Exploration of the synergistic effect of chrysene-based core and benzothiophene acceptors on photovoltaic properties of organic solar cells

To improve the efficacy of organic solar cells (OSCs), novel small acceptor molecules (CTD1-CTD7) were designed by modification at the terminal acceptors of reference compound CTR. The optoelectronic properties of the investigated compounds (CTD1-CTD7) were accomplished by employing density functional theory (DFT) in combination with time-dependent density functional theory (TD-DFT). The M06 functional along with a 6-311G(d,p) basis set was utilized for calculating various parameters such as: frontier molecular orbitals (FMO), absorption maxima (λmax), binding energy (Eb), transition density matrix (TDM), density of states (DOS), and open circuit voltage (Voc) of entitled chromophores. A red shift in the absorption spectra of all designed chromophores (CTD1-CTD7) was observed as compared to CTR, accompanied by low excitation energy. Particularly, CTD4 was characterized by the highest λmax value of 685.791 nm and the lowest transition energy value of 1.801 eV which might be ascribed to the robust electron-withdrawing end-capped acceptor group. The observed reduced binding energy (Eb) was linked to an elevated rate of exciton dissociation and substantial charge transfer from central core in HOMO towards terminal acceptors in LUMO. These results were further supported by the outcomes from TDM and DOS analyses. Among all entitled chromophores, CTD4 exhibited bathochromic shift (685.791 nm), minimum HOMO/LUMO band gap of 2.347 eV with greater CT. Thus, it can be concluded that by employing molecular engineering with efficient acceptor moieties, the efficiency of photovoltaic materials could be improved.

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 (1.72 eV) and fill factor (0.9228). Energy loss of the model (R) is 0.57 eV 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.

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

CONTEXT

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 (1.76 eV), highest λmax (876 nm), lowest Ex (1.41 eV), and lowest binding energy (0.21 eV). 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 1.68 eV) have higher values of VOC than R (1.51 eV). All novel molecules having outperforming attributes will be better candidates to enhance the efficacy of OSCs for future use.

METHODS

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.

Machine learning assisted designing of non-fullerene electron acceptors: A quest for lower exciton binding energy

The designing of acceptors materials for the organic solar cells is a hot topic. The normal experimental methods are tedious and expensive for large screening. Machine learning guided exploration is more suitable solution. Bagging regression, random forest regression, gradient boosting regression, and linear regression are trained to predict exciton binding energy. Breaking Retrosynthetically Interesting Chemical Substructures (BRICS) methodology has utilized for designing of new non-fullerene acceptors (NFAs). The predicted values were used to select the designed NFAs. On the selected NFAs, clustering and chemical similarity analyses are also performed. Chemical fingerprints are used for this purpose, and the synthetic accessibility score of the new NFAs is also investigated.30 NFAs have selected with low exciton binding energy values. This approach will allow for the rapid screening of NFAs for organic solar cells. Our proposed framework stands out as a valuable tool for strategically selecting the most effective NFAs for organic solar cells and offers a streamlined approach for material discovery.

End-capped engineering of Quinoxaline core-based non-fullerene acceptor materials with improved power conversion efficiency

Improving the light-harvesting efficiency and boosting open circuit voltage are crucial challenges for enhancing the efficiency of organic solar cells. This work introduces seven new molecules (SA1-SA7) to upgrade the optoelectronic and photovoltaic properties of Q-C-F molecule-based solar cells. All recently designed molecules have the same alkyl-substituted Quinoxaline core and CPDT donor but vary in the end-capped acceptor subunits. All the investigated molecules have revealed superior properties than the model (R) by having absorbance ranging from 681 nm to 782 nm in the gaseous medium while 726 nm-861 nm in chloroform solvent, with the lowest band gap ranging from 1.91 to 2.19 eV SA1 molecule demonstrated the highest λmax (861 nm) in chloroform solvent and the lowest band gap (1.91 eV). SA2 molecule has manifested highest dipole moment (4.5089 D), lower exciton binding energy in gaseous (0.33 eV) and chloroform solvent (0.47 eV), and lower charge mobility of hole (0.0077693) and electron (0.0042470). At the same time, SA7 showed the highest open circuit voltage (1.56 eV) and fill factor (0.9166) due to solid electron-pulling acceptor moieties. From these supportive outcomes, it is inferred that our computationally investigated molecules may be promising candidates to be used in advanced versions of OSCs in the upcoming period.

