Impact of Linking‐Site on Photovoltaic Performance of Giant Molecular Acceptors Containing N‐Type Linker

Advanced Functional Materials, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 11, 2025

Abstract Connecting small molecule acceptors through conjugated or nonconjugated linker to form giant molecular (GMAs) represents a strategic approach enhancing the morphological stability of organic solar cells (OSCs). In this study, we employed benzothiadiazole (BT) as typical n ‐type design and synthesize two GMAs linking‐site isomerization: i‐BT‐DY o‐BT‐DY. Compared i‐BT‐DY, o‐BT‐DY exhibits enhanced crystallinity more favorable face‐on orientation but lower electron mobility. This can be well explained by theoretical calculations, demonstrates delocalized LUMO distribution significantly stronger intramolecular super‐exchange coupling (43.7 meV versus 22.2 for o‐BT‐DY). Additionally, also red‐shifted absorption. Combining these attributes, PM6: blend achieved an impressive power conversion efficiency (PCE) 18.86%. The PCE further increased 19.49% in ternary blend. As expected, OSCs based on both exhibit exceptional long‐term photostability (T85% >1000 hours). work deepens our understanding how linkers at different linking sites influence performance GMAs, concluding that interaction, rather than intermolecular, are primary factor affecting charge transport acceptors. it highlights potential components OSCs.

Language: Английский

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Balance Processing and Molecular Packing via Structural Disordering in a Random Terpolymer for Over 19% Efficiency Non‐Halogenated Solvent Organic Solar Cells

Advanced Energy Materials, Journal Year: 2025, Volume and Issue: unknown

Published: March 4, 2025

Abstract Achieving commercial viability for organic solar cells (OSCs) requires non‐toxic, non‐halogenated solvent processing. However, poor solubility and suboptimal morphology of commonly used active layer materials have been limiting their applications high‐performance OSCs. This study introduces a novel random terpolymer, PM7‐TTz50, designed to overcome these challenges. By incorporating 50 mol% co‐planar thiophene‐thiazolothiazole (TTz) unit into the PM7 backbones, resulting terpolymer achieves enhanced in eco‐friendly solvents. Furthermore, PM7‐TTz50's strong aggregation tendency, coupled with high‐boiling‐point processing—which prolongs aggregate/crystal growth—enhances molecular stacking ordering. approach supports efficient charge transport minimizes non‐radiative recombination, yielding power conversion efficiencies (PCEs) exceeding 19% over 16% w/o additives. Additionally, PM7‐TTz50 demonstrates broad compatibility various non‐fullerene acceptors (NFAs), leading material uniformity reproducibility device fabrication.

Language: Английский

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Impact of Symmetric vs Asymmetric Conjugated Extensions in Acceptors on the Photovoltaic Performance of Organic Solar Cells

Nano Energy, Journal Year: 2025, Volume and Issue: unknown, P. 111028 - 111028

Published: April 1, 2025

Language: Английский

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Lowering Toxicity of Solvent in Organic Solar Cells Manufacturing for 20% Efficiency

Advanced Materials, Journal Year: 2025, Volume and Issue: unknown

Published: April 23, 2025

Abstract Thin film organic photovoltaics (OPVs) aim to harness solar energy environmentally friendly, highly efficient, and cost‐effective means, thereby offering a sustainable solution for production ecological preservation. Efforts are undertook optimize engineering preparation technology OPV devices mini‐modules, through the development of low‐ecological‐impact solvent processing method. A newly developed strategy employing benign o ‐xylene (OXY) with synergistic dual additives (DIM DIB) achieved an optimal power conversion efficiency (PCE) 20.0% ( J SC 26.6 mA cm −2 , V OC 0.935 V, FF 80.3%) alongside exceptional stability metrics (82%–1500h). The mini‐module processed optimized TCE:OXY (1:3 v/v) demonstrated scalable performance reaching 17.6% (18.4 2 ), representing highest in safe based OPVs. Suitable microscale patterns contributed broader range receiving angles, enabling more flexible installation geometries building‐integrated applications.

