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Surface functionalization with atoms serves as an important strategy to modulate the catalytic activities of low-dimensional nanomaterials. Herein, we developed a facile hydrogen incorporation strategy for improving the catalytic activities of SnS2 nanosheets toward CO2 electroreduction. Compared with SnS2 nanosheets, the hydrogen-incorporated SnS2 (denoted as H-SnS2) nanosheets exhibited high current density and Faradaic efficiency (FE) for formate. At -0.9 V vs RHE, H-SnS2 nanosheets displayed a maximum FE of 93% for carbonaceous product, which rivals the activities of most Sn-based catalysts in CO2 electroreduction. Mechanistic studies disclosed that the incorporation of surface hydrogen induced the electron injection into the structures of H-SnS2 nanosheets, which largely facilitates the process of CO2 activation. Density functional theory (DFT) calculations further revealed that hydrogen incorporation decreased the energy barrier for the formation of HCOO* intermediates, thus contributing to the CO2-to-formate conversion on H-SnS2 nanosheets.

Azole derived products acquired significant consideration in everyday life based on their improved biological potential to the semiconducting substances. The research focused in-depth within pyrazol, and oxazole compounds 1–4 concerning charge transport, structural, optical as well as electronic properties. The density functional theory (DFT) along with time-dependent DFT were used for the optimization of their ground state geometries and excitation energies. We also investigated the molecule’s electron coupling constants (|V RP|) as well as electron injection (ΔG inject) values. For better understanding, charge transport and electronic characteristics were performed through quantum chemical computations. The |V RP| and ΔG inject values of pyrazole, as well as oxazole molecules, exhibited that these compounds could be competent for dye-sensitized solar cell applications. The pyrazole higher diagonal band gap enlightening these might have enhanced fill factor (FF) along with short-circuit current density (J sc ). We have also explored the electron injection, energy level offset, dissociation of excitons, and band alignment of studied compounds to shed light on the functionality of these compounds for photovoltaic and semiconductor device applications.

Boron-dipyrromethene (BODIPY) is one promising class of sensitizers for dye-sensitized solar cells (DSSCs) due to unique merits of high absorption coefficient and versatile structural modification capability. However, such derivatives usually suffer from limited power conversion efficiencies (PCEs) because of narrow light absorption band and low electron injection. To aid the discovery of BODIPY sensitizers, we employ an inverse design method to design efficient sensitizers by integrating data mining and first-principle techniques. We establish robust data-mining models using genetic algorithm and multiple linear regression, where the features are filtered from 5515 descriptors and their meanings are explicitly explored for next inverse designs. Based on the features’ understanding, we design candidates NH1-6 and predict their PCEs, demonstrating remarkable enhancements (58% maximum) compared to previous works. Furthermore, their optoelectronic properties including maximum absorption wavelengths, oscillator strengths, bandgaps, transferred charges, charge transferred distances, TiO2 conduction band shifts, short-circuit currents and electron injection efficiencies simulated via first-principle calculations indicate significant increasements (93 nm, 122.41%, 23.70%, 36.36%, 471.17%, 63.64%, 28.55%, 107.86% maximum), which testifies the corresponding highly predicted PCEs and may overcome BODIPY dyes’ shortcomings. The as-designed BODIPY sensitizers can be promising candidates for DSSCs, and such method could help accelerate the discovery of other energy materials.

Phase transition engineering, with the ability to alter the electronic structure and physicochemical properties of materials, has been widely used to achieve the thermodynamically unstable metallic...

The electron is unique and is regarded as the smallest reagent. In addition, electron transfer is universally involved not only in chemical systems but also in many other systems such as electrical conduction and life activity. In the field of synthetic organic chemistry, development of novel electron injection methods has led to a new phase of chemical bond formation techniques. In addition to conventional metallic reagents and electrolytic techniques, synthetically valuable reactions with noble metal-free electron initiators driven by thermal or photochemical stimulus have recently been developed intensively. In particular, visible-light organic photoredox catalysis has rapidly spread among synthetic chemists as a game-changing strategy because of its sustainability and versatility. This review focuses on modern state-of-the-art electron injection strategies for organic synthesis.

We now report full details of the collisional ET process at the interface between the solvated porphyrin dye (a representative molecular dye) and heterogeneous TiO2 particles (a well-defined n-type...

