Electron Transfer Integrals Research Articles

Rebuilding Peripheral F, Cl, Br Footprints on Acceptors Enables Binary Organic Photovoltaic Efficiency Exceeding 19.7%

Given homomorphic fluorine, chlorine and bromine atoms are featured with gradually enlarged polarizability/atomic radius but decreased electronegativity, the rational screen of halogen species and location on small molecular acceptors (SMAs) is quite essential for acquiring desirable molecular packing to boost efficiency of organic solar cells (OSCs). Herein, three isomeric SMAs (CH‐F, CH‐C and CH‐B) are constructed by delicately rebuilding peripheral F, Cl, Br footprints on both central and end units. Such a re‐permutation of peripheral halogens could not only maintain the structural symmetry of SMAs to the maximum, but also acquire extra asymmetric benefits of enhanced dipole moment and intramolecular charge transfer, etc. Moreover, central brominating enhances molecular crystallinity of CH‐B without introducing undesirable steric hindrance on end groups, thus rendering a better balance between high crystallization and domain size control in PM6:CH‐B blend. Further benefitting from the large dielectric constant, small exciton binding energy, optimized molecular packing and great electron transfer integral, CH‐B affords the first class binary OSC efficiency of 19.78%, moreover, the highest efficiency of 18.35% thus far when increasing active layer thickness to ~300 nm. Our successful screening in rebuilding peripheral halogen footprints provides the valuable insight into further rational design of SMAs for record‐breaking OSCs.

Rebuilding Peripheral F, Cl, Br Footprints on Acceptors Enables Binary Organic Photovoltaic Efficiency Exceeding 19.7%

Given homomorphic fluorine, chlorine and bromine atoms are featured with gradually enlarged polarizability/atomic radius but decreased electronegativity, the rational screen of halogen species and location on small molecular acceptors (SMAs) is quite essential for acquiring desirable molecular packing to boost efficiency of organic solar cells (OSCs). Herein, three isomeric SMAs (CH‐F, CH‐C and CH‐B) are constructed by delicately rebuilding peripheral F, Cl, Br footprints on both central and end units. Such a re‐permutation of peripheral halogens could not only maintain the structural symmetry of SMAs to the maximum, but also acquire extra asymmetric benefits of enhanced dipole moment and intramolecular charge transfer, etc. Moreover, central brominating enhances molecular crystallinity of CH‐B without introducing undesirable steric hindrance on end groups, thus rendering a better balance between high crystallization and domain size control in PM6:CH‐B blend. Further benefitting from the large dielectric constant, small exciton binding energy, optimized molecular packing and great electron transfer integral, CH‐B affords the first class binary OSC efficiency of 19.78%, moreover, the highest efficiency of 18.35% thus far when increasing active layer thickness to ~300 nm. Our successful screening in rebuilding peripheral halogen footprints provides the valuable insight into further rational design of SMAs for record‐breaking OSCs.

Effect of Halogen Substituents on Charge Transport Properties of n-type Organic Semiconductors: A Theoretical Study.

Organic semiconductors (OSCs) have received significant attention as promising materials for electronic devices. In this study, we investigate the impact of halogen groups on the charge transport properties of n-type OSC-6,13 bis((triisopropylsilyl)ethynyl)-5,7,12,14-tetraazapentacene (TIPS-TAP). The computed mobilities for TIPS-TAPs substituted with F and Cl exhibit excellent agreement with the experimental values, while the simulation overestimates the electron mobility for TIPS-TAP. Interestingly, the mobility of TIPS-TAP-4F is significantly lower than that of TIPS-TAP-4Cl/Br, despite their similar packing structures. This discrepancy can be attributed to the strong electron-withdrawing effect of fluoride, which reduces the electron transfer integral and increases the reorganization energy. While molecular packing is widely recognized as a dominant factor in charge transport in OSCs, our study highlights the crucial role of electronic effects in charge transport in OSCs. This study provides new insights into the mechanisms underlying charge transport in OSCs.

