Side-chain Engineering Research Articles

Nonhalogenated Solvent-Processed Efficient Ternary All-Polymer Solar Cells Enabled by the Introduction of a Naphthyloxy Group into the Side Chain of Polymer Donors.

Conjugated polymer donors are crucial for enhancing the power conversion efficiencies (PCEs) in all-polymer solar cells (All-PSCs) in nonhalogenated solvents. In this work, three wide-band-gap polymer donors (Sil-D1, Ph-Sil-D1, and Nap-Sil-D1) based on dithienobenzothiadiazole (DTBT) and benzodithiophene (BDT) donor moieties optimized by side chain engineering were designed and synthesized. Alkyl (Sil-D1), phenyloxy (Ph-Sil-D1), and naphthyloxy (Nap-Sil-D1) alkyl siloxane side chain units were incorporated into these polymer donors, respectively. Notably, the Nap-Sil-D1 polymer donor had a greater conjugation length, π-electron delocalization, and improved dipole moment. The deepest highest occupied molecular orbital level of Nap-Sil-D1, with a high absorption coefficient, showed better aggregation properties. In addition, reduced bimolecular recombination and trap-state density generated a high charge transfer to cause a significant enhancement of open-circuit voltage, current density, and fill factor values of 0.94 V, 25.5 mA/cm2, and 70.4%, respectively, for the Nap-Sil-D1-blended All-PSC ternary device (PM6:Nap-Sil-D1:PY-IT), with the highest PCE of 16.8% in the o-xylene solvent, compared to other polymers (Sil-D1 and Ph-Sil-D1) with PCEs of 15.5 and 16.2%. As a result, this optimized device architecture was found to be the most promising as a nonhalogenated solvent processed in additive-free ternary All-PSCs with good stability.

Hybridized Naphthotubes: Side-Chain Engineering, Molecular Recognition and Applications in Shear-Induced Hydrogels

Hybridized Naphthotubes: Side-Chain Engineering, Molecular Recognition and Applications in Shear-Induced Hydrogels

Advancements in optical and optoelectronic characteristics of benzotriazole-based asymmetric non-fullerene acceptors for organic photovoltaics

The development of energy-efficient non-fullerene acceptors (NFAs) has attracted much attention in producing efficient organic solar cells (OSCs). These innovative materials are considered a promising alternative to traditional fullerene acceptors because they absorb a broader light range and potentially enhance the OSC performance. Herein, we engineered eleven new asymmetric caterpillar-shaped materials with an A1-D-A2-A1 core as NFAs for OSCs. These efficient materials offer a high absorption efficiency, wide energy level range, and efficient charge transport capabilities. To engineer these caterpillar-shaped NFAs (FT1-FT11), we performed various synergistic modulations of end-capped electron-withdrawing moieties and side-chain engineering on the synthetic reference molecule (FT). The electron and hole reorganization energies, binding energy, transition energy, transition density analysis, electrostatic potential, and photovoltaic characterizations have been performed for these designed caterpillar-shaped (FT1–FT11) series. The designed materials (FT1–FT11) showed a lower binding energy of 0.45 eV, a narrower bandgap (2.11 eV), higher absorption (ranges from 700.44 nm to 781.05), and low electron and hole mobilities (0.0029 and 0.0031) compared to reference molecule FT. To investigate the charge transport process, we employed polymer donor PTB7-Th and efficient NFA acceptor FT11 to establish a donor:acceptor complex (FT11:PTB7-Th). The complex study demonstrates a significant charge transformation at the donor-acceptor interface. As a result, the developed compounds (FT1–FT11), with their superior optoelectronic capabilities, could be viewed as a viable and sustainable choice to fabricate next-generation efficient OSCs.

