Intramolecular Charge Transfer Effect Research Articles

Polarity responsive polysiloxanes with twisting intramolecular charge transfer effect for monitoring lipophagy process and the detection of volatile organic compounds

Polarity plays a critical role in biology and materials science, serving as a complex parameter. Imbalances in polarity within subcellular organelles are closely associated with various diseases. Moreover, volatile organic compounds (VOC) with low polarity pose significant health and safety risks, therefore, researchers have shown great interest in accurately detecting polarity. However, precise observation of polarity changes within organisms and identification of low-polarity volatile organic solvents are formidable challenges. To overcome these difficulties, we developed a versatile polymeric twisting intramolecular charge transfer (TICT) effect Polysiloxane-n (PDMS-n), utilizing polysiloxane molecular chains as "smart guides" to connect TICT molecules, inspired by the concept of "threading a needle." With the aid of PDMS-n, the process of polarity changes during cellular lipophagy was monitored in situ with high accuracy. Remarkably, the polarity changes of the local microstructure of the PDMS films were successfully visualized. PDMS-Films were also constructed, which enabled the recognition of Dichloromethane (DCM) gas during swelling. This work will contribute to the understanding of changes in cellular physiological processes, and facilitate the sensitive detection of VOCs.

A Highly fluorescent vinylene-linked covalent organic framework for chemical sensing of pH and NH3 gas with wide dynamic range

Herein, a vinylene-linked covalent organic framework (TMT-BPDA-COF) was prepared via the Aldol condensation of 2,4,6-trimethyl-1,3,5-triazine (TMT) and 4,4'-biphenyl dimethyl formaldehyde (BPDA). TMT-BPDA-COF displayed high crystallinity and thermal stability, and robust chemical stability in strong acid, strong base and common organic solvents. TMT-BPDA-COF nanosheets emitted strong yellow fluorescence with the quantum yield of 14.9% and showed fast reversible response toward pH with a wide range (pH 0.0 ∼ 14.0) based on the intramolecular charge transfer effect. Furthermore, portable fluorescent sensors were prepared by incorporated TMT-BPDA-COF nanosheets into agarose gel and cellulose acetate butyrate (CAB), respectively. TMT-BPDA-COF gel showed a wide pH response range over pH 0.0 ∼ 14.0 with a linear range of pH 4.0 ∼ 14.0. TMT-BPDA-COF CAB film exhibited high sensitivity for sensing of NH3 gas with a limit of detection of 1.6 ppb. TMT-BPDA-COF agarose gel and CAB film also exhibited good reversibility and reproducibility in response to pH and NH3 gas, respectively. We expect TMT-BPDA-COF-based sensors, which feature fast response, high sensitivity, wide response range, good reproducibility and reversibility, can apply to detect pH and NH3 gas in the field of environment and industry.

Bis-chalcone Fluorescent Probe for Hydrazine Ratio Sensing in Environment and Organism.

In this paper, four novel hydrazine fluorescent probes X1-X4 with bis-chalcone structure were designed and synthesized. Through the measurement of its optical properties, it is found that it can quickly identify hydrazine, high sensitivity, low detection limit, and good anti-interference ability. The recognition of hydrazine by probes X1-X4 is not affected in the pH range of 4-10, X2 has the highest sensitivity, and the detection limit is as low as 0.336 × 10-7 M. Through Gaussian quantization calculation of probe molecules and their reaction products with hydrazine, it is speculated that the recognition mechanism is the closure of intramolecular charge transfer effect. In addition, the cytotoxicity and imaging of HeLa cells were tested, which showed that probes X1-X4 could be used to detect hydrazine in cells.

Near-Infrared Conjugated Polymers Containing Thermally Activated Delayed Fluorescence Units Enable Enhanced Photothermal Therapy.

Photothermal therapy (PTT) using near-infrared (NIR) conjugated polymers as photosensitizers has exhibited enormous potential for tumor treatment. However, most NIR conjugated polymers have poor therapeutic efficacy due to their faint absorbance in the NIR region and low photothermal conversion efficiency (PCE). Herein, a valuable strategy for designing NIR polymeric photosensitizer PEKBs with an enhanced PCE accompanied by strong NIR absorbance is proposed by means of inserting TPA-AQ as a thermally activated delayed fluorescence unit into a polymeric backbone. In these PEKBs, PEKB-244 with the appropriate molar content of the TPA-AQ unit displays the strongest NIR absorbance and the highest PCE of 64.5%. Theoretical calculation results demonstrate that the TPA-AQ unit in the polymeric backbone can modulate the intramolecular charge transfer effects and the excited energy decay routes for generating higher heat. The prepared nanoparticles (PEKB-244 NPs) exhibit remarkable photothermal conversion capacities and great biocompatibility in aqueous solutions. Moreover, PEKB-244 NPs also show outstanding photothermal stability, displaying negligible changes in the absorbance within 808 nm irradiation of 1 h (800 mW cm-2). Both in vitro and in vivo experimental results further indicate that PEKB-244 NPs can substantially kill cancer cells under NIR laser irradiation. We anticipate that this novel molecular design strategy can be employed to develop excellent NIR photosensitizers for cancer photothermal therapy.

