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Asymmetric Electron Acceptors for Higha??Efficiency and Lowa??Energya??Loss Organic Photovoltaics
摘要： Low energy loss and efficient charge separation under small driving forces are the prerequisites for realizing high power conversion efficiency (PCE) in organic photovoltaics (OPVs). Here, a new molecular design of nonfullerene acceptors (NFAs) is proposed to address above two issues simultaneously by introducing asymmetric terminals. Two NFAs, BTP-S1 and BTP-S2, are constructed by introducing halogenated indandione (A1) and 3-dicyanomethylene-1-indanone (A2) as two different conjugated terminals on the central fused core (D), wherein they share the same backbone as well-known NFA Y6, but at different terminals. Such asymmetric NFAs with A1-D-A2 structure exhibit superior photovoltaic properties when blended with polymer donor PM6. Energy loss analysis reveals that asymmetric molecule BTP-S2 with six chlorine atoms attached at the terminals enables the corresponding devices to give an outstanding electroluminescence quantum efficiency of 2.3 × 10?2%, one order of magnitude higher than devices based on symmetric Y6 (4.4 × 10?3%), thus significantly lowering the nonradiative loss and energy loss of the corresponding devices. Besides, asymmetric BTP-S1 and BTP-S2 with multiple halogen atoms at the terminals exhibit fast hole transfer to the donor PM6. As a result, OPVs based on the PM6:BTP-S2 blend realize a PCE of 16.37%, higher than that (15.79%) of PM6:Y6-based OPVs. A further optimization of the ternary blend (PM6:Y6:BTP-S2) results in a best PCE of 17.43%, which is among the highest efficiencies for single-junction OPVs. This work provides an effective approach to simultaneously lower the energy loss and promote the charge separation of OPVs by molecular design strategy.
关键词： asymmetric acceptors,molecular design strategies,nonfullerene acceptors,charge separation,organic photovoltaics
更新于2025-09-23 15:21:01
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Aromatic imide/amide-based organic small-molecule emitters for organic light-emitting diodes
摘要： Organic electroluminescence materials play an important role in improving the optoelectronic performance of organic light-emitting diodes (OLEDs). Aromatic imide/amide-based organic small-molecule emitters have caught increasing attention due to their unique properties, such as strong electron-withdrawing characteristics, rigid structures and high-fluorescence quantum yields. In recent years, aromatic imide/amide semiconductors have been developed rapidly, but few reviews have been specially reported on their application in OLEDs. This study classified aromatic imides/amides into maleimide (MAI), phthalimide (PHI), naphthalimide (NAI), perylenediimide (PDI), and other imide/amide units according to the chemical structure to summarize the advances of imide/amide-based organic small-molecule emitters from the perspective of device performance and molecular design rules over the past 20 years. The luminescent mechanism was also explored. The findings of this study might provide a constructive guide towards future exploration and promote the further development of innovative imide/amide-based emitters.
关键词： Aromatic imides/amides,organic small-molecule emitters,device performance,organic light-emitting diodes,molecular design
更新于2025-09-23 15:19:57
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Recent Progress in Chlorinated Organic Photovoltaic Materials
摘要： Over the past few years, the development of new materials has contributed to rapid increases in the power conversion efficiencies (PCEs) of organic photovoltaic (OPV) cells to over 17%, showing great potential for the commercialization of this technology in the near future. At this stage, designing new materials with superior performance and low cost simultaneously is of crucial importance. Chlorinated materials are emerging as new stars with very high PCEs, creating a molecular design trend to replace the most popular fluorinated materials. For example, by using chlorinated non-fullerene acceptors, we recently got a record PCE of 17% for single-junction OPV cells. Firmly based on recent advances, herein we focus on the topic of chlorinated OPV materials, aiming to provide a guideline for further molecular design.
关键词： chlorinated materials,organic photovoltaic cells,power conversion efficiencies,non-fullerene acceptors,molecular design
更新于2025-09-23 15:19:57
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Azobenzene-based small molecular photoswitches for protein modulation
摘要： Molecular photoswitches are a class of chemical structures that can readily isomerize between distinct geometries upon irradiation with light. Molecular photoswitches are utilized to control protein structure and function with temporal and spatial precision. In this review, we summarize the recent progress in the development of azobenzene-based molecular photoswitches and their applications in the photocontrol of protein structure and function. For clarity of discussion, we divide the known photoswitchable proteins into different categories: protein motifs, ion channels, receptors, and enzymes. Basic approaches and considerations for the structure-guided design of photoswitchable ligands are discussed. The applications and limitations of current photoswitches are also discussed.
