Highest Occupied Molecular Orbital Energy Research Articles

Exploring alkali metal cation⋯hydrogen interaction in the formation half sandwich complexes with cycloalkanes: a DFT approach

Abstract Gas and solvent phase stability of half sandwich complexes between cycloalkanes viz. cyclopropane, cyclobutane, cyclopentane, cyclohexane, bicyclo[2.2.2]octane and adamantane with alkali metal cations (Li+, Na+ and K+) are analysed using density functional theory (DFT). M06-2X/6-31++G(d,p) level is primarily used for the study. The studied half sandwich complexes are stable in gas phase (stabilization energy upto 26.55 kcal mol−1). Presence of solvent phase irrespective of its dielectric, imparts negative impact on the stability of the chosen complexes. The formation of the complexes is exothermic in nature. The process of complexation is both enthalpy (ΔH) and free energy (ΔG) driven. Variation in HOMO (highest occupied molecular orbital) energy also indicates towards the chemical stability of complexes. The interaction is non-covalent with primary contribution from induction component. NBO analysis indicates that C–H bond is the donor and antibonding metal orbital is the acceptor site in the process of complexation. Stability of the complexes depends on the size of the interacting monomers.

Engineering of Hole Transporting Interface by Incorporating the Atomic-Precision Ag6 Nanoclusters for High-Efficiency Blue Perovskite Light-Emitting Diodes.

Properties of the underlying hole transport layer (HTL) play a crucial role in determining the optoelectronic performance of perovskite light-emitting devices (PeLEDs). However, endowing the current HTL system with a deep highest occupied molecular orbital (HOMO) level concurrent with high hole mobility is still a big challenge, in particular being an open constraint toward high-efficiency blue PeLEDs. In this regard, employing the poly(9-vinylcarbazole) as a model, we perform efficient incorporation of the atomic-precision metal nanoclusters (NCs), [Ag6PL6, PL = (S)-4-phenylthiazolidine-2-thione], to achieve significant tailoring in both HOMO energy level and hole mobility. As a result, the as-modified PeLEDs exhibit an external quantum efficiency (EQE) of 14.29% at 488 nm. The presented study exemplifies the success of metal NC involved HTL engineering and offers a simple yet effective additive strategy to settle the blue PeLED HTL dilemma, which paves the way for the fabrication of highly efficient blue PeLEDs.

Quantum Chemical Calculations of 3-Benzyl-4-(3-Ethoxy-2-(4-Toluenesulfonlyoxy)-Benzlyideneamino]-4,5-Dihydro-1H-1,2,4-Triazol-5-One

In this study, 3-Benzyl-4-(3-ethoxy-2-(4-toluenesulfonlyoxy)-benzlyideneamino]-4,5-dihydro-1H-1,2,4-triazol-5-one was theoretically investigated. Initialy, the molecule was optimized by using DFT(B3LYP)/6-31G(d, p) basis set. The molecule’s structural parameters (dihedral angles, bond lengths and bond angles), HOMO (the highest occupied molecular orbital) and LUMO (the lowest unoccupied molecular orbital) energies, vibrational frequencies, thermodynamic and electronic properties (thermal capacity , rotation constants, entropy , total energy, electronegativity, electron affinity, chemical softness and hardness), the energy gap (ΔEgap = ELUMO-EHOMO), mulliken atomic charges, the surface maps were calculated by using Gaussian09W program. 13C- NMR and 1H-NMR chemical shift values of molecule also were calculated by GIAO. In additon, theoretical infrared (IR) vibration frequencies values which were scaled with certain scala factor were obtained using the veda4f program. Infrared spectra of molecul were formed according to obtained these values. The all spectroscopic and structural data of compounds were calculated by using 6-31G(d, p) basis set with density functional method (DFT/B3LYP) and compared with experimental values.