Molecular design of D-π-A-π-D small molecule donor materials with narrow energy gap for organic solar cells applications

CONTEXT

Developing novel materials present a great challenge to improve the photovoltaic performance of organic solar cells (OSCs). In this paper, we designed a series of the donor-π bridge-acceptor-π bridge-donor (D-π-A-π-D) structure molecules. These molecules consist of diketopyrrolopyrrole (DPP) moiety as core, 9-hexyl-carbazole moiety as terminal groups, and different planar electron-rich aromatic groups as π-bridges. The density functional theory (DFT) and time-dependent DFT (TD-DFT) computations showed that the frontier molecular orbital (FMO) energy levels, energy gaps, electron-driving forces (ΔEL-L), open-circuit voltage (Voc), fill factor (FF), reorganization energy (λ), exciton binding energy (Eb), and absorption spectra of the designed molecules can be effectively adjusted by the introduction of different π-bridges. The designed molecules have narrow energy gap and strong absorption spectra, which are beneficial for improving the photoelectric conversion efficiency of organic solar cells. In addition, the designed molecules possess large ΔEL-L, large Voc, and FF values and low Eb when the typical fullerene derivatives are used as acceptors. The FMO energy levels of the designed molecules can provide match well with the typical fullerene acceptors PC61BM, bisPC61BM, and PC71BM. Our results suggest that the designed molecules are expected to be promising donor materials for OSCs.

METHODS

All DFT and TD-DFT calculations were carried out using the Gaussian 09 code. The computational technique chosen was the hybrid functional B3LYP and the 6-31G(d,p) basis set. The benzene and chloroform solvent effects have been considered using the polarized continuum model (PCM) at the TD-DFT level. The simulated absorption spectra of designed molecules were plotted by using the GaussSum 1.0 program.

Anthracene-bridged sensitizers for environmentally compatible dye-sensitized solar cells: In silico modelling and prediction

Advancement in solar cells has gained the attention of researchers due to increasing demand and renewable energy sources. Modeling of electron absorbers and donors has been performed extensively for the development of efficient solar cells. In this regard, efforts are being made for designing effective units for the active layer of solar cells. In this study, CXC22 was utilized as a reference in which acetylenic anthracene acted as a π bridge and infrastructure was D-π-A. We theoretically designed four novel dye-sensitized solar cells JU1-JU4 by utilizing reference molecules to improve the photovoltaic and optoelectronic properties. All designed molecules differ from R by donor moiety modifications. Different approaches were done to R and all molecules to explore different analyses like binding energies, excitation energies, dipole moment, TDM (transition density matrix), PDOS (partial density of states), absorption maxima, and charge transfer analysis. For the evaluation of results, we used the DFT technique and the findings demonstrated that the JU3 molecule showed a better redshift absorption value (761 nm) as compared to all other molecules due to the presence of anthracene in the donor moiety which lengthens the conjugation. JU3 was proven to be the best candidate among all due to improved excitation energy (1.69), low energy band gap (1.93), higher λ_max value, and improved electron and hole energy values leading toward higher power conversion efficiency. All the other theoretically formed molecules exhibited comparable outcomes as compared to a reference. As a result, this work revealed the potential of organic dyes with anthracene bridges for indoor optoelectronic applications. These unique systems are effective contributors to the development of high-performance solar cells. Thus, we provided efficient systems to the experimentalists for the future development of solar cells.

Tailoring the solar cell efficiency of Y-series based non-fullerene acceptors through end cap modification