Composite side chain induced ordered preaggregation in liquid state for high-performance non-halogen solvent processed organic solar cells

Eco-friendly organic solar cells (OSCs) have become a promising choice for commercialization, particularly emphasizing the importance of using non-halogenated solvents. However, non-halogenated OSCs with high-performance remain limited due to the uncontrollable preaggregation behaviors of photovoltaic materials in these solvents. Here, composite side chain engineering was shown to enhance photovoltaic performance of non-halogenated solvents processed OSCs by developing two small molecular acceptors, C10ch-F and C10ch-Cl, and to study the preaggregation behavior in toluene. Through a combination of in situ absorption analyses and molecular dynamics simulations, we demonstrated that the cyclohexyl moiety at the tail of the linear chain acted as a fixative, effectively mitigating the entanglement of the amorphous long chains and prolonging the kinetics of film formation process, resulting in reinforced molecular packing with a preferential face-on orientation. With effective charge generation, transport, and collection, C10ch-Cl-based device from Tol showed an impressive PCE of 18.4 % and 19.2 % in the binary and ternary systems. Moreover, the PCE remained at 80 % of its initial value after 790 h of continuous illumination, indicating excellent photostability. The uncovered preaggregation and realized excellent performance obtained through the composite side chain strategy may allow for further synthetic advances, potentially leading to significantly improved eco-friendly OSCs.

Tailored thermoelectric performance of poly(phenylene butadiynylene)s/carbon nanotubes nanocomposites towards wearable thermoelectric generator application

In this study, two conjugated polymers (CPs) featuring poly(phenylene butadiynylene) (PPB) were meticulously synthesized and composited with single-walled carbon nanotubes (SWCNTs) to investigate their thermoelectric properties and fabricate wearable thermoelectric generators (TEGs). These CPs, designated as P1 and P2, were tailored with distinct side chain configurations by incorporating 2-butyloctyloxy and 6-(methyldioctylsilyl)hexyloxy groups, respectively. Notably, P2, characterized by longer side chains with branchpoints farther from the backbone, exhibited planar backbone structure and enhanced solubility, consequently engendering stronger π–π interaction with SWCNTs and facilitating the disperse of SWCNTs through polymer wrapping at bundle surface. Such characteristics therefore contributed to the superior thermoelectric performances of the P2/SWCNTs nanocomposite, yielding a higher power factor (PF) of 216.5 μW m−1 K−2 for the spin-coated film. Furthermore, the corresponding wearable TEGs, which were constructed through spray-coating with 14 legs, resulted in an output power of approximately 49.6 nW under a temperature difference of 25 K, exhibiting successful harvesting of waste heat. Further applications also demonstrated operational efficacy under diverse conditions. These findings not only underscored the significance of side chain engineering in tailoring the thermoelectric properties of CP/SWCNTs nanocomposites but also demonstrated the feasibility of fabricating high-performance wearable thermoelectric devices applicable in versatile contexts.

D/A heterojunction photocatalysts interspersed onto biochar to couple photocatalysis and adsorption for visible light-responsive efficient removal of pollutants

Phenol has various applications in industry, due to its hazardousness, solubility, and volatility, it persists in water and poses a risk to human health. People are excited by the progress of photodegradation technology that facilitates water pollution treatment. The effect of side-chain engineering is proven to enhance photodegradation performance by improving optoelectronic properties. Therefore, here is a strategy that introduces functional groups to change the electron cloud density, achieving excellent optoelectronic properties evidenced by efficient exciton dissociation, separation, and fine-tuned energy level. Subsequently, by coupling of photocatalysis and adsorption, the donor/acceptor (D/A) heterojunction photocatalysts (PBDB-T: BTTIC-TT, PBDB-T: BTTIC-Ph) are designed via loading on coconut-shell carbon to process phenol. The results indicate that the champion photocatalyst PBDB-T: BTTIC-TT possesses superior optoelectronic properties, which can be attributed to the stronger electron-withdrawing ability of thieno[3,2-b]thiophene than benzene. Consequently, the synergistic efficiency of adsorption and photocatalysis of phenol (10, 20 mg/L) are removed within 10 mins over 90 % which is still valid after twenty cycles. Surprisingly, a high concentration of phenol (100 mg/L) also exhibited excellent removal efficiency of over 80 % within 60 min.

The Multi-Functional Third Acceptor Realizes the Synergistic Improvement in Photovoltaic Parameters and the High-Ratio Tolerance of Ternary Organic Photovoltaics.