Incorporating a weak acceptor unit into PTB7-Th to tune the open circuit voltage for non-fullerene polymer solar cells

PTB7-Th is one of the most effective polymer donors which have drawn huge attention in organic solar cells. However, the highest occupied molecular orbital (HOMO) level of PTB7-Th is relatively high, which limit open circuit voltage (Voc) of the cell devices. In this work, to develop the new members of PTB7-Th family materials with higher Vocs, two new random terpolymers PTB7-Th(0.9) and PTB7-Th(0.8) have been synthesized, in which contains 10% or 20% benzo[1,2-b:4,5-b′]dithiophene-2,6-dicarboxylate (VBDTC, a weak acceptor unit) moiety in PTB7-Th. It was found that the incorporating of VBDTC unit has great influence on optical and electronic properties of the related polymers. Comparison with PTB7-Th, the PTB7-Th(0.9) and PTB7-Th(0.8) exhibit blue shift in the UV−visible spectra, which forming a more complementary absorption with the low band gap non-fullerene acceptors, like ITIC and Y6. Increasing the percentage of VBDTC moiety, it can sufficiently deepen the low-lying HOMO level of the related polymers, which would expect to an enhancement in Voc. Non-fullerene solar cells blended with ITIC, PTB7-Th(0.9) exhibited a Voc of 0.839 V, with power conversion efficiency (PCE) of 4.86%. Interestingly, PTB7-Th(0.8) showed superior photovoltaic performance with a Voc of 0.862 V, and PCE of 5.24%. And when blended with Y6, the PCE of PTB7-Th(0.8) based device was further improved to 6.13%, due to increasing the short-circuit current (Jsc). The comprehensive study reveals that it is an effective strategy to tune the absorption spectra and deepens the HOMO energy level of the PTB7-Th related polymers by incorporation of a weak acceptor unit, thus, achieving higher Voc as well as photovoltaic performance.

Synthesis of D-A-Type Polymers Containing Thieno[3,2-b]thiophene Unit, Their Composites with Carbon, and Lithium Storage Performance as Anode Materials

Conjugated organic polymers have attracted extensive attention due to their light weight, mechanical flexibility, and structural diversity. However, poor electronic conductivity limits their application in the electrodes of lithium-ion batteries (LIBs). In this paper, two composites of D-A (donor-acceptor) polymer and activated carbon (AC)—PTPP@AC and PTPTD@AC—were designed and successfully prepared using thieno[3,2-b]thiophene (BTh) as the donor unit, benzo [1,2-b:6,5-b′] dithiophene-4,5-dione or 7a,11a-Dihydro-3,4-dithia-7,12-diaza[a,c]anthracene as the acceptor unit and AC as the substrate. PTPP@AC and PTPTD@AC were then studied as anode materials for LIBs. The successful preparation of the target products was demonstrated by FT-IR, Raman spectra, XRD, and XPS. Electrochemical properties, such as the specific capacity, cycling stability, and rate performance of the electrode materials, were tested by cyclic voltammetry and galvanostatic charge–discharge (GCD). The storage process of lithium ions was investigated by XPS and CV tests. Compared with PTPP@AC, PTPTD@AC had a higher reversible specific capacity (247.3 mAh g−1 after 300 cycles at 0.1 A g−1), a better rate performance (at 1 A g−1, specific capacity of 87.3 mAh g−1), and a higher long-term cycling performance (after 1000 cycles of 0.5 A g−1, the specific capacity remains at 146.6 mAh g−1). The better electrochemical performance of PTPTD compared to PTPP was due to the former’s significantly higher HOMO (highest occupied molecular orbital) energy level than that of PTPP, while the Eg of PTPTD was smaller than that of PTPP. The experimental results show that D-A conjugated polymers have great potential for applications as electrode materials for rechargeable batteries.

Experimental and Theoretical Spectroscopic Investigation on Coumarin Based Derivatives for Non-Linear Optoelectronics Application.

