Search

Non-fullerene acceptor (NFA) based bulk heterojunction organic solar cells (BHJOSC) offer a promising pathway for advancing organic photovoltaic (OPV) technology. These solar cells have the potential to improve performance and offer greater versatility in material design. Due to their broad absorption spectra, tunable energy levels, and reduced energy loss, researchers are actively exploring NFA materials and device architectures to further enhance the efficiency and viability of these solar cells. In this study, we focus on efficiency enhancement and investigating the influence of varying bandgap, thickness, and electron affinity of (PBDBT) Poly[[4,8-bis[5-(2-ethylhexyl)-2-thienyl]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl]-2,5-thiophenediyl[5,7-bis(2-ethylhexyl)-4,8-dioxo-4H,8H-benzo[1,2-c:4,5-c′]dithiophene-1,3-di yl]]/-2,2'-((2Z,2'Z)-((6,6'-(5,10,10-tris(2-ethylhexyl)-5,10-dihydroindeno[1,2-b]indole-2,7-diyl)bis(2-octylthieno[3,4-b]thio-phene-6,4-diyl))bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1diylidene))dimalononitrile (PBDBT-INTIC) based NFABHJOSC with the incorporation of graphene derivative in the hole transport layer (HTL) and electron transport layer (ETL). To conduct our research, we utilize a One-Dimensional Solar Cell Capacitance Simulator (SCAPS1D) for simulation studies. Additionally, we also examine the impact of varying the work function of anode in our investigation. This comprehensive study aims to provide valuable insights into the performance and characteristics of NFABHJOSC, contributing to the advancement of organic photovoltaic technology [ABSTRACT FROM AUTHOR]

Armchair (5, 5) carbon nanotubes doped with germanium atoms (Ge, n = 1-4) were explored theoretically in this work. Density functional theory (DFT) with hybrid functional Becke 3-parameter Lee–Yang–Parr (B3LYP) and a basis set 6-31G* were used to investigate the structural and electronic properties of the resulting nanotubes. The stability of the substitutional Ge atoms was thus studied and explained in terms of the binding energy per dopant atom. The density of state and HOMO-LUMO gap showed that electrical conductivity increases gradually with the number of dopants. The ionization potential, electron affinity, chemical hardness and softness, and chemical potential were also calculated. [ABSTRACT FROM AUTHOR]

Using the density functional theory technique, the chemical compound 2-(tert-Butylamino)-1-[4-hydroxy-3-(hydroxymethyl)phenyl]ethanol was investigated for use as a corrosion inhibitor. By using the commonly used harmful corrosion inhibitors, the toxicity has increased. Due to strict environmental regulations regarding the usage and disposal, there is a concern in replacing the hazardous corrosion inhibitors with effective non toxic inhibitors. The organic compounds can be used as a corrosion inhibitors as it becomes a popular and cost - effective approach of preventing corrosion in metals. In order to ascertain how potential corrosion inhibitors may act, quantum chemical parameters including EHOMO, ELUMO, Energy gap (Δ E), dipole moment (µ), electron affinity (A), ionisation potential (I), absolute electronegativity (χ), global hardness (η), softness (S), and electrophilicity index (ω), are determined with B3LYP / 6 - 311++ G(d,p) level. UV-Visible spectrum studies has also been computed employing TD– DFT method. [ABSTRACT FROM AUTHOR]

