Parallel-like Bulk Heterojunction Polymer Solar Cells

Here we demonstrate a conceptually new approach, the parallel-like bulk heterojunction (PBHJ), which maintains the simple device configuration and low-cost processing of single-junction BHJ cells while inheriting the major benefit of incorporating multiple polymers in tandem cells. In this PBHJ, free charge carriers travel through their corresponding donor-polymer-linked channels and fullerene-enriched domain to the electrodes, equivalent to a parallel-like connection. The short-circuit current (<i>J</i>_sc) of the PBHJ solar cell is nearly identical to the sum of those of the individual “subcells”, while the open-circuit voltage (<i>V</i>_oc) is between those of the “subcells”. Preliminary optimization of the PBHJ devices gives improvements of up to 40% in <i>J</i>_sc and 30% in overall efficiency (η) in comparison with single-junction BHJ devices

Values of bacteria, fungi and the rate of bacteria and fungi in treated soils inoculation with strain CHL1 (b, d, f) or not (a, c, e).

<p>Symbols represent the mean of triplicate samples and error bars indicate the standard deviation. S₁₀, S₃₀, S₅₀, S₁₀₀, S₁₀₀₀ mean 10, 30, 50, 100, 1000μg kg^-1 chlorimuron-ethyl treatment group, respectively. ‘-’ indicates without strain CHL1 inoculation; ‘+’ indicates inoculation with strain CHL1.</p

Values of the Shannon-Wiener index of microbes in treated soils inoculation with strain CHL1 (b) or not (a).

<p>Symbols represent the mean of triplicate samples and error bars indicate the standard deviation. S₁₀, S₃₀, S₅₀, S₁₀₀, S₁₀₀₀ mean 10, 30, 50, 100, 1000μg kg^-1 chlorimuron-ethyl treatment group, respectively. ‘-’ indicates without strain CHL1 inoculation; ‘+’ indicates inoculation with strain CHL1.</p

The degradation of chlorimuron-ethyl in treated soils.

<p>Values represent the mean (±SD) of three replicates.</p><p>*S₁₀, S₃₀, S₅₀, S₁₀₀, S₁₀₀₀ mean 10, 30, 50, 100, 1000μg kg^-1 chlorimuron-ethyl treatment group, respectively. ‘-’ indicates without strain CHL1 inoculation; ‘+’ indicates inoculation with strain CHL1.</p><p>The degradation of chlorimuron-ethyl in treated soils.</p

Multivariate analysis of variance by three-way ANOVA of the sum of all PLFAs, ratios of GN/GP and bacteria/fungi, the stress level and the Shannon index.

<p>*The categorical factors are inoculation with strain CHL1, treatment (S₀, S₁₀, S₃₀, S₅₀, S₁₀₀, S₁₀₀₀), incubation time (1, 7, 15, 30, 45, 60 days). Presented are the F-values with the level of significance.</p><p>Multivariate analysis of variance by three-way ANOVA of the sum of all PLFAs, ratios of GN/GP and bacteria/fungi, the stress level and the Shannon index.</p

Values of total PLFAs biomass in treated soils inoculation with strain CHL1 (b) or not (a).

<p>Symbols represent the mean of triplicate samples and error bars indicate the standard deviation. S₁₀, S₃₀, S₅₀, S₁₀₀, S₁₀₀₀ mean 10, 30, 50, 100, 1000μg kg^-1 chlorimuron-ethyl treatment group, respectively. ‘-’ indicates without strain CHL1 inoculation; ‘+’ indicates inoculation with strain CHL1.</p

Values of Gram negative bacteria (GN), Gram positive bacteria (GP) and the rate of GN and GP in treated soils inoculation with strain CHL1 (b, d, f) or not (a, c, e).

<p>Symbols represent the mean of triplicate samples and error bars indicate the standard deviation. S₁₀, S₃₀, S₅₀, S₁₀₀, S₁₀₀₀ mean 10, 30, 50, 100, 1000μg kg^-1 chlorimuron-ethyl treatment group, respectively. ‘-’ indicates without strain CHL1 inoculation; ‘+’ indicates inoculation with strain CHL1.</p

PCA plot of the microbial community structure of all treatments on days 7, 30 and 60.

<p>S₀, S₁₀, S₃₀, S₅₀, S₁₀₀ and S₁₀₀₀ mean 0, 10, 30, 50, 100 and 1000μg kg^-1 chlorimuron-ethyl treatment group, respectively. ‘-’ indicates without strain CHL1 inoculation; ‘+’ indicates inoculation with strain CHL1.</p

Solubility and Thermodynamic Stability of the Enantiotropic Polymorphs of 2,3,5-Trimethyl-1,4-diacetoxybenzene

The solubility data of two polymorphs of 2,3,5-trimethyl-1,4-diacetoxybenzene (TMHQ-DA) in ethanol, 1-propanol, 2-propanol, and 1-butanol at various temperatures were experimentally measured using gravimetrical method and correlated by the modified Apelblat model and the van’t Hoff equation, respectively. Differential scanning calorimetry (DSC) and thermogravimetry (TG) analyses were performed to investigate the thermodynamic stability and the transition of the two forms of TMHQ-DA. An enantiotropic relationship was found between TMHQ-DA Form A and TMHQ-DA Form B, and the transition point between them was experimentally determined to be 314.50 ± 1 K. A thermodynamic model for estimation of the transition point was also derived, and the estimated results are satisfactorily consistent with the experimental values. Finally, the accuracy of the transition point obtained in this research was validated by the polymorphic transformation experiments monitored using Raman spectroscopy

Mobility-Controlled Performance of Thick Solar Cells Based on Fluorinated Copolymers

Developing novel materials and device architectures to further enhance the efficiency of polymer solar cells requires a fundamental understanding of the impact of chemical structures on photovoltaic properties. Given that device characteristics depend on many parameters, deriving structure–property relationships has been very challenging. Here we report that a single parameter, hole mobility, determines the fill factor of several hundred nanometer thick bulk heterojunction photovoltaic devices based on a series of copolymers with varying amount of fluorine substitution. We attribute the steady increase of hole mobility with fluorine content to changes in polymer molecular ordering. Importantly, all other parameters, including the efficiency of free charge generation and the coefficient of nongeminate recombination, are nearly identical. Our work emphasizes the need to achieve high mobility in combination with strongly suppressed charge recombination for the thick devices required by mass production technologies