The spectral properties of MBTC (4-((4-((Benzo[d]oxazol-2-ylthio)methyl)-1H-1,2,3-triazol-1-yl)methyl)-7-methoxy-2H-chromen-2-one), CBTC (4-((4(((5Chlorobenzo[d]oxazol-2-yl)thio)methyl)-1H-1,2,3-triazol-1-yl)methyl)-2H-benzo[h]chromen-2-one) and TBTC (4-((4-((Benzo[d]oxazol-2-ylthio)methyl)-1H-1,2,3-triazol-1-yl)methyl)6(tertbutyl)2Hchromen-2-one) were studied in series of solvents with different polarity at room temperature to explore their solvatochromic effect and dipole moment. Stokes shift revealed a bathochromic shift with varying solvent polarity for all molecules which implies π-π*transition. The ground state and excited state dipole moment of the molecules are calculated experimentally using salvatochromic methods like Lippert-Mataga, Bakhshiev, Kawaski-chamma-viallet, and Reichardt's microscopic solvent polarity functions and computationally by density functional theory (DFT) method. It is observed that the excited state dipole moment is higher than the ground state so synthesized molecules are more polar in the excited state than in the ground state. Using the DFT method HOMO and LUMO energy values were obtained and compared with values obtained by the cyclic voltammetry. Using the values of HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) we have estimated energy gap, chemical hardness (ɳ), chemical softness (s), ionization potential (IP), electron affinity (EA), electronegativity (χ), electrophilicity (ω), and chemical potential (μ) of the molecules were estimated. The energy gap of MBTC, CBTC, and TBTC were found to be low, that is 3.861eV, 3.822eV, and 3.801eV respectively, this indicates molecules are more reactiveand it has the easiestπ-π*transition. Further electrophilic and nucleophilic sites were figured out using molecular electrostatic potential (MESP) which is useful in photochemical reactions. Hence the quantum chemical calculation and spectroscopic properties of the molecules can give a better understanding of their use in an optoelectronic device.

A potential sensor for assessing thorium (IV) based on Albuterol sulfate fluorescence enhancement: A density functional theory (DFT) study

• Introducing a new fluorescent sensor for assessing Th(IV) in environmental samples. • Fluorescence mechanism was discussed. • HOMO and LUMO energy levels has been calculated by DFT. This study introduces a potential fluorescence sensor for assessing thorium (Th(IV)) in aquatic environments. In the presence of Th(IV), Albuterol Sulfate ( ABS ) 4-[2-( tert -butylamino)-1-hydroxyethyl]-2-(hydroxymethyl)phenol; sulfuric acid exhibits significant fluorescence enhancement at 600 nm. The current ABS ligand sensor shows wide linear range from 6.0 × 10 −8 – 2.5 × 10 −7 mol/L and pH range of 4–6. Interestingly, when all evaluated interference ions coexisted, the change in fluorescence emission intensity of ABS -Th complex was roughly 2.3 %. The binding mode is studied and indicating a 2:1 complex formation between ABS ligand and Th (IV). Density functional theory (DFT) has been utilized to examine the interaction characteristics between the present ABS ligand sensor and Th(IV) and to compute the geometric configuration of the ABS and ABS -Th through the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energy levels. The interaction properties exhibit considerable effect on the HOMO and LUMO properties of the complexes, as well as a fluorescence enhancement that could be attributable to the heavy atom effect of Th (IV). The ABS sensor shows remarkable features and provides good performance compared to some of the optical sensors, making it a potential new fluorescence sensor for Th(IV) assessment.

Edge carboxylation-induced charge separation dynamics of graphene quantum dot/cellulose nanocomposites

Graphene quantum dot (GQD)@cellulose nanocomposites possess optoelectronic properties of interest for photovoltaic applications. However, the optoelectronic properties related to the shapes and edge types of GQDs have not been fully explored. In the present work, we investigate the effects of carboxylation on the energy alignment and charge separation dynamics at the interface of GQD@cellulose nanocomposites using density functional theory calculations. Our results show that the GQD@cellulose nanocomposites composed of hexagonal GQDs with armchair edges exhibit better photoelectric performance than those composed of other types of GQDs. Carboxylation stabilizes the energy level of the highest occupied molecular orbital (HOMO) of the triangular GQDs with armchair edges but destabilizes the HOMO energy level of cellulose, resulting in hole transfer from the GQDs to cellulose upon photoexcitation. However, the calculated hole transfer rate is lower than the nonradiative recombination rate because excitonic effects dominate the dynamics of charge separation in GQD@cellulose nanocomposites.