We have analyzed the effect of Ch3Nh3PbI3 interfacial layer on Cu2O/TiO2 based solar cells using SCAPS 1D. The initial investigation has shown that insertion of interfacial layer has resulted in better efficiency and lesser impact of defect variations. The Ag/Cu2O/Ch3Nh3PbI3/TiO2/FTO solar cells have shown enhanced efficiency in comparison to Ag/Cu2O/TiO2/FTO solar cell. Further, we have varied the thickness and defect density of Cu2O and it is observed that the impact of thickness variation is relatively less on the efficiencies of Ag/Cu2O/Ch3Nh3PbI3/TiO2/FTO solar cell. The optimized obtained thickness of Cu2O is 2 µm. The thickness and electron affinity of TiO2 is varied to understand its impact on the performance of solar cells. Later, we have varied the interfacial defects of the solar cells and have observed that the Ch3Nh3PbI3/TiO2 interface have affected the efficiencies drastically in comparison to Cu2O/Ch3Nh3PbI3 interface in Ag/Cu2O/Ch3Nh3PbI3/TiO2/FTO solar cells. We have also studied the effect of thickness variation of Ch3Nh3PbI3 layer and it has shown increased efficiency with increase in thickness which is eventually tending towards saturation. Finally, we have tried to understand the impact of temperature variation on the performance of the solar cells. [ABSTRACT FROM AUTHOR]

Pyromellitic diimide in addition of naphthalimide display a tricyclic planner structure while the experimental study showed pyromellitic diimide apears a red shift to naphthalimide because of the greater donor effect of the two imide groups and to their high electron affinities resulting from bend the terminal imine group. The planner structure (2d) without bending (3d) play major factor in electron transport. [ABSTRACT FROM AUTHOR]

The most widely hybrid functional, (B3LYP) (Becke's3 parameter exchange correlation functional which uses 3 parameters) with LanL2DZ (DFT) (Density functional theory) was proved its cogency in computing the optimization of geometry and determining the parameters of geometrical (angles and bonds length) of (PVA-SeO2-SiC) nanocomposites. The structural stability and electronics properties of the nanoparticle were calculated by energy, HOMO-LUMO gap, ionization potentials and electron affinity. The absorbance of polyvinyl alcohol (PVA) increases with an adding (SeO2) nanoparticles. The results of structure and electronics characteristics for (PVA-SeO2-SiC) structures indicated that the designed structures have energy gap (2.231eV). The ultraviolet–visible (UV–Vis) range (400–700 nm) optical behavior of Nano composite consisted of poly (poly (vinyl alcohol) and (SeO2) was studied for optoelectronic device applications. [ABSTRACT FROM AUTHOR]

In the present work, electronic properties of bisphenol A polycarbonate (BPA-PC) including natural charge distribution, global scalar parameters, and molecular electrostatic potential surfaces, have been calculated by using DFT/M06-2X and HF methods with a 6-31++G(d,p) basis set. The results show that the high positive charge was 1.06536 in.C17, and the high negative charges were -0.55030, -0.62666, and -0.74152 in O16, O18, and O19 respectively. The relative high ionization potential and low electron affinity reflect the stability of BPA-PC molecule. The molecular electrostatic potential of the molecule has been evaluated to distinguish the rich and poor electron regions on the surface. Moreover, thermodynamic properties like entropy, heat capacity, and enthalpy have been calculated using the M06-2X method with a 6-31++G(d,p) basis set. It is found that all the investigated thermodynamic properties increase with temperature. [ABSTRACT FROM AUTHOR]

Electronic structure calculations on nanoclusters of GaInNAs/GaNInAs semiconducting alloy provide two stable structures, one of which is in linear form and the other one in ladder form. All calculations have been performed under the framework of Density Functional Theory (DFT) using the B3LYP functional. The basis set LANL2DZ was used in all calculations done in the software package Gaussian 16W. The manuscript discusses properties of the compounds such as, optimized energy, frontier orbital energy gap, dipole moment, ionization potential, electron affinity, binding energy, embedded energy and other parameters. The application of these compounds or alloys is mainly in the production of light emitting diodes (LEDs) and other optoelectronic devices. [ABSTRACT FROM AUTHOR]