Solution-phase spectroelectrochemistry was used to study electron injection into colloidal CdSe quantum dots (QDs) with sizes ranging from 3.4 to 11.1 nm in tetrahydrofuran (THF). The absorbance an...

This study investigates the charge injection barrier at the phthalocyanine (H2Pc)/Pd using accumulated charge measurement (ACM). Because the hole injection barrier is relatively small, the voltage ...

Facile patterning of electrodes is required for various electronic applications, particularly in solution-processed oxide thin-film transistors (TFTs). In this study, source and drain electrodes were prepared from silver nanowires (AgNWs) using spray-coating and hot press techniques. Although spray coating allowed production of AgNW patterns, which could function as electrodes in oxide TFT, the as-sprayed films did not provide a sufficient physical contact with oxide semiconductors and formed interspaces that impeded electron injection. At the same time, hot press technique produced denser AgNW networks that had a tight contact with the oxide semiconductors. As a result, hot-pressed films were considered as satisfactory source and drain electrodes for high-performance oxide TFTs, as they provided an easy electron injection. Finally, the prepared oxide TFTs with hot-pressed AgNW electrodes exhibited average field-effect mobility of 4.75 ± 1.5 cm2/V, significantly higher than that of the TFTs with as-sprayed AgNW electrodes (0.08 ± 0.05 cm2/V).

Dye detachment issue in the TiO2-mediated dye-sensitized photocatalytic system engenders an electron injection route based on collisional quenching between the detached solution-phase dye and dispe...

Perovskite nanocrystal light-emitting devices (PNC LEDs) exhibit great potential in display and lighting applications. Balanced hole and electron injection in the light-emitting layer is undoubtedly an effective way to improve LED performance. Here, bismuth (Bi) was introduced into PNC LEDs to form a silver-bismuth (Ag-Bi) bilayer anode. Ag diffused into a defective 2 nm thick Bi layer to form an alloy-like state that promoted hole injection, reduced the charge transfer resistance, and enhanced charge transfer, leading to more balanced hole-electron carriers in the emission layer through hole injection enhancement. As a result, the turn-on voltage and brightness changed from 2.41 V and 2200 cd m

Two modifications of the molecular structures of Aurantinidin and Betanidin dyes were modeled, and the optical and electrical properties were calculated by using density functional theory (DFT) and time-dependent DFT (TD–DFT). The modification of the structures was done by connecting the units through vinyl groups and using regular electron acceptor and electron donor moieties to the original structures. It has been demonstrated that the modifications improved the electron injection properties of the molecules with higher light-harvesting efficiencies, an increase in the driving force of electron injection ($$\Delta G_{\text{inject}}$$), better regeneration energies ($$\Delta G_{\text{reg}}$$) and open-circuit photovoltages ($$V_{\text{OC}}$$).

Lighting today is expected to be light weighted, flexible, highly efficient, non-expensive and fabricated in an environment friendly way. Organic light emitting diodes (OLEDs) meet all of these requirements and can be applied using inexpensive and roll-to-roll compatible printing techniques. This work demonstrates the ultrasonic spray coating (USSC) of polyethylenimine (PEI) and polyethylenimine(ethoxylated) (PEIE) as electron injection/transport layer (EIL/ETL) for OLEDs. This high-end printing technique employs ultrasonic atomization to break down a liquid into a spray of homogeneous small (20 µm) droplets. The PEI(E) layer was optimised using USSC and subjected to a complete morphological and electro-optical characterisation. For all manufactured devices current and voltage characteristics and luminous performances were obtained. This study confirms the versatility of USSC and the suitability of PEI(E) as excellent EIL/ETL for OLEDs and paves the way towards fully printed devices.