Y-series-based non-fullerene acceptors (NFAs) have achieved significant deliberation by chemists and physicists because the promising optical and photochemical properties associated with high-performance OSCs can be further tuned through end-capped modification. In this work, such modifications of Y-series benzothiadiazole-based NFAs were accomplished theoretically to propose new acceptors for photovoltaic cells (PVCs). The recently synthesized Y-series non-fullerene acceptor m-BTP-PhC6 was taken as a reference acceptor. We designed five new acceptors (BTP1-BTP5) through the structural modification at both ends of acceptor groups and evaluated their performance by applying DFT and TD-DFT. The newly engineered molecules exhibited a narrower bandgap (E_g) than the reference (R) resulting in better intramolecular charge transfer (ICT). Further, the designed acceptors expressed the maximum absorption in the region of 600-800 nm revealing a redshift in their absorption spectrum. Low excitation energy and low exciton binding energy were noted for designed acceptors confirming them as better candidates for high PCE of solar cells. Low reorganizational energy for the mobility of holes and electrons was also observed for the designed molecules, indicating improved charge transfer properties. The newly tailored acceptor BTP4 was found to be the promising candidate among all acceptors because of lower bandgap, lower exciton binding energy, reorganizational energy, and redshift of the absorption spectrum. The complex analysis of BTP4 with donor polymer PTB7-Th and PM6 was executed at the same DFT level. Furthermore, FMOs studies showed relatively rich electron density in the acceptor groups of LUMO as compared to the reference molecule. The overall theoretical results of this study showed that the designed acceptors played a productive and effective role in uplifting the efficiency of fullerene-free energy devices.

Design new organic material based on triphenylamine (TPA) with D-π-A-π-D structure used as an electron donor for organic solar cells: A DFT approach

Because of the increasing scarcity of fossil fuels and the growing need for energy, it has become necessary to research new renewable energy resources. In this study, five new high-performance materials (TP-FA₁F-TP - TP-FA₅F-TP) of the D-π-A-π-D configuration based on triphenylamine (TPA) were theoretically investigated by applying DFT and TD-DFT methods for future application as heterojunction organic solar cells (BHJ). The influence of the modification of the acceptor (A) of the parent molecule TP-FTzF-TP on the structural, electronic, photovoltaic and optical properties of the TP-FA1F-TP - TP-FA5F-TP organic molecules was investigated in detail. TP-FA₁F-TP - TP-FA₅F-TP showed E_gap in the interval of 1.44-2.01 eV with λ_abs in the range of 536-774 nm, open-circuit voltage (V_oc) values varied between 0.3 and 0.56 V and power conversion efficiencies (PCE) ranging from (3-6) %. Our results also show that the donor molecules suggested in this research exhibit an improved performance compared to the recently synthesized TP-FTzF-TP, such as a lowest HOMO energy, a smaller E_gap, and a greater absorption spectrum, and can lead to higher performance. Indeed, this theoretical research could lead to the future synthesis of better compounds as active substances used in BHJ.

Transition Metal-Decorated Mg12O12 Nanoclusters as Biosensors and Efficient Drug Carriers for the Metformin Anticancer Drug

Drug carriers have been designed and investigated remarkably due to their effective use in the modern medication process. In this study, the decoration of the Mg₁₂O₁₂ nanocluster has been done with transition metals (Ni and Zn) for effective adsorption of metformin (anticancer drug). Decoration of Ni and Zn on a nanocluster allows two geometries, and similarly, the adsorption of metformin also provides two geometries. Density functional theory and time-dependent density functional theory have been employed at the B3LYP with 6-311G(d,p) level. The decoration of Ni and Zn offers good attachment and detachment of the drug, which is observed from their good adsorption energy values. Further, the reduction in the energy band gap is noted in the metformin-adsorbed nanocluster, which allows high charge transfer from a lower energy level to a high energy level. The drug carrier systems show an efficient working mechanism in a water solvent with the visible-light absorption range. Natural bonding orbital and dipole moment values suggested that the adsorption of the metformin causes charge separation in these systems. Moreover, low values of chemical softness with a high electrophilic index recommended that these systems are naturally stable with the least reactivity. Thus, we offer novel kinds of Ni- and Zn-decorated Mg₁₂O₁₂ nanoclusters as efficient carriers for metformin and also recommend them to experimentalists for the future development of drug carriers.

Synthesis, characterization and exploration of photovoltaic behavior of hydrazide based scaffolds: a concise experimental and DFT study