The search for corrosion inhibitors based on natural products that are environmentally friendly with high inhibition efficiency is still the focus of current research. The corrosion inhibition efficiency of nicotine and its derivatives has been studied using DFT and ab initio MP2 method. This research focuses on the use of electronic parameters and the natural bond analysis approach to explain the corrosion inhibition performance of nicotine and its derivatives. The electronic properties of molecules, including the frontier molecular orbitals (HOMO and LUMO energy), ionization potential, electron affinity, electronegativity, number of electron transfer from inhibitors to metal and interaction energy have a strong relationship with inhibition performance. Interaction mechanism is obtained from natural bond between inhibitors with iron metal in more detail. The presence of electron donor groups within the framework of inhibitors show significant contribution toward the corrosion inhibition performance. [ABSTRACT FROM AUTHOR]

The theoretical and computational calculation of the stability, vibrational, structural and electronic properties of PVDF-co-HFP polymer are depicted using the B3LYP functional and 6-31+G (d,p) basis set of Gaussian03. All the observations were carried out for monomer and dimer of Poly(vinylidene fluoride-co-hexachloropropylene) PVDF-co-HFP polymer. Density functional theory (DFT) calculations are convenient to model orbital energies of conjugated polymers, hitherto incongruity between theory and experiment exist. In the following step, the outcomes obtained from quantum chemical calculation accomplished for PVDF-co-HFP, as preliminary polymer composites (PCs) study, are reported. Frontier orbitals (HOMO, LUMO) configurations and energies were acquire for monomer and dimer of PVDF-co-HFP Polymer. The increase of the PVDF-co-HFP’s chain length leads to decreasing its energy gap, chemical hardness. While the electron affinity, chemical softness, and ionization potential shows increasing order. [ABSTRACT FROM AUTHOR]

The density functional theory based calculations have been performed to study TiFn in neutral and anionic form for n = 1 to 5. The ground state structures have been analyzed with their preferred spin multiplicities. In neutral species, Ti atom binds successively to four F atoms but up to five in case of anions. Thus, the maximum oxidation state of Ti is limited to +4. The TiFn‾ anions are found to be more stable as compared to their neutral counterparts due to their larger binding energies per atom. The electron affinity of TiFn species has been calculated and explained by atomic charges and frontier molecular orbital surfaces. We notice that the electron affinity of TiFn increases only slowly up to n = 4 but abruptly to the peak value of 6.53 eV for n= 5. The enormous electron affinity of TiF5 suggests its superhalogen behavior, which results due to extra electron delocalization over peripheral F atoms. [ABSTRACT FROM AUTHOR]

In the present paper, electronic structure and electro-optical properties of 4-(4-ethoxybenzilideneamino) benzoic acid (eBABA), a pure nematic liquid crystal have been examined using DFT-B3LYP/6‒31G(d,p) method. This liquid crystal transforms from crystal to nematic phase at 215˚C and nematic to isotropic phase at 290˚C. Molecular electrostatic potential, HOMO and LUMO surfaces have been scanned. Electro-optical parameters such as the dipole moment, polarizability, anisotropy in polarizability, molar refractivity along with some electronic parameters such as ionization potential, electron affinity, chemical hardness and absolute electronegativity of eBABA molecule have been calculated. Further, infrared (IR) spectrum has been analyzed so as to examine the functional groups of eBABA liquid crystal molecule. [ABSTRACT FROM AUTHOR]

Organic light-emitting diodes (OLEDs) materials have occupied significance in device applications due to their lightweight, thin, quick switching speed, flexible, easy to fabricate and low-cost features. The 8-quinolinolato-lithium (Liq) is commonly used as an electron injector in the layer of OLEDs. Herein, we study 8-quinolinolato-sodium (Naq) and 8- quinolinolato-potassium (Kq) and compare them with Liq using density functional theory approach. We analyze the molecular structure of 8-quinolinolate-alkali (Mq) for M = Li, Na and K and notice that the structure of Mq remains planar for all the three substitutions. The increased dipole moments of Mq with the change of substitution (M) suggest that its enhanced solubility in polar solvents, which tends to reduce the electron injection barrier. Furthermore, the higher polarizability of Naq and Kq indicates that the molecule is chemically more reactive than Liq and therefore, is expected to respond quickly when the field is applied. Moreover, the electron affinities of Mq increase with the substitution of Na and K, which is also desirable for improved electron transport behavior. However, the reorganization energy of Naq and Kq is slightly higher than that of Liq, which is not desirable for the transport of charge carriers in OLED devices. Therefore, the findings of this study demand further assessment for the application of Naq and Kq instead of Liq in OLED devices. [ABSTRACT FROM AUTHOR]