Biosorption of Rhodamine B dye from aqueous solution by Rhus coriaria L. plant: Equilibrium, kinetic, thermodynamic and DFT calculations

Water-soluble basic rhodamine B (RhB) was adsorbed onto fruit powders of Rhus coriaria L. (Anacardiaceae), sumac in batch reactions. Adsorption was optimized by employing concentration, pH, and time parameters. Experimental data were in accordance with the Freundlich isotherm, adsorption obeyed the pseudo-second-order kinetics, and thermodynamic parameters indicated that adsorption was exothermic, spontaneous, and chemical. Results were also evaluated by theoretical means: lowest Unoccupied Molecular Orbitals (LUMO), and the Highest Occupied Molecular Orbitals (HOMO). The HOMO energy values of the rhodamine B molecule had the highest activity with -3.3729 at the B3LYP level, -6.0361 at the HF level, and -4.3299 at the M062X level. In the calculations made, it was seen that the rhodamine B molecule has more electron density on the oxygen molecules. Taken together, the findings suggested that the dried fruit of the Rhus coriaria L. could be a useful biosorbent for the removal of dyes from aqueous media.

Synergistic high efficiency and low energy loss of all-small-molecule organic solar cells based on benzotriazole-based π-bridge unit

Reducing energy loss (Vloss) is one of the most crucial challenges in organic photovoltaic cells. The Vloss, determined by the differences between the optical band gap (Eg) of the active layer material and the open-circuit voltage (Voc) of the device, is generally alleviated by lowering the energy difference between the lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) level of the donor (D) and acceptor (A). In this work, we synthesized two A-π-D-π-A-type small-molecule donors (SMDs) SM-benzotriazole (BTz)-1 and SM-BTz-2 by introducing a BTz π-bridge unit and terminal regulation. The BTz π-bridge unit significantly lowers the HOMO energy level of SMDs, resulting in high Voc and high mobility, achieving a balance of low energy loss (<0.5 eV) and high efficiency. Ultimately, the organic solar cells based on SM-BTz-2 as the donor and Y6 as the acceptor obtain a high Voc of 0.91 V, Jsc of 22.8 mA cm−2, fill factor of 68%, and power conversion efficiency (PCE) of 14.12%, which is one of the highest efficiencies based on the SMDs with triazole π-bridges to date. What’s more, the BTz π-bridge unit is a potential unit that can improve mobility and reduce energy loss.

Towards Efficient Blue Delayed-Fluorescence Molecules by Modulating Torsion Angle Between Electron Donor and Acceptor

Towards Efficient Blue Delayed-Fluorescence Molecules by Modulating Torsion Angle Between Electron Donor and Acceptor

Phosphonium-Based Ionic Thermally Activated Delayed Fluorescence Emitters for High-Performance Partially Solution-Processed Organic Light-Emitting Diodes

Phosphonium-Based Ionic Thermally Activated Delayed Fluorescence Emitters for High-Performance Partially Solution-Processed Organic Light-Emitting Diodes

Enhanced efficiency of polymer solar cells via simple fluorination on the π-bridge of polymer donors

