Charge generation mechanism tuned <i>via</i> film morphology in small molecule bulk-heterojunction photovoltaic materials

Lou, Sylvia J.; Loser, Stephen; Luck, Kyle A.; Zhou, Nanjia; Leonardi, Matthew J.; Timalsina, Amod; Manley, Eric F.; Hayes, Dugan; Strzalka, Joseph; Hersam, Mark C.; Chang, Robert P. H.; Marks, Tobin J.; Chen, Lin X.

doi:10.1039/d0tc03393f

Cited by 9 publications

(5 citation statements)

References 90 publications

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“…Although the revolution of photocharge generation route indicates that the D/A heterojunction might be no longer be necessary for efficient OSC just like its inorganic counterparts, severe bimolecular recombination due to the lack of respective extraction pathways is a major obstacle for achieving considerable PCE value in single-component OSC devices. 15,16…”

Section: Introductionmentioning

confidence: 99%

N-dopants optimize the utilization of spontaneously formed photocharges in organic solar cells

Tang

Zheng

Zhou

et al. 2023

Energy Environ. Sci.

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Section: Introductionmentioning

confidence: 99%

N-dopants optimize the utilization of spontaneously formed photocharges in organic solar cells

Tang

Zheng

Zhou

et al. 2023

Energy Environ. Sci.

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“…In the charge transfer process, the more holes migrate from the acceptor to the donor, the more advantageous to improve external quantum efficiency (EQE) or J sc . According to the amount of net charge transfer (Δ q ), excited states can be divided into three classes: Frenkel exciton state (FE), Δ q < 0.3 e; charge transfer state (CT), Δ q > 0.7 e; and hybrid charge transfer state (HCT), 0.3 e < Δ q < 0.7 e. , (The details about Δ q are provided in Section S2.) After being excited by light irradiation, excitons, that is, tightly bound pairs containing an electron and a hole, are generated.…”

Section: Resultsmentioning

confidence: 99%

Designing Benzodithiophene-Based Small Molecule Donors for Organic Solar Cells by Regulation of Halogenation Effects

Liu,

Yang,

Bai

et al. 2023

J. Phys. Chem. A

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The donors are key components of organic solar cells (OSCs) and play crucial roles in their photovoltaic performance. Herein, we designed two new donors (BTR-γ-Cl and BTR-γ-F) by finely optimizing small molecule donors (BTR-Cl and BTR-F) with a high performance. The optoelectronic properties of the four donors and their interfacial properties with the well-known acceptor Y6 were studied by density functional theory and time-dependent density functional theory. Our calculations show that the studied four donors have large hole mobility and strong interactions with Y6, where the BTR-γ-Cl/Y6 has the largest binding energy. Importantly, the proportion of charge transfer (CT) states increases at the BTR-γ-Cl/Y6 (50%) and BTR-γ-F/Y6 (45%) interfaces. The newly designed donors are more likely to achieve CT states through intermolecular electric field (IEF) and hot exciton mechanisms than the parent molecules; meanwhile, donors containing Cl atoms are more inclined to produce CT states through the direct excitation mechanism than those containing F atoms. Our results not only provided two promising donors but also shed light on the halogenation effects on donors in OSCs, which might be important to design efficient photovoltaic materials.

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“…The above is due to the intermolecular arrangement of the molecules that compose the active layer of organic solar cells. This arrangement affects the exciton diffusion and the charge generation and recombination [ 3 , 4 , 5 , 6 ]. The morphology of the active layer then influences the performance of organic solar cells.…”

Section: Introductionmentioning

confidence: 99%

Morphology Determines an Efficient Coherent Electron Transport for Push–Pull Organic Semiconductors Based on Triphenylamine and Dicyanovinyl Groups

2023

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The morphology of the active layer in organic solar cells is fundamental for achieving high power conversion efficiency. However, the morphological characteristics for optimal performance are still being investigated. An atomistic computational approach is required to determine the relationship between active layer morphology and performance. Since the organic solar cell has multiple phases and interfaces, the computational modeling of charge generation and transport is challenging. We then used a set of push–pull semiconductors to illustrate how the electronic transmission spectrum, derived from the Landauer–Büttiker formalism, can be used to investigate the efficiency of coherent charge transport across anisotropic organic solids. The electronic transmission spectrum was calculated from the electronic band structure obtained using the density-functional-based tight-binding method. We found that coherent charge transport was more efficient along the direction parallel with the interface between the electron-acceptor and electron-donor moieties for a herringbone morphology.

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Charge generation mechanism tuned via film morphology in small molecule bulk-heterojunction photovoltaic materials

Abstract: Small organic molecules have emerged as promising component materials for organic photovoltaic devices. Compared to most conjugated polymers for the same application, small molecules have unique morphologies that promote electronic...

Cited by 9 publications

References 90 publications

N-dopants optimize the utilization of spontaneously formed photocharges in organic solar cells

N-dopants optimize the utilization of spontaneously formed photocharges in organic solar cells

Designing Benzodithiophene-Based Small Molecule Donors for Organic Solar Cells by Regulation of Halogenation Effects

Morphology Determines an Efficient Coherent Electron Transport for Push–Pull Organic Semiconductors Based on Triphenylamine and Dicyanovinyl Groups

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