One of the most frequently asked questions in photovoltaics is about efficiencies. Wurtzite Cadmium sulfide (CdS) thin films have properties that are suitable for solar cell fabrication especially in tandem solar cells. According to the start point of nanostructure using in solar cells like tandem, we have gone to use the wurtzoid instead of wurtzite structure for CdS as a window in tandem solar cell. Simulation of nanostructure parameters of CdS in wurtzoid structure have been performed with Gaussian 09 program with its view. For simulation study; optimization of structure, total energy, energy gap, potential of ionization, electron affinity, work function, electronegativity, chemical potential (Fermi energy), electrophilicity, chemical hardness, softness, and amount of charge transport have been investigated. For experimental work CdS in wurtzoid structure as a window was produced by pulse laser deposition (PLO) onto perovskites thin films which are prepared by solution processing drop casting in tandem solar cell. The analysis provides: the fill factor and the power conversion efficiency. The energy gap of the CdS wurtzoid molecule is 3.190eV. The efficiency of tandem perovskite solar cell with CdS wurtzoid window was reached 22.3 %. [ABSTRACT FROM AUTHOR]

Amongst various metal oxides, Zinc Oxide (ZnO) is widely used semiconducting material amongst various II-VI group materials due to its various properties like wide energy band gap (3.3 eV), strong binding energy of 60 meV, higher transparency,low electron affinity sensitivity and selectivity for device grade applications. For this study purpose, for this study purpose (ZnO) thin films have been deposited by Successive Ionic Layer Adsorption and Reaction (SILAR) technique on amorphous glass substrate at room temperature. These films were then annealed for about 2 hours in air atmosphere. The structural studies reveal the increase in grain size upto 400oC. The change in crystallite size were observed in the Atomic Force Microscopy ( AFM) images. The optical studies were also in well agreement with the structural analysis. [ABSTRACT FROM AUTHOR]

Density Function Theory (DFT) method was achieved by studying solvent effect such as water and ethanol on the electronic and vibrational spectra of formic molecule by using the B3LYP functional and the 6-31G basis set. The optimized structure, energy gap, electron affinity, ionization potential, zero point, Infrared (IR) and UV-Vis spectra were computed. All these properties have been calculated by using Gaussian09 program and Gaussian view 5.08 program according to density function (DFT) method, while the UV-Vis spectra have been computed by using TD-DFT method. [ABSTRACT FROM AUTHOR]

We present charge transport properties of tetra hydroxy pyrene (THP) organic molecule using quantum chemical density functional theory (DFT). The reorganization energies were found to be 0.34eV (λh) and 0.79 eV (λe) eV for THP molecule. The HOMO and LUMO transfer integrals were calculated as 0.34 eV and 0.19 eV at the inter planar distance of3.4 A0, and these were also found to decay exponentially in the translation orientation from3.4 to 4.8 A0, periodically in the shifting from 0 to 6.0 A0 and rotational angle from 00 to 1800, respectively. Hole and electron mobilities of the compound were calculated to be 6.04 cm² V-1 sec-1 and 0.25 cm² V-1 sec-1 respectively. The electron affinity (EA), ionization potential (IP), HOMO/LUMO energy, and HOMO-LUMO energy gaps were also calculated. [ABSTRACT FROM AUTHOR]