Solar energy being a non-depleting energy resource, has attracted scientists' attention to develop efficient solar cells to meet energy demands. Herein, a series of hydrazinylthiazole-4-carbohydrazide organic photovoltaic compounds (BDTC1-BDTC7) with an A1-D1-A2-D2 framework was synthesized with 48-62% yields, and their spectroscopic characterization was accomplished using FT-IR, HRMS, ¹H and ¹³C-NMR techniques. Density functional theory (DFT) and time dependent DFT analyses were performed utilizing the M06/6-31G(d,p) functional to calculate the photovoltaic and optoelectronic properties of BDTC1-BDTC7via numerous simulations of the frontier molecular orbitals (FMOs), transition density matrix (TDM), open circuit voltage (V _oc) and density of states (DOS). Moreover, the conducted analysis on the FMOs revealed efficient transference of charge from the highest occupied to the lowest unoccupied molecular orbitals (HOMO → LUMO), further supported by TDM and DOS analyses. Furthermore, the values of binding energy (E _b = 0.295 to 1.150 eV), as well as reorganization energy of the holes (-0.038-0.025 eV) and electrons (-0.023-0.00 eV), were found to be smaller for all the studied compounds, which suggests a higher exciton dissociation rate with greater hole mobility in BDTC1-BDTC7. V _oc analysis was accomplished with respect to HOMO_PBDB-T-LUMO_ACCEPTOR. Among all the synthesized molecules, BDTC7 was found to have a reduced band gap (3.583 eV), with a bathochromic shift and absorption maximum at 448.990 nm, and a promising V _oc (1.97 V), thus it is regarded as a potential candidate for high performance photovoltaic applications.

Designing efficient A-D-A1-D-A type fullerene free acceptor molecules with enhanced power conversion efficiency for solar cell applications

The achievement of highly efficient power conversion efficiency (PCE) is a big concern for non-fullerene organic solar cells (NF-OSCs) because PCE can depend on numerous variables. Here, new five novel acceptor molecules without fullerenes were developed and investigated using DFT (density functional theory) and TD-DFT (time dependent-density functional theory). Compared to the recently synthesized molecule (PZ-dIDTC6), the developed molecules display a narrow optical band gap, exhibiting a red shift in the absorption spectrum. The developed molecules (YM1-YM5) express high mobility of electrons and holes in the active layer of OSCs (organic solar cells). In addition, high open-circuit voltage (V_oc) values with maximum charge density shifting are noted in designed molecules. YM1-YM5 is also associated with low binding energy and excitation energy. This work proves that noncovalent conformational locking is favourable for improving PCE devices.

Designing of gigantic first-order hyperpolarizability molecules via joining the promising organic fragments: a DFT study

A suitable substitution of carbazole with a π-spacer group like cyanoethynylethene offers exciting future opportunities in terms of smart nonlinear optical material. In the quest of better organic nonlinear optical material, we have designed a series of derivatives based on carbazole and cyanoethynylethene fragment combinations in a unique fashion by employing the density functional (DFT) methods. The calculated time-dependent density functional theory (TD-DFT) calculations infer that the gigantic first static hyperpolarizability (β_tot) values are due to a lower energy gap and higher transition dipole moment for the crucial electronic transition. Furthermore, to see the in-depth execution for enhanced second-order nonlinear optics and the structure property relationship on nonlinear optics (NLO) behavior, we have performed frontier molecular orbitals (FMO), density of state (DOS), and transition density matrix (TDM). Furthermore, CAM-B3LYP functional-based calculated results infer that the designed molecule 10 show the first static hyperpolarizability is 923.93 × 10^-30 esu which is 69 times larger than that of p-nitroaniline.

High electron mobility due to extra π-conjugation in the end-capped units of non-fullerene acceptor molecules: a DFT/TD-DFT-based prediction

A combination of high open-circuit voltage (V_oc) and short-circuit current density (Jsc) typically creates effective organic solar cells (OSCs). To enhance the open-circuit voltage, we have designed three new fullerene-free acceptor molecules with elongated π-conjugation in the end-capped units. Y-series-based newly designed molecules (CPSS-4F, CPSS-4Cl, CPSS-4CN) exhibited a narrow energy bandgap with high electron mobility. Red shift in the absorption spectrum with high intensities is also noted for designed molecules. Low binding and excitation energies of designed molecules favor easy excitation of exciton in the excited state. Further, CPSS-4F, CPSS-4Cl, and CPSS-4CN exhibited better open-circuit voltage with favorable molecular orbitals contributions. Transition density analysis (TDM) was also performed to locate the total transitions in the designed molecules. Outcomes of all analyses suggested that designed molecules are effective contributors to the active layer of organic solar cells.

