Organic-inorganic Hybrid Heterojunction Research Articles

Facile Synthesis of Organic-Inorganic Hybrid Heterojunctions of Glycolated Conjugated Polymer-TiO2-X for Efficient Photocatalytic Hydrogen Evolution.

The utilization of the organic-inorganic hybrid photocatalysts for water splitting has gained significant attention due to their ability to combine the advantages of both materials and generate synergistic effects. However, they are still far from practical application due to the limited understanding of the interactions between these two components and the complexity of their preparation process. Herein, a facial approach by combining a glycolated conjugated polymer with a TiO2-X mesoporous sphere to prepare high-efficiency hybrid photocatalysts is presented. The functionalization of conjugated polymers with hydrophilic oligo (ethylene glycol) side chains can not only facilitate the dispersion of conjugated polymers in water but also promote the interaction with TiO2-X forming stable heterojunction nanoparticles. An apparent quantum yield of 53.3% at 365nm and a hydrogen evolution rate of 35.7mmol h-1 g-1 is achieved by the photocatalyst in the presence of Pt co-catalyst. Advanced photophysical studies based on femtosecond transient absorption spectroscopy and in situ, XPS analyses reveal the charge transfer mechanism at type II heterojunction interfaces. This work shows the promising prospect of glycolated polymers in the construction of hybrid heterojunctions for photocatalytic hydrogen production and offers a deep understanding of high photocatalytic performance by such heterojunction photocatalysts.

Efficient removal of bisphenol A from water using a novel organic–inorganic hybrid heterojunction

Organic-inorganic hybrid heterojunctions have the ability to efficiently remove trace pollutants from water due to efficient photosensitivity. In this work, an organic–inorganic hybrid S-scheme heterojunction photosensitizer (RCP-BW) was successfully fabricated by growing cross-linked β-CD/riboflavin copolymer on the surface of bismuth tungstate (Bi2WO6). The fabrication of the copolymer retains the photosensitivity of riboflavin and the confinement effect of β-CD and forms an internal electric field with Bi2WO6 to enhance the photoelectron transport ability. Photogenerated electrons are transferred and stacked from Bi2WO6 to β-CD/riboflavin copolymers, which greatly enhances the ability of organic copolymers to reduce oxygen and produce superoxide radicals. We combined electrochemistry, free radical chemistry and DFT to study the photoelectron migration mechanism and photocatalytic performance enhancement mechanism in S-scheme heterojunctions. The pseudo-first-order reaction kinetic constant (kRCP-BW = 0.081 min−1) for BPA degradation was four times that of unmodified BW (kBW = 0.020 min−1). β-CD regulates the band structure of riboflavin to match with Bi2WO6, and utilizes charged contaminants and intermediate degradation products to promote the production of reactive oxygen species through interface electron transfer and excited state transition energy transfer. This work provides theoretical support and technical means for photocatalytic oxidation technology to control endocrine disruptors.

Suppressing Carrier Recombination in BiVO4/PEDOT:PSS Heterojunction for High-Performance Photodetector.

The organic-inorganic hybrid heterojunction is introduced for the first time to break through the performance bottleneck of BiVO4-based photodetectors. Through a facile solution process, a p-n heterojunction is established at the BiVO4/PEDOT:PSS interface, and the built-in electric field is designed to separate photogenerated charge carriers. The hybrid heterojunction outputs a significantly increased photocurrent, which is 24 000 times larger than that of the bare BiVO4 thin film. The photodetector shows a satisfactory performance with a responsivity (R) and specific detectivity (D*) of 107.8 mA/W and 4.13 × 1010 Jones at 482 nm illumination. In addition to the fast response speed (100 ms), the device also exhibits an impressive long-term stability with a negligible attenuation in photocurrent after more than 700 cycles. This work provides a novel strategy to suppress carrier recombination of BiVO4, and the coupling of metal oxides and organic semiconductors opens up a new avenue for fabricating high-performance photodetectors.

