A DFT Study on New Photovoltaic Dyes to Investigate their NLO Tuning at Near Infrared Region (NIR) as Pull-push Effect by End Capped Acceptors

Structure-based screening of sp2 hybridized small donor bridges as donor: acceptor switches for optical and photovoltaic applications: DFT way

CONTEXT

This research aims to investigate the potential of pyrazine-based small donor moieties as donor-acceptor switches for optical and photovoltaic applications. The designed organic dyes have a high light harvesting efficiency (LHE) and can potentially generate significant electrical energy.

METHODS

The study focuses on understanding the structural and electronic properties of these dyes through the analysis of dihedral angles, bond lengths, and energies of frontier molecular orbitals The UV-Vis spectroscopy parameters of the designed organic dyes revealed their absorption characteristics, including transition energies, wavelengths (λmax), and oscillator strengths (f). The photovoltaic properties of the developed organic dyes show a range of values: a range of 0.95-0.99 for LHE and a range of 1.77-33.02 W for maximum power output (Pmax) with the highest value for dye DDP5. For their stabilization energies, their natural bond orbitals had values ranging from 0.56 to 128.48 kcal/mol, their E(j)E(i) values from 0.22 to 1.29 a.u, and their Fi,j values from 0.024 to 0.213 kcal/mol. Out of all dyes, the DDP5 produced highest push-pull effect and can be good choice for further studies. The design of these novel organic materials for effective and economical solar energy conversion will be aided by evaluating the potential of 5,10-diphenyl-5,10-dihydrophenazine as a donor moiety and determining the structure-property correlations controlling the photovoltaic performance of the compounds.

Design and Exploration of Benzene Like Azobis Triazoles for Long-range Push-Pull Photo-Switching Attributes

This research paper presents a comprehensive study on the design and photovoltaic parameters of azobenzene type 24 photo switches (PSs) of triazole by density functional theory (DFT). The focus was on investigating how to create a long-range push-pull effect of different substituents on the PS properties for their application in photovoltaics by further substituent decoration. Their range of values for the maximum wavelength (λmax) ranged 315-556 nm while their HOMO-LUMO energies (Egaps) were 0.57-6.35eV. The stability of the PS was evaluated by measuring hardness (η) and softness (σ) values. Additionally, photovoltaic parameters such as open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), and maximum power (Pmax) were calculated to assess the performance of the PS as photovoltaic materials. The results revealed that PSs 6 exhibited promising photovoltaic parameters to include Voc values ranging from 0.4-1.63eV, FF values ranging from 0.5438-0.929, Jsc values ranging from 19.27-50.75 mA/cm2, and Pmax values ranging from 14.72-75.91W. This indicates its potential as an efficient light-harvesting material for photovoltaic applications. Moreover, this study presents a pioneering investigation on the correlation between rotational velocity (R) and Mayer bond index (MBI) for the first time. The findings revealed a significant correlation between R and MBI, providing valuable insights into the structural dynamics of the PS. This novel finding opens up new avenues for understanding the structural dynamics of PS and their potential applications in various fields, including photovoltaics. The study provides valuable insights into the structure-property relationships of azobenzene-based PS and their suitability for photovoltaic devices. Further investigations are warranted to optimize the design of the PS, enhance their photovoltaic performance, and explore the underlying mechanisms of the correlation between R and MBIs.

Enhancing NLO performance by utilizing tyrian purple dye as donor moiety in organic DSSCs with end capped acceptors: A theoretical study

A series of new organic dyes (T1-T6) with nonfullerene acceptors have been theoretically designed around the chemical structure of tyrian purple (T) natural dye. For their ground state energy parameters, all the molecular geometries of those dyes were optimized by density functional theory (DFT) at its Becke, 3-parameter, Lee-Yang-Parr (B3LYP) level of theory with 6-31G+(d,p) basis sets. When benchmarking against several long range and range separated levels of theory, the Coulomb attenuated B3LYP (CAM-B3LYP) produced most accurate absorption maxima (λmax) value to that of T so it was further employed for further Time dependent DFT (TD-DFT) calculations. Frontier molecular orbitals (FMOs) with natural bond orbital (NBO) studies were used to study their intra molecular charge transfer (ICT). All of the dyes had their energy gaps (Eg) values between their FMOs to range around 0.96-3.39 eV, whereas the starting reference dye had an Eg of 1.30 eV. Their ionization potential (IP) values were ranged to be 3.07-7.25 eV which indicated their nature to loss electrons. The λ max in chloroform was marginally red-shifted with a value 600-625 from T (580 nm). The dye T6 showed its highest linear polarizability (<α>), and first and second order hyperpolarizabilities (β and γ). The synthetic experts can find the present research to design finest NLO materials for current and future uses.

Molecular modeling of the structural, electronic, excited state dynamic, and the photovoltaic properties of the oligomers of n-corannulene (n = 1-4)

Despite the fact that n-corannulene oligomers (n = 1-4) have a variety of electronic and optical properties, including the ability to be tuned and the potential to be used as light-harvesting materials, there has not been a computational assessment of their structural, electronic, and optical properties. Herein, a computational evaluation of the concerned materials regarding their potent use in solar cell technology has been conducted via DFT/CAM-B3LYP and M062X/6-311+G level of theory. It was observed that the calculated 1st frequency of the n-Corannulene (n = 1-4) were 144.15, 106.36, 48.96 and 42.21 respectively. Notably, the computed cohesive energy value increased as the number of Corannulene units increases while the electronic characteristics revealed that the chemical activity of the structures increased as the number of oligomers rose. Both calculation techniques demonstrate that the number of n-Corannulene oligomers increases the HOMO energy while decreasing the LUMO energy based on the external electric field (EF) effect. The findings demonstrated that as EF intensity increases, the energy gap (Eg/eV = |EHOMO-ELUMO|) of these molecular systems decreases which can be attributed to a decrease in the electron transfer potential barrier. The 4-Corannulene systems showed the highest wave length of adsorption for the investigated compound at 546.18 nm, with the highest oscillator strength of 0.2708 and the lowest transition energy of 2.2700 eV, arising from S0-S1 (H-L) and the highest major percentage contribution of 93.34 % in comparison to the investigated compounds. We are hopeful that this research will help experimental researchers understand the potential of n-Corannulene, specifically 4-corannulene, as powerful material for a variety of applications ranging from solar cell, photovoltaic properties and many others.

