Enhanced Photocurrent Response Research Articles

Ultrasensitive and specific photoelectrochemical sensor for hydrogen peroxide detection based on pillar[5]arene-functionalized Au nanoparticles and MWNTs hybrid BiOBr heterojunction.

A photoelectrochemical sensor for target detection of hydrogen peroxide was designed based on a new heterojunction nanocomposite which was sulfhydryl-borate ester-modified A1/B1-type pillar[5]arene (BP5)-functionalized Au NPs and multi-walled carbon nanotubes hybridized with bismuth bromide oxide (Au@BP5/MWNTs-BiOBr). The specific sensor was based on the direct induction of oxidation by hydrogen peroxide of the borate ester group of pillar[5]arene. Additionally, the local surface plasmon resonance (LSPR) of Au NPs enhanced visible light capture, the host-guest complexation of BP5 with H2O2 enhanced photocurrent response, the layer-by-layer stacked nanoflower structure of BiOBr provided large specific surface area with more active sites, and the conductivity of MWNTs enhanced the charge separation efficiency and significantly improves the stability of PEC. Their synthesis effect significantly increased the photocurrent signal and further enhanced the detection result. Under the optimal conditions, the linear concentration range of H2O2 detected by the Au@BP5/MWNTs-BiOBr sensor was from 1 to 60pmol/L. The limit of detection (LOD) and the limit of quantification (LOQ) of the method were 0.333pmol/L and 1pmol/L, respectively, and the sensitivity was 6.471pmol/L. Importantly, the PEC sensor has good stability, reproducibility, and interference resistance and can be used for the detection of hydrogen peroxide in real cells.

Split-type photoelectrochemical immunoassay for sensitive quantification of carcinoembryonic antigen based on target-induced in situ formation of Z-type heterojunction.

Carcinoembryonic antigen (CEA), a vital biomarker, plays a significant role in the early diagnosis and prognostic estimation of malignant tumors. In this study, a split-type photoelectrochemical immunoassay for the sensitive quantification of CEA has been successfully developed based on the target-induced in situ formation of a Z-type heterojunction. First, gold nanoparticle-decorated ZnIn2S4 (AuNPs/ZnIn2S4) composites were synthesized and used for the fabrication of photoelectrodes. Then, the detection antibody labeled with Ag nanoparticles was formed and applied for the biorecognition of CEA and subsequent liberation of Ag+ ions to induce the in situ formation of Ag2S/AuNPs/ZnIn2S4, a Z-type heterojunction, on the photoelectrode. The Z-type Ag2S/AuNPs/ZnIn2S4 heterojunction with effectively promoted separation of photogenerated charge carriers could lead to a markedly enhanced photocurrent response and highly sensitive quantification of CEA. Moreover, the three-dimensional spatial structure of ZnIn2S4 provides abundant active sites for the reaction and exhibits non-enzymatic properties, which are conducive to the further improvement of the analytical performance of CEA. The developed split-type photoelectrochemical immunoassay with good sensitivity, satisfactory selectivity, reliable stability, wide dynamic linear range (0.01-20 ng mL-1), and low detection limit (7.3 pg mL-1) offers valuable insights into the development of novel PEC biosensing models for the detection of tumor biomarkers and holds potential application value in the field of disease diagnosis.

Photocurrent Polarity Reversal Induced by Electron-Donor Release for the Highly Sensitive Photoelectrochemical Detection of Vascular Endothelial Growth Factor 165.

Photocurrent polarity reversal is a switching process between the anodic and cathodic pathways and is critical for eliminating false positivity and improving detection sensitivity in photoelectrochemical (PEC) sensing. In this study, we construct a PEC sensor with excellent photocurrent polarity reversal induced by ascorbic acid (AA) as an electron donor with the energy level matching the photoactive material zirconium metal-organic framework (ZrMOF). The ZrMOF-modified electrode demonstrates cathodic photocurrent in the presence of O2 as an electron acceptor, while the anodic photocurrent is generated in the presence of AA, achieving photocurrent polarity reversal. By the in situ release of AA from AA-encapsulated apoferritin modified with DNA 2 (AA@APO-S2) as a detection tag in the presence of trypsin after the recognition of hairpin DNA-modified indium tin oxide to the reaction product of aptamer/DNA 1 with the target protein and the following rolling cycle amplification for introducing the detection tag to the sensing interface, the reversed photocurrent shows an enhanced photocurrent response to the target protein, leading to a highly sensitive PEC sensing strategy. This strategy realizes the detection of vascular endothelial growth factor 165 with good specificity, a wide linear range, and a low detection limit down to 5.3 fM. The actual sample analysis offers the detection results of the proposed PEC sensor comparable to those of commercial enzyme-linked immunosorbent assay tests, indicating the promising application of the photocurrent polarity reversal-based PEC sensing strategy in biomolecule detection and clinical diagnosis.