Peripherally tetra-4-carboxyethylphenoxy substituted oxotitanium (IV), cobalt(II), zinc(II) and metal free phthalocyanines were synthesized to research the sensitizing abilities of these dye molecules in standard dye sensitized solar cells (DSSCs). All the synthesized phthalocyanine complexes have been characterized by using elemental analyses, UV-Vis, FT-IR, H-1 NMR and MALDI-TOF MS spectroscopic techniques. Electrochemistry of metallo phthalocyanines (MPcs) were studied with electrochemical and in-situ spectroelectrochemical measurements. H2Pc (7) and ZnPc (5) illustrated similar Pc based electron transfer reactions. Differently, CoPc (6) and TiOPc (4) illustrated metal based redox reactions, which enhanced the redox functionality of these complexes. Metal based reductions for CoPc (6) and TiOPc (4) were recorded in addition to the Pc based one. In-situ spectroelectrochemical measurements supported the proposed voltametric mechanism. Moreover, the color and spectra of the electrogenerated species were determined with the in-situ spectroelectrochemical analyses to predict possible optoelectrochemical application of the complexes. Pronounced optical and color changes during the electrolysis of the complexes indicated electrooptical and possible solid state electrochemical functionality of the complexes. TiO2 semiconductor on the fluoride doped indium tin oxide coated glass electrode (FTO) was decorated with H2Pc (7) and TiOPc (4) bearing four carboxyl anchoring groups and they were first of all tested as possible dye for the DSSC. H2Pc (7), TiOPc (4), CoPc (6) and ZnPc (5) dyes used in DSSCs showed 2.9%, 3.3%, 1.02% and 2.2% of power conversion efficiencies respectively.

The efficient cleavage of the N≡N bond is vital to N2 fixation but remains challenging. In this issue of Chem, Zhang and co-workers report that the interfacial polarization fields triggered by protrusion-shaped Fe single atoms on monolayer MoS2 can promote N≡N splitting via electron injection, resulting in a praiseworthy nitrogen electroreduction.

Dye-sensitized solar cells and photocatalysts that consist of a light-absorbing dye and a wide gap oxide semiconductor substrate have been studied extensively as a means of solar energy conversion....

The early photophysical events occurring in the dinuclear metal complex [(ttb-terpy)(I)Ru(μ-dntpz)Ru(bpy)2]3+ (2; ttb-terpy = 4,4',4''-tri-tert-butyl-terpy; bpy = 2,2'-bipyridine; dntpz = 2,5-di-(1,8-dinaphthyrid-2-yl)pyrazine) - a species containing the chromophoric {(bpy)2Ru(μ-dntpz)}2+ subunit and the catalytic {(I)(ttb-terpy)Ru(μ-dntpz)}+ unit, already reported to be able to perform photocatalytic water oxidation - have been studied by ultrafast pump-probe spectroscopy in acetonitrile solution. The model species [Ru(bpy)2(dntpz)]2+ (1), [(bpy)2Ru(μ-dntpz)Ru(bpy)2]4+ (3), and [(ttb-terpy)(I)Ru((μ-dntpz)Ru[(ttb-terpy)(I)]2+ (4) have also been studied. For completeness, the absorption spectra, redox behavior of 1-4 and the spectroelectrochemistry of the dinuclear species 2-4 have been investigated. The usual 3MLCT (metal-to-ligand charge transfer) decay, characterized by relatively long lifetimes on the ns timescale, takes place in 1 and 3, whose lowest-energy level involves a {(bpy)2Ru(dntpz)}2+ unit, whereas for 2 and 4, whose lowest-energy excited state involves a 3MLCT centered on the {(I)(ttb-terpy)Ru(μ-dntpz)}+ subunit, the excited-state lifetimes are on the ps timescale, possibly involving population of a low-lying 3MC (metal-centered) level. Compound 2 also exhibits a fast process, with a time constant of 170 fs, which is attributed to intercomponent energy transfer from the MLCT state centered in the {(bpy)2Ru(μ-dntpz)}2+ unit to the MLCT state involving the {(I)(ttb-terpy)Ru(μ-dntpz)}+ unit. Both the intercomponent energy transfer and the MLCT-to-MC activation process take place from non-equilibrated MLCT states.

For efficient electron injection, a method to control the work functions (WFs) of ZnO electrodes in organic light-emitting devices (OLEDs) is reported in this study. First, ZnO was modified by doping of tetraalkylammonium salts (TRAX) into polyethylenimine ethoxylated (PEIE) for the WF control. Tetrabutylammonium salts (TBAX), where X = chloride, bromide, iodide, acetate, thiocyanate, and tetrafluoroborate anions, were doped into PEIE. A WF of nondoped PEIE-modified ZnO was 3.65 eV, whereas TBAX-doped PEIE-modified ZnO exhibited WFs ranging from 3.52 to 3.00 eV depending on the anion. TBAX salts exhibited different electron-donating capabilities depending on the anion, and the doping of TBAX with a large electron-donating capability exhibited a large WF reduction effect. In addition, tetraethyl- and tetrahexylammonium chlorides were doped into PEIE. PEIE doped with TRACl containing long alkyl chains exhibited a large WF reduction effect due to its low electron-accepting capabilities. In addition, the WF reduction mechanism was considered by the depth direction analysis of the PEIE:TBAX films. Finally, the ZnO/PEIE:TRAX bilayers were applied as electron injection layers in poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] emissive-layer-based OLEDs with an inverted structure. The ZnO/PEIE:TBAX devices with low WFs exhibited low driving voltages.