Photoinduced charge transfer in small-molecule organic solar cells dependent on external electric field

In this paper, MTDATA is selected as the electron donor and BPhen as the acceptor. The trianiline structure of the donor molecule provides a variety of charge transfer pathways for charge separation. Based on Marcus theory, the photoinduced charge transfer properties of non-fullerene acceptor organic solar cells (NFA-OSCs) in external electric field (Fext) were studied. By analyzing the changes of reorganization energy (λ), Gibbs free energy (ΔG), electron transfer integral (Vda) and charge transfer rate under the influence of Fext, it was found that Fext can effectively regulate the charge transfer. Moreover, the change of charge transfer rate under Fext is similar to Vda, indicating that Vda is the main factor affecting charge transfer rate. To a certain extent, this study provides theoretical support for improving the photoelectric performance of NFA-OSCs.

Synthesis, antioxidant activity, antimicrobial efficacy and molecular docking studies of 4-chloro-2-(1-(4-methoxyphenyl)-4,5-diphenyl-1H-imidazol-2-yl)phenol and its transition metal complexes.

Herein, a one-pot synthesis of tetra-substituted imidazole, 4-chloro-2-(1-(4-methoxyphenyl)-4,5-diphenyl-1H-imidazol-2-yl)phenol (HL), is reported by the reaction of benzil, 5-bromosalicylaldehyde, ammonium acetate and anisidine. The synthesized imidazole was reacted with salts of 1st row transition metals (Co(ii), Ni(ii), Cu(ii), Mn(ii) and Zn(ii)) to obtain metal complexes. The structure of the compounds was confirmed using various spectroscopic and analytical techniques. HL, which is crystalline, was characterized by SC-XRD. Subsequently, the synthesized compounds were evaluated for their antioxidant and antimicrobial activities. Antimicrobial studies revealed the more noxious nature of metal complexes compared to ligand against various strains of bacteria and fungi. Molecular docking results based on the binding energy values also supported the experimental results of the antioxidant activities of the compounds. HL was found to be a better antioxidant than metal complexes. For a better insight into the structure, computational studies of the compounds were also carried out. A clear intra-molecular charge transfer was perceived in the ligand and its metal complexes. The transfer integral values for holes (36.48 meV) were found to be higher than the electron transfer integrals (24.76 meV), which indicated that the ligand would be a better hole transporter. According to the frontier molecular orbitals of the dimer, the charge transfer within the molecule is found from monomer 1 to 2.

Influence of Intermolecular Packing on Light Emitting Efficiency and Carrier‐Mobility of Organic Semiconductors: Theoretical Descriptor for Molecular Design

AbstractIntegration of luminescence and carrier transport is of prime interest for optoelectronics, but full with challenges in organic semiconductors. Previously, it has been demonstrated that intermolecular charge transfer (ICT) in the herringbone H‐aggregate can lend oscillator strength to the lowest‐lying dark state if electron transfer (te) and hole transfer (th) integrals are in phase (same sign) and greater than , where J is exciton coupling. In this work, both herringbone and π–π stackings are considered and a universal descriptor is proposed. It is found that for π–π stacking with I > 1 and for herringbone with , respectively, the lowest dark state could become bright through mixing ICT component. Accordingly, it is found that eclipsed packing and use of molecules with acene‐like frontier molecular orbital profiles favor larger I value than the other packing patterns. Finally, with the help of the proposed descriptor, 13 high‐mobility emissive unit cores from 32 fused ring molecules are effectively screened out.

Prototype of cell for quantum cellular automata: Multimode vibronic model for a two-electron mixed valence molecular square

Multimode vibronic model for the two-electron square-planar mixed valence cluster is developed and applied to analysis of localization-delocalization phenomenon. The model involves interaction of the excess electrons both with “breathing” (Piepho-Krausz-Schatz- PKS-type) vibrations and with the intercenter vibrations modulating electron transfer integrals. We demonstrate that the coupling with two B1g-vbrations can be substituted by the effective coupling with the “interaction mode”. As a result, complex three-mode vibronic problem proves to be reduced to the two-mode problem involving the interaction mode of B1g-symmetry having hybrid nature and pure intercenter A1g-vibration. The analysis of minima of the lower adiabatic potential surface shows that the two vibrations produce competitive effects on the localization-delocalization properties. Thus, the dominating coupling with B1g-vibration is shown to form the double-well adiabatic potential surface, with the electronic pair in each minimum being predominantly localized on one of diagonals of the square, while the dominating coupling with the A1g-mode gives rise to single-well surface describing fully delocalized electronic pair. Finally, keeping in mind applications of square-planar two-electron clusters as molecular cells in quantum cellular automata we reveal the role of different vibrations in the shape of cell–cell response function.