Photoelectrocatalytic degradation of emerging organic pollutants in water on an FTO/BiVO4/NiS photoanode

This study demonstrates the facile synthesis of bismuth vanadate-nickel sulfide (BiVO4/NiS) heterojunction via a solvothermal process coated on a fluorine-doped tin oxide (FTO) substrate for photoelectrochemical (PEC) degradation of sulfamethoxazole (SMX) and Rhodamine B (RhB). The two semiconductors were rationally designed for the p-n heterojunction as it enhances the charge-separation and light-absorbing properties for efficient degradation of organic pollutants. The successful preparation of the BiVO4/NiS composite was confirmed using structural, morphological, and optical analysis such as X-ray diffraction (XRD), transmitted electron microscopy (TEM), energy dispersive X-ray analysis (EDX), scanning electron microscopy (SEM), ultraviolet–visible diffuse reflectance spectroscopy (UV-DRS). The electrochemical and photoelectrochemical properties were investigated using electrochemical impedance spectroscopy (EIS), Mott-Schottky (M−S), and photocurrent response. Compared with the individual components, the FTO/BiVO4/NiS photoanode showed an enhanced photocurrent response of 0.4 mA/cm2 at 1.5 V potential, 16 and folds higher than the pristine BiVO4. The composite showed a band gap of 1.9 eV, 2.28 eV, and 2.18 eV for the FTO/NiS, FTO/BiVO4, and FTO/BiVO4/NiS, respectively. Moreover, the PEC degradation of the two analytes indicated that the FTO/BiVO4/NiS photoanode successfully degraded SMX (58%) and RhB (73%) in 120 min time intervals with a rate constant of 0.00755 min−1 and 0.108 min−1. Scavenger studies revealed that holes and superoxides were significant contributors to the mineralization of the analytes.

Ag2S QDs integration with MnO2 nanosheets for the sensitive detection of Cr (VI) via the redox reaction induced photoelectrochemical variation

The heavy metal Cr (VI) will remain, accumulate, and migrate after entering the environment or ecosystem, causing serious harm to the environment. Here, a photoelectrochemical sensor was developed for Cr (VI), utilizing the Ag2S quantum dots (QDs) and MnO2 nanosheets as photoactive components. By introducing Ag2S QDs with a narrow gap, a staggered energy level match is created which effectively prevents the carrier recombination in MnO2 nanosheets, resulting in an enhanced photocurrent response. In the presence of the electron donor, l-ascorbic acid (AA), the photocurrent of the Ag2S QDs and MnO2 nanosheets modified photoelectrode is further enhanced. As AA has the ability to convert Cr (VI) to Cr (Ⅲ), the photocurrent may decline due to the decrease in the electron donors when Cr (VI) is added. This phenomenon can be utilized for the sensitive detection of Cr (VI) over a wider linear range (100 pM-30 μM) with a lower detection limit of 6.46 pM (S/N = 3). This work using the strategy that the targets induced the variations of the electron donor shows the advantages of good sensitivity and nice selectivity. The sensor holds many advantages such as simple fabrication process, economical material expense, and consistent photocurrent signals. It also holds significant potential for environmental monitoring and serves as a practical photoelectric sensing approach for detecting Cr (VI).

Enhanced glucose sensing performance of p-n Cu2O homojunction promoted by Cu(I)/Cu(III) redox process

Developing enzyme-free glucose sensors that rely on transitional metal oxides has become a tendency to satisfy the growing demands of glucose monitor. In this work, the photoactive Cu2O film has been prepared by electrochemical deposition for effective and selective detection of glucose. Characterizations including XRD, Raman spectrum, UV–vis reflectance spectrum, and electrochemical testing were performed. We found that the as-prepared Cu2O films were self-composed of p-n Cu2O homojunction structure with enhanced photocurrent response for PEC-type glucose sensing. Further investigation on p-n Cu2O indicates that the intrinsic charge recombination has been retarded, which paves the way to construct photoelectrochemical-type (PEC-type) glucose sensors. Benefitted from the properties of p-n Cu2O homojunction, high sensitive PEC-type glucose detection has been achieved at the dual-range of 1 μM to 10 μM and 20 μM to 11 mM. We attribute to our investigations can provide in-depth understanding on electric assist-redox and glucose catalytic processes for the detection of glucose, that may guide the fabrication of glucose sensors with high sensitivity and selectivity.

