Acceptor Molecules Research Articles

Crystals of 4,7-Di-2-thienyl-2,1,3-benzothiadiazole and Its Derivative with Terminal Trimethylsilyl Substituents: Synthesis, Growth, Structure, and Optical-Fluorescent Properties

Among short donor–acceptor molecules with a central benzothiadiazole fragment, 4,7-di-2-thienyl-2,1,3-benzothiadiazole (T-BTD) is one of the most well-known compounds, valued for its photophysical and semiconductor properties. We have synthesized a derivative of 4,7-di-2-thienyl-2,1,3-benzothiadiazole with trimethylsilyl end-substituents, 4,7-bis(5-(trimethylsilyl)thiophen-2-yl)benzothiadiazole (TMS-T-BTD). The phase transition parameters and thermal stability of T-BTD and TMS-T-BTD were investigated using DSC and TGA methods. The presence of the trimethylsilyl end-groups in TMS-T-BTD significantly enhances solubility, increases the melting temperature, and improves the resistance of TMS-T-BTD to evaporation in the liquid state. Single crystals of T-BTD and TMS-T-BTD were grown from solutions, with the largest sizes being 7 × 2 × 0.5 mm3 and 8 × 1 × 0.45 mm3, respectively. Using single-crystal X-ray diffraction at 293 K, the crystal structure of T-BTD was refined in the rhombic system (sp.gr. Pcab, Z = 8), while for TMS-T-BTD, it was determined for the first time in the monoclinic system (sp.gr. P21/c, Z = 4). The relationship between observed growth anisotropy and molecular packing in the crystals was analyzed. The results of investigations into the spectral-fluorescent properties of solutions in hexane and THF are presented. The solvatochromic effect was studied in a series of solvents, including hexane, THF, dichloromethane, and acetonitrile. The photostability of the compounds in hexane solutions was examined. It was found that the quantum yield of photodestruction for T-BTD is 13 times higher than that of TMS-T-BTD. The fluorescent properties of T-BTD and TMS-T-BTD crystals were investigated.

An efficient end-capped engineering of pyrrole-based acceptor molecules for high-performance organic solar cells.

Various innovative molecules have been designed and explored for use in organic photovoltaics. In this study, we devised novel molecules (KZ1-KZ7) specifically for organic solar cells (OSCs). The newly formulated acceptor compounds possess a lower bandgap (Eg = 1.85-2.02), along with bathochromic shift (λmax = 713-788 nm) compared to the reference (Eg = 2.04 eV and λmax = 774 nm). Moreover, the FMO results identified the distinct charge transfer from HOMO to LUMO, which was strongly corroborated by the TDM maps. Similarly, the new designed molecules show less excitation energy (Ex = 1.31-1.54(gas)) than reference (Ex = 1.72). Likewise, all designed molecules (KZ1-KZ7) have demonstrated an analogous open circuit voltage (Voc) with the donor polymer PTB7-Th. All seven designed molecules (KZ1-KZ7) exhibited more fill factor ranging from 97.08 to 97.29 than reference 95.25 and PCE of between 8 and 20% at short circuit current densities of 9, 12, and 15 mA cm-2. Overall, the findings support that designed molecules can be potential molecules for future practical applications. Geometric calculations were conducted with Gaussian 09W software, and the findings were visualized using Gauss View software. DFT and TD-DFT were employed to evaluate various parameters for R and designed molecules (KZ1-KZ7). Firstly, four functionals including B3LYP, CAM-B3LYP, MPW1PW91, and ωB97XD with 6-31G(d,p) DFT level were applied to R to decide the best level for results. After appropriate analysis, the MPW1PW91/6-31G(d,p) was selected for further examination by comparing the experimental and DFT-based absorption graphs of R. External and internal reorganization energy are the two main factors contributing to reorganization energy. External energy refers to changes in external environment, while internal energy deals with information related to internal geometrical symmetry or the internal environment. The effect of outside factors or external reorganizational energy is omitted because it creates too little change.