The synthesis of 3D organic-inorganic hybrid heterojunctions of g-C3N4 nanoneedles@Ti3C2 MXene with superior photocatalytic H2 evolution.

3D organic-inorganic hybrid heterojunctions of 1D carbon nitride (g-C3N4) nanoneedles anchoring on 2D Ti3C2 MXene nanosheets have been constructed via a green molten salt treatment. The Ti3C2 MXene nanosheets and molten salt treatment guide the formation of ordered nanoneedle-like g-C3N4. Both the formed heterojunctions and the nanoneedle-like structures contribute charge separation and transfer for superior photocatalytic H2 evolution.

G-C3N4/PDI@ZnIn2S4 2D/2D organic–inorganic hybrid heterojunction with enhanced visible light photocatalytic property

In this study, we designed and fabricated novel g-C3N4/PDI@ZnIn2S4 2D/2D organic/inorganic hybrid heterojunctions consist of g-C3N4/PDI nanosheets and ZnIn2S4 nanosheets by a two-step-heating route followed by an oil-bath process for the first time. The synthesized heterojunctions were used as photocatalysts for the visible-light photodegradation of Rhodamine B (RhB), the composite photocatalysts displayed enhanced photocatalytic performance. Among them, the optimal photocatalyst exhibited significantly enhanced photocatalytic activity of up to 83.92 % after 120 min, which is nearly 7.0, 2.2, and 1.4 times higher than that of bare g-C3N4, g-C3N4/PDI, and ZnIn2S4, respectively. The enhanced photocatalytic activities can be attributed to the close interface contact and matched band structure between g-C3N4/PDI and ZnIn2S4, resulting in the formation of efficient heterojunctions, which accelerate the separation and transfer of photo-induced charges and improve the utilization of visible light. This work confirms the promising application prospects of g-C3N4/PDI@ZnIn2S4 photocatalysts in environmentalremediationfields.

Enhanced Emission of Molybdenum Disulfide by Organic–Inorganic Hybrid Heterojunctions

Enhanced Emission of Molybdenum Disulfide by Organic–Inorganic Hybrid Heterojunctions

Achieving low contact resistivity in PEDOT:PSS/n-Si solar cells

Good conductivity and transparency in the visible spectrum along with low processing temperatures and ease of fabrication make Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) a widely accepted polymer for organic-inorganic hybrid heterojunction solar cells. Although the overall conductivity of the PEDOT:PSS is high, the PSS segregates more at the surfaces of the deposited film. This leads to high contact resistivity of PEDOT:PSS film with metal and silicon. In this report, we explore the effect of the spin coating rates on the contact resistivity of PEDOT:PSS with the metal and silicon and the associated performance of PEDOT:PSS/n-Si solar cells. Two different spin speeds of 1000 rpm and 4000 rpm were used to deposit the PEDOT:PSS films over silicon. The PEDOT:PSS films were also deposited in single- and double-layer forms. We could achieve very low contact resistivity of PEDOT:PSS with silicon through spin speed optimizations. Hence, the overall performance of the PEDOT:PSS/n-Si solar cells improves with the spin speed for both single- and double-layer PEDOT:PSS film depositions.

A Deep-Ultraviolet Photodetector of a Hybrid Organic-Inorganic p-CoPc/n-Ga2O3 Heterostructure Highlighting Ultra-Sensitive

A practical method for organic–inorganic hybrid heterojunction photodetector by spin-coating the cobalt phthalocyanine (CoPc) solution onto the β-gallium oxide (β-Ga2O3) film is available to realize the sensitive detection of ultraviolet light signals. We have carefully measured and calculated the optoelectronic performance of the prepared device. The device demonstrates excellent rectification characteristics under different light intensities, and the rectification ratio reaches 144.96 under 900 μW/cm2 at ±5 V. Benefiting from the construction of CoPc/Ga2O3 heterojunction, the device shows an extremely low dark current of 5.73 fA, a high detectivity of 1.92 × 1017 Jones, a responsivity of 18.4 mA/W, and a high light-to-dark current ratio of 3.76 × 106. In addition, the intrinsic physical mechanism of the device is investigated through the energy band diagram under different conditions. The device is equipped with the possibility to work under self-powered mode and has good stability in the air environment.

