A combined experimental theoretical approach for energy gap determination, photophysical, photostable, optoelectronic, NLO, and organic light emitting diode (OLED) application: Synthesized coumarin derivative

Detection of Latent Fingerprints with Simple AIE-Active p-Phenylenediamine Schiff Bases

Detection of latent fingerprints (LFPs) is pivotal in recognizing the individuals involved in the crime. To achieve this, many attempts have been made to obtain highly sensitive fluorophores with low adhesiveness; however, this remains a challenge. The present research explores the synthesis and application of aggregation-induced emission active phenylenediamine-based Schiff bases 3a and 3b for latent fingerprint detection. The Schiff base, exhibiting enhanced fluorescence upon aggregation, demonstrates remarkable sensitivity and selectivity towards latent fingerprints. The synthesized compounds offer a unique approach, capitalizing on the aggregation-induced enhanced emission phenomenon, providing clear and vivid visualization of latent fingerprints on various surfaces, including rubber, plastic, glass, metals, aluminum foil, and ceramics. A simple powder dusting method was utilized to visualize the latent fingerprints. This technique successfully produced high-resolution images, giving all the 1-3 levels of specifications of the developed fingerprints. The photostability of the synthesized molecule was also evaluated by checking the emission produced by the compounds after storing them for a longer period under ambient conditions. The AIE Active Phenylenediamine-based Schiff bases provide a simple tool to visualize LFPs. The CIE (x, y) coordinates for 3a and 3b were (0.416, 0.556) and (0.317, 0.452), respectively, indicating green-yellow emission under UV 365 nm illumination.

Anthocyanins of Delonix Regia Floral Petals: A Novel Approach on Fluorescence Enhancement, Forster Resonance Energy Transfer Mechanism and Photostability Studies for Optoelectronic Applications

In this work, we focused on extracting the anthocyanin dye in acetone, butanol, ethanol, and water solvents from Delonix regia flowers by a simple maceration extraction process. The identification of functional group analysis, vibrational studies, energy transfer mechanisms, optoelectronic properties, photostability studies, FRET-assisted potential light emissions and photometric properties of the anthocyanin dyes are successively investigated. FTIR spectroscopy and vibrational studies have confirmed the existence of polyphenolic groups in 2-phenyl chromenylium (anthocyanin) dyes. The optoelectronic results show the least direct bandgap (2.04 eV), indirect bandgap (1.55 eV), Urbach energy (0.380 eV), high refractive index (1.20), dielectric constant (2.794), and high optical conductivity (1.954 × 103 S/m) for the anthocyanin dye extracted found in water solvent. The photoluminescence properties such as Stoke's shift, high quantum yield, and lifetime results show that anthocyanin dyes are promising candidates for red-LEDs and optical materials. The absorption and emission spectra of the anthocyanin dyes follow the mirror image rule and the Franck-Condon factor exists between vibrational energy levels corresponding to all the electronic transitions. The excellent correspondence between the absorption and emission spectra reinforces that the anthocyanins are efficient (46%) FRET probes. Further, photometric properties such as CIE, CRI, CCT and colour purity results of anthocyanins in all studied solvents revealed that this material exhibits orange to red shades (x = 0.48 → 0.54 and y = 0.36 →0.45) and is well suitable for have great potential in the manufacturing of Organic-LEDs and other optoelectronic device applications.

Dimerization effects on the electronic properties of candidate OLED materials for optimized performance: a quantum DFT study

In recent years, there has been growing interest in organic light-emitting diode (OLED) materials, highlighting the importance of a thorough understanding of the key factors that influence their electronic and non-linear optical (NLO) properties. To achieve this objective, we considered five candidate OLED compounds: dibenzothio-phen-sulfone-3-yl-9-phenyl-9H-carbazole (DBTS-CzP), 9H-thioxanthene-9-one-dibenzothiophene-sulfone (TXO-CzP), spiro[fluorene-9,9-thioxanthene]-10,10-dioxide (SpDBTS-CzP), 9-[4-(diphenylphosphoryl)-2,2-dimethyl-4-biphenylyl]-9H-carbazole (mCBPPO), and N,N-bis[2-(pyridin-2-yl)phenyl]-N,N-di(n-butyl)phenylamine (DPA-2Py). We employed density functional theory (DFT) and time-dependent DFT (TD-DFT) methods to investigate how dimerization can affect their electronic and NLO characteristics. The results of electronic structure analysis, including HOMO-LUMO gaps and NLO characteristics, reveal that dimerization enhances dipole moments and polarizabilities, facilitating improved charge transfer and electronic transitions. Among the studied compounds, TXO-CzP demonstrates stable electronic properties and exhibits enhanced NLO characteristics post-dimerization-such as efficient charge mobility and superior color purity-positioning it as a promising candidate for advanced OLED applications. These findings underscore dimerized structures' potential to enhance optoelectronic device performance.

