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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...

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...

Durable solar cells with tunable color and diaphaneity are very promising for building integrated photovoltaic applications. In this paper we employ donor–acceptor organic dyes U3, U4, U5, and R6 f...

Recently, extracting hot electrons from plasmonic nanostructures and utilizing them to enhance the optical quantum yield of two-dimensional transition-metal dichalcogenides (TMDs) have been topics ...

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.

Organic phototransistors (OPTs) have been extensively investigated as photodetectors because of their internal photocurrent amplification. However, OPTs tend to show high dark current because they ...

The steady-state photoluminescence (PL) of CsPbBr3 films with varying thicknesses was studied under light-soaking on semiconductive and insulating contacts, showing reversible changes in PL, entirely dependent on the nature of the contact and film thicknesses. The PL at 50–100 nm CsPbBr3 on TiO2 increased, and decreased in thicker layers, with no thickness-dependent PL in CsPbBr3 on glass/Al2O3. These observations are described using a spatial charge distribution model which interprets the migration of Br– and VBr+ under light-soaking as suppressing electron injection into the TiO2 due to upward band bending, enhancing PL at the interface and nonradiative recombination further away from it.

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.

The main stages of the study of spin-polarized electron injection into InSb semiconductor are considered. The characteristics of electromagnetic absorption and radiation due to spin-polarized electron injection into an InSb are given. The fundamental parameters of spin-polarized electrons, such as the relaxation time and spin diffusion length, are determined. The spin polarization of the conduction electrons in InSb is measured by direct detection.

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.

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

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.

Two new series of RuII complexes (6–10 bearing an imine bond and 16–20 bearing a sulfonamidate fragment) based 8-aminoquinoline backbone were prepared and characterized by NMR, FT-IR, elemental analysis, UV–vis, CV etc. and tested as a photoactive dye for dye-sensitized solar cells (DSSC). The performance of the RuII-arene containing imine bond complex types (6–10) as a dye on DSSCs produced cells with power conversion efficiencies (PCEs) of around 0.03–0.10%. The [(N-Quinoline-8-yl-benzenesulfonamido)(p-cymene)chlororuthenium(II)] (SD-E1311) complex, which we previously produced was tested instead of the complexes bearing the imine bond (6–10) and its PCE for SD-E1311 was found as 0.12%. Herein, the increase of the Voc is quite interesting and, for this reason, the sulfonamidate based complexes were selected for the backbone structure. To enhance immobilization to the titanium oxide layer and solubility and electron injection of the corresponding excited dye on the DSSC process, 2,2′-bipyridine-4,4′-dicarboxylic acid as the anchor group and thiocyanate ligands were selected instead of p-cymene and chloro ligands over the sulfonamidate complex. Then, the photoactive dye properties of the new RuII complexes (16–20) were investigated and the results showed that the 16–20 dyes bearing sulfonamidate, carboxylic anchoring and thiocyanate fragments benefited the short-circuit current and the open-circuit voltage, and had PCEs of 1.26%, 1.08%, 1.58%, 0.90% and 1.36% under AM1.5G irradiation, respectively. The working devices, results also show that the 16–20 dyes demonstrated average performances with a PCEmax. of 1.58% which was occurred with 18 complex.

Recently, CdSeTe Quantum Dot Sensitized Solar Cells (QDSSC) have shown remarkable advances in the photo conversion efficiency. In this work, the synthesis of CdSeTe QD is demonstrated and its performance as a sensitizer evaluated in a TiO 2 solar cell device. A photoconversion efficiency of 6.4% was obtained with the configuration TiO 2 /CdS/CdSeTe/ZnS that represent a fivefold increment compared to TiO 2 /CdSeTe/ZnS. The corresponding photocurrent was 20.3 mA/cm 2 as a result of the increase in the absorption range with the introduction of CdSeTe QDs and the electron injection of CdS. Electrochemical impedance spectroscopy (EIS) analysis confirms that such improvement was obtained as a result of the surface passivation of TiO 2 with the deposition of CdS acting also as a sensitizer if the appropriate energy level alignment between CdS and CdSeTe QDs is observed.