Controllable Electron Transfer in Mixed-Valence Bridged Norbornylogous Compounds: Ab Initio Calculation Combined with a Parametric Model and Through-Bond and Through-Space Interpretation.

In the context of a computationally guided approach to the controllable electron transfer in mixed-valence (MV) systems, in this article, we study the electron transfer (ET) in the series of oxidized norbornadiene C7H8 (I) and its polycyclic derivatives, C12H12 (II), C17H16, (III), C27H24 (IV), and C32H28 (V), with variable lengths of the bridge connecting redox sites. The work combines an ab initio CASSCF evaluation of the electronic structure of systems I-V with the parametric description in the framework of the biorbital two-mode vibronic model. The model involves coupling with the "breathing" mode and intercenter vibration modulating the distances between the redox fragments. The ab initio calculations were performed for two types of optimized structures of I-V: (a) charge-localized global minimum (Cs) and (b) symmetric configuration (C2v) with the delocalized charge. This allows one to estimate the potential barrier separating charge-localized configurations as well as vibronic coupling parameters and the electron transfer integral. Along with the adiabatic approach, the quantum-mechanical analysis of the vibronic levels has been applied to precisely estimate the quantum effect of tunneling splitting. We estimate the "through-space" and "through-bond" contributions to the parameters interrelated with the charge transfer (CT). The through-space effect proves to be a major factor of ET at a short distance between the redox centers, whereas the through-bond contribution is dominant at a long distance. Vibronic coupling under the condition of through-space ET leads to the localization of the positive charge on the π-chromophore, while the through-bond component of ET results in compensating σ-shifts and subsequent charge delocalization over the bridge. The limitations of the parametric approach were discussed in the context of the two components contributing to the ET. Particularly, the bridge polarization in the course of through-bond ET proves to be beyond the basis of the employed parametric model.

HJ-aggregates of donor-acceptor-donor oligomers and polymers.

A vibronic exciton model is developed to account for the spectral signatures of HJ-aggregates of oligomers and polymers containing donor-acceptor-donor (DAD) repeat units. In (DAD)N π-stacks, J-aggregate-promoting intrachain interactions compete with H-aggregate-promoting interchain interactions. The latter includes Coulombic coupling, which arises from "side-by-side" fragment transition dipole moments as well as intermolecular charge transfer (ICT), which is enhanced in geometries with substantial overlap between donors on one chain and acceptors on a neighboring chain. J-behavior is dominant in single (DAD)N chains with enhanced intrachain order as evidenced by an increased red-shift in the low-energy absorption band along with a heightened A1/A2 peak ratio, where A1 and A2 are the oscillator strengths of the first two vibronic peaks in the progression sourced by the symmetric quinoidal-aromatic vibration. By contrast, the positive H-promoting interchain Coulomb interactions operative in aggregates cause the vibronic ratio to attenuate, similar to what has been established in H-aggregates of homopolymers such as P3HT. An attenuated A1/A2 ratio can also be caused by H-promoting ICT which occurs when the electron and hole transfer integrals are out-of-phase. In this case, the A1 peak is red-shifted, in contrast to conventional Kasha H-aggregates. With slight modifications, the ratio formula derived previously for P3HT aggregates is shown to apply to (DAD)N aggregates as well, allowing one to determine the effective free-exciton interchain coupling from the A1/A2 ratio. Applications are made to polymers based on 2T-DPP-2T and 2T-BT-2T repeat units, where the importance of the admixture of the excited acceptor state in the lowest energy band is emphasized.

Intermolecular Charge-Transfer-Induced Strong Optical Emission from Herringbone H-Aggregates.

Luminescence in molecular aggregates can be quenched either by intermolecular charge transfer or by forming a dipole-forbidden lower Frenkel exciton in H-aggregate. Taking intermolecular charge transfer and excitonic coupling into a three-state model through localized diabatization, we demonstrate that the low-lying intermolecular charge-transfer state could couple with the upper bright Frenkel exciton to form dipole-allowed S1 that lies below the dark state, which accounts for the recent experimentally discovered strong luminescence in organic light-emitting transistors (OLETs) system with DPA and dNaAnt herringbone aggregates. The condition of forming such bright state is that the electron and hole transfer integrals, te and th, are of the same sign, and should be notably larger than the excitonic coupling (J), that is , te × th > 2J2. This theoretical finding not only rationalizes recent experiments but unravels an exciting scenario where strong luminescence and high charge mobilities become compatible, which is a preferable condition for both OLETs and electrically pumped lasing.