The ternary strategy proves effective for breakthroughs in organic photovoltaics (OPVs). Elevating three photovoltaic parameters synergistically, especially the proportion-insensitive third component, is crucial for efficient ternary devices. This work introduces a molecular design strategy by comprehensively analyzing asymmetric end groups, side-chain engineering, and halogenation to explore the outstanding optoelectronic properties of the proportion-insensitive third component in efficient ternary systems. Three asymmetric non-fullerene acceptors (BTP-SA1, BTP-SA2, and BTP-SA3) are synthesized based on the Y6 framework and incorporated as the third component into the D18:Y6 binary system. BTP-SA3, featuring asymmetric terminal (difluoro-indone and dichloride-cyanoindone terminal), with branched alkyl side chains, exhibited high open-circuit voltage (VOC), balanced crystallinity and compatibility, achieving synergistic enhancements in VOC (0.862V), short circuit-current density (JSC, 27.52mA cm-2), fill fact (FF, 81.01%), and power convert efficiency (PCE, 19.19%). Device based on D18/Y6:BTP-SA3 (layer-by-layer processed) reached a high efficiency of 19.36%, demonstrating a high tolerance for BTP-SA3 (10-50%). This work provides novel insights into optimizing OPVs performances in multi-component systems and designing components with enhanced tolerance.

Ultralow-Energy-Consumption Photosynaptic Transistor Utilizing Conjugated Polymers/Perovskite Quantum Dots Nanocomposites With Ligand Density Optimization.

The photosynaptic transistor stands as a promising contender for overcoming the von Neumann bottleneck in the realm of photo-communication. In this context, photonic synaptic transistors is developed through a straightforward solution process, employing an organic semiconducting polymer with pendant-naphthalene-containing side chains (PDPPNA) in combination with ligand-density-engineered CsPbBr3 perovskite quantum dots (PQDs). This fabrication approach allows the devices to emulate fundamental synaptic behaviors, encompassing excitatory postsynaptic current, paired-pulse facilitation, the transition from short-to-long-term memory, and the concept of "learning experience." Notably, the phototransistor, incorporating the blend of the PDPPNA and CsPbBr3 PQDs washed with ethyl acetate, achieved an exceptional memory ratio of 104. Simultaneously, the same device exhibited an impressive paired-pulse facilitation ratio of 223% at a moderate operating voltage of -4V and an extraordinarily low energy consumption of 0.215 aJ at an ultralow operating voltage of -0.1mV. Consequently, these low-voltage synaptic devices, constructed with a pendant side-chain engineering of organic semiconductors and a ligand density engineering of PQDs through a simple fabrication process, exhibit substantial potential for replicating the visual memory capabilities of the human brain.

Post-Functionalization of Thiophene-Fluorene Alternating Copolymers via Anodic Phosphonylation

Phosphonylated polymers are promising materials because of their application in sensor chemistry and their unique electronic properties. Among these polymers, conjugated polymers containing dialkylphosphonate at their side chains have been used in chemical sensors1 and exhibit unique electronic properties.2 However, there have been a few reports on phosphonylation into the conjugated polymer main chains except for poly(3-hexylthiophene) (P3HT)3 and polyaniline derivatives,4 demonstrating that the effect of phosphonate on their main chains has been unclear. To introduce the phosphonate into their main chains, electrochemical post-functionalization is an attractive approach because of the simple protocol and mild reaction conditions.5 Recently, anodic phosphonylation of P3HT at the main chains with trialkyl phosphite was reported.3 However, the applicable precursor polymer is limited to P3HT. Furthermore, the substitution degree was quite low (0.25), indicating that it is necessary to be improved for establishment.Here, to expand applicable precursor polymers and improve the substitution degree, anodic phosphonylation of thiophene–fluorene alternating copolymers (P(Fl-Th)) was conducted (Figure 1), and then we obtained the phosphonylated conjugated polymer (P(Fl-Th-phos(Et)) (substitution degree: 0.26). The obtained polymer showed that phosphonate was introduced selectively into electron-rich thiophene rings. However, the substitution degree was still low. When a 2,6-lutidine was added to the reaction solution, the substitution degree was increased up to 0.83. Furthermore, the substitution degree could be controlled by tuning the amount of charge passed, and the optoelectronic properties of P(Fl-Th-Phos(Et)) were gradually changed through control of the substitution degree. In addition, it was found that various trialkyl phosphite were available in anodic phosphonylation.To functionalize the fluorene units, we carried out anodic phosphonylation of P(Fl-EDOT) which was di-substituted at thiophene moieties, and then the degree of phosphonylation reached 0.75 under the constant-current condition. On the other hand, when we performed constant-potential anodic phosphonylation of P(Fl-EDOT), the substitution degree was improved up to 0.98, indicating that the use of constant-potential electrolysis enabled quantitative anodic phosphonylation.These results demonstrate that anodic phosphonylation can be applied to versatile π-conjugated polymers and that the position of phosphonate introduction can be controlled through the design of appropriate precursor polymers. In addition, due to two alkyl chains, the phosphonate group could enable further modification such as side-chain engineering of conjugated polymers.References G. Zhou, G. Qian, L. Ma, Y. Cheng, Z. Xie, L. Wang, X. Jing, F. Wang, Macromolecules, 2005, 38, 5416–5424.J. Hopkins, K. Fidanovski, L. Travaglini, D. Ta, J. Hook, P. Wagner, K. Wagner, A. Lauto, C. Cazorla, D. Officer, D. Mawad, Chem. Mater., 2022, 34, 140–151.K. Taniguchi, T. Kurioka, N. Shida, I. Tomita, S. Inagi, Polym. J., 2022, 54, 1171–1178.T. Amaya, I. Kurata, Y. Inada, T. Hatai, T. Hirao, RSC Adv., 2017, 7, 39306–39313.T. Kurioka, S. Inagi, Chem. Rec., 2021, 21, 2107–2119. Figure 1