Efficient designing of half-moon-shaped chalcogen heterocycles as non-fullerene acceptors for organic solar cells

One key strategy to further improve the power conversion efficiency (PCE) of organic solar cells (OSCs) is to incorporate various complementary functional groups in a molecule. Such strategies proved attractive for tuning the photovoltaic performances of the materials and can show a much higher absorption phenomenon with narrower band gaps. Despite the outstanding benefits, materials selection and their efficient modeling is also an extremely challenging job for the development of OSCs materials. In this manuscript, we proficiently developed an efficient series of small molecule-based non-fullerene acceptors (SM-NFAs) SN1-SN9 for OSCs and characterized by density functional theory (DFT) and time-dependent DFT (TD-DFT). The characteristics required to estimate electron and hole mobility, and open-circuit voltage (V_oc) were investigated by optimizing the geometrical parameters, absorption spectra, exciton binding energy, frontier molecular orbitals (FMOs), electronic structures, and charge transfer rates. The outcomes of these materials showed that all newly constructed small-molecule-based non-fullerene acceptors exhibit broader and better absorption efficiency (λ_max = 761 to 778 nm) and exciton dissociation, while much lower LUMO energy levels which may help to enhance the reorganizational energies. Further, a narrow bandgap also offers better photovoltaic properties. Hence, the designed molecules exhibited narrow bandgap values (E_g = 2.82 to 2.98 eV) which are lower than that of the reference molecule (3.05 eV). High V_oc and photocurrent density values with lower excitation and binding energies eventually increase the PCEs of the OSC devices. The obtained results have shown that designed molecules could be effective aspirants for high-performance OSCs.

Quantum chemical designing of novel fullerene-free acceptor molecules for organic solar cell applications

Organic solar cells (OSCs) with bulk heterojunction (BHJ) structures consisting of electron-donor and electron-acceptor materials have achieved impressive progress over the past decade, demonstrating their great potential in practical applications. In this study, we have designed five fullerene-free acceptor-based molecules containing indaceno-dithiophene as a central core moiety. We studied the optoelectronic features of these newly architecture molecules by using DFT and TD-DFT approaches. For the investigation of the optoelectronic characteristics of the reference and newly designed molecules, we performed different parameters including FMO's, absorption maxima, excitation energy, transition density matrix (TDM) along with binding energy, dipole moment, the partial density of states, charge mobility, and charge transfer analysis. Among all engineered molecules, SK1 has proven to be the most efficient solar cell due to its promising optoelectronic and photovoltaic properties. SK1 reveals smaller band-gap (E_gap = 1.959 eV) and lesser λ_h (0.0070 eV) and λ_e (0.0051 eV). SK1 illustrated comparable binding energy value (0.33 eV) and lowest excitation energy (1.62 eV) which will lead to improved power conversion efficiency values. The SK1 molecule demonstrated the highest λ_max value (764 nm) in the solvent phase which could lead to redshift absorption for achieving the high efficiency of OSCs. This molecular modeling approves that the best working efficiency of organic solar devices can be achieved by terminal group modifications due to their promising photovoltaic and optoelectronic properties. It is evident from the current analysis that all the theoretically fabricated molecules (SK1-SK5) are fabulous and highly suggested to experimental workers for their synthesis and advancement of these highly competent solar devices in the future.

Designing and Encapsulation of Inorganic Al12N12 Nanoclusters with Be, Mg, and Ca Metals for Efficient Hydrogen Adsorption: A Step Forward Towards Hydrogen Storage Materials