Efficient electron injection from cathode to electron transport layer is generally required to realize high-performance inverted organic light-emitting devices (IOLEDs). In this work, highly efficient IOLEDs are developed by employing a non-doped charge-generation unit of 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN)/Al/LiF as electron-injection layers (EILs). The ultraviolet photoelectron spectroscopy (UPS) shows that the insertion of HAT-CN layer reduces the work function of EILs by 0.21 eV. Combined with the current-voltage characteristics of electron-only devices, the role of the HAT-CN layer in promoting electron injection is confirmed. What's more, the double EILs device with Rubrene as a probe verifies the strong hole blocking ability of HAT-CN/Al/LiF. Based on the EILs, the inverted blue phosphorescent OLEDs with a maximum current efficiency of 29.4 cd/A are realized. The excellent performance proves the superiority of HAT-CN/Al/LiF as EILs.

Owing to composition and corresponding defect states, the optical and electronic properties of quantum dots (QDs) have a major impact on the performance of quantum dot sensitized solar cells (QDSCs). A series of CuInS 2 QDs with intentionally introduced defects from Cu-deficiency were synthesized under air circumstance by the organometallic high temperature method. Feature of tunable photoluminescence of CuInS 2 QDs with long lifetime has been demonstrated, which was mainly attributed to the donor-acceptor pair recombination, contributed above 70% to the whole emission profiles. The rate constants of electron transfer ( k et ) from CuInS 2 QDs to TiO 2 varied from 0.09 × 10 10 s −1 to 1.48 × 10 10 s −1 , depending on the compositions of the QDs. CuInS 2 QDSCs exhibited power conversion efficiency of 5.71% under one full sun illumination. The improved photovoltaic performance of CuInS 2 QDSCs is mainly originated from broadened optoelectronic response range up to ∼950 nm, and fast electron injection from QDs to TiO 2 films, which provide strong photoresponse beyond 60% over the window below 700 nm. The synthetic approach combined with defects created by composition modulation introduces a new approach towards the goal of high performance QDSCs.

To improve the electron injection efficiency from PbS quantum dots to TiO 2 nanorods and prevent the direct contact of spiro -OMeTAD and TiO 2 nanorods, a compact PbS quantum-dot thin film can be successfully obtained on TiO 2 nanorod arrays 360 nm in length by repeated spin coating of Pb(Ac) 2 , Na 2 S and 1,2-ethanedithiol solution in a step-by-step process. The corresponding solid-state quantum-dot-sensitized solar cells are fabricated using a novel structured FTO/compact PbS quantum-dot thin film sensitized TiO 2 nanorod array/ spiro -OMeTAD/Au that achieves a photoelectric conversion efficiency of 3.57% under AM 1.5 G illumination (100 mW cm −2 ), which represents a high value among all-solid-state PbS quantum-dot-sensitized TiO 2 nanorod array solar cells.

In this work, a series of porphyrin-based sensitizers, coded as ZnTEP, ZnTTEP, and ZnTTTD in which different kinds of thienyl groups are used as the π-linker, have been designed and successfully synthesized. Their synthesis, photophysical and electrochemical properties, and theoretical DFT calculations, as well as their applications in dye-sensitized solar cells (DSSCs) are reported. The results showed that the power conversion efficiency (η) increases in the order of 1.14, 2.15 and 3.51% for ZnTEP, ZnTTEP and ZnTTTD, respectively. A significant improvement in the η value was achieved with ZnTTTD-based solar cells, which was approximately three times the magnitude when compared to the lowest ZnTEP-based solar cells. Moreover, the effects of chenodeoxycholic acid (CDCA) in a dye solution as a co-adsorbent on the photovoltaic performance of DSSCs were investigated. It was found that the coadsorption of CDCA can hinder the formation of dye aggregates and the improve electron injection yield and thus Jsc. The η value for ZnTTTD with the CDCA co-sensitizer dramatically increases up to 6.51%. This understanding of π-linker and co-sensitizer effects on the performance of porphyrins will serve as a guideline for the design of future dye sensitizers for DSSCs.