The density functional theory (DFT) protocol together with B3LYP/6-311G(d,p) level of theory has been utilized to explore and compare the structural features and molecular characteristics of two naturally occurring flavonoid compounds eriodictyol and fustin. The –OH bond dissociation energy (BDE) for all the radical species have been computed and interpreted in accordance with the radical scavenging activity. The ionization potential (IP) value of fustin flavonoid compound was found to be within the range of synthetic food additives. The polar nature and their capacity to polarise other atoms are established through the dipole moment analysis. Additionally, various parameters that are relevant to chemical potential such as electron affinity, hardness, softness, electro negativity and electrophilic index were calculated and analysed in the light of quercetin flavonoid compound in view of their antioxidant activity. The antioxidant capability of fustin is found to be superior to eriodictyol flavonoid. [ABSTRACT FROM AUTHOR]

Ionization potential and electron affinity of organic semicondutors are important quantities, which are relevant to charge injection barriers. The electrostatic and dynamical contributions to the polarization energies for the injected charges in pentacene polymorphs were investigated. While the dynamical polarization induced narrowing of the energy gap, the electrostatic effect shifted up or down the frontier energy levels, which is sensitive to the molecular orientation at the surface. [ABSTRACT FROM AUTHOR]

Synthetic antioxidants such as butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) are found to be toxic, hence non-carcinogenic naturally occurring radical scavengers especially flavonoids have gained considerable importance in the past two decades. In the present investigation, the radical scavenging activity of Cglycosyl flavonoids is evaluated using theoretical approach which could broaden its scope in therapeutic applications. Gas and solvent phase studies of structural and molecular characteristics of C-glycosyl flavonoid, isovitexin is investigated through hydrogen atom transfer mechanism (HAT), Electron transfer-proton transfer (ET-PT) and Sequential proton loss electron transfer (SPLET) by Density functional theory (DFT) using hybrid parameters. The computed values of the adiabatic ionization potential, electron affinity, hardness, softness, electronegativity and electrophilic index indicate that isovitexin possess good radical scavenging activity. The behavior of different -OH groups in polyphenolic compounds is assessed by considering electronic effects of the neighbouring groups and the overall geometry of molecule which in turn helps in analyzing the antioxidant capacity of the polyphenolic molecule. The studies indicate that the H-atom abstraction from 4'-OH site is preferred during the radical scavenging process. From Mulliken spin density analysis and FMOs, B-ring is found to be more delocalized center and capable of electron donation. Comparison of antioxidant activity of vitexin and isovitexin leads to the conclusion that isovitexin acts as a better radical scavenger. This is an evidence for the importance of position of glucose unit in the flavonoid. [ABSTRACT FROM AUTHOR]

Electronic structure properties of 4-n- methoxy-4'-cyanobiphenyl, a pure nematic liquid crystal have been examined using an ab-initio, HF/6-31G(d,p) technique with GAMESS program. Conformational and charge distribution analysis have been carried out. MEP, HOMO and LUMO surfaces have been scanned. Ionization potential, electron affinity, electronegativity, global hardness and softness of the liquid crystal molecule have been calculated. Further, stacking, side by side and end to end interactions between a molecular pair have been evaluated. Results have been used to elucidate the physico-chemical and liquid crystalline properties of the system. [ABSTRACT FROM AUTHOR]

We analyze energies, electron affinities and polarizabilities of small anions exposed to an external confinement. The second electron in free O2- and S2- anions is unbound. We investigate the stabilizing effect of the spherical harmonicoscillator confining potential a on these anions employing the Hartree-Fock stability analysis as introduced by Čížek and Paldus. With increasing strength of the external harmonic-oscillator confinement potential ω the broken symmetry (BS) solutions are systematically eliminated. For ω larger than 0.1 all BS solutions for O2- disappear. For ω larger than 0.13 the CCSD(T) energy of O2- becomes more negative than the energy of the singly charged O- anion. We relate the harmonicoscillator confining potential to a crystalline environment in which the O2- and S2- anions are stable. We also present a model allowing calculations of the in-crystal polarizabilities of anions. The model is based on CCSD(T) calculations of static polarizabilities of selected anions exposed to the spherical harmonic-oscillator confining potential ω. This artificial confinement potential ω is then related to the ionic radii of the cation in representative crystal lattices. We investigate the polarizability of O2- and S2- anions in MgO, MgS, CaO, CaS, SrO, SrS, BaO and BaS crystals. We compare our results with alternative models for in-crystal polarizabilities. External confinement also stabilizes the uracil anion U-, as is shown by calculations with a stepwise micro-hydration of U-. Upon hydration is the CCSD(T) adiabatic electron affinity (AEA) of uracil enhanced by about 250 up to 570 meV in comparison with AEA of the isolated molecule, depending on the geometry of the hydrated uracil anion complex. We tried to find an analogy of the stabilization effect of the external confinement on the otherwise unstable anions. In uracil and its anion is the external confinement represented by the polarized continuum solvation model with dielectric constant as a variational parameter. The physical behavior of ions exposed to an artificial external, spherical harmonic-oscillator confining potential a, the environment represented by a crystal structure and the confinement represented by the solvent, all have considerable stabilizing effect on the otherwise unstable free anion [ABSTRACT FROM AUTHOR]

