Charge transport processes in nonconjugated redox-active polymers with electrolytes were studied using a diffusion-cooperative model. For the first time, we quantitatively rationalized that the limited Brownian motion of the redox centers bound to the polymers resulted in the 10-fold decline of the bimolecular and heterogeneous charge transfer rate constants, which had been unexplained for half a century. As a next-generation design, a redox-active supramolecular system with high physical mobility was proposed to achieve the rate constant as high as in free solution system (>10 M s) and populated site density (>1 mol/L).

Squaraine dyes are considered an important group of photoactive materials in the field of organic photovoltaic devices. In this work, we purposely tuned the side chains and number of hydroxyl (OH) groups in a series of squaraine (SQ) dyes, i.e., SQ1−4, to investigate the effect of structural variations on the material properties as well as the performance of these dyes as donor materials in bulk heterojunction (BHJ) photovoltaic cells. The material structure and properties of these SQs were systematically characterized using various tools. Solution-processed BHJ photovoltaic cells based on these SQ compounds combined with [6,6]-phenyl-C71-butyric acid methyl ester (PC 71 BM) as an acceptor gave efficient power conversion efficiencies greater than 4.0% under AM 1.5G solar illumination at 100 mW/cm 2 . Our observations show that the OH groups deepened the highest occupied molecular orbital (HOMO) of the donor and thus enhanced the open-circuit voltage, whereas the linear chain improved the charge transport properties in the BHJ films. Both the side chain and the number of OH groups play important roles in determining the aggregation behavior of these SQs in solid-state films: SQ1, which contains four OH groups and branched side chains, exhibits J-aggregation because of the steric hindrance of its side chains; SQ2, which contains four OH groups and linear side chains, exhibits both H-aggregation and J-aggregation; SQ3, which contains two OH groups and linear side chains, exhibits preferential H-aggregation; SQ4, which contains linear side chains without OH groups, exhibits J-aggregation, this is most likely because of its strong intermolecular coupling and intermolecular hydrogen-bonding interactions to form a head-totail packing mode, i.e., J-aggregation. Interestingly, the absorption of J-aggregates in BHJ cells contributes to the cells' photoresponse at long wavelengths, and thus results in higher photocurrent. Our results demonstrate a clear relationship between the molecular structures of SQ dyes and their physical properties that govern their photovoltaic performance.

High titer, rate, yield (TRY), and scalability are challenging metrics to achieve due to trade-offs between carbon use for growth and production. To achieve these metrics, we take the minimal cut set (MCS) approach that predicts metabolic reactions for elimination to couple metabolite production strongly with growth. We compute MCS solution-sets for a non-native product indigoidine, a sustainable pigment, in Pseudomonas putida KT2440, an emerging industrial microbe. From the 63 solution-sets, our omics guided process identifies one experimentally feasible solution requiring 14 simultaneous reaction interventions. We implement a total of 14 genes knockdowns using multiplex-CRISPRi. MCS-based solution shifts production from stationary to exponential phase. We achieve 25.6 g/L, 0.22 g/l/h, and ~50% maximum theoretical yield (0.33 g indigoidine/g glucose). These phenotypes are maintained from batch to fed-batch mode, and across scales (100-ml shake flasks, 250-ml ambr®, and 2-L bioreactors).

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Background: Many microbes used for the rapid discovery and development of metabolic pathways have sensitivities to final products and process reagents. Isopentenol (3-methyl-3-buten-1-ol), a biogasoline candidate, has an established heterologous gene pathway but is toxic to several microbial hosts. Reagents used in the pretreatment of plant biomass, such as ionic liquids, also inhibit growth of many host strains. We explored the use of Corynebacterium glutamicum as an alternative host to address these constraints. Results: We found C. glutamicum ATCC 13032 to be tolerant to both the final product, isopentenol, as well to three classes of ionic liquids. A heterologous mevalonate-based isopentenol pathway was engineered in C. glutamicum. Targeted proteomics for the heterologous pathway proteins indicated that the 3-hydroxy-3-methylglutaryl-coenzyme A reductase protein, HmgR, is a potential rate-limiting enzyme in this synthetic pathway. Isopentenol titers were improved from undetectable to 1.25 g/L by combining three approaches: media optimization; substitution of an NADH-dependent HmgR homolog from Silicibacter pomeroyi; and development of a C. glutamicum ∆poxB ∆ldhA host chassis. Conclusions: We describe the successful expression of a heterologous mevalonate-based pathway in the Grampositive industrial microorganism, C. glutamicum, for the production of the biogasoline candidate, isopentenol. We identified critical genetic factors to harness the isopentenol pathway in C. glutamicum. Further media and cultivation optimization enabled isopentenol production from sorghum biomass hydrolysates.

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For rapid charging of lithium-ion batteries, a series of novel electrode-active materials have been studied. However, those materials suffered from replacing conventional metal oxides, such as LiCoO2 and LiFePO4, because of the strict performance criteria for commercialization. As an alternative approach, we propose the hybridization of the conventional inorganic active materials with organic redox-active polymers which are characterized by fast electrode kinetics. A new robust organic-radical-substituted polyether was synthesized to yield one of the highest charge transportabilities of nonconjugated polymers with a charge diffusion coefficient of 10–7 cm2/s. The hybrid electrode of LiFePO4 and a small amount of the polymer was able to be charged within several minutes by virtue of the electrocatalytic oxidation of the metal oxide with the radical polymer. In addition, several 4 V class organic redox-active polymers were synthesized for the hybrid with LiCoO2. After hybridization, the LiCoO2 electrodes could also be charged within several minutes with the reduced overvoltages.

These results suggest that psychosocial factors are important in understanding the supportive care and unmet needs of cancer patients receiving rehabilitation interventions.