Pt-anchored MoS2 nanotubes with enzyme reaction for photoelectrochemical biosensing of miRNA-155

The development of photoactive materials based on single-atom catalysts is essential to improve the performance of photoelectrochemical (PEC) biosensors. Herein, we have designed Pt atoms-anchored MoS2 nanotubes (Pt-MoS2NT) as photoactive materials. Catalytic kinetics of Pt-MoS2NT can enable efficient separation of photogenerated electron-hole pairs and extend the charge carrier lifetime, which makes Pt-MoS2NT possess a significantly enhanced photocurrent response compared to MoS2NT. During the detection of miRNA-155, horseradish peroxidase-catalyzed reaction produces a solid precipitate (benzo-4-chlorohexadienone), which can block the electron transport pathway between the electrolyte solution and Pt-MoS2NT, resulting in a significant reduction of the PEC signal. Based on a dual strategy of single-atoms Pt enhanced photocurrent response and enzymatic reaction, the constructed PEC biosensor achieves ultra-sensitive detection of miRNA-155 (detection limit up to 3.1 aM). The present work confirms the advantages of single-atom catalysts for bioassay applications.

Surface plasmon resonance‐enhanced photoelectrochemical immunoassay of prostate‐specific antigen based on BiOCl‐Au heterojunction

AbstractTaking advantage of the high‐efficiency photocurrent response of bismuth oxychloride sensitized with gold nanoparticles (BiOCl−Au) in combination with the antigen‐antibody biological recognition reaction, a convenient photoelectrochemical (PEC) immunoassay (model target: prostate‐specific antigen; PSA) has been fabricated. In particular, the enhanced photocurrent response could be attributed to the enhanced optical absorption of visible light from surface plasmon resonance (SPR) effect of gold nanoparticles in the hierarchical structure of BiOCl layered. To realize the biological detection process, an immunoreaction was implemented between target PSA and alkaline phosphatase (ALP)‐labeled anti‐PSA antibodies. With the formation of ternary sandwich immunocomplex, the carried and loaded ALP catalysed the substrate ascorbic acid 2‐phosphate (AAP) to generate ascorbic acid for increasing the photocurrent intensity of BiOCl−Au/FTO. Under optimum reaction time, the photocurrent peak intensity of BiOCl−Au/FTO increased with the increasing of target PSA concentration in the range of 0.01 ng/mL to 50 ng/mL with a limit of detection (LOD) down to 2.3 pg/mL. In the photocurrent control experiment, the photocurrent of BiOCl−Au/FTO was not only higher than that of BiOCl/FTO, but also showed greater changes in photocurrent under the same target PSA concentration. Impressively, the proposed split‐type PEC immunoassay was applied to detect PSA concentration in human serum samples, giving acceptable and satisfactory accuracy compared with the gold standard PSA ELISA method.

Stable all-solid-state Z-scheme heterojunction Bi2O3-Co3O4@C microsphere photocatalysts for recalcitrant pollutant degradation

We present a strategy for the modification of an ion-exchange resin (D113) as an inexpensive carbon source to obtain a macrospherical photocatalyst precursor that can be transformed into a stable all-solid-state Z-scheme heterojunction catalyst (denoted Bi2O3-Co3O4@C). X-ray diffractometry and Fourier transform infrared and Raman spectroscopy measurements confirmed the presence of highly graphitized carbon in the complex. Significantly, the cost of the as-prepared material was only 1/200 of that of commercial carbon nanotubes and 1/80 of that of graphene oxide. Aided by the organic carbon source, Bi2O3-Co3O4 @C showed an enhanced light absorption, hindered electron–hole recombination, and an enhanced photocurrent response. Under simulated solar irradiation, Bi2O3-Co3O4 @C (20 mg/L) showed degradation efficiencies of 100%, 47.52%, 94.28%, and 100% for methylene blue, rhodamine B, tetracycline, and Cr(VI), respectively, after 120 min. Herein, the highest turnover frequency (TOF) obtained under irradiation was 2.5 h−1 for Cr(VI). Further, the degradation efficiency for methylene blue trihydrate remained 91.46% after five cycles, indicating significantly higher stability than that of a catalyst prepared without graphitic carbon. The optimized band structure and photocatalytic mechanism of Bi2O3-Co3O4@C were determined based on ultraviolet-visible measurements and plane-wave density functional theory calculations in VASP. The findings of this study indicate the promise of the Bi2O3-Co3O4@C macrospheres for industrial applications based on their photocatalytic performance, high stability, low cost, and suitable particle size.

