Accelerating Materials Development via Automation, Machine Learning, and High-Performance Computing

Successful materials innovations can transform society. However, materials research often involves long timelines and low success probabilities, dissuading investors who have expectations of shorter times from bench to business. A combination of emergent technologies could accelerate the pace of novel materials development by 10x or more, aligning the timelines of stakeholders (investors and researchers), markets, and the environment, while increasing return-on-investment. First, tool automation enables rapid experimental testing of candidate materials. Second, high-throughput computing (HPC) concentrates experimental bandwidth on promising compounds by predicting and inferring bulk, interface, and defect-related properties. Third, machine learning connects the former two, where experimental outputs automatically refine theory and help define next experiments. We describe state-of-the-art attempts to realize this vision and identify resource gaps. We posit that over the coming decade, this combination of tools will transform the way we perform materials research. There are considerable first-mover advantages at stake, especially for grand challenges in energy and related fields, including computing, healthcare, urbanization, water, food, and the environment.Comment: 22 pages, 3 figure

Polymer: fullerene bulk-heterojunction solar cells

+133hlm.;24c

Thermally induced transient absorption of light by poly(3,4-ethylenedioxythiophene):Poly(styrene sulfonic acid) (PEDOT:PSS) films: A way to probe charge-carrier thermalization processes

IR-induced transient absorptions in the millisecond and sub-picosecond time domains have been used to study the dynamics of charge carriers of a conducting polymer, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic acid) (PEDOT:PSS). On the millisecond timescale, the transient absorption is ascribed to a thermal effect induced by absorbed IR light. The decay of the transient absorption is limited by the transport of heat from the polymer film to the substrate and corresponds to the decay kinetics of IR-induced changes in the resistivity of the material. Near 1.5 eV, the IR-induced absorption can be modeled in terms of an interband transition. The assignment of the optical transients in terms of carrier heating opens the possibility to study charge carrier thermalization processes using short laser pulses. Pump-probe spectroscopy on a sub-picosecond timescale shows that the initial thermalization of the excited charge carriers occurs with a time const. of less than 500 fs, i.e., faster than for noble metal

Low-bandgap polymer photovoltaic cells

A-novel low-bandgap conjugated polymer (PTPTB, Eg = ~1.6 eV), consisting of alternating electron-rich N-dodecyl-2,5-bis(2'-thienyl)pyrrole (TPT) and electron-deficient 2,1,3-benzothiadiazole (B) units, as a donor material is studied together with a soluble fullerene derivative (PCBM) as acceptor to prepare bulk heterojunction photovoltaic cells. Photoinduced absorption (PIA) and fluorescence spectroscopy on blends of PTPTB and PCBM gave direct spectral evidence of the photogeneration of a charge-separated state. Preliminary results on photovoltaic cells prepared using thin PTPTB:PCBM films as an active layer, sandwiched between ITO/PEDOT:PSS and Al electrodes, showed promising characteristics

Infrared detectors with poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonic acid) (PEDOT/PSS) as the active material

Large area (3×3mm2) infrared detectors which present a fast rise of their output upon pulsed excitation can be made by using PEDOT/PSS with a low surface resistance. Thus, the action of the infrared sensitive device is based on a change in resistance after photo-excitation of charge carriers in PEDOT/PS via their low-energy absorption features. The absence of any measurable delay in the response of the device is consistent with the view that the charges on the polymer chain are responsible for the absorption of infrared radiation

Infrared detectors with poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonic acid) (PEDOT/PSS) as the active material

Large area (3×3mm2) infrared detectors which present a fast rise of their output upon pulsed excitation can be made by using PEDOT/PSS with a low surface resistance. Thus, the action of the infrared sensitive device is based on a change in resistance after photo-excitation of charge carriers in PEDOT/PS via their low-energy absorption features. The absence of any measurable delay in the response of the device is consistent with the view that the charges on the polymer chain are responsible for the absorption of infrared radiation

A Dual Approach of an Oil–Membrane Composite and Boron-Doped Diamond Electrode to Mitigate Biofluid Interferences

Electrochemical biosensors promise a simple method to measure analytes for both point-of-care diagnostics and continuous, wearable biomarker monitors. In a liquid environment, detecting the analyte of interest must compete with other solutes that impact the background current, such as redox-active molecules, conductivity changes in the biofluid, water electrolysis, and electrode fouling. Multiple methods exist to overcome a few of these challenges, but not a comprehensive solution. Presented here is a combined boron-doped diamond electrode and oil–membrane protection approach that broadly mitigates the impact of biofluid interferents without a biorecognition element. The oil–membrane blocks the majority of interferents in biofluids that are hydrophilic while permitting passage of important hydrophobic analytes such as hormones and drugs. The boron-doped diamond then suppresses water electrolysis current and maintains peak electrochemical performance due to the foulant-mitigation benefits of the oil–membrane protection. Results show up to a 365-fold reduction in detection limits using the boron-doped diamond electrode material alone compared with traditional gold in the buffer. Combining the boron-doped diamond material with the oil–membrane protection scheme maintained these detection limits while exposed to human serum for 18 h

Supramolecular hydrogen-bonded oligo(p-phenylene vinylene) polymers

no abstrac