Synthesis, Photophysical Properties and Systematic Evaluation of New Class Fluorescein Based Derivative with Organic Solvents: Spectroscopic and Density Functional Theory Methods for Optoelectronic Applications

In this report the photophysical property of newly synthesized fluorescein based derivative 2-(5-((2,4-dichlorophenyl)diazenyl)-6-hydroxy-3-oxo-3H-xanthen-9-yl)benzoic acid has studied by spectroscopic and theoretical that is by Density Functional Theory technique. The structural and functional group of the synthesized molecule was confirmed by nuclear magnetic resonance and fourier transform infrared spectroscopy technique, and from the result so far obtained has been confirmed that molecule has a stable structure and confirmed the presence the functional groups present in the sample. The optical properties of the molecule are studied using the spectroscopic technique and it has revealed the solute-solvent interaction behaviour of the molecule and it has been observed that the bathochromic shift was of about 5 nm, from the fluorescence measurement it has revealed that the emission has been observed at green region and from the power spectra it has been confirmed the same. The DFT study has been derived for the synthesized molecule the optimized structure, electrostatic potential maps, theoretical energy band gap and HOMO and LUMO visualizations are derived from the Gaussian 09W software and it has been found that the bandgap energy is found to be 2.607 eV for benzene solvent and 3.081 eV in methanol solvent, the electrophilic and nucleophilic sites exhibited at the substitution group of the molecule. The outcomes of the study clearly endorse the synthesized fluorescein derivative suitable for photonic/optoelectronic applications.

Unlocking the Photoluminescence Potential of Tabebuia Rosea Dyes: A Novel Natural Source of Broadband Visible Spectral Fluorescence for OLED Technologies

This investigation delves into the extraction of polyphenols from the flowers of Tabebuia rosea using a basic maceration approach with acetone, ethanol, and methanol as solvents. The spectroscopic analysis of the dye obtained confirms the existence of functional groups in the polyphenol extract. The study also explores optoelectronic, fluorescence, and photometric characteristics associated with polyphenols. Micro-destructive surface techniques, such as XPS led to the acquisition of detailed information on the extracted polyphenol. The XPS analysis verified the chemical composition of the dyes, revealing that C1s, O1s, and N1s peaks are the main signals for the extracted polyphenols. Additionally, the LC-MS analysis reveals the extract contains significant amounts of active compounds in the polyphenols class, which share a common polyphenol structure. FT-IR spectroscopy confirms the presence of functional groups in the polyphenol dye extract. The optical properties showed a narrow direct bandgap (Eg= 3.08eV), indirect bandgap (Eg=2.77eV), high refractive index (n = 1.52), dielectric constant (ε = 8.982), and high optical conductivity (σ = 3.54 x103 S/m) for the polyphenols extracted in methanol solvent. Polyphenols are characterized by high quantum yield, substantial lifetime, and notable Stoke's shift. In addition, these polyphenol dyes demonstrate strong broadband visible spectra and cover a spectrum from blue to green (x = 0.32 → 0.33 and y = 0.33 → 0.38) in different solvent conditions. Such attributes make them advantageous for use in Organic-LEDs and other optoelectronic technologies, underscoring their significant potential in these domains. In addition, polyphenols are important in removing DPPH-free radicals from the environment, contributing to the production of highly antioxidant green materials.

