Highly soluble energy relay dyes for dye-sensitized solar cells

High solubility is a requirement for energy relay dyes (ERDs) to absorb a large portion of incident light and significantly improve the efficiency of dye-sensitized solar cells (DSSCs). Two benzonitrile-soluble ERDs, BL302 and BL315, were synthesized, characterized, and resulted in a 65% increase in the efficiency of TT1-sensitized DSSCs. The high solubility (180 mM) of these ERDs allows for absorption of over 95% of incident light at their peak wavelength. The overall power conversion efficiency of DSSCs with BL302 and BL315 was found to be limited by their energy transfer efficiency of approximately 70%. Losses due to large pore size, dynamic collisional quenching of the ERD, energy transfer to desorbed sensitizing dyes and static quenching by complex formation were investigated and it was found that a majority of the losses are caused by the formation of statically quenched ERDs in solution

Potential function for the Huntingtin protein as a scaffold for selective autophagy

Although dominant gain-of-function triplet repeat expansions in the Huntingtin (HTT) gene are the underlying cause of Huntington disease (HD), understanding the normal functions of nonmutant HTT protein has remained a challenge. We report here findings that suggest that HTT plays a significant role in selective autophagy. Loss of HTT function in Drosophila disrupts starvation-induced autophagy in larvae and conditional knockout of HTT in the mouse CNS causes characteristic cellular hallmarks of disrupted autophagy, including an accumulation of striatal p62/SQSTM1 over time. We observe that specific domains of HTT have structural similarities to yeast Atg proteins that function in selective autophagy, and in particular that the C-terminal domain of HTT shares structural similarity to yeast Atg11, an autophagic scaffold protein. To explore possible functional similarity between HTT and Atg11, we investigated whether the C-terminal domain of HTT interacts with mammalian counterparts of yeast Atg11-interacting proteins. Strikingly, this domain of HTT coimmunoprecipitates with several key Atg11 interactors, including the Atg1/Unc-51–like autophagy activating kinase 1 kinase complex, autophagic receptor proteins, and mammalian Atg8 homologs. Mutation of a phylogenetically conserved WXXL domain in a C-terminal HTT fragment reduces coprecipitation with mammalian Atg8 homolog GABARAPL1, suggesting a direct interaction. Collectively, these data support a possible central role for HTT as an Atg11-like scaffold protein. These findings have relevance to both mechanisms of disease pathogenesis and to therapeutic intervention strategies that reduce levels of both mutant and normal HTT.Hereditary Disease Foundation (U.S.)Cure Huntington’s Disease Initiative, Inc.Fox Family Foundatio

Sequential "click'' functionalization of mesoporous titania for energy-relay dye enhanced dye-sensitized solar cells

Energy relay dyes (ERDs) have been investigated previously as a mean to achieve panchromatic spectral response in dye-sensitized solar cells via energy transfer. To reduced the distance between the ERDs and energy-accepting injection dyes (IDs) on the surface of a mesoporous titanium dioxide electrode, the ERDs were immobilized adjacent to the IDs via a sequential functionalization approach. In the first step, azidobenzoic acid molecules were co-adsorbed on the mesoporous titanium dioxide surface with the ID. In the second step, the highly selective copper(I)-catalyzed 1,3-dipolar azide-alkyne cycloaddition "click'' reaction was employed to couple an alkyne-functionalized ERD to the azidobenzoic acid monolayer. The cycloaddition step in the mesoporous electrode was slowed dramatically due to reactants and catalysts forming agglomerates. In solar cell devices, the close proximity between the surface-immobilized ERD and energy-accepting squaraine sensitizer dyes results in energy transfer efficiencies of up to 91%. The relative improvement in device performance due to the additional ERD spectral response was 124%, which is among the highest reported. The sequential functionalization approach described herein is transferrable to other applications requiring the functionalization of electrodes with complex molecules

Silicon-Naphthalo/Phthalocyanine-Hybrid Sensitizer for Efficient Red Response in Dye-Sensitized Solar Cells

Introduction of a naphthalocyanine moiety to phthalocyanine allows for a gradual red shift of the absorption spectrum in the resulting chromophore. Using silicon as a core atom allows for the introduction of additional siloxane side chains which mitigate dye aggregation. A dye-sensitized solar cell with this hybrid sensitizer exhibits a broad and flat IPCE of 80% between 600 and 750 nm and high photocurrent densities of 19.0 mA/cm²

Effect of Al₂O₃ Recombination Barrier Layers Deposited by Atomic Layer Deposition in Solid-State CdS Quantum Dot-Sensitized Solar Cells

Despite the promise of quantum dots (QDs) as a light-absorbing material to replace the dye in dye-sensitized solar cells, quantum dot-sensitized solar cell (QDSSC) efficiencies remain low, due in part to high rates of recombination. In this article, we demonstrate that ultrathin recombination barrier layers of Al₂O₃ deposited by atomic layer deposition can improve the performance of cadmium sulfide (CdS) quantum dot-sensitized solar cells with spiro-OMeTAD as the solid-state hole transport material. We explored depositing the Al₂O₃ barrier layers either before or after the QDs, resulting in TiO₂/Al₂O₃/QD and TiO₂/QD/Al₂O₃ configurations. The effects of barrier layer configuration and thickness were tracked through current–voltage measurements of device performance and transient photovoltage measurements of electron lifetimes. The Al₂O₃ layers were found to suppress dark current and increase electron lifetimes with increasing Al₂O₃ thickness in both configurations. For thin barrier layers, gains in open-circuit voltage and concomitant increases in efficiency were observed, although at greater thicknesses, losses in photocurrent caused net decreases in efficiency. A close comparison of the electron lifetimes in TiO₂ in the TiO₂/Al₂O₃/QD and TiO₂/QD/Al₂O₃ configurations suggests that electron transfer from TiO₂ to spiro-OMeTAD is a major source of recombination in ss-QDSSCs, though recombination of TiO₂ electrons with oxidized QDs can also limit electron lifetimes, particularly if the regeneration of oxidized QDs is hindered by a too-thick coating of the barrier layer

Nacionalismos deportivos con “clase”: el rugby argentino en la era profesional/global

Men’s rugby in Buenos Aires is going through a phase of professionalization and globalization which is blurring the long-standing link between that sport and the upper-middle and upper classes of the city. Based on two ethnographic studies of porteño (Buenos Aires) rugby players, this article analyses rugby as a space for the creation of “otherness” within the country as a whole, one which legitimizes Buenos Aires as the symbolic center of the nation to the detriment of its “interior”. This phenomenon is reflected in the organization of the sport and the dispute between “amateurs” and “professionals”, which in turn, has a moral aspect insofar as both sides claim that they are the true representatives of the nation. An analysis of the careers of well-known former rugby players from Buenos Aires throws light on attempts to construct a nationalism “with class” in the context of the new globalization of sports which shape narratives about national identity and class