关键词： protein modulation,molecular design,azobenzene,photocontrol,photoswitches
更新于2025-09-19 17:15:36
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Efficient Modulation of End Groups for the Asymmetric Small Molecule Acceptors Enabling Organic Solar Cells with over 15% Efficiency
摘要： Non-fullerene organic solar cells (OSCs) have attracted tremendous interest and made an impressive breakthrough, largely due to advances in high-performance small molecule acceptors (SMAs). The relationship between short-circuit current density (JSC) and open-circuit voltage (VOC) is usually shown as one falls and another rises. Controlling the trade-off between JSC and VOC to harvest high power conversion efficiencies (PCEs) still remains as a challenge. Herein, dithieno[3,2-b:2?,3?-d]pyrrole (DTP) based asymmetric SMAs with different chlorinated dicyanoindanone-based end groups, named TPIC, TPIC-2Cl and TPIC-4Cl, are designed and synthesized. These asymmetric acceptors exhibit remarkable red-shifted absorption profile, while energy levels are simultaneously down-shifted when the numbers of chlorine atoms alter from 0, 1 to 2, due to the gradually improved electronegativity. As a result, PM7: TPIC-4Cl based OSCs achieved a champion PCE of 15.31%, which is the highest PCEs for non-fullerene binary OSCs based on asymmetric SMAs. The superiority of PM7: TPIC-4Cl system consists of the balanced charge transport, favorable phase separation, efficient exciton dissociation and extraction, coupled with remarkable π–π stacking and crystallinity of the SMAs. Our results highlight the important strategy of asymmetric molecular design to optimize the trade-off between VOC and JSC, reaching a high PCE.
关键词： asymmetric molecular design,small molecule acceptors,chlorinated dicyanoindanone-based end groups,Non-fullerene organic solar cells,power conversion efficiencies
更新于2025-09-19 17:13:59
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Asymmetric Siloxane-Functional Side Chains Enable High-Performance Donor Copolymers for Photovoltaic Applications
摘要： In this work, three benzodithiophene (BDT)-benzotriazole (BTA) alternated wide bandgap (WBG) copolymers attaching symmetric or asymmetric conjugated side chains, namely PDBTFBTA-2T, PBDTFTBA-TSi and PBDTFBTA-2Si, were developed for efficient nonfullerene polymer solar cells. The symmetry effect of the side chains was investigated in detail on the overall properties of these donor polymers. The results demonstrated that the introduced siloxane functional groups showed less effect on the absorptions and frontier orbital levels of the prepared polymers but had significant effect on the miscibility between these polymer donors and nonfullerene acceptor. If increasing the content of siloxane functional groups, the miscibility of the polymer donors and Y6 would be improved, leading to the decreased domain size and more mixed domains. Interestingly, the active blend based on PBDTFTBA-TSi with asymmetric side chains exhibited more balanced miscibility, carrier mobility and phase separation, benefiting exciton diffusion and dissociation. Therefore, a champion power conversion efficiency (PCE) of 14.18% was achieved finally in PBDTFTBA-TSi devices, which was 20.6% and 19.0% higher than the symmetric counterparts of PBTFBTA-2T devices (PCE = 11.76%) and PBDTFBTA-2Si devices (PCE = 11.92%), respectively. This work highlights that the asymmetric side chain engineering based on siloxane functional groups is a promising design strategy for high-performance polymer donor semiconductors.
关键词： molecular design strategy,nonfullerene polymer solar cells,siloxane functional group,wide bandgap copolymers,asymmetric side chains
更新于2025-09-19 17:13:59
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Machine learning–assisted molecular design and efficiency prediction for high-performance organic photovoltaic materials
摘要： In the process of finding high-performance materials for organic photovoltaics (OPVs), it is meaningful if one can establish the relationship between chemical structures and photovoltaic properties even before synthesizing them. Here, we first establish a database containing over 1700 donor materials reported in the literature. Through supervised learning, our machine learning (ML) models can build up the structure-property relationship and, thus, implement fast screening of OPV materials. We explore several expressions for molecule structures, i.e., images, ASCII strings, descriptors, and fingerprints, as inputs for various ML algorithms. It is found that fingerprints with length over 1000 bits can obtain high prediction accuracy. The reliability of our approach is further verified by screening 10 newly designed donor materials. Good consistency between model predictions and experimental outcomes is obtained. The result indicates that ML is a powerful tool to prescreen new OPV materials, thus accelerating the development of the OPV field.