Light Harvesting Materials: A Study on Förster Resonance Energy Transfer and Optoelectronic Properties of Potential Nerium oleander Flowers

The present study focused on extracting the anthocyanin dyes in ethanol, acidic ethanol, methanol, and acidic methanol solvents from Nerium oleander flowers by a simple maceration extraction process. FTIR spectroscopy and vibrational studies have confirmed the existence of polyphenolic groups in 2-phenyl chromenylium (anthocyanin) dyes. The optoelectronic results show the least direct bandgap (2.89 eV), indirect bandgap (1.98 eV), Urbach energy (0.120 eV), high refractive index (1.654), dielectric constant (3.294) and high optical conductivity (1.813 103 S/m) for the anthocyanin dye extracted found in acidic ethanol solvent. The photoluminescence properties such as Stokes' shift, quantum yield, and lifetime results show that anthocyanin dyes are promising candidates for red-LEDs and optical materials. The excellent correspondence between the absorption and emission spectra reinforces that the anthocyanins are efficient (89%) FRET probes. Further, the donor and acceptor undergo redshift in excitation and emission spectra in all studied solvents. The photometric properties such as CIE, CRI, CCT and color purity results of anthocyanins in all studied solvents revealed that this material exhibits pink to red shades (x = 0.40 → 0.50 and y = 0.46 → 0.39) and is well suitable for have great potential in the manufacturing of Organic-LEDs and other optoelectronic device applications.

Visible Light-Induced Metal-free Arylation of Coumarin-3-carboxylates with Arylboronic Acids

The present work represents a novel methodology for the selective arylation of coumarin-3-carboxylates with arylboronic acids via a photochemical route, marking the first-ever attempt for the direct alkenyl C-H arylation using rose bengal as a photocatalyst, which is a readily available and cost-effective alternative to transition metal catalysis. The reaction proceeds smoothly in MeOH/H2O solvent media in the presence of radical initiator affording the arylated products in good yields (60-80 %). The reaction parameters such as visible light, radical initiator, oxidant, anhydrous solvent, and inert atmosphere play a crucial role for the success of this methodology. The substituents present on the substrate show a significant effect on the conversion. This study provides a valuable contribution to the field of organic synthesis offering a new and efficient approach to the arylation of coumarin-3-carboxylic acid esters with a broad substrate scope and high functional group tolerance. It is a versatile method and provides a direct access to biologically relevant 4-arylcoumarin-3-carboxylates.

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.

Enhanced performance of organic light-emitting diodes by integrating quasi-periodic micro-nano structures

To integrate a quasi-periodic micro-nano structure (PMS) to the organic light-emitting devices (OLEDs) is an efficient way to enhance the performance of OLEDs. In this paper, the PMS prepared by the phase separation of Polystyrene and Poly (methyl methacrylate) was integrated to the OLEDs with the structures of Glass/PMS/Ag (30 nm)/MoO₃ (5 nm)/(NPB) (40 nm)/(Alq₃) (60 nm)/LiF (0.5 nm)/Al (150 nm). The maximum luminance intensity and external quantum efficiency increased to 10700 cd/m² and 1.11 %, which is 48 % and 44 % higher than that of 7209 cd/m² and 0.77 % of the planar reference device. The enhanced performance of OLEDs was ascribed to the attenuation of surface plasmon polariton loss caused by the PMS, which was testified by the Finite-Difference Time-Domain (FDTD) simulation. The PMS was also transferred to the hole transfer layer (PEDOT: PSS) of OLEDs by nano-imprinting lithography with the structure of Glass/(ITO) (100 nm)/PEDOT: PSS (100 nm) (with PMS)/NPB (10 nm)/Alq₃ (50 nm)/LiF (0.5 nm)/Al (100 nm). The performance was also improved by the optimized PMS and the light out-coupling efficiency increased to about 49.5 %, which is much higher than that of 28.8 % in the OLEDs with PMS Ag anode and 20 % in the planar reference devices. This suggests that the PMS can improve the OLED device performance regardless of the functional layer in which the PMS is integrated.

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.

Exploration of Pull-Push Effect for Novel Photovoltaic Dyes with A-π-D Design: A DFT/TD-DFT Investigation