Nanoclusters such as [Formula: see text][Formula: see text] have received increased attention due to their diverse applications in the fields of optoelectronics and energy storage. In this paper, we have investigated a series of alkaline earth metal (AEM)-encapsulated [Formula: see text][Formula: see text] nanoclusters for hydrogen adsorption. Thermodynamic adsorption parameters, optical and nonlinear optical properties were investigated using density functional theory (DFT) at the B3LYP/6-31G(d,p) level of theory. Encapsulation of AEMs (Be, Mg and Ca) is an effective strategy to improve the NLO reaction and thermodynamic and adsorption properties of [Formula: see text][Formula: see text] nanoclusters. The adsorption energies ranging from [Formula: see text]26.57[Formula: see text]kJ/mol to [Formula: see text]213.33[Formula: see text]kJ/mol for the three guests (Be, Mg and Ca) capsulated [Formula: see text][Formula: see text] nanoclusters are observed. The adsorption energy is affected by the size of the nanocage. Therefore, Ca- and Mg-encapsulated cages show higher values of adsorption energy. Overall, an increase in adsorption energy ([Formula: see text][Formula: see text]kJ/mol to [Formula: see text]91.06[Formula: see text]kJ/mol) is observed for (Be, Mg and Ca) encapsulated [Formula: see text][Formula: see text] nanoclusters compared to untreated [Formula: see text][Formula: see text] and H2-[Formula: see text][Formula: see text] cages. Moreover, adsorption of hydrogen on AEMs encapsulated in [Formula: see text][Formula: see text] leads to a decrease in the HOMO-LUMO energy gap with an enhancement of linear and nonlinear hyperpolarizability. All hydrogen-adsorbed AEMs [Formula: see text][Formula: see text] nanocages exhibit large [Formula: see text] and [Formula: see text] values, suggesting that these systems are potential candidates for optical materials. Various geometrical parameters such as frontier molecular orbitals (FMOs), partial density of states, global quantum descriptor of reactivity, natural bond orbital testing and molecular electrostatic strength analyses were performed to investigate the thermodynamic stability of all the studied systems. The results obtained confirmed that the designed systems are suitable for hydrogen storage. Therefore, we recommend that these systems be investigated for their hydrogen storage and optical properties.

Chemically Modified Quinoidal Oligothiophenes for Enhanced Linear and Third-Order Nonlinear Optical Properties

In the present investigation, quantum chemical calculations have been performed in a systematic way to explore the optoelectronic, charge transfer, and nonlinear optical (NLO) properties of different bis(dicyanomethylene) end-functionalized quinoidal oligothiophenes. The effect of different conformations (linking modes of thiophene rings) on conformational, optoelectronic, and NLO properties are studied from the best-performed dimer to octamer. The optical and NLO properties of all the selected systems (1-7) are calculated by means of density functional theory (DFT) methods. Among all the designed compounds, the largest linear isotropic (αiso) polarizability value of 603.1 × 10-24 esu is shown by compound 7 which is ∼12, ∼16, ∼9, ∼11, ∼10, and ∼4 times larger as compared to compounds 1-6, respectively. A relative investigation is performed considering the expansion in third-order NLO polarizability as a function of size and conformational modes. Among all the investigated systems, system 7 shows the highest value of static second hyperpolarizability ⟨γ⟩ with an amplitude of 7607 × 10-36 esu at the M06/6-311G** level of theory, which is ∼521, ∼505, ∼38, ∼884, ∼185, and ∼15 times more than that of compounds 1-6, respectively. The extensively larger ⟨γ⟩ amplitude of compound 7 with higher oscillator strength and lower transition energy indicates that NLO properties are remarkably dependent upon linking modes of thiophene rings and its chain length. Furthermore, to trace the origin of higher nonlinearities, TD-DFT calculations are also performed at the same TD-M06/6-311G** level of theory. Additionally, a comprehensive understanding of the effect of structure/property relationship on the NLO polarizabilities of these investigated quinoidal oligothiophenes is obtained through the inspection of Frontier molecular orbitals, the density of states (TDOS and PDOS), and molecular electrostatic potential diagrams including the transition density matrix. Hence, the current examination will not just feature the NLO capability of entitled compounds yet additionally incite the interest of experimentalists to adequately modify the structure of these oligothiophenes for efficient optical and NLO applications.

A Theoretical Framework of Zinc-Decorated Inorganic Mg12O12 Nanoclusters for Efficient COCl2 Adsorption: A Step Forward toward the Development of COCl2 Sensing Materials

