Multi-channel exciton dissociation in D18/Y6 complexes for high-efficiency organic photovoltaics

Cao, Zhixing; Yang, Shu; Wang, Bo; Shen, Xingxing; Han, Guangchao; Yi, Yuanping

doi:10.1039/d0ta07996k

Cited by 50 publications

(36 citation statements)

References 40 publications

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“…In addition, considering a low driving force for exciton dissociation via hole transfer (Δ G ED ) in these nonfullerene OSCs, [46–48] the Δ G ED is assumed to be −0.1 eV. As seen in Figure 5c, the calculated k ED for Y6 is on the order of 10 12 s −1 , which is in good agreement with the previous results for nonfullerene‐based blends [48, 49] . As expected, the k ED of m ‐BP is the lowest among the studied compounds and can be further decreased due to the weaker electronic coupling caused by the reduced HOMO delocalization.…”

Section: Figuresupporting

confidence: 87%

The Intrinsic Role of the Fusion Mode and Electron‐Deficient Core in Fused‐Ring Electron Acceptors for Organic Photovoltaics

Guo

Han

2022

Angewandte Chemie

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The A-DA'D-A fused-ring electron acceptors with an angular fusion mode and electron-deficient core has significantly boosted organic photovoltaic efficiency.Here, the intrinsic role of the peculiar structure is revealed by comparing representative A-DA'D-A acceptor Y6 with its A-D-A counterparts having different fusion modes. Owing to the more delocalized HOMO and deeper LUMO level, Y6 exhibits stronger and redshifted absorption relative to the linear and angular fused A-D-A acceptors, respectively. Moreover, the change from linear to angular fusion substantially reduces the electron-vibration couplings, which is responsible for the faster exciton diffusion, exciton dissociation, and electron transport for Y6 than the linear fused A-D-A acceptor. Notably, the electron-vibration coupling for exciton dissociation is further decreased by introducing the electron-deficient core, thus contributing to the efficient charge generation under low driving forces in the Y6-based devices.

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Section: Figuresupporting

confidence: 87%

The Intrinsic Role of the Fusion Mode and Electron‐Deficient Core in Fused‐Ring Electron Acceptors for Organic Photovoltaics

Guo

Han

2022

Angewandte Chemie

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“…The differences between the experiment and calculation are 0.4–1.0 eV for the HOMO/LUMO energy, which seem acceptable because these deviations are similar to previous DFT calculations. [ 22–24 ] These discrepancies should be attributed to one reason: Only a single‐molecule model with PCM is considered here, but in a thin film, any organic molecule is surrounded by other molecules and the FMOs of these molecules must interfere with each other; therefore, the energies of FMOs in a thin film are different from those of a single molecule. [ 25 ] However, the decreases of the HOMO/LUMO energy and energy gap from Y6 to BTPTT‐4Cl in experiments are 0.03/0.10 and 0.07 eV, whereas in computations these decreases are 0.02/0.09 and 0.08 eV, respectively.…”

Section: Resultsmentioning

confidence: 99%

Designing and Screening High‐Performance Non‐Fullerene Acceptors: A Theoretical Exploration of Modified Y6

Qiu

Zheng

2021

Solar RRL

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Recently, the application of the non‐fullerene acceptor (NFA) Y6 and its derivatives has increased the power conversion efficiencies (PCEs) of organic solar cells (OSCs) up to 18.22%. It has opened up a new revolutionary direction of the molecular design of high‐performance NFAs. Despite the recent exciting experimental progress of Y6‐based OSCs, studies of molecular modifications of Y6, which may be the most effective way to improve the PCE of OSCs, are still few. Herein, a series of modified Y6 molecules is systematically designed and modeled. Their physical and optical properties are predicted with reliable density functional theory (DFT) and time‐dependent DFT calculations. The dipole moments, frontier molecular orbital energies, UV–vis absorption spectra, singlet–triplet energy gaps, exciton binding energies, charge transfer rate constants at the donor–acceptor interface, and electron mobility are computed to comprehensively analyze the potential of these Y6 derivatives. The results show that proper extension of the backbone by inserting thiophene rings with a single‐bond connection is conducive to designing highly efficient NFAs. The most striking finding here is that one (named BTPTT‐4F‐2T) of the screened Y6 derivatives is superior to prototype Y6 in all aspects and may be the next star high‐performance NFA.

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“…In addition, the understanding of the relatively novel widebandgap polymer PDTBT2T-FTBDT is still minimal, since there are only a few reports on this novel material today. [31,32] Therefore, deep insights into the mechanism of the film formation kinetics of the homopolmyer PDTBT2T-FTBDT and of PDTBT2T-FTBDT blended with small acceptor molecules are of great importance to successfully transit from highly efficient spin-coated lab-scale devices to a large scale slot-die coating manufacturing.…”

Section: Introductionmentioning

confidence: 99%

Revealing Donor–Acceptor Interaction on the Printed Active Layer Morphology and the Formation Kinetics for Nonfullerene Organic Solar Cells at Ambient Conditions

Jiang

Chotard

Luo

et al. 2022

Advanced Energy Materials

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Slot‐die coating is a powerful method for upscaling the production of organic solar cells (OSCs) with low energy consumption print processes at ambient conditions. Herein, chlorobenzene (CB) and chloroform (CF) are compared as host solvents for printing films of the neat novel fused‐ring unit based wide‐bandgap donor polymer (PDTBT2T‐FTBDT), the small molecule nonfullerene acceptor based on a fused ring with a benzothiadiazole core (BTP‐4F) as well as the respective PDTBT2T‐FTBDT:BTP‐4F blend films at room temperature in air. Using CF printing of the PDTBT2T‐FTBDT:BTP‐4F active layer, OSCs with a high power conversion efficiency of up to 13.2% are reached in ambient conditions. In comparison to CB printed blend films, the active layer printed out of CF has a superior morphology, a smoother film surface and a more pronounced face‐on orientation of the crystallites, which altogether result in an enhanced exciton dissociation, a superior charge transport, and suppressed nonradiative charge carrier recombination. Based on in situ studies of the slot‐die coating process of PDTBT2T‐FTBDT, BTP‐4F, and PDTBT2T‐FTBDT:BTP‐4F films, the details of the film formation kinetics are clarified, which cause the superior behavior for CF compared to CB printing due to balancing the aggregation and crystallization of donor and acceptor.

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Multi-channel exciton dissociation in D18/Y6 complexes for high-efficiency organic photovoltaics

Abstract: Interfacial charge transfer between donor and acceptor plays a crucial role in determining the photo-induced charge generation mechanisms and efficiencies for organic solar cells. Here, we have theoretically investigated the...

Cited by 50 publications

References 40 publications

The Intrinsic Role of the Fusion Mode and Electron‐Deficient Core in Fused‐Ring Electron Acceptors for Organic Photovoltaics

The Intrinsic Role of the Fusion Mode and Electron‐Deficient Core in Fused‐Ring Electron Acceptors for Organic Photovoltaics

Designing and Screening High‐Performance Non‐Fullerene Acceptors: A Theoretical Exploration of Modified Y6

Revealing Donor–Acceptor Interaction on the Printed Active Layer Morphology and the Formation Kinetics for Nonfullerene Organic Solar Cells at Ambient Conditions

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