Effect of 1‐Fluoro‐2‐iodobenzene Solvent Additive on the Crystallization of Donors and Acceptors, and Ultrafast Carrier Dynamics in Polymer Solar Cells

AbstractControlled sequential crystallization of donors and acceptors is a critical factor for achieving enhanced phase separation and efficient charge transfer performance in polymer solar cells (PSCs). In this study, a comprehensive investigation of a structurally simple solvent additive, 1‐fluoro‐2‐iodobenzene (OFIB) is conducted, which efficiently controls the morphology of the active layer, resulting in fibrous assembly and significantly enhancing the power conversion efficiency from 16.34% to 18.38% based on the PM6:L8‐BO system. Density functional theory, molecular dynamics simulations, and grazing incidence small‐ and wide‐angle X‐ray scattering techniques reveal that the addition of OFIB to the processed blend aligns the orientation of the acceptor molecules, thereby enhancing the overall π–π stacking in the active layer. OFIB establishes nearly equal‐strength π–π interactions with the conjugated frameworks of both the donor and acceptor materials, benefiting from the multiple electron conjugation between its iodine atom and the conjugated framework in the active layer. Femtosecond‐timescale photophysical studies demonstrate that the OFIB‐optimized active layer shows reduced exciton losses at the donor–acceptor interface. This study offers a new perspective on the mechanism underlying the function of solvent additives and presents a comprehensive research methodology that will guide the development of next‐generation non‐fullerene acceptors for efficient PSCs.

Molecular Engineering of Indacenodifuran-Based Non-Fullerene Acceptors for Efficient Organic Solar Cells

Energy-efficient non-fullerene acceptors attracting great attention for developing efficient organic solar cells (OSCs). Though many materials have been developed to improve the optical and optoelectronic characteristics of OSCs, the search continues to strengthen this field further. Therefore, herein, we designed an environmentally-benign indacenodifuran-based electron acceptor molecules (MH1-MH8) by substituting various end-capped electron-withdrawing moieties (COOH, SO3H, NO2, and CN). The open-circuit-voltages, binding energy, transition energy, transition density analysis, and electron and hole reorganization energies for MH1–MH8 were computed for these materials. These designed materials MH1-MH8 have better photovoltaic, photophysical, and electrical properties than R due to their narrower bandgap (1.91 eV), higher absorption (725.56 and 785.46 nm in gas and chloroform), low-mobility of electrons (0.0033) and holes (0.0019), and lower binding energy of 0.20 eV). We have also performed a charge transfer study by establishing a donor:acceptor complex MH2:PTB7-TH, showing a great charge transformation at the donor:acceptor interface. Thus, the designed compounds (MH1-MH8) with excellent optoelectronic properties could be considered a promising and environmentally friendly option to create compelling organic solar cells.

Manipulating Vertical Phase Separation Enables Pseudoplanar Heterojunction Organic Solar Cells Over 19% Efficiency via Ternary Polymerization.

Controlling vertical phase separation of the active layer to enable efficient exciton dissociation and charge carrier transport is crucial to boost power conversion efficiencies (PCEs) of pseudoplanar heterojunction (PPHJ) organic solar cells (OSCs). However, how to optimize the vertical phase separation of PPHJ OSCs via molecule design is rarely reported yet. Herein, ternary polymerization strategy is employed to develop a series of polymer donors, DL1-DL4, and regulate their solubility, molecular aggregation, molecular orientation, and miscibility, thus efficiently manipulating vertical phase separation in PPHJ OSCs. Among them, DL1 not only has enhanced solubility, inhibited molecular aggregation and partial edge-on orientation to facilitate acceptor molecules, Y6, to permeate into polymer layer and increase donor/acceptor interfaces, but also sustains high crystallinity and appropriate miscibility with Y6 to acquire ordered molecular packing, thus achieving optimized vertical phase separation to well juggle exciton dissociation and charge transport in PPHJ devices. Therefore, DL1/Y6 based PPHJ OSCs gain the best exciton dissociation probability, highest charge carrier mobilities and weakest charge recombination, and thus afford an impressive PCE of 19.10%, which is the record value for terpolymer donors. It demonstrates that ternary polymerization is an efficient method to optimize vertical phase separation in PPHJ OSCs for high PCEs.