The spectral sensitization of single-crystal p-GaP by semiconducting single-walled carbon nanotubes (s-SWCNT) via hole injection into the p-GaP valence band is reported. The results are compared to SWNCT sensitized n-type single-crystal substrates: TiO2, SnO2, and n-GaP. It was found that the sensitized photocurrents from CoMoCAT and HiPco s-SWCNTs were from a hole injection mechanism on all substrates, even when electron injection into the conduction band should be energetically favored. The results suggest an intrinsic p-type character of the s-SWCNTs surface films investigated in this work.

A little more than a monolayer-thick pure-boron (PureB) layer was deposited on silicon at 250 °C by chemical vapor deposition (CVD), forming junctions with low saturation current. They displayed the same efficient suppression of electron injection as PureB diodes fabricated with a few nm-thick PureB layer deposited at 400 °C. Assuming high concentrations of acceptor states at the B-to-Si interface, induced by a fixed negative charge in the range from $\textsf {5}\times \textsf {10}^{\textbf {13}}$ cm $^{-\textbf {2}}$ to $\textsf {5}\times \textsf {10}^{\textbf {14}}$ cm $^{-\textbf {2}}$ , would be consistent with the experiments and device simulations that exhibit an efficient suppression of electron injection. Metallization of the B-layers was studied, showing that in many situations, thinning of the layer to monolayer thickness will lead to a significant increase in the electron injection.

Engineered nanomaterials (ENMs) have been developed for imaging, drug delivery, diagnosis, and clinical therapeutic purposes because of their outstanding physicochemical characteristics. However, the function and ultimate efficiency of nanomedicines remain unsatisfactory for clinical application, mainly because of our insufficient understanding of nanomaterial/nanomedicine-biology (nano-bio) interactions. The nonequilibrated, complex, and heterogeneous nature of the biological milieu inevitably influences the dynamic bioidentity of nanoformulations at each site (i.e., the interfaces at different biological fluids (biofluids), environments, or biological structures) of nano-bio interactions. The continuous interplay between a nanomedicine and the biological molecules and structures in the biological environments can, for example, affect cellular uptake or completely alter the designed function of the nanomedicine. Accordingly, the weak and strong driving forces at the nano-bio interface may elicit structural reconformation, decrease bioactivity, and induce dysfunction of the nanomaterial and/or redox reactions with biological molecules, all of which may elicit unintended and unexpected biological outcomes. In contrast, these driving forces also can be manipulated to mitigate the toxicity of ENMs or improve the targeting abilities of ENMs. Therefore, a comprehensive understanding of the underlying mechanisms of nano-bio interactions is paramount for the intelligent design of safe and effective nanomedicines. In this Account, we summarize our recent progress in probing the nano-bio interaction of nanomedicines, focusing on the driving force and redox reaction at the nano-bio interface, which have been recognized as the main factors that regulate the functions and toxicities of nanomedicines. First, we provide insight into the driving force that shapes the boundary of different nano-bio interfaces (including proteins, cell membranes, and biofluids), for instance, hydrophobic, electrostatic, hydrogen bond, molecular recognition, metal-coordinate, and stereoselective interactions that influence the different nano-bio interactions at each contact site in the biological environment. The physicochemical properties of both the nanoparticle and the biomolecule are varied, causing structure recombination, dysfunction, and bioactivity loss of proteins; correspondingly, the surface properties, biological functions, intracellular uptake pathways, and fate of ENMs are also influenced. Second, with the help of these driving forces, four kinds of redox interactions with reactive oxygen species (ROS), antioxidant, sorbate, and the prosthetic group of oxidoreductases are utilized to regulate the intracellular redox equilibrium and construct synergetic nanomedicines for combating bacteria and cancers. Three kinds of electron-transfer mechanisms are involved in designing nanomedicines, including direct electron injection, sorbate-mediated, and irradiation-induced processes. Finally, we discuss the factors that influence the nano-bio interactions and propose corresponding strategies to manipulate the nano-bio interactions for advancing nanomedicine design. We expect our efforts in understanding the nano-bio interaction and the future development of this field will bring nanomedicine to human use more quickly.

