Conjugated Polymer Heteroatom Engineering Enables High Detectivity Symmetric Ambipolar Phototransistors

Solution-processed high-performing ambipolar organic phototransistors (OPTs) can enable low-cost integrated circuits. Here, a heteroatom engineering approach to modify the electron affinity of a low band gap diketopyrrolopyrole (DPP) co-polymer, resulting in well-balanced charge transport, a more preferential edge-on orientation and higher crystallinity, is demonstrated. Changing the comonomer heteroatom from sulfur (benzothiadiazole (BT)) to oxygen (benzooxadiazole (BO)) leads to an increased electron affinity and introduces higher ambipolarity. Organic thin film transistors fabricated from the novel PDPP-BO exhibit charge carrier mobility of 0.6 and 0.3 cm2 Vs⁻1 for electrons and holes, respectively. Due to the high sensitivity of the PDPP-based material and the balanced transport in PDPP-BO, its application as an NIR detector in an OPT architecture is presented. By maintaining a high on/off ratio (9 × 104), ambipolar OPTs are shown with photoresponsivity of 69 and 99 A W⁻1 and specific detectivity of 8 × 107 for the p-type operation and 4 × 109 Jones for the n-type regime. The high symmetric NIR-ambipolar OPTs are also evaluated as ambipolar photo-inverters, and show a 46% gain enhancement under illumination.

Designing a Multifunctional Catalyst for the Direct Production of Gasoline-Range Isoparaffins from CO2

The production of carbon-neutral fuels from CO₂ presents an avenue for causing an appreciable effect in terms of volume toward the mitigation of global carbon emissions. To that end, the production of isoparaffin-rich fuels is highly desirable. Here, we demonstrate the potential of a multifunctional catalyst combination, consisting of a methanol producer (InCo) and a Zn-modified zeolite beta, which produces a mostly isoparaffinic hydrocarbon mixture from CO₂ (up to ∼85% isoparaffin selectivity among hydrocarbons) at a CO₂ conversion of >15%. The catalyst combination was thoroughly characterized via an extensive complement of techniques. Specifically, operando X-ray absorption spectroscopy (XAS) reveals that Zn (which plays a crucial role of providing a hydrogenating function, improving the stability of the overall catalyst combination and isomerization performance) is likely present in the form of Zn₆O₆ clusters within the zeolite component, in contrast to previously reported estimations.

Turning Waste into Value: Potassium-Promoted Red Mud as an Effective Catalyst for the Hydrogenation of CO2

Since 1887, red mud has been an unavoidable waste derived from the production of alumina in the Bayer process. Because of its high alkalinity and metal loading, red mud disposal and storage constitute a significant environmental risk. With worldwide storage capacity reaching its limits and no alternatives to the Bayer Process, the development of methods for the valorization of red mud is a must. In this study, red mud is converted into an efficient catalyst for the valorization of CO₂ . By simple potassium promotion, 45 % conversion of CO₂ with a light olefin (C₂ -C₄ ) selectivity of 36 % is achieved at 375 °C, 30 bar, and 9600 mL g^-1  h^-1 , matching the performance of some of the best catalysts reported to date.