Perovskite as a spin current generator

We theoretically show that materials with perovskite-type crystal structures provide a platform for spin current generation, taking advantage of a mechanism requiring neither the spin-orbit coupling nor a ferromagnetic moment, but is based on spin-split band structures in certain kinds of collinear antiferromagnetic states. By investigating a multiband Hubbard model for transition metal compounds by means of the Hartree-Fock approximation and the Boltzmann transport theory, we find that a pure spin current is induced by an electric field applied to a C-type antiferromagnetic metallic phase. The spin current generation originates from a cooperative effect of spatially anisotropic electron transfer integrals owing to the GdFeO$_3$-type lattice distortion, which is ubiquitous in many perovskites, and the collinear spin configuration. We discuss our finding from the symmetry point of view, in comparison with other spin current generator candidates with collinear antiferomagnetism. We also propose several ways to detect the phenomenon in candidate perovskite materials.

Toward multifunctional molecular cells for quantum cellular automata: exploitation of interconnected charge and spin degrees of freedom.

We discuss the possibility of using mixed-valence (MV) dimers comprising paramagnetic metal ions as molecular cells for quantum cellular automata (QCA). Thus, we propose to combine the underlying idea behind the functionality of QCA of using the charge distributions to encode binary information with the additional functional options provided by the spin degrees of freedom. The multifunctional ("smart") cell is supposed to consist of multielectron MV dn-dn+1-type (1 ≤ n ≤ 8) dimers of transition metal ions as building blocks for composing bi-dimeric square planar cells for QCA. The theoretical model of such a cell involves the double exchange (DE), Heisenberg-Dirac-Van Vleck (HDVV) exchange, Coulomb repulsion between the two excess electrons belonging to different dimeric half-cells and also the vibronic coupling. Consideration is focused on the topical case in which the difference in Coulomb energies of the two excess electrons occupying nearest neighboring and distant positions significantly exceeds both the electron transfer integral and the vibronic energy. In this case the ground spin-state of the isolated square cell is shown to be the result of competition of the second-order DE producing a ferromagnetic effect and the HDVV exchange that is assumed to be antiferromagnetic. In order to reveal the functionality of the magnetic cells, the cell-cell response function is studied within the developed model. The interaction of the working cell with the polarized driver-cell is shown to produce an antiferromagnetic effect tending to suppress the ferromagnetic second-order DE. As a result, under some conditions the electric field of the driver cell is shown to force the working cell to exhibit spin-switching from the state with maximum dimeric spin values to that having minimal spin values.

Vibronic exciton model for low bandgap donor-acceptor polymers.

A vibronic exciton model is introduced to describe the excited state band structure and associated absorption spectra of low bandgap donor-acceptor conjugated polymers. The Hamiltonian is represented in a diabatic basis consisting of Frenkel-like donor and acceptor fragment excitations as well as charge-transfer (CT) excitations between neighboring fragments. States are coupled to each other through electron and hole transfer as well as Coulombically, through interacting fragment transition dipole moments. Local vibronic coupling involving the prominent aromatic-quinoidal vibrational mode, which is responsible for pronounced vibronic progressions in most conjugated oligomers and polymers, is also included. The DAD repeat unit is shown to behave like a J-aggregate trimer, driven by both the sizable in-phase electron and hole transfer integrals between donor and acceptor fragments as well as negative Coulomb coupling between donor and acceptor fragment excitations. The J-aggregate behavior is enhanced in the polymer limit through inter-repeat unit coupling, with the 0-0 vibronic peak significantly enhanced in the lowest-energy near-IR band. In addition, the radiative rate is enhanced by the number of coherently connected repeat units. The near-IR band is shown to possess roughly equal admixtures of CT and Frenkel-like excitations. Applications are made to the polymer PffBT4T-2DT, with the simulated absorption spectrum quantitatively capturing the salient features of the measured spectrum.

Monoradicals and Diradicals of Dibenzofluoreno[3,2-b]fluorene Isomers: Mechanisms of Electronic Delocalization.