Aggregation induced emission enhancement (AIEE) of newly synthesized (E)-2-(((2-(1-(2,3-dihydrobenzo[b] [1,4] dioxin-5-yl)-1H-phenanthro[9,10-d]imidazol-2-yl)phenyl)imino) methyl)naphthalen-1-ol (HBDPPIN) was analyzed in aqueous media. The AIEE active HBDPPIN in aggregated state exhibit turn-off emission with Cu2+ whereas HBDPPIN-Cu2+ complex reveal turn-on fluorescence with Al3+. The detection limit was calculated as 4.13 × 10–2 μM for Cu2+ and 9.4 × 10−1 μM for Al3+. The interfacial carrier transfer in the fabricated Cu-TiO2-HBDPPIN-Ag film depends on the interfacial contact of the layers: hole injection barrier of EAg-HBDPPIN > ETiO2-HBDPPIN, however, the electron injection barrier of ETiO2-HBDPPIN → C T HBDPPIN → C T TiO2 is the predominant charge transfer direction in Cu-TiO2-HBDPPIN-Ag film. The binding energy/energy gap (Eb /Eg) of HBDPPIN-CuO composites dependent on the nature of CuO cluster and carrier transfer in HBDPPIN-Cu6O6 composite is faster than other composites.

Polyacrylonitrile (PAN) was adsorbed onto the TiO2 surface, and the resulting photoelectrodes were applied in dye-sensitized solar cells (DSSCs). The DSSC with the PAN-modified TiO2 showed an increase in its short-circuit current (Jsc) and a decrease in its open-circuit voltage (Voc), resulting in a 17% enhancement of its photovoltaic performance when compared to the reference cell. By incorporating PAN onto the surface of the TiO2, a surface dipole was formed, which induced a conduction band edge shift of the TiO2 in a positive direction. This shift led to a considerable improvement in the electron injection efficiency, and hence the Jsc.

Inspired by the successful application of heterocyclic components as robust anchoring groups in porphyrin dyes, we designed three novel organic analogues utilizing indenoperylene-based dye C275 as the skeleton prototype and three different heterocyclic units as anchoring groups in this research. In light of the theoretical studies on these three investigated dyes and the corresponding dye/(TiO2)38 compounds, two heterocyclic units (tropolone and 8-carboxylquinoline) were screened as alternative anchoring groups for dye-sensitized solar cells (DSCs). Especially, An1 and An2 dyes based on these two anchoring units show their remarkable performances in interfacial properties compared to those of C275 dye, involving larger conduction band CB up-shift (An1/(TiO2)38, ΔECB = 0.23eV and An2/(TiO2)38, ΔECB = 0.20eV) system, distinguished balance between the electron injection rate (An1/(TiO2)38, kinj = 8.71 × 1014 s−1 and An2/(TiO2)38, kinj = 8.52 × 1014 s−1) and electron–hole recombination (An1/(TiO2)38, krec = 1.63 × 107 s−1 and An2/(TiO2)38, krec = 2.75 × 107 s−1). Therefore, this work may be supplied several promising candidate for experimental synthesis in organic dye sensitized solar cells.

Polystyrene sulfonate (PSS) functionalized ZnO nanowires were hydrothermally synthesized and assembled into a UV-activated optoelectronic NO2 sensor for the first time. In situ PSS functionalization during hydrothermal synthesis not only facilitated the formation of high-quality ZnO nanowires with small diameters and high aspect ratios, but also significantly improved the UV photoconductance of ZnO nanowires through photo-induced electron injection, leading to the enhanced optoelectronic properties of ZnO nanowires. The optoelectronic NO2 sensors based on PSS-functionalized ZnO nanowires showed much higher responses and faster response rates under UV illumination at room temperature (25 °C). The responses ranged from 60% to 690% toward NO2 concentrations of 50 ppb to 2 ppm. Moreover, the optoelectronic sensors exhibited excellent reversibility, good stability and a low detection limit (5 ppb), making the efficient, optically controlled sensing of ppb-level NO2 gas possible.