Promising impact of push–pull configuration into designed octacyclic naphthalene-based organic scaffolds for nonlinear optical amplitudes: a quantum chemical approach

In opto-electronics, non-fullerene (NF) derivatives are regarded as efficient non-linear optical (NLO) materials. The present investigation was based on designing NF naphthalene-based derivatives (PCMD1–D9) with D-π-A configuration from PCMR. DFT analysis at M06/6-311G (d,p) level was accomplished to explore the photonic behavior of PCMD1–D9 compounds. Various kind of analysis like; UV–Vis, density of state (DOS), natural bond orbitals (NBOs), transition density matrix (TDM) and frontier molecular orbitals (FMOs) analyses were accomplished to understand the NLO properties of said chromophores. The configuration change led to considerable charge distribution over highest occupied and lowest unoccupied molecular orbitals with minimum band difference. The energy gap trend for all the entitled compounds was observed as; PCMD8 < PCMD5 = PCMD9 < PCMD6 < PCMD7 < PCMD4 < PCMD3 < PCMD2 < PCMD1 with the least band gap of 2.048 eV in PCMD8 among all the compounds. The UV–Visible spectrum of the entitled chromophores manifested high values of λmax in derivatives contrary to PCMR. Additionally, NBO findings explored effective intramolecular charge transfer and maximum energy of stabilization (34.31 kcal/mol) for PCMD8 chromophore. The highest linear polarizability (<α>) and dipole moment (µtot) values were exhibited by PCMD5 at 2.712 × 10–22. and 1.995 × 10–17 esu, respectively. PCMD8 push–pull configured molecular entity exhibited highest first hyper-polarizability (βtot) at 4.747 × 10–27 esu and second hyper-polarizability at 6.867 × 10–32 esu. Overall, all the formulated chromophores exhibited significant NLO results contrary to PCMR. Hence, through this structural tailoring via various acceptors, effective NLO materials were obtained for optoelectronic applications.

Rofecoxib derivatives as NIR fluorescent probes for mitochondrial viscosity and in vivo imaging of Aβ plaques

Alzheimer's disease (AD) is a multifaceted neurodegenerative disorder for which the underlying causes remain largely unknown. Therefore, the development of imaging agents capable of detecting biomarkers associated with this disease is crucial. Dual-functional probes are particularly important as they can track two biomarkers at the same time and examine their interaction. Herein, Two red-emissive dual-functional fluorescent probes, RC-1 and RA-2, have been designed and synthesized based on the Rofecoxib scaffold. When probes (RC-1 and RA-2) are in viscous media or bound to Aβ aggregates, there is a dramatic enhancement in fluorescence emission due to the constraint of the twisted intramolecular charge transfer effect (TICT). RC-1 with ideal blood–brain barrier (BBB) penetrability enables visualization of Aβ plaques in vivo AD mice. These results suggest that RC-1 and RA-2 have the potential to serve as powerful fluorescence imaging agents for Aβ and mitochondria-related pathology in AD.

Novel Dibenzofulvene‐Based NIR‐II Emission Phototheranostic Agent with an 82.6% Photothermal Conversion Efficiency for Photothermal Therapy

