We present a workflow to aid the discovery of new dyes for the role of a photosensitive unit in the dye-sensitized photo-electrochemical cells (DS-PECs). New structures are generated in a fully ...automated way using the Compound Attachment Tool (CAT) introduced in this work. These structures are characterized with efficient approximate density functional theory (DFT) methods, and molecules with favorable optical properties are suggested for possible further use in DS-PECs. As around 2500 structures are generated in this work, and as we aim for still larger volumes of compounds to screen in subsequent applications, we have assessed the reliability of low-cost screening methods and show that simplified time-dependent density functional theory (sTDDFT) provides a satisfying accuracy/cost ratio. From the dyes considered, we propose a set that can be suitable for panchromatic sensitization of the photoelectrode in DS-PECs to further increase DS-PEC efficiency.
Dye-sensitized solar cells and dye-sensitized photoelectrochemical cells have attracted much interest in recent years for solar energy conversion. More effort is still required to increase the ...efficiency of these devices, which is closely linked to the crucial process of photoinduced charge separation. Computational studies can provide insights into this fundamental process and suggest molecular components and interfaces that feature optimal energy-level alignment before time-consuming trial-and-error experimental realization. Here, we use a combination of density functional based tight binding and an extended Hückel approach to perform quantum classical simulations of photoinduced electron injection in a TiO2 dye-sensitized photoanode with explicit solvation at a reasonable computational cost. In particular, we evaluate injection capabilities of core-extended naphthalene diimide (NDI) dyes with three different anchoring groups. Our results stress the importance of nuclear motion as well as conformational and trajectory sampling for a realistic description of the injection process. Furthermore, explicit solvation highly influences the conformational space explored by the dye and anchoring molecules, especially concerning the adsorption mode. Taking these effects into account, the core-extended NDI with a catechol-based anchoring moiety is shown to be the most promising ultrafast electron injector. Our strategy allows for a more systematic computational search for appropriate molecular chromophores in dye-sensitized devices for solar energy conversion.
Sustainable solutions for hydrogen production, such as dye-sensitized photoelectrochemical cells (DS-PEC), rely on the fundamental properties of its components whose modularity allows for their ...separate investigation. In this work, we design and execute a high-throughput scheme to tune the ground state oxidation potential (GSOP) of perylene-type dyes by functionalizing them with different ligands. This allows us to identify promising candidates which can then be used to improve the cell's efficiency. First, we investigate the accuracy of different theoretical approaches by benchmarking them against experimentally determined GSOPs. We test different methods to calculate the vertical oxidation potential, including
GW
with different levels of self-consistency, Kohn-Sham (KS) orbital energies and total energy differences. We find that there is little difference in the performance of these methods. However, we show that it is crucial to take into account solvent effects as well as the structural relaxation of the dye after oxidation. Other thermodynamic contributions are negligible. Based on this benchmark, we decide on an optimal strategy, balancing computational cost and accuracy, to screen more than 1000 dyes and identify promising candidates which could be used to construct more robust DS-PECs.
The alignment of the GSOP, calculated with the adiabatic approach for large number of dyes, with the limitations of a hypothetical system - the CB edge of TiO
2
semiconductor and highest oxidation potential of Ru-based WOC.
Photocatalytic water oxidation remains the bottleneck in many artificial photosynthesis devices. The efficiency of this challenging process is inherently linked to the thermodynamic and electronic ...properties of the chromophore and the water oxidation catalyst (WOC). Computational investigations can facilitate the search for favorable chromophore‐catalyst combinations. However, this remains a demanding task due to the requirements on the computational method that should be able to correctly describe different spin and oxidation states of the transition metal, the influence of solvation and the different rates of the charge transfer and water oxidation processes. To determine a suitable method with favorable cost/accuracy ratios, the full catalytic cycle of a molecular ruthenium based WOC is investigated using different computational methods, including density functional theory (DFT) with different functionals (GGA, Hybrid, Double Hybrid) as well as the semi‐empirical tight binding approach GFN‐xTB. A workflow with low computational cost is proposed that combines GFN‐xTB and DFT and provides reliable results. GFN‐xTB geometries and frequencies combined with single‐point DFT energies give free energy changes along the catalytic cycle that closely follow the full DFT results and show satisfactory agreement with experiment, while significantly decreasing the computational cost. This workflow allows for cost efficient determination of energetic, thermodynamic and dynamic properties of WOCs.
Water oxidation catalysts play a crucial role in the development of solar energy conversion devices. Thus, it is important to have computational tools that can reliably predict the catalytic mechanism and the energetics along the catalytic cycle. The approach proposed in this work combines a good accuracy with a small computational cost.
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•Hybrid cluster-continuum model.•pKa values calculations.•Primary amines.•Molecular dynamics simulations.