This study investigates low-temperature cross-linking of polyethyleneimine ethoxylated (PEIE) using four types of silane coupling agents, including trimethyl[3-(trimethoxysilyl)propyl]ammonium chloride (TTSPAC), trimethoxyphenylsilane (TMPS), trimethoxy[3-(phenylamino)propyl]silane (TPAPS) and 1,2-bis(trimethoxysilyl)ethane (BTMSE). The results of this study indicated that all the silane coupling agents reacted with PEIE at low temperatures ranging from 65 to 120 °C. The reacted PEIE exhibited solvent tolerance, indicating the cross-linking of PEIE. The cross-linked PEIE films were applied to electron injection layers (EILs) in solution-processed organic light-emitting devices. The device with PEIE: TTSPAC EIL showed a shorter device lifetime than that with only PEIE EIL. The shorter device lifetimes were attributed to the migration of chloride anions of TTSPAC. Conversely, the devices with PEIE: TMPS, TPAPS and BTMSE EILs, which did not contain mobile ions, had longer device lifetimes than that with only PEIE EIL. These results suggested that these improvements of device stability resulted from the cross-linking of PEIE.

Two new carboxylated 1,3-indanedione sensitizers (MPhe-ind and BPhe-ind) were synthesized and their dye-sensitized solar cells (DSSC) performance were compared with the corresponding standard cyanoacetic acid sensitizers (MPhe-cn and BPhe-cn). The carboxylated 1,3-indanedione sensitizers have shown almost 100 nm enhanced absorption curves compared to the cyanoacetic acid dyes with an extended IPCE curve up to 800 nm. Despite greater absorption and electrochemical properties, the synthesized dyes showed moderate efficiencies (2.10% and 2.67%) than standard dyes. The low electron injection efficiency and recombination of carboxylated 1,3-indanedione might be responsible for low efficiency. Detailed investigation studies have been performed and complemented with the theoretical studies.

In this work, we systematically investigate the impacts of electron-donor based on Triphenylamine (TPA). The Geometry structure, energy levels, light-harvesting ability and ultraviolet-visible absorption spectra were calculated by using Density Functional Theory (DFT) and Time-Dependent-DFT. The electron injection rate of the TPA-N(CH3)2 based dyes has 0.71 eV for high among the dye sensitizer. The First and Second order Hyperpolarizability of the 11.95 × 10−30 e.s.u and 12195.54 a.u, respectively for TPA-N(CH3)2 based dye. The calculated absorption spectra were showed in the ultra-violet visible region for power conversion region. The study reveals that the electron transfer character of TPA-N(CH3)2 based dyes can be made suitable for applications in Dye-Sensitized Solar Cells.

Capacitance transient spectroscopy and dc current–voltage ( I–V ) characterization are employed to analyze charging/discharging effects and transport in 200-nm-thin carbon-doped GaN layers (GaN:C) with a low ( ${N}_{\textsf {C}} = \textsf {10}^{\textsf {18}}$ cm $^{-\textsf {3}}$ ) and high ( ${N}_{\textsf {C}} = \textsf {10}^{\textsf {19}}$ or ${N}_{\textsf {C}}= \textsf {7}\times \textsf {10}^{\textsf {19}}$ cm $^{-\textsf {3}}$ ) carbon concentration ${N}_{\textsf {C}}$ . The discharging and charging events are found to be governed by transport properties of GaN:C for whole ${N}_{\textsf {C}}$ range. However, distinct temperature behavior has been found as a function of ${N}_{\textsf {C}}$ . In the samples with low ${N}_{\textsf {C}}$ , an Arrhenius-like behavior with an activation energy of 0.8 eV indicates that the hole transport in valence band (VB) is the limiting process and the carrier exchange occurs between VB and the defect level. In contrast, in samples with high ${N}_{\textsf {C}}$ , a non-Arrhenius charging/discharging behavior with exp( aT )-dependence ( ${a}$ being a constant) in a wide temperature range (150–560 K) indicates that the transport is governed by defect bands (DBs) where the carrier exchange occurs between DBs and the carbon defect level. For samples with ${N}_{\textsf {C}} \ge \textsf {10}^{\textsf {19}}$ cm $^{-\textsf {3}}$ , the large charge accumulation in GaN:C produces a large energy barrier to prevent electron injection from n-GaN to GaN:C, thus making GaN:C blocking. This is in contrast to samples with ${N}_{\textsf {C}} = \textsf {10}^{\textsf {18}}$ cm $^{-\textsf {3}}$ where the barrier is low, rendering thus the bilayer leaky. Detailed physical models for carrier capture and emission processes and carrier transport are provided for both cases. The developed knowledge is important for understanding the role of growth parameters such as ${N}_{\textsf {C}}$ and dislocation densities, as well as for reliability testing and defect analysis.