An Insight into the Mechanism of Alkyl Side-Chain Engineering of BTCN on Its Photovoltaic Properties─A Theoretical Study

An Insight into the Mechanism of Alkyl Side-Chain Engineering of BTCN on Its Photovoltaic Properties─A Theoretical Study

Side-chain-engineered fluorescent dyes for 3D and long-term dynamic tracking of the plasma membrane in living cells

The plasma membrane involves in many important biological events such as cell fusion and programmed cell death, but most of current plasma membrane probes cannot meet the requirement of long-term specific anchoring to the plasma membrane. Herein, we propose a molecular side-chain engineering strategy to modulate the long-term imaging performance of fluorescent dyes to the plasma membrane by regulating the cell permeability and anchoring ability. A series of FMR dyes with different lengths of side chains were designed and synthesized, and their transmembrane behaviours and staining performance were evaluated in living HeLa cells. We found that short-chain and medium-chain FMR dyes have excellent cell permeability without the labeling ability to the plasma membrane while the long-chain FMR dyes specifically stain the plasma membrane and can be firmly anchored to the plasma membrane for a long period of time. These long-chain FMR dyes have high stain specificality to the plasma membrane, and C10-FMR can be anchored to the plasma membrane of living cells for 2 h, which enables it to continuously monitor dynamic changes of the plasma membrane. The three-dimensional precision imaging of various cells was achieved using C10-FMR, which provides an opportunity to obtain complete information on the three-dimensional spatial morphology of the plasma membrane. The PEG-induced cell fusion of chicken red blood cells and H2O2-induced apoptosis of HeLa cells were monitored by real-time tracking of dynamic changes of the plasma membrane during these processes, which provide solid examples to prove the usefulness of these fluorescent dyes as long-term imaging tools. This work validates the hypothesis that cell permeability of membrane dyes can be readily regulated by tuning the side chains, and provides the effective design strategy of fluorescent dyes for 3D and long-term dynamic tracking of the plasma membrane of diverse animal cells.

Trifluorovinyl-ether (TFVE) substituted side-chain polynorbornene for preparing crosslinked polymer with high performance

Characteristics and properties of polynorbornene can be regulated through side-chain engineering. In this contribution, a linear polynorbornene (PNI-TFVE) containing trifluorovinyl-ether (TFVE) side groups was synthesized via ring-opening metathesis polymerization. This linear polynorbornene was soluble in common organic solvents and showed good film-forming ability. Upon thermal post-polymerization, this linear PNI-TFVE can be easily transformed into crosslinked polynorbornene (PNI-PFCB) with perfluorocyclobutyl linkers. The resulted PNI-PFCB exhibited outstanding thermal stability with ultra-high glass transition temperature above 350 °C and a 5 % weight loss temperature of 479 °C. Due to the high crosslinking density and high fluorine content of PFCB, crosslinked PNI-PFCB also exhibited low thermal expansion of 73 ppm °C−1, as well as favourable storage modulus and hydrophobicity.

Inner/Outer Side Chain Engineering of Non-Fullerene Acceptors for Efficient Large-Area Organic Solar Modules Based on Non-Halogenated Solution Processing in Air.