Organic Cocrystal Design to Promote Absorption and Triplet Excitons Formation for Sensitive Scintillator

AbstractOrganic materials show good mechanical flexibility, easy processing, and large‐area manufacturing, while weak X‐ray absorption and low sensitivity for X‐ray scintillator media. As seen originally, this is a synergistic result of the lack of heavy elements in the molecule that can effectively truncate X‐rays and the massive dissipation of triplet excitons produced by molecular ionization. Herein, cocrystal with phosphorescence enhancement is found to be brilliant in addressing the shortcomings of organic scintillators. The results show that heavy atoms can be easily introduce into the donor unit of organic cocrystal to satisfy the X‐ray absorption and effectively activate the triplet excitons via promoting intersystem crossing (ISC). Moreover, the rational structural design of the acceptor molecule can achieve coupling with the donor for inhibiting the non‐radiative loss of the triplet exciton. Finally, the preferred PNPA (4,4′‐Dibromobiphenyl and N‐phenylnaphthalen‐2‐amine) cocrystals achieve record X‐ray‐induce exciton utilization and emit bright phosphorescent light. Meanwhile, the related device shows durable radiation stability, spatial resolution (>11 lp mm−1), low detection limit (<0.6 µGyair s−1), and effective dynamic imaging application. Hence, it is believed the organic cocrystal‐designed principle can provide guidance to develop advanced sensitive X‐ray scintillators in the future.

Unraveling pnicogen bonding cooperativity: Insights from molecular electrostatic potential analysis.

A theoretical investigation on the cooperativity of a series of binary, ternary, and quaternary complexes interconnected by pnicogen bonds has been conducted using calculations at the M06-2X/aug-cc-pVTZ level of density functional theory. By measuring changes in the molecular electrostatic potential (MESP) at the nucleus of interacting atoms in all of the complexes, it is possible to quantify the substantial reorganization of the electron density triggered by the formation of pnicogen bonds. The positive change in MESP, indicating a loss of electron density from the donor molecule in a dimer, facilitates the acceptance of electron density from a third molecule, resulting in the formation of a ternary complex with a stronger pnicogen bond compared to the one present in the binary complex. Similarly, the acceptor molecule in a dimer with a negative change in MESP showed an enhanced tendency to donate electron density to an electron-deficient third molecule. The MESP analysis provided valuable insights into the donor/acceptor characteristics of pnicogen bonds within the quaternary complexes. The proposed MESP hypotheses are consistent with the positive cooperativity observed in the pnicogen-bonded clusters. To quantify the changes in MESP, both at the donor atom (ΔVdonor ) and the acceptor atom (ΔVacceptor ), for all pnicogen bonds in the cluster, the total change in MESP (ΔΔVn ) was measured as ΔΔVn  = ∑(ΔVdonor )-∑(ΔVacceptor ). Remarkably, ΔΔVn exhibited a strong linear relationship with the sum of the bond energies of the pnicogen bonds in the cluster. This establishes the MESP analysis as a robust approach for understanding the strength and cooperative behavior of pnicogen-bonded clusters. Additionally, the MESP features provided clear evidence of pnicogen bond formation, further supporting the reliability of this approach.

Approach toward Low Energy Loss in Symmetrical Nonfullerene Acceptor Molecules Inspired by Insertion of Different π-Spacers for Developing Efficient Organic Solar Cells.

In this quantum approach, by adding bridge/π-spacer fragments between the donor and acceptor parts of a newly constructed DF-PCIC (A-D-A type) molecule, it is the aim to improve the photovoltaic characteristics of organic solar cells (OSCs). After π-spacer insertion into the reference molecule (DF-R), six new molecules (DF-M1 to DF-M6) were designed. The optoelectronic attributes of newly inspected molecules were theoretically calculated using MPW1PW91/6-31G(d,p) level of theory. All newly proposed molecules possessed a lower band gap (Eg), a higher value of absorption, lower reorganization energy, greater dipole moment, and lower energies of excitations than the DF-R molecule. The frontier molecular orbital study proclaimed that the DF-M1 molecule has the lowest band gap of 1.62 eV in comparison to the 2.41 eV value of DF-R. Absorption properties represented that DF-M1 and DF-M2 molecules show the highest absorption values of up to 1006 and 1004 nm, respectively, in the near-infrared region. Regarding the reorganization energy, DF-M2 has the lowest value of λe (0.0683896 eV) and the lowest value of λh (0.1566471 eV). DF-M2 and DF-M5 manifested greater dipole moments with the values of 5.514665 and 7.143434 D, respectively. The open circuit voltage (VOC) of all the acceptors was calculated with J61, a donor complex. DF-M4 and DF-M6 molecules showed higher values of VOC and fill factor than the DF-R molecule. Based on the given results, it was supposed that all the newly presented molecules might prove themselves to be better than the reference and thus might be of great interest to experimentalists. Thus, they are suggested to be used to develop proficient OSC devices with improved photovoltaic prospects in the near future.