Most photovoltaic (PV) technologies are opaque to maximize visible light absorption. However, see-through solar cells open additional perspectives for PV integration. Looking beyond maximizing visible light harvesting, this work considers the human eye photopic response to optimize a selective near-infrared sensitizer based on a polymethine cyanine structure (VG20-C-x) to render dye-sensitized solar cells (DSSCs) fully transparent and colorless. This peculiarity was achieved by conferring to the dye the ability to strongly and sharply absorb beyond 800 nm (S-0-S-1 transition) while rejecting the upper S-0-S-n contributions far in the blue where the human retina is poorly sensitive. When associated with an aggregation-free anatase TiO2 photoanode, the selective NIR-DSSC can display 3.1% power conversion efficiency, up to 76% average visible transmittance (AVT), a value approaching the 78% AVT value of a standard double glazing window while reaching a color rendering index (CRI) of 92.1%. The ultrafast and fast charge transfer processes are herein discussed, clarifying the different relaxation channels from the dye monomer excited states and highlighting the limiting steps to provide future directions to enhance the performances of this nonintrusive NIR-DSSC technology.

A series of catechol-based sensitizers, Cat-I to Cat-XV, for a possible application in type II DSSCs is presented. The electronic structures and excited state properties of free and bound to (TiO2)9 dyes have been analysed and compared by means of Density Functional Theory (DFT) and Time Dependent DFT (TDDFT) methods. In particular, the effect of introducing electron-donating and electron-withdrawing substituents, as well as the effect of introducing an ethylene spacer as π bridge between the substituents and the catechol unit to increase the conjugation has been investigated. Moreover, key aspects that could strongly influence the direct (type II) electron injection mechanism are analyzed and discussed. The results of the calculations suggest that the introduction of the π bridge contributes to enhance the dye-to-TiO2 charge transfer (DTCT) efficiency regardless of the presence of electron-donating or electron-withdrawing substituents.

Modern lighting is expected to be light weight, flexible, efficient, non-expensive and environmentally friendly fabricated. Organic light emitting diodes (OLEDs) meet all these requirements and can be manufactured using inexpensive and roll-to-roll compatible printing techniques. They, however, often use low work function, highly reactive metals, such as barium and calcium to facilitate electron injection, deposited using expensive and non-continuous vacuum techniques. Efficient and stable alternatives can be found in the aliphatic amines, polyethylenimine (PEI) and polyethylenimine(ethoxylated) (PEIE), that shift the work function of aluminum favorably for electron injection. This work demonstrates ultrasonic spray coating of PEI(E) as electron injection and transport layer for OLEDs, reducing the work function of the aluminum cathode by 0.355 eV allowing a luminous efficacy comparable to that of the OLEDs using calcium/aluminum electrodes. Slightly higher luminous results are noted for the OLEDs with spin coated PEI(E), indicating that the surface morphology and thickness of the PEI(E) layer are crucial factors: ultrasonic spray coated PEI(E) layers have an increased overall thickness and surface roughness. This study shows the potential of ultrasonic spray coating and the suitability of PEI(E) as excellent electron injection and transport layer for OLEDs and paves the way towards fully spray coated OLEDs. K E Y W O R D S electron injection and transport layer, organic light emitting diodes, printing techniques, ultrasonic spray coating This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Oxidoreductase enzymes often perform technologically useful chemical transformations using abundant metal cofactors with high efficiency under ambient conditions. The understanding of the catalytic mechanism of these enzymes is, however, highly dependent on the availability of well-characterized and optimized time-resolved analytical techniques. We have developed an approach for rapidly injecting electrons into a catalytic system using a photoactivated nanomaterial in combination with a range of redox mediators to produce a potential jump in solution, which then initiates turnover via electron transfer (ET) to the catalyst. The ET events at the nanomaterial-mediator-catalyst interfaces are, however, highly sensitive to the experimental conditions such as photon flux, relative concentrations of system components, and pH. Here, we present a systematic optimization of these experimental parameters for a specific catalytic system, namely, [FeFe] hydrogenase from