The preparation of a series of dibenzo- and tetrabenzo-fused fluoreno[3,2-b]fluorenes is disclosed, and the diradicaloid properties of these molecules are compared with those of a similar, previously reported series of anthracene-based diradicaloids. Insights on the diradical mode of delocalization tuning by constitutional isomerism of the external naphthalenes has been explored by means of the physical approach (dissection of the electronic properties in terms of electronic repulsion and transfer integral) of diradicals. This study has also been extended to the redox species of the two series of compounds and found that the radical cations have the same stabilization mode by delocalization that the neutral diradicals while the radical anions, contrarily, are stabilized by aromatization of the central core. The synthesis of the fluorenofluorene series and their characterization by electronic absorption and vibrational Raman spectroscopies, X-ray diffraction, SQUID measurements, electrochemistry, in situ UV-vis-NIR absorption spectroelectrochemistry, and theoretical calculations are presented. This work attempts to unify the properties of different series of diradicaloids in a common argument as well as the properties of the carbocations and carbanions derived from them.

Nanostructure of organic semiconductor thin films: Molecular dynamics modeling with solvent evaporation

We present a procedure for simulating solution deposition of organic thin-films on explicitly modeled substrates via solvent evaporation simulations in a molecular dynamics framework. Additionally, we have developed force fields for the family of IDTBR nonfullerene acceptors, which have been widely employed in the literature as $n$-type materials in several types of organic semiconductor devices, and we analyzed their structure-property relationships using a combination of grazing incidence x-ray scattering measurements, atomistic molecular dynamics simulations, and quantum chemical calculations. We find that thermal fluctuations can have a significant impact on calculated electron transfer integrals, and that the $\ensuremath{\pi}$-stacking interactions of the electron withdrawing benzothiadiazole building blocks are key to high electron coupling in amorphous thin films of $n$-type materials.

A theoretical study on cyclometalated iridium (III) complexes by using a density functional theory

Cyclometalated iridium (III) complexes (Ir1–Ir4) are calculated in detail with computational chemistry methods. The calculated structural parameters of Ir3 are compared with experimental values and a good fit is obtained. IR spectra are calculated at B3LYP/LANL2DZ/6-31G(d) level in the gases phase. Calculated1H-NMR chemical shift values of the mentioned complexes are compared with the experimental data and all chemical shifts are assigned to the respective atoms. The quantum chemical parameters such as absolute hardness ([Formula: see text]), absolute softness ([Formula: see text]) electronegativity ([Formula: see text]), chemical potential ([Formula: see text]) and electronic charges ([Formula: see text]) are calculated and are associated with the experimental anti-cancer properties of the related complexes. Nonlinear optic properties of the Ir1–Ir4 were investigated with the average linear polarizability ([Formula: see text]), the anisotropy of the polarizability ([Formula: see text]), first hyperpolarizability ([Formula: see text]) values. Hole transfer ([Formula: see text]), electron transfer integrals ([Formula: see text]), hole reorganization energies ([Formula: see text]) and electron reorganization energies ([Formula: see text]) are examined. In addition, molecular docking study was performed. It was found that the molecular docking results are similar to the experimental anti-cancer trend.

Two-dimensional electronic and charge-transport properties of a monolayer organic crystal: Impacts of the collinear transfer-integral correlations

Abstract Electronic transfer integrals between the frontier orbitals of adjacent molecules represent the most important parameter governing charge transport in organic crystals. Different transfer integrals may be significantly modulated by the same modes of molecular vibrations as a result of nonlocal electron-phonon couplings, leading to spatial correlations between the transfer integrals. Here, by employing a multiscale modeling approach, we investigate theoretically the impacts of transfer-integral correlations (TICs) on the two-dimensional electronic and charge-transport properties of a monolayer pentacene crystal. In particular, we focus on the collinear TICs that are present between molecular pairs along the same direction of molecular packings in the crystal. We reveal that the interplay of the collinear TICs along different directions leads to diverse landscapes of nonlocal electron-phonon couplings in reciprocal space, of which the impacts explicitly manifest themselves in the band structures at finite temperatures. We also evaluate the anisotropic hole mobility of the pentacene monolayer and demonstrate that the consequence of the collinear TICs can be reflected in the behaviors of the temperature-dependent band-like mobility observed in experiment. These findings provide an insight into how nonlocal electron-phonon couplings operate through TICs to impact the electronic and electrical properties of organic crystals in two dimension.