Achieving efficient and large-area organic solar modules via non-halogenated solution processing is vital for the commercialization yet challenging. The primary hurdle is the conservation of the ideal film-formation kinetics and bulk-heterojunction (BHJ) morphology of large-area organic solar cells (OSCs). A cutting-edge non-fullerene acceptor (NFA), Y6, shows efficient power conversion efficiencies (PCEs) when processed with toxic halogenated solvents, but exhibits poor solubility in non-halogenated solvents, resulting in suboptimal morphology. Therefore, in this study, the impact of modifying the inner and outer side-chains of Y6 on OSC performance is investigated. The study reveals that blending a polymer donor, PM6, with one of the modified NFAs, namely N-HD, achieved an impressive PCE of 18.3% on a small-area OSC. This modified NFA displays improved solubility in o-xylene at room temperature, which facilitated the formation of a favorable BHJ morphology. A large-area (55 cm2) sub-module delivered an impressive PCE of 12.2% based on N-HD using o-xylene under ambient conditions. These findings underscore the significant impact of the modified Y6 derivatives on structural arrangements and film processing over a large-area module at room temperature. Consequently, these results are poised to deepen the comprehension of the scaling challenges encountered in OSCs and may contribute to their commercialization.

Air processed, high open‐circuit voltage indoor organic photovoltaic cells based on side chain modified N‐annulated perylene diimides

AbstractTo achieve high‐performance indoor organic photovoltaics (OPVs), it is important to match the photoactive layer optical absorption with the light‐source emission. This can be accomplished by developing organic photoactive materials that can efficiently absorb visible light and thus minimize energy losses. While indoor OPVs have achieved efficiencies above 33% under low light intensities, the power output is limited by low open circuit voltages (VOC), often well below 1 V. In this study, we present a series of visible‐light absorbing (energy gap >1.90 eV) non‐fullerene acceptors (NFAs) based on perylene diimide dimers, which have been systematically modified with side chains of varying polarity and steric bulk (trimethyl benzyl, ethyl adamantane, trialkoxyl phenyl, and oligo ethylene glycol). Our results show that the incorporation of sterically bulky side chains such as ethyl adamantane and trimethyl benzyl, blended with the common widegap polymer PTQ10, provides photoactive layers with absorption greater than 2.0 eV, and consequently, VOCs higher than 1.2 V are achieved under AM 1.5 G illumination. Importantly, we found that the NFA with ethyl adamantane based side chains (tPDI2N‐ethyl adamantane, compound 4) exhibited the best performance, with minimized energy loss. As a result, devices using PTQ10:tPDI2N‐ethyl adamantane photoactive layers demonstrated excellent indoor efficiencies of over 16% and 18 μW cm−2 power output under a 2700 K LED lamp at 300 lux, and showed better repeatability compared to other systems. The PTQ10:tPDI2N‐ethyl adamantane based devices maintained a high VOC (>1.0 V) across a wide range of indoor lighting conditions, including 2700 K and 6500 K LED lamps. Overall, this work provides a sidechain engineering method to create NFAs for efficient indoor OPV devices.

Double-bridged N–B←N bipyridyl-based airfoil-shaped small molecule dyes: π-bridge regulation on photovoltaic performance

The double-bridged N–B←N bipyridine unit (BNBP) with boron-nitrogen covalent bond and coordination bond can reduce the electronic energy level of the π-conjugated system, resulting in a reduction of band gap and a red shift in the absorption spectrum. Embedding the BNBP building block into organic optoelectronic materials provides a novel possibility in molecule design. In this paper, under the guidance of density functional theory (DFT) calculations, a series of 3D “airfoil-shaped” small molecule donors (SMDs) have been designed and successfully synthesized through Sonogashira, Suzuki and Stille coupling reactions. BNBP is adopted as the central electron-withdrawing unit and strong electron-rich triphenylamine (TPA) as the terminal group. The novel “airfoil-shaped” structure plays a supporting role in reducing the carrier recombination in the active layer. It reveals that molecular design engineering can achieve the expected results by the following steps: Firstly, the introduction of electron-rich alkoxy groups into the end of TPA through side chain engineering helps to improve the solubility and film-forming properties of the materials. Then, the π-bridge regulation not only extends the conjugate structure, but also plays a crucial role in the regulation of photovoltaic properties. It is worth noting that the compound BNBP(3TTPA)2 was synthesized by introducing thiophene oligomer into BNBP-based SMDs for the first time. Finally, the compound BNBP(EDPPTPA)2 was constructed by combining BNBP with DPP dye unit. Its narrow band gap is only 1.36 eV, which is one of the narrowest band gaps in small molecular organic-boron materials. In particular, compared with the starting compound BNBP(ETPA)2, the synergistic effects of DPP and BNBP broaden the edge absorption wavelength to 814 nm, resulting in a red shift of 170 nm. The power conversion efficiency (PCE) of 4.48 % is obtained in BNBP(EDPPTPA)2-based bulk heterojunction (BHJ) organic solar cells (OSCs), which is more than twice that of reference compound BNBP(ETPA)2. This work provides important references for the future development of 3D BNBP-based organic-boron SMDs and the structural regulation of materials through molecular engineering.