New D-&pi, A configured organic sensitizers featuring halogen-substituted oxindole-bridged acceptor units have been synthesized for dye-sensitized solar cells applications. Among fluorine, bromine, and iodine substitution, the cell based on bromine incorporated dye exhibited the highest efficiency. The oxindoles in these sensitizers were found to assist the electron injection through the chelation of their amide carbonyl groups to the TiO2 surface. This study provides an alternate approach for future rational dye design to gain excellent DSSC performance.

Perovskite light-emitting diodes (PeLEDs) exhibit high external quantum efficiencies (EQEs), emerging as a next-generation lighting and display technology. Nevertheless, they suffer from severe efficiency roll-off at high luminance, particularly in the case of blue and green emissions, which is one of the major bottlenecks in their industrial applications. Here, we attack this problem using a rare-earth metal, Yb, as cathode interface layer (CIL) for green PeLEDs. By adopting a new device configuration of ITO/TFB/FA-based quasi-2D perovskite/TPBi/Yb/Ag, we achieved a peak current efficiency (CE) of 22.3 cd/A with a corresponding EQE of 5.28% and a high maximum luminance of 19 160 cd/m

Ultra-high-resolution optical microscopic techniques are used to measure the reflectance and photoluminescence (PL) spectrum of individual monolayered MoS2 of dimensions below 200 × 200 nm, while placed on top of a thin film conjugated polymer (CP). p-type and n-type CPs such as poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM), respectively, modified the optical band gap of the MoS2 sheet differently. However, the optical band gap is decreased after integration with P3HT, while it is increased after being combined with PCBM. The acceptable reason for the modification of the band gap of MoS2 by CPs is the generation of interlayer excitons (ILE) at their interface. The optical band gap of MoS2 is further changed by introducing an inert polymer spacer of different thickness to separate MoS2 from the CP. This is attributed to the reduction of the efficiency of excitonic interactions and lowering the exciton binding energy, which is induced by the increase of the dielectric function at the CP-MoS2 interface. No sign of electron injection to the conduction band of MoS2 after integration with P3HT or PCBM, as no significant shift of the A1' Raman band of MoS2 was measured on top of CPs, which is sensitive to the electron injection.

The purpose of this study is to experimentally determine the effect of electron injection on the minority carrier lifetime in Gallium Nitride. Earlier studies of electron injection in GaN have provided an indirect proof of lifetime enhancement through the increase of minority carrier diffusion length and the decrease in the cathodoluminescence intensity. These changes in the minority transport properties, caused by electron injection, are brought forth through defect and trap levels in the bandgap. Furthermore, a thorough discussion of the electron injection model and role of these trap levels is presented.

This article reviews the semiconductor and metal-based nanohybrid-sensitized photoelectrochemical (PEC) cells for hydrogen generation from water. The nanoscale hybridization of sensitizers in the photoanode can enhance light harvesting, interfacial charge transfer, charge separation, and induce a catalytic effect in dependence on the kind of the components and interfacial junction state. Subsequent to the introduction, second and third sections present the basic structure and design of the nanohybrid-sensitized PEC cell. Fourth section deals with the effect of the interfacial bond between quantum dots and TiO2 on the electron injection process. Fifth section mainly describes the formation of heteroepitaxial junction between the components of nanohybrids. In the sixth section, the state-of-the-art nanohybrid-sensitized PEC cells are treated with a particular emphasis placed on the interface state.

The 8-hydroxyquinolinato lithium (Liq)|Ag system has been evaluated as the electron-injection layer for the MoOx| N,N′-di (1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine (NPB) charge-generation layer in tandem organic light-emitting diode (OLED) devices. From current-voltage studies of single-stack devices, it is determined that Liq is a relatively poor electron-transport material. However, Liq is found to be useful as an electron-injection layer with activation by Ag. Efficient tandem devices have been obtained using Liq|Ag as the electron-injection layer adjacent to the MoOx|NPB charge-generation layer, where the optimal Ag thickness is about 20–40 A and the activation of Liq can be seen with as little as 1 A of Ag.