Electron donating effect of amine groups on charge transfer and photophysical properties of 1,3-diphenyl-1H-pyrazolo[3,4-b]quinolone at molecular and solid state bulk levels

Effect of various electron donating amines, i.e., dimethylamine (DMA), diphenylamine (DPA), phenylnaphthylamine (PNA) and dinaphthylamine (DPA) at 6 position on the electronic, photophysical and charge transfer properties of 1,3-diphenyl-1H-pyrazolo[3,4-b]quinolone (DPPQ) as a parent molecule has been explored at the molecular and solid state bulk level. The effect of substituents on absorption and emission was studied at TD-B3LYP/6-31G** level in acetonitrile. The computed emission wavelengths were being red shifted for DMA-DPPQ, DPA-DPPQ, PNA-DPPQ than that of parent molecule which might be green, yellow, orange and red light emitters. The charge transfer nature of various DPPQ derivatives has been explored on the bases of ionization potential, hole extraction potential, electron affinity, reorganization energies, transfer integrals and intrinsic mobility. The DMA substitution at position 6 of DPPQ boost up the electron transfer integrals leading to balanced charge transport for holes and electrons. Moreover, total/partial density of states and optical properties (dielectric constant, extinction coefficient refractive indices, reflectivity and conductivity) at solid state bulk scale have been explored. Different properties of interest at molecular and solid state levels revealed that 1,3-diphenyl-1H-pyrazolo[3,4-b]quinolone derivatives would be efficient materials to be used in multifunctional organic semiconductor devices.

Exploring the Optoelectronic and Charge Transfer Nature of Ferrocene Derivatives: A First-Principles Approach

Optoelectronic and charge transfer properties of three ferrocene derivatives 4-(4-methoxybenzyl)-1-(1-ferrocenylethyl)thio-semicarbazone (1), 4-(2-fluorobenzyl)-1-(1-ferrocenylethyl)thiosemicarbazone (2) and 4-(3,4-dimethylphenyl)-1-(1-ferrocenylethyl)thiosemicarbazone (3) were probed by first-principles study. Density functional theory (DFT) was carried out to elucidate the structural and electronic properties. The B3LYP/6-31G**(LANL2DZ) level was adopted to shed light on the structural parameters and frontier molecular orbitals. The computed geometrical parameters are rationale to the X-ray crystallographic data. The intra-molecular charge transfer from ligand to metal was perceived in ferrocene derivatives. The absorption and emission spectra were computed employing time domain TD-B3LYP/6-31G** (LANL2DZ) level. The hole and electron transfer integrals were estimated to figure out the charge transfer nature in particular ferrocene derivatives. The larger electron transfer integral values are anticipating that these studied Compounds 1–3 might be better electron transfer materials. Moreover, the effect of electron activating groups (–CH3 and –OCH3) and electron deactivating group (-F) was studied on the transfer integrals, structural and electro-optical properties.

Charge carrier and optoelectronic properties of phenylimidazo[1,5-a]pyridine-containing small molecules at molecular and solid-state bulk scales

Various optoelectronic and charge transfer properties of 3-(1H-indol-3-yl)-1-phenylimidazo[1,5-a]pyridine (Comp 1), 1,3-diphenylimidazo[1,5-a]pyridine (Comp 2), and 3-(Anthracen-9-yl)-1-phenylimidazo[1,5-a]pyridine (Comp 3) have been explored at the molecular and solid state bulk level. The absorption and emission spectra (λabs and λemi) were calculated by time domain B3LYP/6-311G*, CAM-B3LYP/6-311G*, LC-BLYP/6-311G* and PBE0/6-311G* levels. The hybrid functionals B3LYP and PBE0 successfully reproduced experimental λabs and λemi more accurately than the long-range corrected functionals. Effect of indol, phenyl and anthracenyl moieties on various properties of interests has been explored. The indol and phenyl units lead to smaller hole reorganization energies and greater transfer integrals resulting superior hole intrinsic mobility for Comps 1 and 2. The substitution of anthracenyl moiety at phenylimidazo[1,5-a]pyridine core increase the electron affinity and electron transfer integrals while decrease the electron reorganization energy. The n- or p-type charge transfer nature of Comp 3 or Comps 1 and 2 has been explored, respectively. The frontier molecular orbitals, ionization potential, electron affinity, reorganization energy, transfer integral, intrinsic mobility, density of states, dielectric constant, extinction coefficient, refractive indices, reflectivity and conductivity shown that imidazo[1,5-a]pyridine derivatives would be efficient materials to be used in multifunctional organic semiconductor devices.