Observation of aligned dipoles and angular chromism of exciplexes in organic molecular heterostructures

The dipole characteristics of Frenkel excitons and charge-transfer excitons between donor and acceptor molecules in organic heterostructures such as exciplexes are important in organic photonics and optoelectronics. For the bilayer of the organic donor 4,4′,4′′-tris[(3-methylphenyl)phenylamino]triphenylamine and acceptor 2,4,6-tris(biphenyl-3-yl)-1,3,5-triazine molecules, the exciplexes form aligned dipoles perpendicular to the Frenkel excitons, as observed in back focal plane photoluminescence images. The angular chromism of exciplexes observed in the 100 meV range indicates possible delocalization and angle-sensing photonic applications. The blue shift of the peak position and increase in the linewidth of photoluminescene spectra with increasing excitation power are caused by the repulsive aligned exciplex dipole moments with a long lifetime (4.65 μs). Electroluminescence spectra of the exciplex from organic light-emitting diodes using the bilayer are blue-shifted with increasing bias, suggesting unidirectional alignment of the exciplex dipole moments. The observation of exciplex dipole moment alignments across molecular interfaces can facilitate the controlled coupling of exciton species and increase efficiency of organic light-emitting diodes.

Ultrafast spectroscopy of size-dependent hole-transfer-mediated triplet energy transfer in a quantum dot-molecule complex

Triplet energy transfer (TET) from quantum dots to molecules has attracted tremendous attention in the last decade because the long-lived triplet state of molecules benefits various photophysical or photochemical processes and quantum dots (QDs), as the triplet sensitizer, provide prominent optical absorption and emission tunable through flexible size and composition control. Although several dynamical models for some certain QD-molecule complexes have been proposed, the TET mechanism in such complexes is still incomplete due to intricate energy level configuration. More specifics of TET being revealed is advantageous for its further applications. In this paper, a series of QD-molecule complexes composed of CdSe QDs with different diameters and 5-tetracene carboxylic acid (TCA) are assembled. The precise size control of CdSe QDs is realized by combining the transmission electron microscope and steady-state spectra. All CdSe-TCA complexes display expected Type-II like band alignment, which favors the hole-transfer-mediated TET confirmed by a series of spectral measurements. On the surface, ultrafast spectroscopy shows the charge dynamics, specifically the stepwise hole and electron transfer during TET, slow down with increasing size of the CdSe QDs. However, comprehensive analysis of the experimental results reveals that the hole transfer and the following electron transfer essentially depend on the energy level difference and wavefunction overlap between the QD donor and molecule acceptor rather than simply the QD size. The conclusions can facilitate our understanding of the TET mechanism in a QD-molecule complex and help optimize the performance of TET-related photoelectronic devices designed based on size control.

A computational insight into enhancement of photovoltaic properties of non-fullerene acceptors by end-group modulations in the structural framework of INPIC molecule

Improving the open circuit voltage is a major challenge for enhancing the overall efficiency of organic solar cells. Current work has concentrated on improving open-circuit voltage by designing new molecular frameworks from an INPIC molecule having a conjugated fused core. We modulated the structure by changing the terminal groups of the reference molecule (INPIC) with seven strong electron-withdrawing units. We investigated various optoelectronic attributes, charge transfer, and photovoltaic and geometrical parameters by compiling the B3LYP/6-31G(d,p) functional of the DFT approach. The optical absorption for modulated molecules ranges from 748.51 nm to 845.96 nm while showing higher oscillation strength than INPIC. At the same time, their impressive charge transport is attributed to their smaller excitation and exciton binding energy, higher electron/hole mobility, narrower band gap, and a more than 99 % intramolecular charge transfer. The larger dipole moments help in the dense interaction of acceptors with employed donor J61 which, in turn, improves charge transfer at the donor-acceptor interface. One of the triumphs that are difficult to get in organic molecules is success in achieving a higher open circuit voltage (VOC). Our conceptualized molecular frameworks of acceptors are featured with a notable VOC improvement in the range of 1.84–2.05 eV. Thus, the results of the current investigation pave the root for architecting the acceptor molecules with impressive optoelectrical properties that may be capable of providing high photovoltaic output. Thus these acceptors can be utilized for the development of advanced organic solar cells in future.

