Synthesis and Photophysical, Electrochemical, and DFT Studies of Piperidyl and Pyrrolidinyl Chalcones.

Small organic molecules with interesting optical and electrochemical properties find applications as organic luminescent materials. In this work, we report the synthesis of novel chalcones with D-A-D and D-A-D-A architecture, followed by their optical, electrochemical, and computational studies. The absorption band of these compounds occurs at 360-480 nm with emission maxima appearing around 513-552 nm. The large Stokes shifts (Δλ) for all compounds (90-132 nm) suggest intramolecular charge transfer (ICT) in the excited states. The molar absorptivity and fluorescence quantum yields were found to be in the range of 1.7-4.26 × 104 M-1 cm-1 and 0.29-0.39, respectively. The electrochemical parameters were determined by using cyclic voltammetry (CV). Density functional theory (DFT) calculations of all compounds were made by using B3LYP/G (d,p) functionals in chloroform and were found to have a good correlation with experimental results. Preliminary studies of absorption, photoluminescence, CV, and their theoretical correlation suggest that these compounds may be optimized for their applications in optoelectronics, sensing, and bioimaging.

Tuning the optoelectronic properties of acridine-triphenylamine (ACR-TPA) based novel hole transporting material for high efficiency perovskite and organic solar cell.

In this research, five distinct small donor molecules (designated as ACR-TPA-X1, ACR-TPA-X2, ACR-TPA-X3, ACR-TPA-X4, ACR-TPA-X5) are constructed by replacing the methoxy groups on both sides of the model molecule (ACR-TPA-R) with thiophene bridged acceptor moieties. We have used the B3LYP/6-31G (d,p) model for our computational studies. Our model molecule's morphological alteration has resulted in a lowered Eg of 1.77-2.51 eV as compared to model (ACR-TPA-R=3.84 eV). ACR-TPA-X2 investigated the λmax at 776 nm. ACR-TPA-X4 was found to be most miscible with dichloromethane (DCM). The greatest VOC(1.21 eV) was observed in ACR-TPA-X1. Among all of the variants, ACR-TPA-X1 had the highest PCE (23.42%). It was found that ACR-TPA-X4 had the highest electron mobility (0.00370 eV) and ACR-TPA-X5 had the highest hole mobility (0.00324 eV) of all the materials examined. The findings prove the worth of the methods used, paving the way for the development of effective small donors for OSCs and HTMs for PSCs.

Designing of anthracene-arylamine hole transporting materials for organic and perovskite solar cells.

This study focuses on the creation of 5 small donor molecules (A102W1-A102W5) by substituting the one-sided methoxy group of model (A102R) with different thiophene bridged acceptor moieties. B3LYP/6-31**G (d,p) model has been employed for computational analysis. The best miscibility was found for A102W3 in dichloromethane (DCM) solvent, where its λmax was also found to be at 753 nm, its Eg was found to be 1.55 eV as well as dipole moment in DCM was 21.47 D. The percentage of PCE among all the variants was greatest for A102W2 (25.31%). The electron reorganization energy shown by A102W4 was 0.00470 eV, whereas the hole reorganization energy investigated in A102W2 was 0.00586 eV representing their maximum electron and hole mobility respectively amongst all. Results validate the value of specified techniques, opening a new door to create efficient small donors for OSCs and HTMs for PSCs.

Alkaline earth metals (Be, Mg, Ca) doped hexamine complexant with enhanced electronic and nonlinear optical properties.

Organic complexant hexamine (hexamethylenetetramine, HMTA) is doped with alkaline earth (AE) metals, and new complexes are designed systematically to explore their nonlinear optical (NLO) properties by carrying out DFT calculations. Optimization of afresh designed geometries has shown their sufficient thermodynamic stability. Moreover, the energy band gap of pure HMTA is 10.62 eV which is reduced up to 2.63 eV for our doped complexes. This shows that alkaline earth metals are effective in enhancing the electronic properties of a system. Time-dependent DFT calculations are achieved, and results show that higher absorption maxima (λmax) along with small transition energies (ΔE) have significantly increased the hyperpolarizability (ß0) values (21,338-220,585 au). This higher hyperpolarizability is an elementary prerequisite for improved NLO response of a material. Transition density matrix (TDM) analysis, density of states (DOS) analysis, and electron density difference map (EDDM) studies are executed to get information about electronic distribution, crucial transitions, and electron transfer properties. As a result of these findings, it can be concluded that alkaline earth metal-doped HMTA might be a competitor for NLO materials with remarkable optical and electronic properties and better future applications in the field of optoelectronics.