We describe a theoretical study of the charge transport properties of the organic dimethyl benzo difuran (DMBDF) molecule based on density functional theory (DFT). Reorganization energy, ionization potential (IP), electron affinity (EA), energy gaps, transfer integral (t) and charge mobility (μ) has been studied to depict the transport properties in the conjugated organic molecules. We computed, large homo transfer integral and IP value leading to high hole mobility (4.46 cm²/V sec). However, the electron reorganization energy (0.34 eV) and the electron mobility of 1.62 cm²/V sec, infers that the DMBDF organic molecule bears an ambipolar character. [ABSTRACT FROM AUTHOR]

Surface-Assisted Laser Desorption Ionization (SALDI) involves desorbing and ionizing analyte molecules from a nanoporous substrate by laser irradiation for detection in a mass spectrometer. In this work experiments were designed to better understand the mechanisms governing desorption and ionization for Desorption Ionization On Silicon (DIOS), a variant of SALDI which uses porous silicon (pSi) as a substrate. Experiments are also reported for other nanoporous semiconducting materials (WO3, TiO2) which exhibit very similar behaviors; specifically, that both protonated analyte ions and analyte radical cations can be generated with relative intensities that depend on the position of the incident laser focus relative to substrate surface. While thermal desorption appears to be important, preliminary evidence suggests that the ionization mechanism leading to protonated analytes involves in part electrons and holes formed when photoexciting the substrate above its electronic band gap, and the presence of defect states within the band gap. Radical cation formation appears to be driven in part by electron transfer due to the large electron affinity of each substrate used in this work. [ABSTRACT FROM AUTHOR]

In a very recent article (Chem. Eur. J. 14, 8652-8660 (2008)), the present author has shown that the picture of the local softness and local hardness is incomplete and that the understanding of these reactivity indices must be "redefined". In fact, the local softness and hardness contain the "same potential" information and they have to be considered as "local abundance" or "concentration" of their corresponding properties. In this contribution, we will analyze the implications in the applicability of the local version of the HSAB principle. [ABSTRACT FROM AUTHOR]

We present fully relativistic coupled cluster calculations of ionization potentials, electron affinities, and polarizabilities of superheavy elements 114 and 118, along with their lighter homologues, lead and radon. The combination of the 4-component Dirac Hamiltonian with the state of the art coupled cluster approach allows us to achieve very good agreement with experimental values for the lighter elements; similar precision can be expected for our predictions for the superheavy atoms. The trends in the atomic properties are discussed, demonstrating the strong relativistic effects. Using the calculated atomic properties, adsorption enthalpies of the superheavy atoms on inert surfaces are estimated and shown to be rather low for both elements. [ABSTRACT FROM AUTHOR]