Two new Rh2(II,II) dyes were synthesized and anchored to TiO2 for charge injection upon irradiation. The 1ML-LCT (metal/ligand-to-ligand charge transfer) excited state is populated upon excitation, which decays to the corresponding 3ML-LCT state. Ultrafast electron injection into TiO2 from the Rh2(II,II) dyes was achieved with low energy, red light excitation.

Color-tuning for phosphorescent emitters in organic light-emitting diodes (OLEDs) across the entire visible spectrum is prerequisite to fulfil flexible full-color displays and white solid-state lighting. Heteroleptic 2-phenylpyridine-type (ppy-type) Ir(III) and Pt(II) complexes as phosphorescent emitters have been well exploited in the electroluminescence (EL) field due to their outstanding EL performance. Furthermore, the photophysical characters of these heteroleptic Ir(III) and Pt(II) complexes are generally dominated by the nature of cyclometalating ppy-type ligands. Accordingly, either sophisticated modification or judicious combination of different cyclometalating ppy-type ligands will provide a wonderful platform to tune their emission color. In this personal account, we put a special emphasis on our contributions to the novel color-tuning strategies in these heteroleptic ppy-type Ir(III) and Pt(II) complexes. In addition, afforded by our novel color-tuning strategies, ambipolar character or enhanced electron injection/transport (EI/ET) features can be furnished to bring high EL performances.

A series of metal-quinolate (MQ2) materials (M = Be2+, Mg2+, Ca2+, and Sr2+) were theoretically investigated to understand their electronic and charge transport properties as an application of electron injection layer (EIL) and additive material to electron transporting layer (ETL). It was found that the Be2+, Mg2+, and Ca2+ are tetragonally coordinated to the quinolate ligands whereas the Sr2+ is planarly coordinated. The analyses of electronic properties indicated that the stable lowest unoccupied molecular orbital (LUMO) energy level of these materials relative to LiQ is expected to improve the electron injection from cathode and enhance the electron transport in ETL. In perspective of electrochemical reactivity, the chemical hardness values of MQ2 materials showed that hole and electron carriers can be easily facilitated in order of BeQ2

We have prepared titania nanoparticles with an organic dye sensitiser and diarylethene molecular switch attached to the surface. Spectroscopic investigations show that the dye sensitiser's electron injection efficiency is reduced when the diarylethene is switched from its colourless, ring-open isomer to its coloured, ring-closed isomer, due to the introduction of a competing energy transfer pathway.

Simple hydrochloric acid treatment of the corresponding pyridine precursors enable the resulting pyridine hydrochlorides to act as the solution-processed bifunctional electron injection/electron transporting materials. The all-solution-processed super yellow-based fluorescent OLEDs revealed excellent performance with an external quantum efficiency of up to 6.6% and extremely low efficiency roll-off over a wide range of luminance.

A TCAD-based approach has been used to investigate the leakage current and breakdown regime of vertical GaN/AlGaN/Si structures at different ambient temperatures. TCAD modeling has been used to assess possible mechanisms of the forward-bias leakage current. A good agreement with experimental data has been obtained by implementing both trap-assisted and Poole–Frenkel conduction mechanisms into the deeper buffer layers, indicating that conduction is dominated by electron injection from silicon into a continuum of states at a given energy offset in the transition layer, which might be associated with conductive dislocation defects. The latter mechanisms have been proven to anticipate the onset of breakdown at high temperatures.