Remarkable non-linear optical properties of gold cluster doped graphyne (GY): A DFT study.

The nonlinear optical (NLO) properties of gold (Au) doped graphyne (GY) complexes are the subject of this quantum mechanical investigation. Detailed profiling of GY@Aucenter, GY@Auside, GY@2Auabove,GY@2Auperpendicular, and GY@3Aucenter is accomplished at CAM-B3LYP/LANL2DZ. The differential influence of various GY based complexes on molecular geometry, vertical ionization energy (VIE), interaction energy (Eint), frontier molecular orbitals (FMOs), density of states (DOS), absorption maximum (λmax), molecular electrostatic potential (MEP), electron density distribution map (EDDM), transition density matrix (TDM), dipole moment (µ) and non-linear optical (NLO) properties have been investigated. Non-covalent interaction (NCI) analysis has been done to explore the sort of interactions in designed complexes. The vibrational frequencies are probed via infrared (IR) analysis. Doping tactics in all complexes dramatically changed charge carrier properties, such as shrinking band gap (Eg) and increasing λmax in the range of 3.97-5.58 eV and 288-562 nm respectively, compared to pure GY with 5.78 eV Eg and 265 nm λmax. When compared to GY (αO = 281.54 andßO = 0.21 au), GY@3Aucenter exhibited a significant increase in static mean polarizability (αO = 415 au) and the mean first hyperpolarizability (ßo = 3652 au) attributable to its lowest excitation energy (ΔE). GY doping has been discovered to be advantageous for designing potential nanoscale devices by focusing on the symphony between small Au clusters and GY and their impacts on NLO aspects.

Symmetrical end-capped molecular engineering of star-shaped triphenylamine-based derivatives having remarkable photovoltaic properties for efficient organic solar cells.

In the present research work, four novel triphenylamine (TPA)-based acceptor molecules have been architectured to step up the solar efficiency of organic solar cells. The four designed molecules abbreviated as T1-T4 have a common TPA donor core and different strong electron pulling peripheral acceptor groups connected through thiophene spacers. Computational simulations of T1-T4 were performed to compute and compare their optoelectronic properties with well-known reference molecule S(TPA-DPP) designated as R in the current project. For geometric optimizations of designed molecules, MPW1PW91 functional along with a basis set of 6-31G (d, p) was enforced. Assessment of the optoelectronic features of newly reported 3-D molecules (T1-T4) has been executed through density functional theory (DFT) and time-dependent density functional theory (TD-DFT) computations. Transition density matrix (TDM) and density of state (DOS) evaluations were performed for the investigation of exciton dynamics and electronic contribution between two states. All the derived molecules exhibited admirable photovoltaic features when compared to that of the reference molecule. Amidst all these newly modified molecules, T3 manifested itself as the finest candidate having the least energy band gap (1.84 eV) and the highest λmax (865 nm) in dichloromethane solvent. Also, T1 molecule has the lowest hole reorganization energy (0.0036 eV) value. These designed candidates (T1-T4) confirm that peripheral acceptor tempering is an effectual approach for the attainment of the desirable optoelectronic properties.

Silver cluster doped graphyne (GY) with outstanding non-linear optical properties.

This research study addresses the computational simulations of optical and nonlinear optical (NLO) characteristics of silver (Ag) cluster doped graphyne (GY) complexes. By precisely following DFT and TD-DFT hypothetical computations, in-depth characterization of GY@Agcenter, GY@Agside, GY@2Agperpendicular, GY@2Agabove, and GY@3Agcenter is accomplished using CAM-B3LYP/LANL2DZ while the CAM-B3LYP/mixed basis set is used for study of 2GY@Agcenter, 2GY@Agside, 2GY@2Agperpendicular, 2GY@2Agabove, and 2GY@3Agcenter. The effects of various graphyne surface based complexes on hyperpolarizabilities, frontier molecular orbitals (FMOs), density of states (DOS), absorption maximum (λ max), binding energy (E b), dipole moment (µ), electron density distribution map (EDDM), transition density matrix (TDM), electrostatic potential (ESP), vertical ionization energy (E VI) and electrical conductivity (σ) have been investigated. Infrared (IR), non-covalent interaction (NCI) analysis accompanied by isosurface are performed to study the vibrational frequencies and type of interaction. Doping strategies in all complexes impressively reformed charge transfer characteristics such as narrowing band gap (E g) in the range of 2.58-4.73 eV and enhanced λ max lying in the range of 368-536 nm as compared to pure GY with 5.78 eV E g and 265 nm λ max for (GY@Agcenter-GY@3Agcenter). In the case of (2GY@Agcenter-2GY@3Agcenter), when compared to 2GY with 5.58 eV E g and 275 nm absorption, maximum doping techniques have more effectively modified λ max in the region of 400-548 nm and E g, which is in the order of 2.55-4.62 eV. GY@3Agcenter and 2GY@3Agcenter reflected a noteworthy increment in linear polarizability α O (436.90 au) and (586 au) and the first hyperpolarizability ß O (5048.77 au) and (17 270 au) because of their lowest excitation energy (ΔE) when studied in comparison with GY (α O = 281.54 and ß O = 0.21 au) and 2GY surface (α O = 416 and ß O = 0.06 au). Focusing on harmony between the tiny Ag clusters and graphyne surface as well as their influences on NLO properties, graphyne doping using its two-unit cells (2GY) is found to be expedient for the development of future nanoscale devices.