Side-chain engineering for regulating structure and properties of a novel visible-light-driven perylene diimide-based supramolecular photocatalyst

Systematic and in-depth explorations of the effects of side-chain modulation on the molecular assembly, optoelectronic properties, and photocatalytic properties of supramolecular systems, as well as the kinetics of charge separation and migration in these systems, are rare. In this study, a novel supramolecular photocatalyst with an alkoxy side chain (S-EPDI) was successfully developed through subtle design of the short and linear alkoxyl side chains, affording a phenol degradation efficiency approximately four times that of the counterpart with an alkyl side chain (S-APDI). Notably, combined density functional theory (DFT) calculations, absorption spectroscopy, and other characterizations revealed that the perylene diimide (PDI) molecular units, through π-π stacking, formed a unique rotationally offset stacked supramolecular structure, exhibiting a significant dipole moment. This gave rise to the formation of a larger inherent electric field within S-EPDI compared to S-APDI. Moreover, the study quantitatively demonstrated that a stronger inherent electric field and lower rate of surface charge recombination facilitate efficient separation of the photogenerated carriers. Therefore, the side-chain molecular engineering method employed in this study offers an effective approach for modulating the kinetics of charge migration.

A Theoretical Investigation for Exploring the Potential Performance of Non-Fullerene Organic Solar Cells Through Side-Chain Engineering Having Diphenylamino Groups to Enhance Photovoltaic Properties.

The development of ecofriendly fabrication phenomenon is essential requirement for commercialization of non-fullerene acceptors. Recently, end-capped modeling is employed for computational design of five non-fullerene acceptors to elevate various photovoltaic properties. All new molecules are formulated by altering the peripheral acceptors of CH3-2F and DFT methodology is employed to explore the opto-electronic, morphological and charge transfer analysis. From the computational investigation, all reported molecules manifested red shifted absorption with remarkable reduced band gap. Among investigated molecules, FA1-FA3 evinced effectively decreased value of band gaps and designed molecules have low excitation energy justifying proficient charge transference. The lower values of binding energy of FA1 and FA2 suggest their facile exciton dissociation leading to improved charge mobility. By blending with J61 donor, FA4 have sufficiently enhanced value of VOC (1.72eV) and fill factor (0.9228). Energy loss of the model (R) is 0.57eV and statistical calculation demonstrate that all our modified molecules except FA3 has profoundly reduced energy loss compelling in its pivotal utilization. From accessible supportive outcomes of recent investigation, it is recommended that our modified chromophore exhibit remarkable noteworthy applications in solar cells for forthcoming innovations.

Accomplishing High-Performance Organic Solar Sub-Modules (≈55 cm2) with >16% Efficiency by Controlling the Aggregation of an Engineered Non-Fullerene Acceptor.

The fabrication of environmentally benign, solvent-processed, efficient, organic photovoltaic sub-modules remains challenging due to the rapid aggregation of the current high performance non-fullerene acceptors (NFAs). In this regard, design of new NFAs capable of achieving optimal aggregation in large-area organic photovoltaic modules has not been realized. Here, an NFA named BTA-HD-Rh is synthesized with longer (hexyl-decyl) side chains that exhibit good solubility and optimal aggregation. Interestingly, integrating a minute amount of new NFA (BTA-HD-Rh) into the PM6:L8-BO system enables the improved solubility in halogen-free solvents (o-xylene:carbon disulfide (O-XY:CS2)) with controlled aggregation is found. Then solar sub-modules are fabricated at ambient condition (temperature at 25±3 °C and humidity: 30-45%). Ultimately, the champion 55 cm2 sub-modules achieve exciting efficiency of >16% in O-XY:CS2 solvents, which is the highest PCE reported for sub-modules. Notably, the highest efficiency of BTA-HD-Rh doped PM6:L8-BO is very well correlated with high miscibility with low Flory-Huggins parameter (0.372), well-defined nanoscale morphology, and high charge transport. This study demonstrates that a careful choice of side chain engineering for an NFA offers fascinating features that control the overall aggregation of active layer, which results in superior sub-module performance with environmental-friendly solvents.