Surface engineering of CsPbBr3 perovskite nanocrystals: hole transfer dynamics and enhanced photocurrent response using a novel organic molecule

A molecularly engineered small organic molecule SPS-Cbz is used as a hole acceptor to study the photoinduced hole-transfer phenomenon using amine-free and amine-based perovskite nanocrystals.

A ZnIn2S4@ReS2/AgInS2-based photoelectrochemical aptasensor for the ultrasensitive detection of kanamycin.

An ultrasensitive photoelectrochemical (PEC) aptasensor was originally designed by using ZnIn2S4/ReS2 as a photoactive material and AgInS2 as a signal amplifier. The signal amplifier AgInS2 was incubated on the terminal of H-DNA (immobilized on the ZnIn2S4/ReS2/FTO surface), leading to an enhanced photocurrent response. Then, due to the introduction of DNA2, the formation of a double-stranded structure caused AgInS2 to keep away from the electrode surface, and the photocurrent was reduced. In the presence of kanamycin, DNA2 was released from the system due to the competition relationship, and a restored photocurrent response was obtained. The combination of ZnIn2S4/ReS2 and AgInS2 accelerated the electron transfer and enhanced the separation efficiency of photogenerated electron-hole pairs, resulting in an improved performance of the PEC aptasensor, which was capable of accurate and sensitive detection of kanamycin in actual samples.

Designing a Stable g-C3N4/BiVO4-Based Photoelectrochemical Aptasensor for Tetracycline Determination

The excessive consumption of tetracycline (TC) could bring a series of unpredictable health and ecological risks. Therefore, it is crucial to develop convenient and effective detection technology for TC. Herein, a "signal on" photoelectrochemical (PEC) aptasensor was constructed for the stable detection of TC. Specifically, the g-C3N4/BiVO4 were used to promote the migration of photo-generated charges to an enhanced photocurrent response. TC aptamer probes were stably fixed on the g-C3N4/BiVO4/FTO electrode as a recognition element via covalent bonding interaction. In the presence of TC, the aptamer probes could directly recognize and capture TC. Subsequently, TC was oxidized by the photogenerated holes of g-C3N4/BiVO4, causing an enhanced photocurrent. The "signal on" PEC aptasensor displayed a distinguished detection performance toward TC in terms of a wide linear range from 0.1 to 500 nM with a low detection limit of 0.06 nM, and possessed high stability, great selectivity, and good application prospects.

Heterostructures of Cut Carbon Nanotube-Filled Array of TiO2 Nanotubes for New Module of Photovoltaic Devices.

In this work, a new photovoltaic device was prepared. The device uses titanium (Ti) foil/TiO2 nanotubes as the photoanode and multi-walled carbon nanotubes (MWCNTs) as a photosensitizer. Titanium dioxide nanotube arrays (TiO2-NTs) were prepared by one-step anodic oxidation. Cut-MWCNTs with a length of less than 100 nm were obtained by the mixed-acid oxidation of MWCNTs. The two materials were combined to form a TiO2-NTs@cut-MWCNT heterostructure by electrophoresis. TiO2-NTs@cut-MWCNTs were characterized by field-emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD), which showed that the two materials were effectively combined. We fabricated the heterostructure into a photovoltaic device, showing an enhanced photocurrent response and an efficiency of 0.0138%, and explained this phenomenon by performing UV-vis absorption spectroscopy and electrochemical tests. It is hoped that this work can provide a reference value for the application of carbon nanotubes in photovoltaic devices.

Millimeter-scale semiconductive metal-organic framework single crystal for X-ray imaging

One of the bottleneck issues in the design of semiconductive metal-organic frameworks is the growth of high-quality single crystals large enough for device fabrication. Here, we report the synthesis and crystal growth of a millimeter-scale semiconductive metal-organic framework (MOF; UO2(SC6H4COO)2(DMF), SCU-15) and further investigate its electrical properties. The single crystal of SCU-15 shows a charge-carrier mobility-lifetime product (μτ) of 2.18 × 10−3 cm2 V−1 and presents a carrier diffusion length exceeding 70 μm under X-ray excitation, which enables a significantly enhanced photocurrent response and detection sensitivity compared with those of the pelleted polycrystalline sample. As a proof of concept, a planar 2 × 3 pixelated detector is constructed to show its potential application in X-ray imaging. This work discloses an example of a millimeter pixel detector based on semiconductive MOF crystals, heralding the opportunity to develop a new generation of radiation-detection sensors.