Acid dissociation constant is a quantitative measure of chemical species ...ability to donate a proton to water molecule and plays important role in aqueous chemistry. Many computational strategies were conceived in order to properly address an acid dissociation equilibrium. In this work, we present new economical cluster-continuum method based on the density functional theory for the accurate calculation of pKa values. By analysing hydration properties of neutral and protonated 2-phenylethylamine sampled in the first principle molecular dynamics simulations, we were able to find key interactions between water molecules and amino group in the neutral and protonated state. This was used to design a reaction scheme, which was shown to yield excellent agreement between the computed and experimental pKa values of selected neurotransmitters. We believe that the proposed scheme can be generalized for computation of acidic properties of other primary and secondary amines.
Dye‐sensitized photoelectrochemical cells are promising devices in solar energy conversion. However, several limitations still have to be addressed, such as the major loss pathway through charge ...recombination at the dye‐semiconductor interface. Charge separating dyes constructed as push‐pull systems can increase the spatial separation of electron and hole, decreasing the recombination rate. Here, a family of dyes, consisting of polyphenylamine donors, fluorene bridges, and perylene monoimide acceptors, was investigated in silico using a combination of semi‐empirical nuclear dynamics and a quantum propagation of photoexcited electron and hole. To optimize the charge separation, several molecular design strategies were investigated, including modifying the donor molecule, increasing the π‐bridge length, and decoupling the molecular components through steric effects. The combination of a triphenylamine donor, using an extended 2‐fluorene π‐bridge, and decoupling the different components by steric hindrance from side groups resulted in a dye with significantly improved charge separation properties in comparison to the original supramolecular complex.
A charged situation: Charge‐separating donor‐π‐acceptor dyes can lower the recombination losses in dye‐sensitized solar and photoelectrochemical cells. Here, charge separators based on polyphenylamine donors, fluorene bridges, and perylene monoimide acceptors are optimized in silico using a quantum‐classical approach combining nuclear and electronic dynamics. Based on the findings, a charge separator is proposed with an increased charge accumulation by approximately 50 %.
Deregulation of transcription factors (TFs) is an important driver of tumorigenesis, but non-invasive assays for assessing transcription factor activity are lacking. Here we develop and validate a ...minimally invasive method for assessing TF activity based on cell-free DNA sequencing and nucleosome footprint analysis. We analyze whole genome sequencing data for >1,000 cell-free DNA samples from cancer patients and healthy controls using a bioinformatics pipeline developed by us that infers accessibility of TF binding sites from cell-free DNA fragmentation patterns. We observe patient-specific as well as tumor-specific patterns, including accurate prediction of tumor subtypes in prostate cancer, with important clinical implications for the management of patients. Furthermore, we show that cell-free DNA TF profiling is capable of detection of early-stage colorectal carcinomas. Our approach for mapping tumor-specific transcription factor binding in vivo based on blood samples makes a key part of the noncoding genome amenable to clinical analysis.
It is frequently argued that to address structural injustice, individuals should participate in collective actions organized by civil society organizations (CSOs), but the role and the normative ...status of CSOs are rarely discussed. In this paper, we argue that CSOs semi-perfect our shared obligation to address structural injustice by defining shared goals as well as taking actions to further them. This assigns a special moral status to CSOs, which in turn gives rise to our duty to support them. Thus, we do not have full discretion when deciding whether to join collective actions or not. Under certain conditions, we can even be forced by others to do our share.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Correction for 'Automated assessment of redox potentials for dyes in dye-sensitized photoelectrochemical cells' by Jelena Beli
et al.
,
Phys. Chem. Chem. Phys.
, 2022,
24
, 197-210,
...https://doi.org/10.1039/D1CP04218A
.
Genomic alterations in metastatic prostate cancer remain incompletely characterized. Here we analyse 493 prostate cancer cases from the TCGA database and perform whole-genome plasma sequencing on 95 ...plasma samples derived from 43 patients with metastatic prostate cancer. From these samples, we identify established driver aberrations in a cancer-related gene in nearly all cases (97.7%), including driver gene fusions (TMPRSS2:ERG), driver focal deletions (PTEN, RYBP and SHQ1) and driver amplifications (AR and MYC). In serial plasma analyses, we observe changes in focal amplifications in 40% of cases. The mean time interval between new amplifications was 26.4 weeks (range: 5-52 weeks), suggesting that they represent rapid adaptations to selection pressure. An increase in neuron-specific enolase is accompanied by clonal pattern changes in the tumour genome, most consistent with subclonal diversification of the tumour. Our findings suggest a high plasticity of prostate cancer genomes with newly occurring focal amplifications as a driving force in progression.
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