In this contribution, a novel fluorinated polymer based on the well-known J52, using the newly developed 3-fluorothiophene as π bridges on the conjugated main chain, named J52-FTh , was synthesized and was used as polymer solar cells (PSCs) donor material. The effects of fluorinated π bridge on the polymer's thermal stability, light absorption, energy level, molecular configuration and photovoltaic performance were systematically studied. It demonstrated that J52-FTh exhibited an enhanced absorption, a narrower optical band gap, a low-lying the highest occupied molecular orbitals (HOMO) energy level and better coplanar compared with J52 without any fluorine substituent on its π bridges. The non-fullerene PSCs based on J52-FTh :ITIC (1:0.8, w/w) achieved a high PCE of 13.32% with a V OC of 0.92 V, a J SC of 21.29 mA cm −2 and an FF of 68%, which was much better than the PSCs based on J52:ITIC with a PCE of 5.51%. The results indicated that fluorination on the polymer's main chain was a simple and efficient strategy toward high efficiency. A novel fluorinated polymer based on the well-known J52, using the newly developed 3-fluorothiophene as π bridges on the conjugated main chain, named J52-FTh , was synthesized and was used as polymer solar cells (PSCs) donor material. The PSCs based on J52-FTh :ITIC achieved a high PCE of 13.32% with a V OC of 0.92 V, a J SC of 21.29 mA cm −2 and a FF of 68%, which was superior to that of the binary PSCs based on J52:ITIC. • A novel fluorinated polymer based on the well-known J52, using the newly developed 3-fluorothiophene as π bridges, named J52-FTh , was synthesized. • The effects of fluorinated π bridge on the polymer’s thermal stability, light absorption, energy level, molecular configuration and photovoltaic performance were systematically studied. • J52-FTh exhibited an enhanced absorption, a narrower optical band gap, a low-lying HOMO energy level and better coplanar compared with J52 without any fluorine substituent on its π bridges. The non-fullerene PSCs based on J52-FTh :ITIC achieved a high PCE of 13.32%, which was much better than the PSCs based on J52:ITIC. • The results indicated that fluorination on the polymer’s main chain was a simple and efficient strategy toward high efficiency.

Synthesis of innovative triphenylamine-functionalized organic photosensitizers outperformed the benchmark dye N719 for high-efficiency dye-sensitized solar cells

Herein, we present a thorough photovoltaic investigation of four triphenylamine organic sensitizers with D–π–A configurations and compare their photovoltaic performances to the conventional ruthenium-based sensitizer N719. SFA-5–8 are synthesized and utilized as sensitizers for dye-sensitized solar cell (DSSC) applications. The effects of the donor unit (triphenylamine), π-conjugation bridge (thiophene ring), and various acceptors (phenylacetonitrile and 2-cyanoacetamide derivatives) were investigated. Moreover, this was asserted by profound calculations of HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energy levels, the molecular electrostatic potential (MEP), and natural bond orbital (NBO) that had been studied for the TPA-sensitizers. Theoretical density functional theory (DFT) was performed to study the distribution of electron density between donor and acceptor moieties. The sensitization by the absorption of sensitizers SFA-5–8 leads to an obvious enhancement in the visible light absorption (300–750 nm) as well as a higher photovoltaic efficiency in the range of (5.53–7.56%). Under optimized conditions, SFA-7 showed outstanding sensitization of nanocrystalline TiO2, resulting in enhancing the visible light absorption and upgrading the power conversion efficiency (PCE) to approximately 7.56% over that reported for the N719 (7.29%). Remarkably, SFA-7 outperformed N719 by 4% in the total conversion efficiency. Significantly, the superior performance of SFA-7 could be mainly ascribed to the higher short-circuit photocurrents (Jsc) in parallel with larger open-circuit voltages (Voc) and more importantly, the presence of different anchoring moieties that could enhance the ability to fill the gaps on the surface of the TiO2 semiconductor. That could be largely reflected in the overall enhancement in the device efficiency. Moreover, the theoretical electronic and photovoltaic properties of all studied sensitizers have been compared with experimental results. All the 2-cyanoacrylamide derivative sensitizers demonstrated robust photovoltaic performance.

Fine-Tuned Morphology Based on Two Well-Miscible Polymer Donors Enables Higher Open-Circuit Voltage and Enhanced Stability for Highly Efficient Ternary All-Polymer Solar Cells.