AbstractOrganic molecules with second near‐infrared (NIR‐II, 1000–1700 nm) emission have significant advantages over NIR‐I (600–900 nm) dyes, and have been widely used as phototheranostic agents (PTAs) and fluorescent probes. However, the two biggest challenges for such reagents are improving photothermal conversion efficiency (PCE), and simplifying tedious synthetic procedures. Herein, different from the traditional NIR skeleton, for the first time, it develops two novel dibenzofulvene‐based NIR‐II emission PTAs via D‐π‐A concept with high PCEs through two simple synthetic steps. The increased intramolecular charge transfer effect and extended π‐conjugation effectively red‐shift their emissions to the NIR‐II region. In addition, the introduction of molecular rotors/vibrators and the formation of π–π stacking prompt the two PTAs to exhibit high PCEs. Notably, FE‐IDMN nanoparticles (FE‐IDMN NPs) achieve an exciting PCE of 82.6%, higher than most reported photothermal agents with NIR‐II emission. FE‐IDMN NPs also possess good colloidal, pH, and photothermal stabilities, as well as excellent photoacoustic response, which is further successfully applied for NIR‐II fluorescence/photoacoustic/photothermal imaging‐guided photothermal therapy. This work provides a simple strategy for constructing new D‐π‐A PTAs with low molecular weight, NIR‐II emission, and high PCE for cancer therapy.

Large enhancement of nonlinear optical absorption and refraction in planar chalcone structure with terminal substitution

The ultrafast nonlinear optical (NLO) properties of novel planar π-conjugated chalcone derivatives, (E)-3-(4-nitrophenyl)-1-(3-bromo-4-fluorophenyl) prop-2-en-1-one (1503) and (E)-3-(4-nitrophenyl)-1-(phenothiazin-2-yl) prop-2-en-1-one (1526) are investigated and compared. The effect of intramolecular charge transfer on NLO absorption and refraction is discussed without changing the planar structural properties of the chalcone molecules. Transient absorption experiments are used to observe the evolution of 1526 from local excited (LE) state to the intramolecular charge transfer (ICT) state. In the Z-scan experiments, 1526 exhibits respectively different nonlinear absorption (NLA) mechanisms (reverse saturable absorption and two-photon induced excited state absorption) at 532 nm (4 ns, 22ps, 190 fs) and 700–900 nm, 190 fs. The NLA and nonlinear refraction (NLR) phenomena of 1526 are observed and discussed in the POPP experiments. The experimental results indicate that the chalcone derivative can become the potential materials for laser protection.

A2 -A1 -D-A1 -A2 -Type Nonfullerene Acceptors.

The A2 -A1 -D-A1 -A2 -type molecules consist of one electron-donating (D) core flanked by two electron-accepting units (A1 and A2 ) and have emerged as an essential branch of nonfullerene acceptors (NFAs). These molecules generally possess higher molecular energy levels and wider optical bandgaps compared with those of the classic A-D-A- and A-DA'D-A-type NFAs, owing to the attenuated intramolecular charge transfer effect. These characteristics make them compelling choices for the fabrication of high-voltage organic photovoltaics (OPVs), ternary OPVs, and indoor OPVs. Herein, the recent progress in the A2 -A1 -D-A1 -A2 -type NFAs are reviewed, including the molecular engineering, structure-property relationships, voltage loss (Vloss ), device stability, and photovoltaic performance of binary, ternary, and indoor OPVs. Finally, the challenges and provided prospects are discussed for the further development of this type of NFAs.

A golgi-targeting and polarity-specific fluorescent probe for the diagnosis of cancer and fatty liver in living cells and tissues

Elucidating the intrinsic relationship between diseases and Golgi apparatus polarity remains a great challenge owing to the lack of the Golgi-specific fluorescent probe for polarity. Until now, the visualization of abnormal Golgi apparatus polarity in clinical cancer patient samples has not been achieved. To meet this urgent challenge, we facilely synthesized a robust Golgi-targeting and polarity-specific fluorescent probe (GCSP), which consists of an electron-acceptor solvatochromic coumarin 343 and an electron-donor Golgi-targeting group phenylsulfonamide. Owing to the typical D-π-A molecular configuration with unique intramolecular charge transfer effect, GCSP exhibits high sensitivity to polarity change in different solvents. Moreover, we revealed that GCSP possessed a satisfactory ability to sensitively monitor Golgi apparatus polarity changes in living cells. Using GCSP, we have successfully shown that Golgi apparatus polarity may serve as an ubiquitous marker for cancer and fatty liver detection. Surprisingly, the visualization of Golgi polarity has been achieved not only at the cellular levels, but also in clinical tissue samples from cancer patients, thus holding great potential in the clinical diagnosis of human cancer. All these features render GCSP an effective tool for the accurate diagnosis of Golgi apparatus related diseases.