Gas sensors are widely explored due to their remarkable detection efficiency for pollutants. Phosgene is a toxic gas and its high concentration in the environment causes some serious health problems like swollen throat, a change in voice, late response of nervous systems, and many more. Therefore, the development of sensors for quick monitoring of COCl2 in the environment is the need of the time. In this aspect, we have explored the adsorption behavior of late transition metal-decorated Mg12O12 nanoclusters for COCl2. Density functional theory at the B3LYP/6-31G(d,p) level is used for optimization, frontier molecular orbital analysis, dipole moment, natural bonding orbitals, bond lengths, adsorption energies, and global reactivity descriptor analysis. Decoration of Zn on pure Mg12O12 delivered two geometries named as Y1 and Y2 with adsorption energy values of -388.91 and -403.11 kJ/mol, respectively. Adsorption of COCl2 on pure Mg12O12 also delivered two geometries (X1 and X2) with different orientations of COCl2. The computed adsorption energy values of X1 and X2 are -44.92 and -71.32 kJ/mol. However, adsorption of COCl2 on Zn-decorated Mg12O12 offered two geometries named as Z1 and Z2 with adsorption energy values of -455.22 and -419.04 kJ/mol, respectively. These adsorption energy values suggested that Zn decoration significantly enhances the adsorption capability of COCl2 gas. Further, the narrow band gap and large dipole moment values of COCl2-adsorbed Zn-decorated Mg12O12 nanoclusters suggested that designed systems are efficient candidates for COCl2 adsorption. Global reactivity indices unveil the great natural stability and least reactivity of designed systems. Results of all analyses suggested that Zn-decorated Mg12O12 nanoclusters are efficient aspirants for the development of high-performance COCl2 sensing materials.

Role of acceptor guests in tuning optoelectronic properties of benzothiadiazole core based non-fullerene acceptors for high-performance bulk-heterojunction organic solar cells

Recently, end-capped acceptors tailoring approach has attracted many researchers because of unceasing higher power conversion efficiencies (PCEs) of resulted compounds. By keeping in view, the crucial role of NFAs in bulk-heterojunction OSCs, herein, we molecularly engineered five new non-fullerene acceptor materials (Y6A1-Y6A5) by modifying a recently synthesized Y6 molecule (R), having 18% power conversion efficiency when combined with D18 donor polymer. The structural-elemental connection, physical-chemical, optoelectronic, and photovoltaic characteristics of novel deigned and reference material (R) are studied with advanced quantum-chemical modulations. Density functional theory and time dependent-density functional theory has been employed through various basis sets to investigate the designed molecules theoretically. Interestingly, all of the newly modeled materials displayed lower excitation energies with lower HOMO-LUMO energy-gaps in-contrast with R molecule. Moreover, a red-shifted absorption and lower reorganizational energies of electron and hole are also a novel feature of these designed materials. The lower binding energy values of modeled materials offers better charge separation and high photo-current density (J_sc) as compared to R. Transition density analysis, open circuit voltage, and molecular electrostatic potential analysis suggested that end-capped acceptors alteration of R molecule is an efficient approach for tuning the optoelectronic properties of non-fullerene-based acceptor molecules (Y6A1-Y6A5). In last, composite study of donor: acceptor (D18:Y6A2) complex has also been carried-out to realize the charge transfer process at the donor-acceptor interface. After all investigations, we hope that our theoretical modeled materials are superior than Y6 molecule, therefore, we endorse these materials for the synthesis to prepare highly-efficient BHJ-OSCs devices.

Designing of Inorganic Al12N12 Nanocluster with Fe, Co, Ni, Cu and Zn Metals for Efficient Hydrogen Storage Materials

Hydrogen is considered as one of the attractive environmentally friendly materials with zero carbon emission. Hydrogen storage is still challenging for its use in various energy applications. That’s why hydrogen gained more and more attention to become a major fuel of today’s energy consumption. Therefore, nowadays, hydrogen storage materials are under extensive research. Herein, efforts are being devoted to design efficient systems which could be used for future hydrogen storage purposes. To this end, we have employed density functional theory (DFT) to optimize the geometries of the designed inorganic Al[Formula: see text]N[Formula: see text] nanoclusters with transition metals (Fe, Co, Ni, Cu and Zn). Various positions of metal encapsulated Al[Formula: see text]N[Formula: see text] are examined for efficient hydrogen adsorption. After adsorption of H2 on late transition metals encapsulated Al[Formula: see text]N[Formula: see text] nanocluster, different geometric parameters like frontier molecular orbitals, adsorption energies and nature bonding orbitals have been performed for exploring the potential of metal encapsulated for hydrogen adsorption. Moreover, molecular electrostatic potential (MEP) analysis was also performed in order to explore the different charge separation upon H2 adsorption on metals encapsulated Al[Formula: see text]N[Formula: see text] nanoclusters. Also, global indices of reactivity like ionization potential, electron affinity, electrophilic index, chemical softness and chemical hardness were also examined by using DFT. The adsorption energy results suggested encapsulation of late transition metals in Al[Formula: see text]N[Formula: see text] nanocage efficiently enhancing the adsorption capability of Al[Formula: see text]N[Formula: see text] for hydrogen adsorption. Results of all analysis suggested that our designed systems are efficient candidates for hydrogen adsorption. Thus, we recommended a novel kind of systems for hydrogen storage materials.

