Curvature for Applications in Polymer Optoelectronic Devices

Thiophene- and thienothiophene-based donor–acceptor (D–A) type semicrystalline copolymers with different backbone curvatures, <b>PTBT14</b> and <b>PTTBT14</b>, were designed and synthesized. Both the polymers exhibit a nearly planar structure via noncovalent S···O and C–H···N attractive interactions, etc., in the polymer chain. <b>PTTBT14</b> is linear, whereas <b>PTBT14</b> is curved owing to ∼160° bond angle of the thiophene linkage. <b>PTTBT14</b> showed the higher degree of interchain ordering with edge-on orientation, resulting in efficient charge transport (0.26 cm² V^–1 s^–1 for <b>PTTBT14</b> compared to 0.02 cm² V^–1 s^–1 for <b>PTBT14</b>) in PFETs with remarkable morphological stability and no deterioration in device properties at temperatures up to 250 °C. On the other hand, the curved shape of <b>PTBT14</b> attributed to its improved photovoltaic properties with a power conversion efficiency of 5.56%. The linear <b>PTTBT14</b> showed much stronger self-interactions with negligible morphological changes and little miscibility with PC₆₁BM, showing the poor photovoltaic characteristics

A Planar Cyclopentadithiophene–Benzothiadiazole-Based Copolymer with sp²‑Hybridized Bis(alkylsulfanyl)methylene Substituents for Organic Thermoelectric Devices

A semicrystalline p-type thermoelectric conjugated polymer based on a polymer backbone of cyclopentadithiophene and benzothiadiazole, poly­[(4,4′-(bis­(hexyldecyl­sulfanyl)­methylene)­cyclopenta­[2,1-<i>b</i>:3,4-<i>b</i>′]­dithiophene)-<i>alt</i>-(benzo­[<i>c</i>]­[1,2,5]­thiadiazole)] (PCPDTSBT), is designed and synthesized by replacing normal alkyl side-chains with bis­(alkylsulfanyl)­methylene substituents. The sp²-hybridized olefinic bis­(alkylsulfanyl)­methylene side-chains and the sulfur–sulfur (S–S) chalcogen interactions extend a chain planarity with strong interchain packing, which is confirmed by density functional calculations and morphological studies, i.e., grazing incidence X-ray scattering measurement. The doping, electrical, morphological, and thermoelectric characteristics of PCPDTSBT are investigated by comparison with those of poly­[(4,4′-bis­(2-ethylhexyl)­cyclopenta­[2,1-<i>b</i>:3,4-<i>b</i>′]­dithiophene)-<i>alt</i>-(benzo­[<i>c</i>]­[1,2,5]­thiadiazole)] (PCPDTBT) with ethylhexyl side-chains. Upon doping with a Lewis acid, B­(C₆F₅)₃, the maximum electrical conductivity (7.47 S cm^–1) of PCPDTSBT is ∼1 order higher than that (0.65 S cm^–1) of PCPDTBT, and the best power factor is measured to be 7.73 μW m^–1 K^–2 for PCPDTSBT with doping 9 mol % of B­(C₆F₅)₃. The Seebeck coefficient–electrical conductivity relation is analyzed by using a charge transport model for polymers, suggesting that the doped PCPDTSBT film has superb charge transport property based on a high crystallinity with olefinic side-chains. This study emphasizes the importance of side-chain engineering by using the sp²-hybridized olefinic substituents to modulate interchain packing, crystalline morphology, and the resulting electrical properties

Benzotriazole-Containing Planar Conjugated Polymers with Noncovalent Conformational Locks for Thermally Stable and Efficient Polymer Field-Effect Transistors

We report a series of benzotriazole-based semicrystalline π-conjugated polymers with noncovalent conformational locks for applications in polymer field-effect transistors. The benzotriazole moiety is a versatile electron-deficient building block that offers two chemically functionalizable sites, 2­(N) and 5, 6­(C) positions, allowing easy modulation of the solution processability and electronic structures of the resulting polymers. Fluorine or alkoxy substituents were introduced to the benzotriazole unit to enhance the molecular ordering through intra- and intermolecular F···S, F···H–C, C–F···π_F, or S···O attractive interactions. The fluorinated polymer (<b>PTBTz-F</b>) showed remarkably enhanced hole mobility (μ_h = 1.9 cm²/(V·s), on/off ratio = 8 × 10⁷) upon thermal annealing at 305 °C, compared to the unsubstituted one (<b>PTBTz</b>) (μ_h = 7.0 × 10^–3 cm²/(V·s), on/off ratio = 3 × 10⁶). Alkoxy unit substitution (<b>PTBTz-OR</b>) also improved the carrier mobility up to 0.019 cm²/(V·s) with an on/off ratio of 4 × 10⁵. Fluorine or alkoxy substitution induced tight interchain ordering with edge-on orientation, as confirmed by X-ray diffraction measurements. In particular, fluorinated <b>PTBTz-F</b> showed high thermal stability (<i>T</i>_d 453 °C) and the remarkable device characteristics with deep frontier orbital levels