Language: Английский

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Morphology-Dependent Excited-State Dynamics of Squaraine Thin Films during Thermal Annealing

The Journal of Physical Chemistry Letters, Journal Year: 2025, Volume and Issue: unknown, P. 4456 - 4462

Published: April 25, 2025

Thermal annealing is a widely used technique to enhance organic photovoltaic (OPV) efficiencies in bulk heterojunction devices. Combining studies and spectroscopic measurements with theoretical modeling provides more complete understanding of how aggregation influences energy transfer, an essential factor for performance. Here, we use situ absorbance single-shot transient absorption (SSTA) spectroscopy characterize the electronic structure excited-state dynamics squaraine molecules embedded inert polymer matrix during thermal annealing. Analysis Hamiltonian based on essential-states model reveals stepwise transformation from disordered ordered species, transfer occurring preferentially aggregates larger interplanar spacing tightly packed aggregates. This study demonstrates annealing-dependent changes charge coupling drive heterogeneous films. work establishes broadly applicable methodology engineering solution-processed materials applications OPVs, field-effect transistors, next-generation optoelectronic

Language: Английский

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Exploring the Effects of Fluorination at the Central Unit of Y6-Type Nonfullerene Acceptors on Photovoltaic Properties: A Computational Investigation

The Journal of Physical Chemistry A, Journal Year: 2025, Volume and Issue: unknown

Published: May 16, 2025

The strategy of modification central units Y6-type nonfullerene acceptors (NFAs) with halogenation has become popular for designing new photovoltaic materials and shown dramatic effects in improving properties. However, the underlying mechanism how these NFAs influences photoelectric properties remains rather elusive. In this paper, focusing on two reported promising Qx-1 Qx-2, varying degrees ring fusion at units, we designed 4 modeled 10 systematically through fluorination units. Using density functional theory (DFT) time-dependent DFT calculations, explore impact an altered fluorinated location Qx-2 molecular planarity, dipole moment, electrostatic potential (ESP) its fluctuation, exciton binding energy (Eb), singlet-triplet gap, absorption spectrum are obtained combinations traditional hybrid or long-range corrected functionals Pople basis sets. We also developed a numerical method to analyze fluctuation ESP quantitatively because recent reports discussed importance. computed data suggest that newly Qx2-bf Qx2-cf they exhibit enhanced lower Eb (by least 0.002 eV), higher averaged 0.247 kcal/mol) compared Qx-2. find core reduces noticeably, increases standard deviation, raises average except ortho (outside) substitutions. These findings offer valuable physical insights into fluorination, which can serve as guide rational design high-performance QX-based NFAs.

Language: Английский

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Cyanobenzene‐Modified Quinoxaline‐Based Acceptors with Optimal Excitonic Behavior Enable Efficient Organic Solar Cells

Advanced Materials, Journal Year: 2025, Volume and Issue: unknown

Published: May 22, 2025

Abstract Cyanogroup (‐CN) is a strongly electron‐withdrawing and highly polar functional group; therefore, cyanation has been extensively utilized to optimize the terminal groups of high‐performance small‐molecule acceptors (SMAs) in organic solar cells (OSCs). Herein, by regulating cyanobenzene substitution central core for first time, four novel SMAs are synthesized, named phCN‐F, phCN‐Cl, 2phCN‐F, 2phCN‐Cl. Theoretical experimental analyses have shown that asymmetric symmetric cyanobenzene‐substitution core, coupled with selective groups, can significantly affect intrinsic excitonic properties molecule. Blends based on molecules possess tighter molecular packing more suitable phase separation facilitate exciton dissociation, charge transport, extraction. The optimal device performance phCN‐F‐based OSC reaches 20.16%, which higher than symmetrically substituted OSCs. Furthermore, devices prepared phCN‐F maintain over 90% their initial efficiency after being heated at 85°C 3000 h, demonstrating excellent thermal stability. This study elucidates potential mechanisms optimizing through providing valuable insights further design record‐breaking SMAs.

Language: Английский

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