Precisely Controlling Polymer Acceptors with Weak Intramolecular Charge Transfer Effect and Superior Coplanarity for Efficient Indoor All-Polymer Solar Cells with over 27% Efficiency.

Indoor photovoltaics (IPVs) are garnering increasing attention from both the academic and industrial communities due to the pressing demand of the ecosystem of Internet-of-Things. All-polymer solar cells (all-PSCs), emerging as a sub-type of organic photovoltaics, with the merits of great film-forming properties, remarkable morphological and light stability, hold great promise to simultaneously achieve high efficiency and long-term operation in IPV's application. However, the dearth of polymer acceptors with medium-bandgap has impeded the rapid development of indoor all-PSCs. Herein, a highly efficient medium-bandgap polymer acceptor (PYFO-V) is reported through the synergistic effects of side chain engineering and linkage modulation and applied for indoor all-PSCs operation. As a result, the PM6:PYFO-V-based indoor all-PSC yields the highest efficiency of 27.1% under LED light condition, marking the highest value for reported binary indoor all-PSCs to date. More importantly, the blade-coated devices using non-halogenated solvent (o-xylene) maintain an efficiency of over 23%, demonstrating the potential for industry-scale fabrication. This work not only highlights the importance of fine-tuning intramolecular charge transfer effect and intrachain coplanarity in developing high-performance medium-bandgap polymer acceptors but also provides a highly efficient strategy for indoor all-PSC application.

Designing efficient materials for high-performance of non-fullerene organic solar cells through side-chain engineering on DBT-4F derivatives by non-fused-ring electron acceptors.

For the advancement in fields of organic and perovskite solar cells, various techniques of structural alterations are being employed on previously reported chromophores. In this study, the end-capped engineering is carried out on DBT-4F (R) by modifying terminal acceptors to improve optoelectronic and photovoltaic attributes. Seven molecules (AD1-AD7) are modeled using different push-pull acceptors. DFT/B3LYP/6-31G along with its time-dependent approach (TD-DFT) are on a payroll to investigate ground state geometries, absorption maxima (λmax), energy gap (Eg), excitation energy (Ex), internal reorganization energy, light harvesting efficiency (LHE), dielectric constant, open circuit voltage (VOC), fill factor (FF), etc. of OSCs. AD1 displayed the lowest band gap (1.76eV), highest λmax (876nm), lowest Ex (1.41eV), and lowest binding energy (0.21eV). Among various calculated parameters, all of the sketched molecules demonstrated greater dielectric constant when compared to R. The highest dielectric constant was exhibited by AD3 (56.26). AD5 exhibited maximum LHE (0.9980). Lower reorganization energies demonstrated improved charge mobility. AD5 and AD7 (1.63 and 1.68eV) have higher values of VOC than R (1.51eV). All novel molecules having outperforming attributes will be better candidates to enhance the efficacy of OSCs for future use. Precisely, a DFT and TD-DFT analysis on all of the proposed organic molecules were conducted, using the functional MPW1PW91 at 6-31G (d,p) basis set to examine their optoelectronic aspects, additionally the solvent-state computations were studied with a TD-SCF simulation. For all these simulations, Guassian 09 and GuassView 5.0 were employed. Moreover, the Origin 6.0, Multiwfn 3.8, and PyMOlyze 1.1 software were utilized for the visual depiction of the graphs of absorption, TDM, and DOS, respectively of the studied molecules. A number of crucial aspects such as FMOs, bandgaps, light-harvesting efficiency, electrostatic potential, dipole moment, ionization potential, open-circuit voltage, fill factor, binding energy, interaction coefficient, chemical hardness-softness, and electrophilicity index were also investigated for the studied molecules.