Self-powered photodetector based on poly(3-hexylthiophene) / Zinc oxide quantum dots Organic-inorganic hybrid heterojunction

The ZnO quantum dots (QDs) was synthesized by the sol–gel method and spin-coated into films to prepare n-ZnO/p-poly(3-hexylthiophene) hybrid heterojunction ultraviolet photodetectors (PDs) with different film thicknesses. Under optimal critical film thickness, 0 bias voltage and ultraviolet light (360 nm) irradiation, the device yields a photo-dark current ratio of ∼ 990, the quantum efficiency of ∼ 1.05 %, the highest photoresponsivity of ∼ 3.04 mA/W, detectivity of ∼ 1010 Jones and fast rise/fall time of ∼ 23 ms. This work paves the way for the development of low-cost and high-performance PDs.

Electrical and Photoelectric Properties of Organic-Inorganic Heterojunctions PEDOT:PSS/n-CdTe

PEDOT: PSS thin films are widely used as transparent coatings in flexible semiconductor devices including solar cells. However, they are not widely used as transparent coatings in combination with crystal substrates. This work shows the possibility of using PEDOT:PSS thin films as a frontal transparent conducting layer in hybrid organic-inorganic Schottky type heterojunctions of the PEDOT:PSS/n‑CdTe, which were prepared by deposition of PEDOT:PSS thin films (using the spin-coating method) on crystalline cadmium telluride substrates. The current-voltage (in a wide temperature range) and capacitance-voltage (at room temperature) characteristics of heterojunctions were measurement and analyzed. It has been established that PEDOT:PSS/n-CdTe heterojunctions have good diode properties with a high rectification ratio RR≈105, a potential barrier height φ0 = 0.95 eV, and series Rs = 91 Ohm and shunt Rsh = 5.7 × 107 Ohm resistances. Analysis of the forward branches of the I–V characteristics of heterojunctions showed that the dominant charge transfer mechanisms are determined by the processes of radiative recombination at low biases (3kT/e <V <0.3 V) and tunneling through a thin depleted layer at high biases (0.3 V <V <0.6 V). Capacity-voltage characteristics are plotted in the Mott-Schottky coordinate, taking into account the influence of series resistance, measured at a frequency of 1 MHz. Used the C-V characteristic was determined the value of the built-in potential Vc = 1.32 V (it correlates well with the cutoff voltage determined from the current-voltage characteristics) and the concentration of uncompensated donors in the n-CdTe substrate ND-NA = 8.79 × 1014 cm-3. Although the photoelectric parameters of unoptimized PEDOT:PSS/n-CdTe heterojunctions are low, their photodiode characteristics (Detectivity D*> 1013 Jones) are very promising for further detailed analysis and improvement. The proposed concept of a hybrid organic-inorganic heterojunction also has potential for use in inexpensive γ- and X-ray detectors.

Highly Selective Self-Powered Organic–Inorganic Hybrid Heterojunction of a Halide Perovskite and InGaZnO NO2 Sensor

Self-powered sensors can lead to disruptive advances in self-sustainable sensing systems that are imperative for evolving human lifestyles. For the first time, we demonstrate the fabrication of a heterojunction sensor using p-type hybrid-halide perovskites (CH3NH3PbBr3) and an n-type semiconducting metal oxide thin film [InGaZnO (IGZO)] for the detection of NO2 gas and power generation. Combining the excellent photoelectric properties of perovskites and the remarkable gas-sensing properties of IGZO at room temperature, the devised sensors generate open-circuit voltage and modulate according to the ambient NO2 concentration. The major challenge in devising self-powered gas sensors is to attain harvesting capability and selectivity simultaneously, owing to perovskites reactivity in the presence of oxygen and humidity. In this work, we developed a novel approach and fabricated a heterojunction sensor using parylene-c as an additional layer to curb the cross-sensitivity and to enhance the selectivity of the sensor. Even under the low concentrations of NO2, the developed sensor exhibits remarkable sensitivity, selectivity, and repeatability. The devices are sensitive and robust even under extreme humidity conditions (80% RH) and synthetic air. The devised sensor configuration is one way to eliminate the cross-sensitivity issue of the perovskite-based devices and serves as a reference for the development of self-powered sensors.