Developing organic solar cells based on a ternary active layer is one of the most effective approaches to improve their photovoltaic performance. However, limited success has been achieved in all-polymer solar cells (all-PSCs). In this study, a ternary all-PSC with improved efficiency and stability is realized by using J71 as the third component to adjust the host system of PBDB-T:PG1. The deeper highest occupied molecular orbital (HOMO) energy level of J71 downshifts the mixed HOMO energy levels of donors. The two polymer donors (PD s) have good miscibility and present Förster resonance energy transfer. When blended with PG1, the optimized morphology is obtained, showing enhanced crystallinity but meanwhile slightly reduced phase separation with improved exciton dissociation and collection efficiency, suppressed charge recombination, and reduced energy loss (0.55eV). Combining the benefits mentioned above, the ternary all-PSC exhibits an excellent efficiency of 12.8% with simultaneously elevated open-circuit voltage (0.96V), short-circuit current density (18.4mAcm-2 ), and fill factor (72.2%). Moreover, the optimized ternary all-PSC shows improved storage and thermal stability. This study demonstrates that the utilization of a ternary all-polymer system based on two well-miscible PD s is an effective strategy to enhance the photovoltaic performance and stability of all-PSCs.

Deep learning for development of organic optoelectronic devices: efficient prescreening of hosts and emitters in deep-blue fluorescent OLEDs

The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies, which are key factors in optoelectronic devices, must be accurately estimated for newly designed materials. Here, we developed a deep learning (DL) model that was trained with an experimental database containing the HOMO and LUMO energies of 3026 organic molecules in solvents or solids and was capable of predicting the HOMO and LUMO energies of molecules with the mean absolute errors of 0.058 eV. Additionally, we demonstrated that our DL model was efficiently used to virtually screen optimal host and emitter molecules for organic light-emitting diodes (OLEDs). Deep-blue fluorescent OLEDs, which were fabricated with emitter and host molecules selected via DL prediction, exhibited narrow emission (bandwidth = 36 nm) at 412 nm and an external quantum efficiency of 6.58%. Our DL-assisted virtual screening method can be further applied to the development of component materials in optoelectronics.

The Selection of Anode and Cathode Materials for Top Emission Organic Light-Emitting Diodes

In this study top emission organic light-emitting diodes (TE-OLED) were successfully fabricated on flexible PET/multilayer disordered silver nanonetwork (MDSN) substrate with conventional LiF/Al as a semitransparent cathode and Ag as a reflective anode. The effects of the hole injection layer, anode buffer layer, and an electron injection layer on the luminescence characteristics of TE-OLEDs were investigated. At first, the thickness of cathode Al is adjusted based upon the overall transmittance of the top-emission cathode and its conductivity. There is a high energy barrier for the hole between the work function of the anode Ag (4.2 eV) and the NPB highest occupied molecular orbital (HOMO) energy level (5.5 eV), which is not favorable for hole injection. This study tested four types of hole injection layer (HIL) materials. Finally, MoO3 was selected as an optimal HIL material, and the optimum thickness was adjusted, enabling the hole to be injected smoothly from the anode to the NPB and then to an emitting layer. The TE-OLED luminance reached 268 cd/m2. There is a high energy barrier between the work function of Ag and MoO3 HOMO (5.3 eV)—about 1.1 eV—which is still not conducive to the hole injection, so a thin layer of high work function metal Au (work function 5.1 eV) was added to the top of the anode silver, which more matches with the MoO3 energy level. It can make the hole easier to inject from the anode to MoO3 (HIL) and protect the silver from oxidation. At 8 V, the luminance is increased to 413.7 cd/m2, and the current efficiency is 0.81 cd/A. The luminance is significantly improved. An electron transport/hole blocking layer TPBi (10 nm) was added to enhance the electron transport capability and effectively block the holes with higher electron mobility and a higher HOMO energy level of TPBi. So that more holes can remain in the emitting layer and increase the chance of the electron-hole recombination to improve the luminance and current efficiency of TE-OLED. At 8 V, the luminance and current efficiency can reach 611.4 cd/m2 and 0.95 cd/A, respectively.