The development of electron injection materials is one of the most important steps for obtaining highly efficient low-driving-voltage organic light-emitting devices (OLEDs). In this paper, we report poly(ionic liquid) (PIL)-based electron injection layers (EILs) for solution-processed OLEDs. We synthesized poly(N-alkyl-4-vinyl-pyridinium iodide) containing three different alkyl chains (propyl, butyl, and hexyl chains) and investigated the charge-transfer interactions between the pyridinium cations and the iodide anions along with the electronic structures and thermal properties of the PILs. We also fabricated and evaluated OLEDs containing PILs as EILs. The fabricated OLEDs exhibited lower driving voltages than the conventional device containing an alkali metal complex (8-quinolinolato lithium) as the EIL. The longer alkyl chain of the PILs was more effective in reducing the driving voltage.

By using density functional theory (DFT) and time-dependent DFT (TD-DFT) methods, the electronic structures and optical properties of a single dye (C239, C259 and C259-N) and co-sensitized dyes (C239+C259 and C239+C259-N) were studied. It is found that the effect of the replacement of dithienopyrrole (DTP) with cyclopentadithiophene (CPDT) in C259 on dye performance is negligible. There is no valley in the light-harvesting efficiency curve for the co-sensitized dyes, and the molar absorbtivity of the co-sensitized dyes at the maximum absorption has been improved compared with a single dye. Further investigations on the co-sensitized dye/TiO 2 complexes show that the A co-sensitization mode with the formation of three O–Ti bonds and a new hydrogen bond is more stable. The co-sensitized dye with the benzoic acid group can stay perpendicular on the titanium surface, this is favourable for electron injection and can weaker electron-hole recombination at dye/TiO 2 interface. Our results can supply a guideline for experimental design of more efficient co-sensitized organic dyes for dye-sensitized solar cells (DSSCs).

Dye-sensitized solar cells (DSSCs) have attracted widespread attention due to their unique features. In the present work, molecular engineered triphenylamine based dyes featuring donor-bridge-acceptor architecture have been considered and investigated for suitable properties for DSSCs applications. Hydantoin anchoring group has been introduced replacing the commonly used cyanoacrylic acid to improve the long-term stability of the device. Results on the effects of varied anchoring groups and pi-spacers have been interpreted from the viewpoint of DFT/TD-DFT calculations. Designed sensitizers exhibit suitable light-harvesting efficiencies, excited-state lifetimes, electron injection and regeneration abilities. Red-shifted electronic spectra are observed for three hydantoin dyes compared to others in the same family. Further analysis of chemical descriptors and observation from full-electron donor-acceptor map reveal that the three dyes among nine are potential materials with promising properties towards improving DSSCs performance.

Solution-processable charge injection materials have gathered considerable attention in the field of organic optoelectronics owing to their ability to enhance device efficiency. Of those candidates, polyethylenimine (PEI) polymers have been widely explored, but their effect on the device physics in organic light-emitting diodes (OLEDs) are not completely elucidated yet. In this work, the impact of ZnO:PEI hybrid nanocomposite as an electron injection layer (EIL) of OLEDs on the device performance is investigated. Two different PEIs with the different spatial molecular configuration of the polymer, either linear or branched-type, are employed. Both PEI polymers have the ability to effectively reduce the work-function of ZnO. The ZnO:linear-PEI EIL shows higher device efficiency in comparison to the ZnO:branched-PEI EIL in the charge-balanced OLEDs, whereas the results are opposite in the charge-imbalanced device setup. This is mainly due to the different role required of EIL materials upon different device working mechanisms. This work shows a series of experimental results of the detailed device characteristics using ZnO:PEI hybrid EILs in order to provide a systematic understanding of the device physics by combining two key concepts together; (1) control of the molecular configuration, and (2) charge carrier dynamics.

By adopting an 4,7-diphenyl-1,10-phenanthroline (Bphen):Ag interlayer with the gradient structure between the cathode and electron injection layer, the electron injection of white inverted top-emitting organic light-emitting devices (WITOLED) was enhanced. The structure of Ag–Ge–Ag anode capping with light outcoupling was used to ensure the spectral stability with the angles. The structure of the emission layer was carefully designed to guarantee the spectral stability with the voltages. The highest current efficiency of the WITOLED can reach 21.7 cd/A. The CIE 1931 coordinates varies only 0.022 in X and 0.015 in Y (0o–60o).