High-Efficiency and Low-Energy-Loss Organic Solar Cells Enabled by Tuning the End Group Modification of the Terthiophene-Based Acceptor Molecules to Enhance Photovoltaic Properties.

In the current study, six nonfullerene small acceptor molecules were designed by end-group modification of terminal acceptors. Density functional theory calculations of all designed molecules were performed, and optoelectronic properties were computed by employing different functionals. Every constructed molecule has a significant bathochromic shift in the maximum absorption value (λmax) except AM6. AM1-AM4 molecules represented a narrow band gap (Eg) and low excitation energy values. The AM1-AM4 and AM6 molecules have higher electron mobility. Comparing AM2 to the reference molecule reveals that AM2 has higher hole mobilities. Compared to the reference molecule, all compounds have excellent light harvesting efficiency values compared to AM1 and AM2. The natural transition orbital investigation showed that AM5 and AM6 had significant electronic transitions. The open-circuit voltage (Voc) values of the computed molecules were calculated by combining the designed acceptor molecules with PTB7-Th. In light of the findings, it is concluded that the designed molecules can be further developed for organic solar cells (OSCs) with superior photovoltaic abilities.

Enhancing photovoltaic performance: Exploring quinoxaline donors in conjunction with Y6 and BTP-4Br small molecule acceptors via DFT calculations

Bulk heterojunction organic solar cells have helped increase power conversion efficiency and characterize and analyze possible factors influencing the improvement of solar-electrical energy conversion. Research in the last decades showed the link between the molecular electronic structure and the morphology of the photoactive layer with the photovoltaic process. Furthermore, both distinctive features are linked to halogenation in the acceptor and donor molecules that constitute the photoactive layer. It is worth mentioning that more attention has been paid to acceptor molecules compared to donors, particularly from the point of view of quantum mechanical calculations. Due to this, in the present work, a systematic study is carried out through density functional theory on the variation of halogenation in donors PBQ5 and PBQ6, which demonstrated outstanding efficiency when introduced into the photoactive layer of an organic solar cell complexed with the Y6 acceptor. Firstly, the correspondence of the electronic structure of both donors with higher efficiency of PBQ6, compared to PBQ5, stands out. An example is the lower position of the HOMO frontier molecular orbital of PBQ6, which predicts a higher open-circuit voltage, just as the experiment shows. Likewise, a smaller gap between the HOMO and LUMO orbitals in PBQ6 proposes an increase in the short-circuit current. The proposal of halogen exchange yields results of significant interest. Theoretical approximations of crucial parameters such as Voc, Jsc, and FF reveal promising avenues for enhancing power conversion efficiency through strategic adjustments in halogenation. In closing, despite the multitude of factors at play in the photoconversion of an organic solar cell—a complexity that poses challenges within the realm of computational theoretical studies—we consider that the uncovered findings can provide valuable insights into the determinants to be manipulated in terms of electronic structure, thereby paving the way for achieving heightened efficiency in photoconversion.

Machine learning study on organic solar cells and virtual screening of designed non-fullerene acceptors

