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  1. Free, publicly-accessible full text available January 10, 2023
  2. Organic electronics technologies have attracted considerable interest over the last few decades and have become promising alternatives to conventional, inorganic platforms for specific applications. To fully exploit the touted potential of plastic electronics, however, other prerequisites than only electronic functions need to be fulfiled, including good mechanical stability, ease of processing and high device reliability. A possible method to overcome these issues is the employment of insulating:semiconducting polymer blends, which have been demonstrated to display favourable rheological and mechanical properties, generally provided by the insulating component, without negatively affecting the optoelectronic performance of the semiconductor. Here, we demonstrate that binary blends comprising the semicrystalline high-density polyethylene (HDPE) in combination with hole- and electron-transporting organic semiconductors allow fabrication of p-type and n-type thin-film transistors of notably improved device stability and, in some scenarios, improved device performance. We observe, for example, considerably lower subthreshold slopes and drastically reduced bias-stress effects in devices fabricated with a hole-transporting diketopyrrolopyrrole polymer derivative when blended with HDPE and significantly enhanced charge-carrier mobilities and shelf life in case of transistors made with blends between HDPE and the electron-transporting poly{[ N , N ′-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)2,6-diyl]- alt -5,5′-(2,2′-bithiophene)}, i.e. P(NDI2OD-T2), also known as N2200, compared to the neat material, highlightingmore »the broad, versatile benefits blending semiconducting species with a semicrystalline commodity polymer can have.« less
  3. The optimal synthesis of advanced nanomaterials with numerous reaction parameters, stages, and routes, poses one of the most complex challenges of modern colloidal science, and current strategies often fail to meet the demands of these combinatorially large systems. In response, an Artificial Chemist is presented: the integration of machine‐learning‐based experiment selection and high‐efficiency autonomous flow chemistry. With the self‐driving Artificial Chemist, made‐to‐measure inorganic perovskite quantum dots (QDs) in flow are autonomously synthesized, and their quantum yield and composition polydispersity at target bandgaps, spanning 1.9 to 2.9 eV, are simultaneously tuned. Utilizing the Artificial Chemist, eleven precision‐tailored QD synthesis compositions are obtained without any prior knowledge, within 30 h, using less than 210 mL of total starting QD solutions, and without user selection of experiments. Using the knowledge generated from these studies, the Artificial Chemist is pre‐trained to use a new batch of precursors and further accelerate the synthetic path discovery of QD compositions, by at least twofold. The knowledge‐transfer strategy further enhances the optoelectronic properties of the in‐flow synthesized QDs (within the same resources as the no‐prior‐knowledge experiments) and mitigates the issues of batch‐to‐batch precursor variability, resulting in QDs averaging within 1 meV from their target peak emission energy.
  4. Abstract

    The emergence of hybrid metal halides (HMH) materials, such as the archetypal CH3NH3PbBr3, provides an appealing material platform for solution-processed spintronic applications due to properties such as unprecedented large Rashba spin-splitting states and highly efficient spin-to-charge (StC) conversion efficiencies. Here we report the first study of StC conversion and spin relaxation time in MAPbBr3single crystals at room temperature using a spin pumping approach. Microwave frequency and power dependence of StC responses are both consistent with the spin pumping model, from which an inverse Rashba–Edelstein effect coherence length of up to ∼30 picometer is obtained, highlighting a good StC conversion efficiency. The magnetic field angular dependence of StC is investigated and can be well-explained by the spin precession model under oblique magnetic field. A long spin relaxation time of up to ∼190 picoseconds is obtained, which can be attributed to the surface Rashba state formed at the MAPbBr3interface. Our oblique Hanle effect by FMR-driven spin pumping technique provides a reliable and sensitive tool for measuring the spin relaxation time in various solution processed HMH single crystals.