We report the effect of gap states on energy level alignment in a typical organic charge generation interface of N,N-bis(1-naphthyl)-N,N-diphenyl-1,1-biphenyl-4,4-diamine (α-NPD)/hexaazatriphenylene−hexacarbonitrile [HAT(CN) 6 ] by using ultraviolet and X-ray photoemission spectroscopy. The gap states tailed from the highest occupied molecular orbital (HOMO) onset of α-NPD dominate the Fermi level pinning at the α-NPD( 6 interface, which is favorable for charges generation upon bias operation and facilitates the electron injection from the HOMO-tail region of α-NPD to the lowest unoccupied molecular orbital (LUMO) region of HAT(CN) 6 .

We report new electron injection lithium complexes, lithium 2-(2-pyridyl)-3-pyridinolate (LIPPy) and lithium 4-phenyl-2-(2-pyridyl)phenolate (LIPPP) for low driving voltage and better stability of organic light emitting diodes (OLEDs). These materials were designed with the help of molecular simulation of anion formation energy and lithium binding energy calculations. Small anion formation energy and low binding energy of lithium complexes show good correlation with expected experimental driving voltage of the OLEDs. Fabricated OLEDs with these new lithium complexes exhibit lower driving voltage, higher power efficiency and longer lifetime as compare to the widely used and commercially available lithium 8-quinolate (Liq) and lithium 2-(2-pyridyl)phenolate (LIPP).

We report efficient red, orange, green and blue organic–inorganic light emitting devices using light emitting polymers and polyethylenimine ethoxylated (PEIE) interlayer with the respective luminance efficiency of 1.3, 2.7, 10 and 4.1 cd A −1 , which is comparable to that of the analogous conventional devices using a low work-function metal cathode. This is enabled by the enhanced electron injection due to the effective reduction of the ZnO work-function by PEIE, as well as hole/exciton-blocking function of PEIE layer. Due to the benign compatibility between PEIE and the neighboring organic layer, the novel phosphorescent organic–inorganic devices using solution-processed small molecule emissive layer show the maximum luminance efficiency of 87.6 cd A −1 and external quantum efficiency of 20.9% at 1000 cd m −2 .

Relatively simple phosphorescent OLED with extremely low operating voltage (∼3.1 V) was devised. To eliminate some components of OLED device, the biased charge injection design was required. To confine the recombination zone toward the anode side, relatively large hole injection barrier (∼0.7 eV) and small electron injection barrier (

Green phosphorescent inverted organic light-emitting diodes (IOLEDs) with 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN)/aluminium/n-doped 4,7-diphenyl-1,10-phenanthroline (Bphen) used as an electron injection layer (EIL) were demonstrated. The IOLED shows the lowest driving voltage of 4.5 V at 10000 cd m−2 to date. The electron injection effects of different interlayers were further investigated by ultraviolet photoelectron spectroscopy (UPS) and evaluating the electron injection efficiency. For application in large-sized OLEDs, a 120 × 120 mm2 flexible IOLED was successfully fabricated based on this inverted structure.

Solution-processed organic light-emitting devices (OLEDs) have progressed as potential candidates for cost-effective solid-state lighting and flat panel displays. In this highlight, we focus on the recent progress of the state-of-the-art solution-processable electron injection materials: (i) alkali metal-containing compounds, (ii) n-type semiconducting metal oxides, (iii) π-conjugated ionic polymers, and (iv) nonionic polymers. These materials are soluble in water, alcohol, or a water–alcohol mixture solvent and can be formed into a film by a solution process. We discuss the essential characteristics of these electron injection materials and the performance of the solution-processed OLEDs made using them.