First Subphthalocyanine Analogue with Fused 6H‐1,4‐diazepine Ring and its Conversion to Aminobenzamide Derivative

AbstractMixed cyclization of 5,7‐diphenyl‐6H‐1,4‐diazepine 2,3‐dicarbonitrile and tetrafluorophthalonitrile in the presence of boron trichloride affords along with symmetrical perfluorinated subphthakocyanine, [F12sPc], two novel subporphyrazine‐type products which were isolated by column chromatography and characterized by mass‐sprectometry, NMR, IR, UV‐VIS and fluorescent spectroscopy. It was established that co‐cyclomerization of dinitriles is accompanied by electrophilic chlorination of 1,4‐diazepine ring by evolved Cl2 resulting in formation of dibenzosubporphyrazine [F8sPc1] with fused 6‐chloro‐5,7‐diphenyl‐6H‐1,4‐diazepine fragment. According to DFT modelling and 1H NMR data, a more stable diastereomer with an axial Cl atom is formed and no inversion of the 1,4‐diazepine ring is observed. Hydrolytic cleavage of the 1,4‐diazepine fragment in [F8sPc1] is observed upon chromatography or in the presence of a strong acid (CF3COOH) and leads to 2‐amino‐3‐benzamide substituted dibenzo subporphyrazine [F8sPc2]. Fluorescence of [F8sPc1] (ΦF=0.03) is ca 10 times lower than for [F12sPc] (ΦF=0.28) due to the combined effect of intramolecular charge transfer (ICT) from the donor diazepine ring to the acceptor sPc macrocycle and heavy atom effect of chlorine. Fluorescence of [F8sPc2] is almost completely quenched by ICT from −NH2 group to the electron‐deficient subporphyrazine core (ΦF&lt;0.001), but addition of acid leads to protonation of the amino group and switch‐ON the fluorescence. Therefore, aminobenzamide substituted subporphyrazines can be considered as perspective pH‐sensitive fluorophores.

An unique furan/thiophene substituted β-diketonate derivatives bearing triphenylamine with dual-state emission

Traditional β-diketones are rarely used as fluorescent emitters. Here, two novel triphenylamine-modified β-diketonate derivatives containing either a furan or thiophene unit (TPA-DK-O and TPA-DK-S) have been designed, synthesized and fully characterized. Both of the emitters have D-A type configuration, and show abnormal dual-state emissive characters with high quantum efficiency both in dissolved and aggregate state owning to rational design strategy. Additionally, owing to their molecular conformational flexibility and inherent intramolecular charge transfer characteristics, TPA-DK-O and TPA-DK-S show intriguing optical features such as solvatochromism, vicosity-dependent fluorescence and temperature response characteristics. The solvatochromism is derived from the intramolecular charge transfer effect which is confirmed by density functional theory calculation and fluorescence in solvents of different polarities. These unique optical properties of TPA-DK-O and TPA-DK-S are expected to be utilized for detecting local viscosity, polarity of system and temperature sensing. Moreover, the excellent dual-state emissive characters of TPA-DK-O are utilized for chemical sensors and cell imaging. The metal ion detection experiments indicated that TPA-DK-O has a fluorescence response capability to Fe3+ and Mg2+, and has a good linear relationship in the concentration range of 48–800 μM and 0–30 μM for Fe3+ and Mg2+, respectively. The cell incubation experiments shows that TPA-DK-O has low toxicity and good biocompatibility for cells. The cell imaging experiments reveals that TPA-DK-O not only stains and images cells, but also responds to Fe3+ in living cells. Making a contrast between TPA-DK-O and TPA-DK-S, it is found that replacing furan with thiophene in the β-diketonate derivatives showed slight effects on optical properties.

A responsive organic probe based photoelectrochemical sensor for hydrazine detection

This study developed a new photoelectrochemical (PEC) sensor for the detection of the hydrazine (N2H4, HZ) based on a donor-π-bridge-acceptor (D-π-A) configuration organic photoactive dye (Dye-HZ). The dye was covalently immobilized on an FTO/TiO2 (FTO: fluorine-doped tin oxide) substrate, resulting in a photoanode FTO/TiO2/Dye-HZ that exhibits a specific PEC response to N2H4. Hydrazine reacts with the acetyl group in the Dye-HZ molecule, leading to its removal and the formation of a hydroxy group. The hydroxy group dissociates a hydrogen ion, forming a phenoxide anion with strong electron-donating characteristics. As a result, the dye molecule exhibits a strong intramolecular charge transfer effect, significantly enhancing absorbance and photoelectric response under visible light irradiation, leading to a remarkable increase in photocurrent and enabling highly sensitive detection of hydrazine. Furthermore, the PEC sensor demonstrates excellent selectivity and can be applied for the detection of hydrazine in real water samples. This study presents an innovative PEC sensing approach for hydrazine based on responsive photoactive molecules, providing new insights for PEC detection of other environmental pollutants.