TiO2/PFO inorganic-organic hybrid heterojunction for self-powered blue light photodetector

Organic-inorganic hybrid heterojunction is very promising for low cost and high performance photodetection device application. We have fabricated a heterojunction composed of n-type inorganic TiO2 nanorod arrays and p-type organic semiconductor polymer [9,9-bis-(2-ethylhexyl)-9H-fluorene-2,7-diyl] (PFO). A peak of 0.32 mA W−1 was observed locating at 410 nm in spectral responsivity curve. The photocurrent response was rapid, repeatable as well as consistent. Under weak blue light (410 nm, 75 μW cm−2) irradiance, the rise time and decay time were observed to be 0.16 and 0.12 s, respectively. These results demonstrated that TiO2/PFO heterojuncton could bring prospect for the development of self-powered blue light photodetectors with high spectral selectivity.

Solution‐Processed Organic/p‐Type Silicon Hybrid Heterojunction Solar Cells

Organic–inorganic hybrid heterojunction solar cells have gained extensive attention due to the simple device structure and low‐cost technological processes, and n‐type silicon has been mainly used as the inorganic absorber in previous research. Herein, hybrid heterojunction solar cells based on p‐type silicon are successfully prepared through a low‐temperature solution method. A preliminary power conversion efficiency over 4% is observed, via optimizing the organic thin‐film deposition and organic/inorganic interface, which enhance the built‐in field and promote the separation of photogenerated carriers in the heterojunction. Therefore, a new idea and possibility are provided for developing low‐cost, high‐performance solar cells.

A self-powered solar-blind photodetector with largeVocenhancing performance based on the PEDOT:PSS/Ga2O3organic–inorganic hybrid heterojunction

A self-powered solar-blind photodetector with largeVocenhancing performance is constructed on the PEDOT:PSS/Ga2O3hybrid heterojunction.

Photocatalytic dye degradation and hydrogen production activity of Ag3PO4/g-C3N4 nanocatalyst

Recently, photocatalysts have received increasing attention owing to their potential to resolve issues regarding the environment and alternative sources of energy. Here, highly effective visible-light-driven organic–inorganic hybrid heterojunction graphitic carbon nitride–silver phosphate nanocomposite (GCN–Ag3PO4 NCs) were synthesized via the hydrothermal method. The synthesized photocatalyst was characterized by X-ray diffraction, Fourier transform infrared, X-ray photoelectron spectroscopy, and UV–Vis diffuse reflectance spectroscopies, scanning electron microscopy and transmission electron microscopy, and subsequently utilized for photocatalytic dye degradation and hydrogen production. The GCN–Ag3PO4 NCs exhibit excellent photocatalytic activity for methylene blue degradation under solar simulator visible light, with a hydrogen production activity higher than that of pristine Ag3PO4. The hydrogen production rate of GCN–Ag3PO4 NCs is 44.5 times higher than that of Ag3PO4. Therefore, GCN–Ag3PO4 NCs are promising as effective photocatalysts for environmental protection.

High performance blue light detector based on ZnO nanowire arrays.

Organic-inorganic hybrid heterojunctions are ever so promising for low-cost and high-efficient photoelectric devices. We report a p-n junction diode composed of inorganic ZnO nanowire arrays (ZNAs) and organic 2, 2', 7, 7'-tetrakis-(N, N-di-p-methoxyphenylamine)- 9, 9'-spirobifluorene (spiro-MeOTAD). A maximum photoresponsivity of 1.32 mA/W is observed under illumination at zero bias. We also demonstrate that the photocurrent time response is observed to be rapid, consistent, as well as repeatable. On blue light weak irradiance (410 nm, 75 μW/cm2), the rise time constant and decay time constant were found to be 0.12 and 0.06 s, respectively. These results suggest ZNAs/spiro-MeOTAD heterojunction as a candidate for an efficient self-powered blue light detector.