A zinc di-corrole dye (Zn-cor dye), which was constructed by substitution of the Ga of a Ga di-corrole dye (Ga-cor dye) with zinc, has been characterized as having a strong light harvesting ability by density functional theory calculations. The charge is separated significantly in its excited states. It is worth noting that inserting different central metals can adjust the optical and charge-transfer properties of these kind of dyes, which are quite promising for the fabrication of high performance dye-sensitized solar cells. Based on the first-principles calculations, possible mechanisms for direct electron injection from the adsorbed dye to TiO2 have been discussed with analyses of the the band structure and DOS of the Zn-cor dye–TiO2 system.

Tandem organic light-emitting devices (OLEDs) were fabricated with a hybrid organic charge generation layer (CGL) composed of bis(ethylenedithio)-tetrathiafulvalene (BEDT-TTF) doped 1,3,5-tris(N-phenylbenzimiazole-2-yl)benzene (TPBi), 1,3-bis(cabazol-9-yl)benzene (mCP), and 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile (HAT-CN) in an attempt to enhance their current efficiency. While the operating voltage of the tandem OLEDs with a hybrid structure composed of BEDT-TTF-doped TPBi, mCP, and a HAT-CN CGL at 10 mA/cm2 was 1 V lower than that of the tandem OLEDs with a typical CGL composed of BEDT-TTF-doped TPBi and a HAT-CN, the corresponding the current efficiency of the tandem OLEDs with a hybrid CGL at 10 mA/cm2 was 2.9 cd/A higher than that of the tandem OLEDs with a typical CGL. The increase in the current efficiency and the decrease in the operating voltage of the tandem OLEDs with the hybrid CGL were attributed to enhanced electron injection due to the insertion of the mCP layer into the hybrid CGL.

While the operating voltage of the tandem organic light-emitting devices (OLEDs) with both an organic p-type 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile charge generation layer and a bis(ethylenedithio)-tetrathiafulvalene (BEDT-TTF)-doped 1,3,5-tris(N-phenylbenzimiazole-2-yl)benzene (TPBi) electron transport layer (ETL) was 1.3 V lower than that of the tandem OLEDs with a BEDT-TTF-undoped TPBi ETL. Luminance efficiency of the tandem OLEDs with a BEDT-TTF-doped TPBi ETL was 3.6 cd/A higher than that of the typical OLEDs. The increase in the luminance efficiency and the decrease in the operating voltage of the tandem OLEDs were attributed to improved electron injection due to the insertion of the BEDT-TTF-doped TPBi ETL.

This study demonstrates the incorporation of a Cs 2 CO 3 :conjugated polyelectrolyte blended interfacial layer between the emissive layer and a silver (Ag) cathode, for realizing all-solution processed polymer light-emitting diodes. For a device with poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT) as the emissive layer, this approach improves the maximum luminance of approximately 80,000 cd/m 2 and maximum current efficiency of 10.6 cd/A. It is clarified that the interfacial layer prevents Ag nanoparticles from penetrating into the emissive layer, resulting in yellow–green emission from F8BT. We also demonstrate the possibility of all-solution processed polymer light-emitting diodes utilizing solution-processed Cs 2 CO 3 :conjugated polyelectrolyte interfacial layer and Ag nano-ink.

N 2 O plasma treatment suppressed the temperature-dependent sub-threshold leakage current of amorphous indium–gallium–zinc-oxide thin film transistors (a-IGZO TFTs). For untreated devices, the transfer curve exhibited abnormal electrical properties at high temperature. The abnormal electrical properties are explained by the energy band diagrams for both forward and reverse sweep. Above 400 K, holes can be generated from trap-assisted transition, and drift to the source side which induces source barrier lowering. The source side barrier lowering enhances electron injection from the source to channel and causes an apparent sub-threshold leakage current. This phenomenon, which is experimentally verified, only appears in the device without N 2 O plasma treatment, but not in the device with N 2 O plasma treatment. The results suggested that the density of states for a-IGZO with N 2 O plasma treatment is much lower than that without plasma treatment.