Single-walled armchair carbon nanotubes (n,n) of one and two unit cells with n = 3,4,5 and 6 have been studied using semi-empirical PM3 and PM6 methods and an effort has been made to understand the reactivity profiles of these nanotubes. The studied carbon nanotubes are saturated with hydrogen at the ends. Various reactivity descriptors like ionization potential, electron affinity, chemical potential, HOMO-LUMO gap are discussed in terms of the frontier molecular orbitals. The HOMO-LUMO gap is found to decrease with increase of the diameter for one unit cell nanotubes whereas it increases in the case of two unit cells nanotubes. Heat of formation and binding energy per carbon atom are also reported for these nanotubes. [ABSTRACT FROM AUTHOR]

DFT and TD-DFT studies of o-phenylenediamine (PDA), 3,5-dinitrosalicylic acid (DNSA) and their charge transfer complex have been carried out at B3LYP/6-311G(d,p) level of theory. Molecular geometry and various other molecular properties like natural atomic charges, ionization potential, electron affinity, band gap, natural bond orbital (NBO) and frontier molecular analysis have been presented at same level of theory. Frontier molecular orbital and natural bond orbital analysis show the charge delocalization from PDA to DNSA. [ABSTRACT FROM AUTHOR]

We have suggested that a small momentum spread of photoelectrons and high quantum efficiency can be obtained concurrently by a photocathode using a semiconductor with a superlattice instead of a bulk. We have begun to search for the suitable semiconductor material of a superlattice photocathode for maintaining the surface with a negative electron affinity state for a long time. We measured quantum efficiency degradation of photocathodes using GaAs and AlGaAs semiconductors with various electron affinities. The AlGaAs semiconductor had a quantum efficiency lifetime of 10 times long compared with the GaAs semiconductor. We found that the AlGaAs semiconductor was the suitable material for the superlattice photocathode with the surface maintaining a negative electron affinity state for a long time. [ABSTRACT FROM AUTHOR]

We study charge recombination rates in blends of MEH-PPV and a comprehensive set of low molecular-weight fluorine-based acceptors, using visible-pump -- IR-probe photoinduced absorption technique. The positions of acceptor's HOMO-LUMO levels are engineered by addition of different chemical substituents. The results clearly show the exponential scaling of the charge recombination rate with the acceptor LUMO energy. The minimal donor-acceptor LUMO energy difference required to form a CTC state is estimated as ∼0.25 eV [ABSTRACT FROM AUTHOR]

The dosage dependences of surface band bending and effective electron affinity under cesium deposition on the Ga-rich GaAs(001) surface, along with the relaxation of these electronic properties after switching off the Cs source are experimentally studied by means of modified photoreflectance spectroscopy and photoemission quantum yield spectroscopy. At small Cs coverages, below half of a monolayer, additional features in the dosage dependence and subsequent downward relaxation of the photoemission current are determined by the variations of band bending. At coverages above half of a monolayer the upward relaxation of the photocurrent is caused supposedly by the decrease of the electron affinity due to restructuring in the nonequilibrium cesium overlayer. [ABSTRACT FROM AUTHOR]

The Kelvin Probe (KP) studies have been carried out on CuO:ZnO nanowires random networks before and after H2S exposure. The results show that on exposure to H2S, the work function of the CuO:ZnO NWs increases by 200 meV. Using conductance and KP data, both the components of work function i.e. band bending and electron affinity has been obtained. It was observed that the affinity values changed substantially with H2S gas exposure. [ABSTRACT FROM AUTHOR]

The Current-Voltage (IV) measurements on Pt/InN Schottky barrier diodes in the temperature range 10–280 K were done. It was found that the contact was Schottky up to 280 K, becoming irreversible ohmic for higher temperatures. The ideality factor, the saturation current and the apparent barrier height were calculated by using the thermionic emission (TE) theory. The ideality factor is temperature dependent, while the saturation current and the barrier height are not. The non conventional Richardson plot exhibits good linearity, corresponding to an activation energy of 2.08 eV and a Richardson constant of 18.7 A m-2 K-2. The Cheung’s method to estimate the value of a possible series resistance RS yields a negligible resistance. From reverse-bias IV analysis, it is found that the experimental carrier density (ND) value increases with temperature. [ABSTRACT FROM AUTHOR]