Machine learning (ML) is effective to establish the complicated trilateral relationship among structures, properties, and photovoltaic performance, which is fundamental issue in developing novel materials for improving power conversion efficiency (PCE) of organic solar cells (OSCs). Herein, we constructed the database of 397 donor–acceptor pairs of OSCs with photovoltaic parameters and descriptor sets, which include donor–acceptor weight ratio within the active layer of the OSCs, root mean square of roughness, and 1024-bit Morgan molecular fingerprint for donor (Fp-D) and acceptor (Fp-A). The ML models random forest (RF), adaptive boosting (AdaBoost), extra trees regression, and gradient boosting regression trees were trained based on the descriptor set. The metrics determination coefficient (R2), Pearson correlation coefficient (r), root mean square error, and mean absolute error were selected to evaluate ML model performances. The results showed that the RF model exhibits the highest accuracy and stability for PCE prediction among these four ML models. Moreover, based on the decomposition of non-fullerene acceptors L8-BO, BTP-ec9, AQx-2, and IEICO, 20 acceptor molecules with symmetric A–D–A and A–π–D–π–A architectures were designed. The photovoltaic parameters of the designed acceptors were predicted using the trained RF model, and the virtual screening of designed acceptors was conducted based on the predicted PCE. The results indicate that six designed acceptors can reach the predicted PCE higher than 12% when P3HT was adopted as a donor. While PM6 was applied as a donor, five designed acceptors can achieve the predicted PCE higher than 16%.

Alkoxy substitution on simple non‐fused electron acceptors for tuning the photoelectric properties of organic solar cells

AbstractIn order to identify high‐performance non‐fused ring electron acceptors for bulk heterojunction (BHJ) solar cells, six structurally diverse molecules are designed and categorized into two series. The first series is anchored by R1 as the reference molecule, featured fixed BDT, IC‐2F end groups and modified π bridges. The second series is anchored by R2 as the reference molecule, incorporated a terminal IC‐2F and a central core modified with EDOT bridge. The electronic structure and photoelectric properties of all acceptor molecules were investigated using density functional theory (DFT) and time‐dependent density functional theory (TD‐DFT). Charge transfer matrix (CTM), Density of states (DOS) and Reorganization energy (RE) etc. were analyzed to provide fundamental knowledge on charge transport and electronic excitation. Among the studied molecules, W2 exhibited a smaller energy gap (1.74 eV) compared to the other molecules, effectively transferring its electron from HOMO to LUMO. At the same time, the W2 molecule has excellent Voc and FF. Furthermore, W2 displayed the largest λmax redshift compared to R1. Although W3 had a smaller value of λh, the comprehensive photovoltaic parameters of W2 were more excellent. The research results not only demonstrated the feasibility of introducing different alkoxy groups to alter the structure of the π bridge and central core is a feasible method for constructing high‐performance NFREAs, but also highlighted that BDT cores combined with EDOT bridges are among the most promising small molecule acceptors (SMAs) that could be considered as reasonable candidates for synthesis and incorporation into organic solar cells. The results of this study are expected to provide seminal ideas for the design of high‐performance non‐fullerene acceptors.

Enzymatic Glycosylation Strategies in the Production of Bioactive Compounds

Enzymatic glycosylation is a versatile and sustainable biotechnological approach that plays a pivotal role in the production of bioactive compounds. This process involves the enzymatic transfer of sugar moieties onto various acceptor molecules, such as small molecules, peptides, or proteins, resulting in the synthesis of glycosides. These glycosides often exhibit enhanced bioactivity, improved solubility, and enhanced stability, making them valuable in pharmaceuticals, nutraceuticals, and the food industry. This review explores the diverse enzymatic glycosylation strategies employed in the synthesis of bioactive compounds. It highlights the enzymatic catalysts involved, including glycosyltransferases, glycosidases, glycophosphorylases, and glycosynthases. It considers the advantages and disadvantages of these biocatalysts in the stereoselective and regioselective synthesis of different types of glycosylated molecules, phenolic and aliphatic alcohols, oligosaccharides, polysaccharides, glycoderivatives, glycopeptides, and glycoproteins with a clear focus on food and pharmaceutical chemistry. Furthermore, the review outlines various sources of sugar donors, activated glycosides, and sugar nucleotides, as well as the utilization of engineered enzymes and microorganisms for glycosylation reactions. The advantages of enzymatic glycosylation, including its high regioselectivity, stereoselectivity, and sustainability, are emphasized. Therefore, these approaches combining the use of different catalytic systems, the improvement of tools such as immobilization technology or chemical or genetic modification to improve the glycosylation process, could be useful tools in continuous biotechnological advancements.