In Silico Designing of Nanoclusters with a Late Transition Metal for NO2 Adsorption: An Efficient Approach toward the Development of NO2 Sensing Materials

Gas sensors are widely used for detection of environmental pollution caused by various environmental factors such as road traffic and combustion of fossil fuels. Nitrogen dioxide (NO2) is one of the leading pollutants of the present age, which causes a number of serious health issues including acute bronchitis, cough, and phlegm, particularly in children. Nowadays, researchers are focused on designing new sensor materials for detection and removal of NO2 from the environment. In this line, we have made an attempt to design NO2 sensing materials by using theoretical techniques. Here, we have reported decoration of Mg12O12 nanoclusters with a late transition metal (Cu) by employing density functional theory at the B3LYP/6-31G(d,p) basis set. The decoration of metal on Mg12O12 gives two geometries (M1 and M2) with adsorption energies of -363.81 and -384.09 kJ/mol, respectively. Adsorption of NO2 on pristine Mg12O12 expressed an adsorption energy value of -62.36 kJ/mol. Adsorption of NO2 on Cu-decorated Mg12O12 nanocages delivered two geometries (N1 and N2) with adsorption energies of -442.56 and -447.64 kJ/mol. Metal-decorated Mg12O12 nanoclusters offer better adsorption of NO2 as compared to pristine Mg12O12 . Adsorption of NO2 on Cu-Mg12O12 nanoclusters also causes narrowing of band gap of magnesium oxide nanoclusters. Large dipole moment, high Q NBO with large electrophilic index in NO2-Cu-Mg12O12 nanoclusters suggested that metal-decorated Mg12O12 nanoclusters are efficient candidates for NO2 adsorption. Different geometric parameters and results of global reactivity descriptors show that NO2-Cu-Mg12O12 nanoclusters are quite stable in nature with least reactivity. Thus, conceptualized systems are potential candidates for applications in NO2 sensing materials.

How Does Bridging Core Modification Alter the Photovoltaic Characteristics of Triphenylamine-Based Hole Transport Materials? Theoretical Understanding and Prediction

Perovskite solar cells have gained immense interest from researchers owing to their good photophysical properties, low-cost production, and high power conversion efficiencies. Hole transport materials (HTMs) play a dominant role in enhancing the power conversion efficiencies (PCEs) and long diffusion length of holes and electrons in perovskite solar cells. In hole transport materials, modification of π-linkers has proved to be an efficient approach for enhancing the overall PCE of perovskite solar cells. In this work, π-linker modification of a recently synthesized H-Bi molecule (R) is achieved with novel π-linkers. After structural modifications, ten novel HTMs (HB1-HB10) with a D-π-D backbone are obtained. The structure-property relationship, and optoelectronic and photovoltaic characteristics of these newly designed hole transport materials are examined comprehensively and compared with reference molecules. In addition, different geometric parameters are also examined with the assistance of density functional theory (DFT) and time-dependent DFT. All the designed molecules exhibit narrow HOMO-LUMO energy gaps (E_g =2.82-2.99 eV) compared with the R molecule (E_g =3.05 eV). The designed molecules express redshifting in their absorption spectra with low values of excitation energy, which in return offer high power conversion efficiencies. Further, density of states and molecular electrostatic potential analysis is performed to locate the different charge sites in the molecules. The reorganizational energies of holes and electrons are found to have good values, suggesting that these novel designed molecules are efficient hole transport materials for perovskite solar cells. In addition, the low binding energy values of the designed molecules (compared with R) offer high current charge density. Finally, complex study of HB9:PC₆₁ BM is also undertaken to understand the charge transfer between the molecules of the complex. The results of all analyses advocate that these novel designed HTMs are promising candidates for the construction of future high-performance perovskite solar cells.

Design and DFT study of nitrogen-rich donor systems for improved photovoltaic performance in dye-sensitized solar cells

Donor modifications, especially through N-annulation, for enhancing the structure–performance relationship of D–π–A systems for DSSC applications.