In Situ Formation of Bi2MoO6-Bi2S3 Heterostructure: A Proof-Of-Concept Study for Photoelectrochemical Bioassay of l-Cysteine.

A novel signal-increased photoelectrochemical (PEC) biosensor for l-cysteine (L-Cys) was proposed based on the Bi2MoO6–Bi2S3 heterostructure formed in situ on the indium–tin oxide (ITO) electrode. To fabricate the PEC biosensor, Bi2MoO6 nanoparticles were prepared by a hydrothermal method and coated on a bare ITO electrode. When L-Cys existed, Bi2S3 was formed in situ on the interface of the Bi2MoO6/ITO electrode by a chemical displacement reaction. Under the visible light irradiation, the Bi2MoO6–Bi2S3/ITO electrode exhibited evident enhancement in photocurrent response compared with the Bi2MoO6/ITO electrode, owing to the signal-increased sensing system and the excellent property of the formed Bi2MoO6–Bi2S3 heterostructure such as the widened light absorption range and efficient separation of photo-induced electron–hole pairs. Under the optimal conditions, the sensor for L-Cys detection has a linear range from 5.0 × 10−11 to 1.0 × 10−4 mol L−1 and a detection limit of 5.0 × 10−12 mol L−1. The recoveries ranging from 90.0% to 110.0% for determining L-Cys in human serum samples validated the applicability of the biosensor. This strategy not only provides a method for L-Cys detection but also broadens the application of the PEC bioanalysis based on in situ formation of photoactive materials.

In-situ preparation of hollow CdCoS2 heterojunction with enhanced photocurrent response for highly photoelectrochemical sensing of organophosphorus pesticides

In this study, a porous hollow CdCoS2(2) microsphere was synthesized based on the ZIF-67-S MOFs derived method of sulfurization reaction and calcination process. Under visible light irradiation, the resulting CdCoS2(2) composite showed a markedly enhanced photoelectrochemical (PEC) response. The photocurrent value of the CdCoS2(2) modified ITO electrode was 93-fold and 41-fold than that of CoS and CdS materials, respectively. Promoting the photo-absorption ability by internal multilight scattering/reflection was due to the porous and hollow nature of CdCoS2(2). Furthermore, obtained CdCoS2(2) heterostructure in-situ with a close contact interface could facilitate the separation/migration of photo-induced carriers. The CdCoS2(2) was also mixed with Ag nanoparticles (NPs) to further improve the PEC response. Acetylcholinesterase (AChE) as a bio-recognition molecule was immobilized on the glutaraldehyde-chitosan (GLD-CS) modified CdCoS2(2)@Ag electrode surface by cross-linking effect. AChE could hydrolyze the acetylcholine chloride (ATCl) to produce an electron donor of thiocholine which led to the elevated photocurrent output. When the bioactivity of AChE was inhibited by the organophosphate pesticides (chlorpyrifos as substrate), the reduced production of thiocholine resulted in a decline in photocurrent. Under optimal conditions, the structured AChE/GLD-CS/CdCoS2(2)@Ag/ITO sensing platform was successfully achieved for chlorpyrifos detection. The wide linear response range was from 0.001 to 270 μg mL−1 and with a low detection limit of 0.57 ng mL−1. The proposed PEC biosensor also exhibited excellent selectivity and good stability, demonstrating the designed porous hollow CdCoS2(2)@Ag heterostructured composite promised to be a great application in the PEC sensors.

A highly sensitive photoelectrochemical biosensor for CEA analysis based on hollow NiS@NiO/TiO2 composite with typal p-n heterostructure