Silane or Siloxane‐Side‐Chain Engineering of Photovoltaic Materials for Organic Solar Cells†

Comprehensive SummaryWith the tactful material design, skillful device engineering, and in‐depth understanding of morphology optimization, organic solar cells (OSCs) have achieved considerable success. Therefore, OSCs have reached high power conversion efficiencies (PCEs) exceeding 19%. Especially, continuously emerging new materials have been considered as one of the key factors to improve the PCEs of OSCs. Among molecular design strategies, side‐chain engineering is an easy and commonly‐used means which can optimize the solubility, alter intermolecular stacking arrangement, fine‐tune the open circuit voltage (VOC), thus ultimately improve the performance. As hybrid side chains, silane and siloxane side chains have considerable effects, not only in increasing the carrier mobility and tuning the energy level, but also in affecting the crystallinity and molecular orientation. In this review, the latest developments in photovoltaic materials based on silane and siloxane side chains are presented to illustrate the structure‐property relationships. The review comprehensively includes silane‐side based polymer/small molecule donors; siloxane‐side based polymer/small molecule donors, and polymer/small molecule acceptors. Then the similarities and differences between these two side chains are demonstrated. Finally, the possible applications and future prospects of silane and siloxane side chains are presented.

Energy transfer assisted plasmonic random laser emission from polymer optical fiber

Here, we analyzed the effect of a donor molecule (Rh6G) on the random laser emission of an acceptor molecule (Rh640 perchlorate) coated on the surface of a polymer optical fiber. Due to the energy transfer mechanism, the random lasing threshold of Rh640 perchlorate was found to be reduced in the presence of Rh6G. Also, the emission spectrum of Rh640 perchlorate was blue-shifted with the addition of Rh6G. Meanwhile, there is an enhancement in the lasing threshold of Rh6G in the presence of Rh640 perchlorate. The present study demonstrates that by properly adjusting the concentrations of both donor and acceptor molecules, we can obtain a dual-color random laser emission from polymer optical fiber.

Computational insights into deep eutectic solvent design: Modeling interactions and thermodynamic feasibility using choline chloride & glycerol

To address climate change and environmental concerns, the chemical process industries are increasingly adopting green technology and exploring eco-friendly waste management practices. Deep Eutectic Solvents (DES) have emerged as promising green solvents with diverse applications in the industries in separation processes, catalysis, drug design, and a lot more. However, the ideal way for modeling ionic interactions within the hydrogen-bond acceptor (HBA) during DES synthesis remains uncertain, and theoretical insight on the formation mechanism of energetically stable DESs from choline chloride (CHL) and urea (URE) is yet to be explored. In this study, we investigate different modeling approaches (no bond, generic bond, or single bond) for ionic interactions in hydrogen-bond acceptor (HBA) molecules during DES synthesis and the thermodynamic feasibility of forming an energetically stable DES using choline chloride (CHL) and urea (URE) through theoretical calculations (PM3, HF, and DFT). Our findings indicate that the choice of modeling approach does not significantly affect the outcomes across calculation levels. The H-X DES formation pathway emerges as the most viable route for CHL: GLC DES synthesis, offering strong binding energy and high exothermicity. This pathway provides a robust solution for synthesizing energetically stable DES with potential applications in various industries. Researchers can consider alternative calculation levels when DFT becomes cost-prohibitive to optimize computational costs. Our study contributes valuable insights into DES design and synthesis, promoting environmentally sustainable and cost-effective processes.

Intrinsic Photoconductivity Spectral Dependence as a Tool for Prediction of Open-Circuit Voltage in Organic Solar Cells

Organic materials are known for their variety of molecules. Methods to predict the parameters of organic photovoltaic (OPV) cells are required to avoid the time- and resource-consuming processes of manufacturing and testing OPVs. Usually, the open-circuit voltage (Uoc) is estimated as the difference between the ionization energy level of the electron donor molecule (Id) and the electron affinity level of the electron acceptor molecule (EAa). Various measurement methods are used to determine the energy level values of pure materials, which, when combined with energy level shifts due to the donor:acceptor interactions, make these estimations less precise. In this work, photoconductivity measurements were applied to the donor:acceptor films. Near threshold energy, the electron can be directly transferred from the donor to the acceptor molecule. The obtained charge transfer energy (ECT) shows the difference between Id and EAa in the film. This difference was compared to the Uoc value of an OPV made of the same donor:acceptor combination. We show that this approach provides less scattered results and a higher correlation coefficient compared to the Uoc estimation using energy level values.