Synthesis, spectroscopic, and density functional theory studies of the corrosion inhibitive behaviour of n-(1,4-dihydro-1,4-dioxonaphthalene-3-yl)pyrazine-2-carboxamide chelator-ligand

The inhibitory effect of N-(1,4-dihydro-1,4-dioxonaphthalene-3-yl) pyrazine-2-carboxamide (HL chelator) on the corrosion of mild steel (Ms) in 1M HCl remained appraised via weight loss (WL) estimations, atomic absorption spectrophotometer (AAS), scanning electron microscope (SEM) and computational studies. The adsorption of the appraised ligand remained found to conform to Langmuir adsorption isotherm (LAI). The data acquired for ΔGads denotes chemisorption adsorption mechanism for the inhibitor while acquired AAS analysis results revealed that the concentration of iron in the inhibited corrosive medium is less than the concentration of iron in the uninhibited solution after immersion with Ms at the same contact time and was also observed to reduce with upsurge in concentration of the inhibitor. SEM micrographs acquired revealed that the existence of the studied compound lessened the degree of corrosion in addition to decreased surface roughness signifying establishment of protective inhibitor film at the Ms surface. The energy of highest occupied molecular orbital (EHOMO) as well as energy of lowest unoccupied molecular orbital (ELUMO) remained estimated via density functional theory (DFT) method from which other parameters were determined. The results acquired from computational studies were in conformity with those from experimental studies and both validate the use of HL chelator as an excellent and efficient inhibitor for the corrosion of Ms in 1 M HCl.

DFT and TD-DFT studies of 1,3,5-Tris (dipheny1amino) benzene derivatives based hole transport materials: application for perovskite solar cells

The current study examined a series of 1,3,5-tris (diphenylamino) benzene derivatives used as hole transport materials in perovskite solar cells (HTM1-HTM9). All calculations were performed utilizing the density functional theory (DFT) and TD/DFT procedures at B3LYP/6-311G level. The ground state geometry, frontier molecular orbital (FMO), photoelectric properties and reorganization energies and the absorption spectra were investigated. The energy levels of highest occupied molecular orbitals (HOMOs) and lowest unoccupied molecular orbitals (LUMOs) were calculated for HTM1-HTM9, compared to all of the compounds under investigation and the spiro-OMeTAD, HTM 8 has the lowest HOMO energy level, indicating a favourable overlap with the MAPbI3 perovskite active layer.

Computational investigation of substituent effects on the fluorescence wavelengths of oxyluciferin analogs

Oxyluciferin, which is the light emitter for firefly bioluminescence, has been subjected to extensive chemical modifications to tune its emission wavelength and quantum yield. However, the exact mechanisms for various electron-donating and withdrawing groups to perturb the photophysical properties of oxyluciferin analogs are still not fully understood. To elucidate the substituent effects on the fluorescence wavelength of oxyluciferin analogs, we applied the absolutely localized molecular orbitals (ALMO)-based frontier orbital analysis to assess various types of interactions (i.e. permanent electrostatics/exchange repulsion, polarization, occupied–occupied orbital mixing, virtual–virtual orbital mixing, and charge-transfer) between the oxyluciferin and substituent orbitals. We suggested two distinct mechanisms that can lead to red-shifted oxyluciferin emission wavelength, a design objective that can help increase the tissue penetration of bioluminescence emission. Within the first mechanism, an electron-donating group (such as an amino or dimethylamino group) can contribute its highest occupied molecular orbital (HOMO) to an out-of-phase combination with oxyluciferin’s HOMO, thus raising the HOMO energy of the substituted analog and narrowing its HOMO-LUMO gap. Alternatively, an electron-withdrawing group (such as a nitro or cyano group) can participate in an in-phase virtual–virtual orbital mixing of fragment LUMOs, thus lowering the LUMO energy of the substituted analog. Such an ALMO-based frontier orbital analysis is expected to lead to intuitive principles for designing analogs of not only the oxyluciferin molecule, but also many other functional dyes.