Theoretical study for tuning the HOMO level of the donor to increase the efficiency through open-circuit voltage of small molecule solar cells
01 Dec 2017-
TL;DR: In this article, the authors used density functional theory (DFT) for pre-synthesis of virtual screening of newly designed small molecules using the concept of medium donor-vinylene-strong acceptor.
Abstract: Density Functional Theory (DFT), the method has been used for the approach of pre-synthesis of virtual screening of newly designed small molecules. The designed four small molecules have been done using the concept of ‘Medium donor-vinylene-strong acceptor’. Malononitrile is flanked on the donor moiety of benzo[1,2-b:6,5-b']dithiophene-4,5-dione(BDTD) connected with vinyl linked benzothiadiazole (BTD) moiety studied with strong electron withdrawing groups (EWG) such as F, CN, and NO 2 onto the benzothiadiazole unit. DFT and TD-DFT method provided results of studied small molecules with 1.79eV–2.06eV band-gap with simulated high energy open-circuit voltage of 1.38V–1.49V for designed small molecules. The calculation also indicates D1, which exhibits the highest power conversion efficiency (∼9%) among the four systems predicted by Schraber diagram. This manuscript describes the detailed investigation of this study.
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TL;DR: Five practical examples involving a wide variety of systems and analysis methods are given to illustrate the usefulness of Multiwfn, a multifunctional program for wavefunction analysis.
Abstract: Multiwfn is a multifunctional program for wavefunction analysis. Its main functions are: (1) Calculating and visualizing real space function, such as electrostatic potential and electron localization function at point, in a line, in a plane or in a spatial scope. (2) Population analysis. (3) Bond order analysis. (4) Orbital composition analysis. (5) Plot density-of-states and spectrum. (6) Topology analysis for electron density. Some other useful utilities involved in quantum chemistry studies are also provided. The built-in graph module enables the results of wavefunction analysis to be plotted directly or exported to high-quality graphic file. The program interface is very user-friendly and suitable for both research and teaching purpose. The code of Multiwfn is substantially optimized and parallelized. Its efficiency is demonstrated to be significantly higher than related programs with the same functions. Five practical examples involving a wide variety of systems and analysis methods are given to illustrate the usefulness of Multiwfn. The program is free of charge and open-source. Its precompiled file and source codes are available from http://multiwfn.codeplex.com.
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"Theoretical study for tuning the HO..." refers background in this paper
...9 [16] and absorption spectra predicted using Gabedit 2....
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TL;DR: Polymer-based organic photovoltaic systems hold the promise for a cost-effective, lightweight solar energy conversion platform, which could benefit from simple solution processing of the active layer.
Abstract: Fossil fuel alternatives, such as solar energy, are moving to the forefront in a variety of research fields. Polymer-based organic photovoltaic systems hold the promise for a cost-effective, lightweight solar energy conversion platform, which could benefit from simple solution processing of the active layer. The function of such excitonic solar cells is based on photoinduced electron transfer from a donor to an acceptor. Fullerenes have become the ubiquitous acceptors because of their high electron affinity and ability to transport charge effectively. The most effective solar cells have been made from bicontinuous polymer–fullerene composites, or so-called bulk heterojunctions. The best solar cells currently achieve an efficiency of about 5 %, thus significant advances in the fundamental understanding of the complex interplay between the active layer morphology and electronic properties are required if this technology is to find viable application.
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TL;DR: The parallel linear constraint solver (P-LINCS) is presented, which allows the constraining of all bonds in macromolecules and the energy conservation properties of (P-)LINCS are assessed in view of improvements in the accuracy of uncoupled angle constraints and integration in single precision.
Abstract: By removing the fastest degrees of freedom, constraints allow for an increase of the time step in molecular simulations. In the last decade parallel simulations have become commonplace. However, up till now efficient parallel constraint algorithms have not been used with domain decomposition. In this paper the parallel linear constraint solver (P-LINCS) is presented, which allows the constraining of all bonds in macromolecules. Additionally the energy conservation properties of (P-)LINCS are assessed in view of improvements in the accuracy of uncoupled angle constraints and integration in single precision.
2,852 citations
"Theoretical study for tuning the HO..." refers methods in this paper
...All time-dependent density functional theory (TD-DFT) calculations were performed under vacuum condition with TD-DFT-PBE0/631G* level and without any structural symmetry constraints [18]....
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TL;DR: In this paper, the synergistic effects of a hydrocarbon solvent, a novel additive, a suitable choice of polymer side chain, and strong temperature-dependent aggregation of the donor polymer are used to produce active layers of organic solar cells in an environmentally friendly way.
Abstract: Organic solar cells have desirable properties, including low cost of materials, high-throughput roll-to-roll production, mechanical flexibility and light weight. However, all top-performance devices are at present processed using halogenated solvents, which are environmentally hazardous and would thus require expensive mitigation to contain the hazards. Attempts to process organic solar cells from non-halogenated solvents lead to inferior performance. Overcoming this hurdle, here we present a hydrocarbon-based processing system that is not only more environmentally friendly but also yields cells with power conversion efficiencies of up to 11.7%. Our processing system incorporates the synergistic effects of a hydrocarbon solvent, a novel additive, a suitable choice of polymer side chain, and strong temperature-dependent aggregation of the donor polymer. Our results not only demonstrate a method of producing active layers of organic solar cells in an environmentally friendly way, but also provide important scientific insights that will facilitate further improvement of the morphology and performance of organic solar cells. The processing of high-performance organic solar cells usually requires environmentally hazardous solvents. Now, hydrocarbon-based processing is shown to achieve relatively high performance in a more environmentally friendly way.
2,052 citations
"Theoretical study for tuning the HO..." refers background in this paper
...Polymer-fullerene based bulk hetero-junction solar cells have demonstrated about 12% efficiency [1]....
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