关键词： organic photovoltaics,molecular design,machine learning,high-performance materials,efficiency prediction
更新于2025-09-12 10:27:22
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Molecular design of novel indacenodithiophene‐based organic dyes for efficient dye‐sensitized solar cells applications
摘要： Indacenodithiophene (IDT)-based high-efficiency photovoltaics have received increasing attention recently. This paper reports a density functional theory investigation of the electronic and optical properties of three IDT-based organic dyes together with the dye/(TiO2)46 interface. In order to enhance the photoelectric properties of IDT dyes, this paper considers two methods for the structure modification of the experimentally reported dye DPInDT (J. Org. Chem. 2011, 76, 8977): the extension of the conjugation length by dithienothiophene as well as the heteroatom substitution of the bridging atoms by electron-rich nitrogen atoms. Our calculations show that both methods obviously affect the distributions of the molecular orbitals and notably red shift the absorption peaks of around 20 nm, with the former method demonstrating enhanced light harvesting efficiency. The structure modifications proposed also enhance the emission spectrum properties for IDT-based organic dyes. The calculated ultrafast injection time of electrons from the excited state of IDT dyes to the (TiO2)46 belongs to the femtosecond order of magnitude, and is ideal for efficient photoelectric conversion process in dye-sensitized solar cells (DSSCs) applications. The IDT dyes designed in this paper have good electronic and spectroscopic properties. This study is expected to provide useful guidance for the development of novel IDT dyes for applications in DSSCs.
关键词： organic dyes,DFT simulations,indacenodithiophene,molecular design
更新于2025-09-12 10:27:22
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Molecular Design Strategies for Efficient Intramolecular Singlet Exciton Fission
摘要： The process of carrier multiplication via singlet fission can potentially exceed Shockley–Queisser limit on the efficiency of single-junction photovoltaics. In the recent past, theoretical analysis provided the principal guidelines on molecular design strategies for singlet fission. In this perspective, we focus instead on correlating experimental results for different classes of reported singlet fission materials to identify principles to aid in the design of new molecules for efficient intramolecular singlet fission. Building on an evaluation of several series of multichromophoric and polymeric singlet fission materials, we extract new suggested strategies for molecular design.
关键词： singlet fission,photovoltaics,exciton multiplication,intramolecular singlet fission,molecular design
更新于2025-09-10 09:29:36
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A molecular design strategy to construct the near-infrared fluorescent probe for selectively sensing human cytochrome P450 2J2
摘要： Cytochrome P450 2J2 (CYP2J2), a key enzyme responsible for oxidative metabolism of various xenobiotics and endogenous compounds, participates in a diverse array of physiological and pathological processes in humans. Its biological role in tumorigenesis and cancer diagnosis remains poorly understood, owing to the lack of molecular tools suitable for real-time monitoring CYP2J2 in complex biological systems. Using molecular design principles we were able to modify the distance between the catalytic unit and metabolic recognition moiety, allowing us to develop a CYP2J2 selective fluorescent probe using a near-infrared fluorophore (E)-2-(2-(6-hydroxy-2, 3-dihydro-1H-xanthen-4-yl)vinyl)-3,3-dimethyl-1-propyl-3H-indol-1-ium iodide (HXPI). To improve the reactivity and isoform specificity, a self-immolative linker was introduced to the HXPI derivatives in order to better fit the narrow substrate channel of CYP2J2, the modification effectively shortened the spatial distance between the metabolic moiety (O-alkyl group) and catalytic center of CYP2J2. After screening a panel of O-alkylated HXPI derivatives, BnXPI displayed the best combination of specificity, sensitivity and applicability for detecting CYP2J2 in vitro and in vivo. Upon O-demethylation by CYP2J2, a self-immolative reaction occurred spontaneously via 1,6-elimination of p-hydroxybenzyl resulting in the release of HXPI. Allowing BnXPI to be successfully used to monitor CYP2J2 activity in real-time for various living systems including cells, tumor tissues, and tumor-bearing animals. In summary, our practical strategy could help the development of a highly specific and broadly applicable tool for monitoring CYP2J2, which offers great promise for exploring the biological functions of CYP2J2 in tumorigenesis.
关键词： Cytochrome P450 2J2,near-infrared fluorescent probe,real-time monitoring,molecular design,CYP2J2,tumorigenesis
更新于2025-09-04 15:30:14