Development of a Ratiometric Fluorescent Probe with Zero Cross-Talk for the Detection of SO2 Derivatives in Foods and Live Cells.

Sulfur dioxide (SO2) derivatives are extensively utilized as both a preservative for foods and an active gaseous signal molecule in various physiological and pathological processes, but their excessive intake would bring harmful effects on human health; so, the determination of SO2 derivatives is of great importance. Herein, we developed a ratiometric fluorescent probe named 2-(2'-hydroxyphenyl)benzothiazole-3-ethyl-1,1,2-trimethyl-1H-benzo[e]indolium (HBT-EMBI) by introducing a hemicyanine unit of EMBI to an HBT group for the detection of SO2 derivatives via an excited-state intramolecular proton transfer (ESIPT) and intramolecular charge transfer (ICT) effects. The probe displays some advantages, such as a colorimetric change from purple to colorless, a ratiometric fluorescence with zero cross-talk, and a remarkably large emission shift (Δλ = 164 nm) under a single-wavelength excitation. Accordingly, the probe HBT-EMBI has been successfully employed for the colorimetric and ratiometric determination of SO2 derivatives in real food samples and the quantitative visualization of SO2 derivative variations in HepG2 cells.

A near-infrared fluorescent probe with remarkably large stokes shift for specifical imaging of peroxynitrite fluctuations in Hela cells

Peroxynitrite (ONOO−), an endogenous reactive nitrogen species, plays an important role in maintaining intracellular homeostasis. Abnormal levels of ONOO− in cells could cause protein oxidation which is confirmed that related with Alzheimer’s diseases, so accurate monitoring of ONOO− in cells is crucial. Herein, a novel fluorescent probe (XPC) based on dicyanomethylene-4H-benzothiopyran was developed by regulating its intramolecular charge transfer (ICT) effect to detect ONOO−. Once reaction with ONOO−, the fluorescence of XPC was turned on and the emission wavelength could reach up to 750 nm. Furthermore, XPC exhibited satisfactory performances for ONOO− such as large Stokes shift (200 nm), good sensitivity (Limit of detection = 13 nM), high selectivity to ONOO− over other a reactive nitrogen species (RNS)/reactive oxygen species (ROS). More importantly, XPC was successfully applied for monitoring the fluctuations of ONOO− in living cells.

A novel central seven-membered BOPYOs: Synthesis, optical properities and optimization of BF2 removal

Many efforts have been made to enrich the variety of BF2 complexes because of their excellent optical properties. However, the investigation on seven-membered ring N, O-chelated BF2 complexes is rare due to their instability with the removal of BF2 unit. Herein, a novel seven-membered ring N, O-chelated BF2 complexes (BOPYOs) with dual-state emission has been synthesized via a facile method. The results of optical properties showed that the fluorescence quantum yield of BOPYO-2 with donor group on 1 and 2-position of 1-indanone unit is much higher than that of BOPYO-1, 3–5 in toluene. The emission spectra of BOPYO-6 or 7 have redshift phenomenon compared with BOPYO-1–5 with weak fluorescence intensity due to their highly distorted structure or intramolecular charge transfer (ICT) effect. BOPYOs show relatively moderate solid emission from orange to deep red color with 596 nm to 686 nm. On the contrary, fluorescence quantum yield of BOPYO-2 in solid is the lowest. The optical properties in solution and solid states are further supported by the single-crystal structure and DFT calculation. Furthermore, the investigation on optimization of BF2 removal shows that the corresponding precursors of BOPYOs could be obtained in protic solvents without adding other catalysts.

Triphenylamine-Based N,O-Bidentate BF2 -Enolimine Initiator for Three-Arm Star Polymethacrylates with Dual-State Fluorescent Emission.

Three-arm star polymethacrylates with dual-phase (solution and solid-state) fluorescent emission have been synthesized via atom transfer radical polymerization (ATRP) using a triphenylamine-derived organboron complex (TAPA-BKI-3Br) as initiator. The as-synthesized three-arm star polymethacrylates exhibited bright emission in both solution and the solid states due to the highly twisted structure and intramolecular charge transfer (ICT) effect of TAPA-BKI core, as well as the steric effect and restriction of intramolecular motions from the polymer arms. And the polymer chains have an important influence on the photophysical behavior of the as-synthesized three-arm star polymethacrylates in the aggregated state.