The π-rich versus π-poor units in 4,6-di(thiophen-2-yl)pyrimidine (DTB) alternating the π-backbone of solar cells dyes have been extended with a push-pull technique to lower their HOMO-LUMO energy gap and to increase Intramolecular Charge Transfer (ICT). Density functional theory was used to optimize the ground state molecular geometries of newly designed dyes (DTB1-DTB6). Time Dependent DFT (TD-DFT) was used to simulate the Uv-vis spectral values at the maximum absorbance values ranging between 481-535 nm. These values were red shifted from DTB value of experimental (333 nm) and theoretical (346 nm). however, their computed absorbance and fluorescence spectra revealed a bathochromic shift of them upon an increasing the solvent polarity. Different DFT functionals such as (B3LYP, CAM-B3LYP, B97XD, and APFD) were employed to choose their proper use Uv-visible analysis to reveal an unexpected coherence at the B3LYP level with experimental values. As a result, the B3LYP with most diffused basis sets of 6-31G + (d,p) were used for further calculations. The parameters of Global Chemical reactivities revealed that all the dyes had a softer nature with their softness value range of 0.27-0.41. their Ionization Potentials (IP) ranged between 6.21-8.10 eV to comply that the new dyes had good electron donating potentials. With a good electron injection potential of -1.47-1.74 eV, aluminum can be the best electrode, while Au is excellent towards a hole injection operation which had the potential range of 1.79-3.68 eV. For Natural Bond Orbital (NBO) assessment, (N14)LP → (F16-F28)π* with stabilization energy of 42.55 kcal/mol was noted for DTB4. Their Second order hyperpolarizability [Formula: see text] values as their Nonlinear Optical (NLO) response ranged between 59.16-232.11 debye-angstrom^-1 which were almost 6 times higher than the reference DTB (8.47D). The NLO attributes has also shown that a dyes with its small bandgap was related with higher hyperpolarizability values. Because of the decreased reorganization frequencies, newly discovered derivatives with electron transfer qualities might be comparable to or equivalent to those of commonly used electron transmission materials.

Theoretical assessments and optical and electrochemical properties of the alkoxylated bischalcone as emissive material in single-layer OLED

A new bischalcone comprising of hexyloxy (-OC₆H_2n+1) chain based on 'Donor (D)-π-Donor (D)' system was successfully designed and synthesized to demonstrate as emitting material for single-layer OLEDs. Density functional theory (DFT) assessment at B3LYP/6-31G(d,p) was computed to obtain frontier molecular orbitals (FMOs), chemical reactivity and molecular electrostatic potential (MEP). The utilization of alkoxy substructure towards the chalcone moiety has increased the solubility and contributed to HOMO-LUMO gap energy level 3.473 eV by UV-Vis spectroscopy and was found to have good agreement with the theoretical calculations. The investigations on their optical, electrochemical and thermal behaviour also were conducted via UV-Vis, cyclic voltammetry (CV), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The entitled alkoxylated bischalcone (CSAB) revealed good thermal stability up to 300 °C and showed high glass transition temperatures. At positive potential, a quasi-reversible oxidation (Eox 1/2) peak at 2.40 V and negative potentials exhibited reduction peak at 0.78 V, respectively. The application of CSAB was tested in the form of thin film in respect to its conductivity in terms of electrical current and electroluminescence behaviour. It gave an intense yellow emission which has provided depth fundamental understanding on its potentiality featuring alkoxylated bischalcone moiety as solution-processed OLED material in optoelectronic interests.

Solvatochromism and estimation of ground and excited state dipole moments of 6-aminoquinoline

The spectral behaviour of 6AQ was investigated using fluorescence spectroscopy in several polar and non-polar solvents. Both the absorption and fluorescence spectra displayed solvatochromism. The Stokes shift increased significantly with increasing solvent polarity and signifies a more polar excited state with possible change in the excited state (ES) geometry. The involvement of π→π^∗ transition was observed. The ground state (GS) and excited state (ES) dipole moments were determined by the solvatochromic shift method using Bilot-Kawaski, Lippert-Mataga, Kawski-Chamma-Viallet, and Reichardt equations. The experimental value of GS dipole moment matches closely with the theoretical value computed using DFT/B3LYP/6-311G(d,p). The ES dipole moment is higher than the GS dipole moment. Besides, the solvatochromic study reveals that the ES of 6AQ is more polarized than the GS due to intramolecular charge transfer (ICT), possibly aided by a change in the geometry of the molecule in the ES. The influence of the non-specific and specific interactions in the photophysical properties of the titled molecule was analyzed using the Catalan scale. The study shows that 6AQ has reasonable band-gap energy and good CIE chromaticity coordinate in the blue region close to the national television standard committee system (NTSC) for the ideal blue CIE coordinate. Therefore, future research into 6AQ as a source of light-emitting diodes and fluorescent sensors may have potential applications in the field of optoelectronics.