Bithieno Thiophene-Based Small Molecules for Application as Donor Materials for Organic Solar Cells and Hole Transport Materials for Perovskite Solar Cells.

This quantum mechanical study focuses on the designing of twelve (MPAM1-MPAM12) bithieno thiophene (BTTI) central core-based small molecules to explore optoelectronic properties as donor candidates for organic solar cells (OSCs) and hole transport materials (HTMs) accompanied by enhanced charge mobility for perovskite solar cells (PSCs). MPAM1-MPAM6 have been designed by the substitution of thiophene-bridged end-capped acceptors on both side terminals of reference (MPAR). MPAM7-MPAM12 are tailored by adopting the same tactic on one side terminal only. MPW1PW91/6-311G (d,p) has been employed for all computational simulations. MPAM12 revealed the highest λmax at 639 nm in dichloromethane (DCM) solvent with the lowest E g of 1.78 eV and dipole moment (20.74 D) in the solvent phase, showing excellent miscibility as compared to the reference. All designed chromophores (MPAM1-MPAM12) demonstrated higher estimated V OC and power conversion efficiency (PCE) when compared to MPAR, suggesting their prominent operational efficiency. Among all, MPAM4 manifested the highest PCE (47.86%). MPAM2 portrayed the highest electron mobility (0.0041573 eV) and MPAM3 exhibited the highest hole mobility (0.0047178 eV). The outcomes highlight the adequacy of the planned strategies, paving a new route for the development of small-molecule HTMs for PSCs and donor contributors for OSCs.

Tuning the optoelectronic properties of triphenylamine (TPA) based small molecules by modifying central core for photovoltaic applications.

Small donor molecules based on fused ring acceptors exhibit encouraging photovoltaic properties and expeditious advancement in organic solar cells. Central core modification of non-fullerene acceptor materials is a favorable methodology to enhance electronic properties and efficiency for OSCs. Herein, four new donor molecules, namely, BDTM1, PYRM2, ANTM3, and NM4 are designed with a strong donor moiety triphenylamine, tetracyanobutadiene as acceptor unit, and thiophene as spacer linked to a modified central core. Geometric parameters, optical, electrical properties, effect of central core modification on tailored molecules BDTM1-NM4 are investigated and compared with reference DPPR. DFT together with TDDFT approaches using MPW1PW91 functional is used to study key parameters like absorption maximum (λmax), frontier molecular approach, ionization potential, electron affinity, the density of states, transition density matrix along with open-circuit voltage (VOC), dipole moment and reorganization energy. Among all these molecules, BDTM1 shows maximum calculated absorption λmax (817 nm) and the lowest band gap (2.54 eV). This bathochromic shift in BDTM1 is due to the presence of 4,8-dimethoxy-2,6-di-2-thienylbenzodithiophene as a strong electron-withdrawing group. Computed reorganization energies (RE) shows that BDTM1 has the highest hole and electron mobility among all designed molecules. Combination of BDTM1 donor and PC61BM acceptor further verifies charge transfer and their interaction. The results illustrate that designed donor molecules (BDTM1-NM4) are better in performance and are recommended for experimentation to develop efficient OSCs. Four new donor molecules, namely, BDTM1, PYRM2, ANTM3, and NM4 are designed with a strong donor moiety triphenylamine, tetracyanobutadiene as acceptor unit and thiophene as spacer linked to a modified central core. Geometric parameters, optical, electrical properties, effect of central core modification on tailored molecules BDTM1-NM4 are investigated and compared with reference DPPR.