Heterostructured construction is regarded as a valuable approach to improve photoelectrochemical (PEC) performances. Herein, porous hollow NiS@NiO spheres were prepared derived from the Ni(TCY) MOFs precursor. Photoactive TiO2 was coupled with as-prepared NiS@NiO to form a close heterojunction interface of NiS@NiO/TiO2. NiS@NiO/TiO2 modified ITO electrode (NiS@NiO/TiO2/ITO) displayed fiercely enhanced photocurrent response, which was 4687-fold than that of NiS@NiO/ITO (0.008 μA) and 8.5-fold than that of TiO2/ITO (4.41 μA), respectively. Remarkable PEC property could be ascribed to the hollow NiS@NiO spheres with thin-shell structure provided there is a larger active surface area for harvesting the visible light. Most importantly, the p-n type NiS@NiO/TiO2 heterojunction could lead to generating more photo-excited charge carriers (e−/h+) and efficiently hinder the recombination of carriers, resulting in significantly augmented photocurrent output. Based on this outstanding PEC property, NiS@NiO/TiO2/ITO electrode fabricated sensing platform (BSA/anti-CEA/NiS@NiO/TiO2/ITO, BSA=Bovine serum albumin) exhibited high sensitivity for monitoring CEA (Carcinoembryonic antigen). Wide linear detection range was from 0.001 to 45 ng mL-1 and with a low detection limit of 1.67 × 10-4 ng mL-1 (S/N = 3). Prepared biosensors also showed good reproducibility, stability and had satisfying specificity. Thus, the proposed NiS@NiO/TiO2 heterostructured composite afforded well-design and synthesis strategy for constructing high-performance photoactive materials from MOFs-derivate.

A label-free photoelectrochemical sensor of S, N co-doped graphene quantum dot (S, N-GQD)-modified electrode for ultrasensitive detection of bisphenol A.

S, N co-doped graphene quantum dot (S, N-GQD) materials have been composited via a one-pot pattern and used as photosensitive materials to construct alabel-free photoelectrochemical (PEC) sensor. The PEC experiments show an enhanced photocurrent response toward Bisphenol A (BPA) sensing due to the increased charge transfer rate and the enhanced absorption of visible light. Compared with dark conditions, the photocurrent signal (- 0.2V vs. SCE) is greatly increased because of the effective oxidation of BPA by photogenerated holes and the rapid electron transfer of S, N-GQDs on the PEC sensing platform. Under optimal conditions linear current response to BPA is in two ranges of0.12-5µM and 5-40µM. The limit of detection is 0.04µM (S/N = 3). The designed sensor has enduring stability and admirable interference immunity. It provides an alternative approach for BPA determination in real samples withrecoveries of 99.3-103% and RSD of 2.0-4.1%.

Porous silica matrix as an efficient strategy to boosted photocatalytic performance of titania/carbon composite

Semiconductor based photocatalysis is considered as a promising route for remediation of polluted water. However, there is still intensive research to overcome high recombination rate of electrons and holes, and low reaction rate, limiting large-scale applications. Therefore, it is crucial to focus on the fabrication of the optimal photocatalysts which could be practically utilized. In this contribution, we propose a composite composed of ultrasmall TiO2 nanoparticles embedded in silica/carbon matrix. This molecular hybrid was fabricated via anchoring a (3-aminopropyl) triethoxysilane on a surface of TiO2 and then the composite was encapsulated in a carbon sphere-like structure formed with biocompatible glucose as carbon precursor. As a result, such a system exhibited impressive photocatalytic activity in the degradation of methylene blue as a model hazardous organic dye. Among examined catalysts, the sample calcinated at 500 °C showed the highest photocatalytic efficiency (~100% photodegradation under UV light after 120 min and ~11.0–fold higher reaction rate constant in comparison to pristine TiO2) and the most enhanced photocurrent response upon irradiation with light 388 nm (~0.74 μA, which is 1.37–fold more compared with TiO2). Therefore, we provide new insights into the fabrication of carbon-based inorganic composite, which have great potential in water treatment.

Enhancing charge separation and photocurrent response of CuO nanocone array by constructing CuO/PC61BM hybrid bulk heterojunction

An inorganic–organic hybrid bulk heterojunction (BHJ) consisting of a CuO nanocone array (NCA)/methyl [6,6]-phenyl-C61-butyrate (PC61BM) was fabricated on a fluorine-doped tin oxide substrate using a hydrothermal method. Scanning electron microscopy showed that the CuO-NCA/PC61BM BHJ hybrid structure was well-formed and that the PC61BM compactly filled the interspaces between the CuO nanocones. A FTO/CuO-NCA/PC61BM/LiF/Ag hybrid BHJ photodiode had a favorable type-II band alignment for charge separation, and this photodiode showed a nearly 10-fold enhanced photocurrent response compared with a FTO/CuO-NCA/LiF/Ag Schottky junction photodiode. Photoelectrochemical impedance spectroscopy and transient absorption spectroscopy demonstrated that the FTO/CuO-NCA/PC61BM/LiF/Ag BHJ device had better photogenerated charge transfer properties and a longer carrier lifetime compared with the FTO/CuO-NCA/LiF/Ag device.