Spectroscopic and computational studies of the solid state photophysical properties of a biscoumarin dye

The solid state photophysical properties of the 3,3'-paraphenyl bis[6,8-dimethoxy-2H-chromen-2-one] symmetrical biscoumarin material were investigated by optical spectroscopy techniques and by theoretical calculations. Vibrational analysis using IR absorption and Raman scattering techniques carried out together with DFT theoretical calculations have confirmed the structure of this biscoumarin. The geometry optimization using different functionals reveal a nonplanar equilibrium structure with a dihedral between the phenyl and the pyran rings of about 142°. The UV-Visible absorption measurements and the TDDFT simulation show that this biscoumarin is characterized by a bicomponent feature resulting from ππ* electronic transitions and Intramolecular Charge Transfer (ICT). Solid state photoluminescence showed a bright blue-green emission at 506 nm with a large stokes shift estimated at 146 nm, and the temperature dependence study of this emission reveals two thermal evolution regimes. Finally, these good optical properties, as well as the stability of the emission, make this biscoumarin dye of potential interest for optoelectronic applications.

Solvent Influence on Absorption Spectra and Tautomeric Equilibria of Symmetric Azomethine-Functionalized Derivatives: Structural Elucidation and Computational Studies

A new series of azomethine-functionalized compounds was synthesized from the condensation of 2-hydroxy-1,3-propanediamine and 2-thienylcarboxaldehydes in the presence of a drying agent. The derivatives were spectroscopically characterized by NMR, LC-MS, UV/Vis, IR and elemental analysis. Variable temperature 1 H-NMR (-60 to +60 °C) was performed to investigate the effect of solvent polarity; the capability of solvent to form H-bond was found to dramatically influencing the tautomerization process of the desired structures. The calculated thermochemical parameters (ΔH298 , ΔG298 and ΔS298 ) at DFT and MP2 levels of theory explained that 3 b exists in equilibrium with two tautomers. The basis of the electronic absorptions was pursued through Time-Dependent Density-Functional Theory (TD-DFT). Analysis of the structural surfaces was inspected and the molecular electrostatic potential (MEP) demonstrated that the three functionalized compounds were relatively analogous in the electronic distributions. Furthermore, the electrophilic and nucleophilic centers lying on the molecular surfaces were probably playing a key-role in stabilizing the compounds through the nonclassical C-H⋅⋅⋅π interactions and hydrogen bonding. The impact of solvent polarity on absorption spectra were investigated via solvatochromic shifts. For instance, compound 3 c displayed a gradual shift of the maximum absorption to the red area when the solvent polarity was increased, recording a 21 nm of bathochromic shift. In contrast, no significant solvent-effect on 3 a and 3 b was observed. The solvation relation was pursued between Gutmann's donicity numbers the experimental λmax ; exhibited almost positive linear performance with a minor oscillation, that ascribe to the possible weak interface between the molecules of solute and designated solvents. The bandgap energy of all products were assessed experimentally using optical absorption spectra following Tauc approach, giving -4.050 (3 a), -3.900 (3 b) and -3.210 (3 c) eV. However, the ΔE were computationally figured out from TD-DFT simulation to be -4.258 (3 a), -4.022 (3 b) and -3.390 (3 c) eV.

Improved Color Purity of Monolithic Full Color Micro-LEDs Using Distributed Bragg Reflector and Blue Light Absorption Material

In this study, CdSe/ZnS core-shell quantum dots (QDs) with various dimensions were used as the color conversion materials. QDs with dimensions of 3 nm and 5 nm were excited by gallium nitride (GaN)-based blue micro-light-emitting diodes (micro-LEDs) with a size of 30 μm × 30 μm to respectively form the green and red lights. The hybrid Bragg reflector (HBR) with high reflectivity at the regions of the blue, green, and red lights was fabricated on the bottom side of the micro-LEDs to reflect the downward light. This could enhance the intensity of the green and red lights for the green and red QDs/micro-LEDs to 11% and 10%. The distributed Bragg reflector (DBR) was fabricated on the QDs color conversion layers to reflect the non-absorbed blue light that was not absorbed by the QDs, which could increase the probability of the QDs excited by the reflected blue light. The blue light absorption material was deposited on the DBR to absorb the blue light that escaped from the DBR, which could enhance the color purity of the resulting green and red QDs/micro-LEDs to 90.9% and 90.3%, respectively.