DFT-guided structural modeling of end-group acceptors at Y123 core for sensitizers as high-performance organic solar dyes and NLO responses

CONTEXT

The organic solar cells (OSCs) are being developed with the goal of improving their photovoltaic capabilities. Here, utilizing computational methods, six new nonfullerene acceptors (NFA) comprising dyes (A1-A6) have been created by end-group alterations of the Y123 framework as a standard (R).

METHODS

The DFT-based investigations at B3LYP/6-31G + (d,p) level were applied to evaluate their properties. The planar geometries associated with these structures, which lead to improved conjugation, were validated by the estimation of molecular geometries. Dyes A1-A6 have shorter E_gap than R, according to a frontier molecular orbital (FMO) investigation, which encourages charge transfer in them. The dyes with their maximum absorption range were shown by optical properties to be 692-711 nm, which is significantly better than R with its 684 nm range. Their electrostatic and Mulliken charge patterns provided additional evidence of the significant separation of charges within these structures. All the dyes A1-A6 had improved light harvesting efficiency (LHE) values as compared to Y123, highlighting their improved capacity to generate charge carriers by light absorption. With the exception of dye A4, all newly developed dyes might have a superior rate of charge carrier mobility than R, according to reorganization energies λ_re. Dyes A3 and A4 had the greatest open-circuit voltage (V_oc). Dye A3 exhibited improvement in all of its examined properties, making it a promising choice in DSSC applications.

Molecular modeling of mordant black dye for future applications as visible light harvesting materials with anchors: design and excited state dynamics

CONTEXT

In this study, new visible light harvesting dyes (MBR1-MBR5) have been designed as efficient materials with silyl based anchoring abilities on semiconducting units for future dye-solar cells applications. Their unique molecular structures of novel D-π-A_{Semiconductor} type were evaluated thoroughly by density functional theory (DFT) calculations. To enhance the optical performance in visible region, a novel dye structure (MBR) was derived from the chemical structure of mordant black (MB) dye with electron acceptor semiconducting units (MBR1-MBR5).

METHODS

The Coulomb-attenuating Becke, 3-parameter, Lee-Yang-Parr (CAM-B3LYP) functional, which had a hybrid and long-range correlation with 6-31G + (d,p), generated a [Formula: see text] (683 nm) that was very comparable to its experimental value (672 nm). The energies of highest occupied molecular orbitals (HOMO), lowest unoccupied molecular orbitals (LUMO), and their HOMO-LUMO energy gaps (HLG) were calculated. Their ionization potentials (IP) varied from 5.616 to 8.320 eV, demonstrating their good electron donating trend. The [Formula: see text] values of dyes displayed a significant red shift from MBR (682 nm) value with range 565-807 nm except MBR1 which was slightly blue shifted. The dye MBR4, which had the smallest HLG (0.23 eV) had the greatest second order nonlinear optical (NLO) response of 144,234 Debye-Angstrom^-1. The DFT calculated results provided insight into the creation of new silyl anchoring groups for future DSSCs material designs with increased stability and effectiveness. The goal of the current study is to forecast the development of novel NLO materials with a D-π-A_{Semiconductor} design that use semiconductors as anchoring groups to adhere to a surface.

Efficient and tunable enhancement of NLO performance for indaceno-based donor moiety in A-π-D-π-D-π-A type first DSSC design by end-capped acceptors

BACKGROUND

The organic dyes with non-fullerene acceptors (NFAs) have aided in the creation of competitive organic solar cells (OSCs) with long-term sustainability. A series of NFA dyes (IDIC-R1-IDIC-R9) have been designed by varying the end-capped fluorinated moieties (PD1-PD6) at indaceno (IDIC) core.

METHODS

All the calculations were performed by density functional theory (DFT) and time-dependent DFT (TD-DFT)-based approaches. All the geometries were optimized at B3LYP/6-31G + (d,p) of DFT level at their ground state energies. Out of several density functionals, the CAM-B3LYP with 6-31G + (d,p) basis sets was selected after a benchmark study to carry out further calculations. All the dyes had their bandgaps in 0.11-3.12 eV while their starting reference dye had a bandgap value of 2.01 eV.

RESULTS

Their ionization potential (IP) implied that these dyes have strong tendency to lose electrons. The λ_max of the dyes was slightly redshifted from the IDIC (476 nm) and IDIC-R (479 nm) when changing solvent polarity from methanol to DCM and then chloroforms. The natural bond orbital (NBO) analysis showed the (S63)LP → (C61-C62)π* with highest stabilization energy. Their electron injection analysis showed that these dyes can be a good anode material against the aluminum and gold electrodes. The intramolecular charge transfer (ICT) process and stability of the dyes were investigated using frontier molecular orbital (FMO) and natural bond orbital (NBO) analysis.

CONCLUSION

Among all dyes, IDIC-R8 has the highest linear polarizability and second-order hyperpolarizability (β_total). All the dyes demonstrated promising non-linear optical (NLO) properties due to their low charge transfer barriers. Scientists would be able to exploit these properties to identify the best NLO materials for existing applications.