We explore in this work the use of Cu as a cathode material in organic light-emitting devices (OLEDs) and find a dual electron–injection enhancement mechanism derived from the LiF layer. Different from what observed previously in Ag- and Au-cathode devices, the LiF buffer layer in the Cu-cathode OLEDs starts to play its role in performance improvement when it is much thinner than 3 nm, the optimal value of buffer thickness, and in the case of optimal thickness, the device exhibits excellent performance comparable to conventional Al-cathode device. The phenomenon observed is ascribed to enhanced electron injection as a result of combined effect of interfacial reaction and tunneling barrier reduction mechanism: while chemical reaction plays a key role at the very beginning of interface formation, tunneling dominates in the subsequent stage leading to the tremendous improvement of the characteristics.

Copolymer including dithienylquinoxaline (TQ) ( 2 . CIE coordinates were close to pure white (0.33, 0.39).

In spite of the impressive efficiencies reported for perovskite solar cells (PSCs), key aspects of their working principles, such as electron injection at the contacts or the suitability of the utilization of a specific scaffold layer, are not yet fully understood. Increasingly complex scaffolds attained by the sequential deposition of TiO2 and SiO2 mesoporous layers onto transparent conducting substrates are used to perform a systematic characterization of both the injection process at the electron selective contact and the scaffold effect in PSCs. By forcing multiple electron injection processes at a controlled sequence of perovskite–TiO2 interfaces before extraction, interfacial injection effects are magnified and hence characterized in detail. An anomalous injection behavior is observed, the fingerprint of which is the presence of significant inductive loops in the impedance spectra with a magnitude that correlates with the number of interfaces in the scaffold. Analysis of the resistive and capacitive behavior of the impedance spectra indicates that the scaffolds could hinder ion migration, with positive consequences such as lowering the recombination rate and implications for the current–potential curve hysteresis. Our results suggest that an appropriate balance between these advantageous effects and the unavoidable charge transport resistive losses introduced by the scaffolds will help in the optimization of PSC performance., The research leading to these results received funding from the European Research Council under the European Union's Seventh Framework Program (FP7/2007–2013)/ERC grant agreement no. 307081 (POLIGHT) and the Spanish Ministry of Economy and Competitiveness under grants MAT2014-54852-R and MAT2015-70611-ERC. MA is grateful to “La Caixa” Foundation and VPPI of the University of Seville for their financial support. Structural characterization was performed at CITIUS, and we are grateful for their support. B. C. H. is grateful for the support of the National Council of Technological and Scientific Development (CNPq), Brazil, through the Science without Borders program.307081, We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI).

In this work, the temperature-dependent DC performance of InP/GaAsSb double heterojunction bipolar transistors (DHBTs) with an InP/InAlAs composite emitter was characterized. The current transport mechanisms in DHBTs with a type-I InAlAs/GaAsSb emitter–base junction interface and a type-II GaAsSb/InP base–collector were studied. The experimental results reveal that electron injection at emitter–base junction could be affected by conduction barrier limited carrier transport. A conduction band edge discontinuity of 9.5 meV for InAlAs/GaAsSb heterojunction was experimentally estimated.

Inverted bottom-emission organic light emitting diodes (IBOLEDs) employing the electron injection structure of indium tin oxide (ITO)/1,4,5,8-naphthalene-tetracarboxylic-dianhydride (NTCDA)/Li2CO3 doped bathocuproine (BCP) (1: 4 Li2CO3: BCP) were fabricated, where NTCDA and BCP stand for NTCDA and BCP, respectively. The NTCDA on ITO was characterized crystalline and n-doped as a result of the interaction between ITO and NTCDA. Compared to the IBOLED using the electron injection structure of ITO/10 nm 1: 4 Li2CO3: BCP, the one utilizing the electron injection structure of ITO/3 nm NTCDA/7 nm 1: 4 Li2CO3: BCP showed the remarkable increases in both current density and efficiency, mainly due to the higher electron conductivity of n-doped NTCDA than that of n- doped BCP. The dependence of the current conduction in IBOLED on the thickness of NTCDA was investigated. We provide a simple method to significantly enhance the performance of IBOLEDs.