Modulating the Luminescence, Photosensitizing Properties, and Mitochondria-Targeting Ability of D-π-A-Structured Dihydrodibenzo[a,c]phenazines.

Herein, pyridinium and 4-vinylpyridinium groups are introduced into the VIE-active N,N'-disubstituted-dihydrodibenzo[a,c]phenazines (DPAC) framework to afford a series of D-π-A-structured dihydrodibenzo[a,c]phenazines in consideration of the aggregation-benefited performance of the DPAC module and the potential mitochondria-targeting capability of the resultant pyridinium-decorated DPACs (DPAC-PyPF6 and DPAC-D-PyPF6). To modulate the properties and elucidate the structure-property relationship, the corresponding pyridinyl/4-vinylpyridinyl-substituted DPACs, i.e., DPAC-Py and DPAC-D-Py, are designed and studied as controls. It is found that the strong intramolecular charge transfer (ICT) effect enables the effective separation of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of DPAC-PyPF6 and DPAC-D-PyPF6, which is conducive to the generation of ROS. By adjusting the electron-accepting group and the π-bridge, the excitation, absorption, luminescence, photosensitizing properties as well as the mitochondria-targeting ability can be finely tuned. Both DPAC-PyPF6 and DPAC-D-PyPF6 display large Stokes shifts (70-222 nm), solvent-dependent absorptions and emissions, aggregation-induced emission (AIE), red fluorescence in the aggregated state (λem = 600-650 nm), aggregation-promoted photosensitizing ability with the relative singlet-oxygen quantum yields higher than 1.10, and a mitochondria-targeting ability with the Pearson coefficients larger than 0.85. DPAC-D-PyPF6 shows absorption maximum at a longer wavelength, slightly redder fluorescence and better photosensitivity as compared to DPAC-PyPF6, which consequently leads to the higher photocytotoxicity under the irradiation of white light as a result of the larger π-conjugation.

Building-up relations between intra- and intermolecular interactions, miscibility, and performance for low-cost, efficient fully non-fused acceptor-based organic solar cells

Although the molecular electronic forces (e.g., intra- and intermolecular interactions) within active layers largely govern the device performance of organic solar cells (OSCs), they are complicated and less understood. In this study, we have synthesized two low-cost isomeric non-fused acceptors (TT-Naph1 and TT-Naph2) with 1-naphthyl and 2-naphthyl aromatic chains, respectively and quantified the molecular interaction−photovoltaic performance relationship. Benefiting from the enhanced dipole moment, TT-Naph2 possesses a strong dipole–dipole intermolecular interaction, while the improved backbone planarity endows TT-Naph1 with a strengthened intramolecular charge-transfer effect, which can regulate the desired blend morphology with the D18 donor polymer as a result of its low miscibility with D18. Less miscible nanostructures are more pronounced in the layer-by-layer (LBL) systems than bulk heterojunction (BHJ) ones, increasing the power conversion efficiencies (PCEs) in the sequence of TT-Naph2 BHJ < TT-Naph1 BHJ < TT-Naph2 LBL < TT-Naph1 LBL. Notably, a ternary LBL OSC based on TT-Naph1 achieved remarkable PCE of 18.41%, one of the top values for LBL-type OSCs. Our findings provide insights into the controlling effect of intra- and intermolecular interactions on the active layers for efficient non-fused acceptor-based OSCs.

New Medium-Bandgap Nonfused Ring Guest Acceptor with a Higher-Lying LUMO Level Enables High-Performance Ternary Organic Solar Cells.

Adding another constituent into a binary system, known as a ternary strategy, represents a simple and effective approach to boosting the power conversion efficiency (PCE) of organic solar cells (OSCs). Herein, we have prepared a new nonfused ring small-molecule acceptor with a medium bandgap, named DFTQA-2FIC, which possesses a high-lying lowest unoccupied molecular orbital energy level and a strong intramolecular charge-transfer effect. We elaborately utilized it as a third component in a typical PM6:Y6 blend to obtain high-performance ternary OSCs. The resulting ternary blend film exhibited superior and balanced hole/electron mobility, enhanced favorable aggregation morphology, and reduced charge carrier recombination. Consequently, an optimized ternary OSC presented a distinctly increased PCE of 17.29%, accompanied by synchronous enhancements in crucial parameters, representing a 7.46% improvement over the binary OSC based on PM6:Y6 with a PCE of 16.09%. This study highlights that incorporating DFTQA-2FIC as a third component in a binary system is suitable for optimizing photovoltaic performance.