Achievement of two logical states through a polymer/silicon interface for organic-inorganic hybrid memory

A hysteresis loop of minority carrier lifetime vs voltage is found in polystyrenesulfonate (PSS)/Si organic-inorganic hybrid heterojunctions, implying an interfacial memory effect. Capacitance-voltage and conductance-voltage hysteresis loops are observed and reveal a memory window. A switchable interface state, which can be controlled by charge transfer based on an electrochemical oxidation/deoxidation process, is suggested to be responsible for this hysteresis effect. We perform first-principle total-energy calculations on the influence of external electric fields and electrons or holes, which are injected into interface states on the adsorption energy of PSS on Si. It is demonstrated that the dependence of the interface adsorption energy difference on the electric field is the origin of this two-state switching. These results offer a concept of organic-inorganic hybrid interface memory being optically or electrically readable, low-cost, and compatible with the flexible organic electronics.

First-principles design of nanostructured hybrid photovoltaics based on layered transition metal phosphates

The performance of bulk organic and hybrid organic-inorganic heterojunction photovoltaics is often limited by high carrier recombination arising from strongly bound excitons and low carrier mobility. Structuring materials to minimize the length scales required for exciton separation and carrier collection is therefore a promising approach for improving efficiency. In this work, first-principles computations are employed to design and characterize a new class of photovoltaic materials composed of layered transition metal phosphates (TMPs) covalently bound to organic absorber molecules to form nanostructured superlattices. Using a combination of transition metal substitution and organic functionalization, the electronic structure of these materials is systematically tuned to design a new hybrid photovoltaic material predicted to exhibit very low recombination due to the presence of a local electric field and spatially isolated, high mobility, two-dimensional electron and hole conducting channels. Furthermore, this material is predicted to have a large open-circuit voltage of 1.7 V. This work suggests that hybrid TMPs constitute an interesting class of materials for further investigation in the search for achieving high efficiency, high power, and low cost photovoltaics.

Flexible diode of polyaniline/ITO heterojunction on PET substrate

Hybrid organic-inorganic heterojunction between polyaniline and ITO film coated on flexible polyethylene terephthalate (PET) substrate has been prepared through vapor phase polymerization process. Polaron and bipolaron like defect states induced hole transport and exceptional mobility makes polyaniline a noble hole transport layer. Thus a p-n junction has been obtained between the hole transport layer of polyaniline and highly conductive n-type layer of ITO film. The synthesis process was carried out using FeCl3 as polymerizing agent in the oxidative chemical polymerization process. The prepared polyaniline has been found to be crystalline on characterization through X-ray diffraction measurement. X-ray photoelectron spectroscopic measurements were done for compositional analysis of the prepared film. The UV–vis-NIR absorbance spectra obtained for polyaniline shows the characteristics absorbance as observed for highly conductive polyaniline and confirms the occurrence of partially oxidized emeraldine form of polyaniline. The energy band gap of the polyaniline has been obtained as 2.52eV, by analyzing the optical transmittance spectra. A rectifying behavior has been observed in the electrical J-V plot, which is of great significance in designing polymer based flexible electronic devices.

The field–dependent interface recombination velocity for organic–inorganic heterojunction

We have derived an analytical formula which describes the field–dependent interface recombination velocity for the boundary of two materials characterized by different permittivities. The interface recombination of charge carriers has been considered in the presence of image force Schottky barrier. We suggest that this effect may play an important role in the loss of current for organic–inorganic hybrid heterojunctions. It has been proved that the presented method is a generalization of the Scott–Malliaras model of surface recombination at the organic/metal interface. We also discuss that this model is intuitively similar but not analogous to the Langevin mechanism of bulk recombination.