Photoelectric Materials Research Articles

Enantioselective Synthesis of Axially Chiral Allylic Nitriles via Nickel-Catalyzed Desymmetric Cyanation of Biaryl Diallylic Alcohols.

Axially chiral nitriles are common motifs in organic photoelectric materials, biological compounds, and agrochemicals. Unfortunately, the limited synthetic approaches to axially chiral nitriles have impeded their availability. Herein, we report the first nickel-catalyzed desymmetric allylic cyanation of biaryl allylic alcohols for the synthesis of axially chiral nitrile structures in high yields with excellent enantioselectivities (up to 90% yield and >99% ee). This process enables the synthesis of a diverse range of axially chiral allylic nitriles bearing β,γ-unsaturated alcohol moieties. Leveraging the allylic alcohol and cyano groups as versatile functionalization handles allow for further derivatization of these axially chiral frameworks. Density functional theory (DFT) calculations suggest that both steric and electronic interactions play crucial roles in determining the enantioselectivity of this transformation. Moreover, this mild and facile protocol is also applicable for gram-scale preparation of the chiral nitriles.

Enantioselective Synthesis of Axially Chiral Allylic Nitriles via Nickel‐Catalyzed Desymmetric Cyanation of Biaryl Diallylic Alcohols

Axially chiral nitriles are common motifs in organic photoelectric materials, biological compounds, and agrochemicals. Unfortunately, the limited synthetic approaches to axially chiral nitriles have impeded their availability. Herein, we report the first nickel‐catalyzed desymmetric allylic cyanation of biaryl allylic alcohols for the synthesis of axially chiral nitrile structures in high yields with excellent enantioselectivities (up to 90% yield and >99% ee). This process enables the synthesis of a diverse range of axially chiral allylic nitriles bearing β,γ‐unsaturated alcohol moieties. Leveraging the allylic alcohol and cyano groups as versatile functionalization handles allow for further derivatization of these axially chiral frameworks. Density functional theory (DFT) calculations suggest that both steric and electronic interactions play crucial roles in determining the enantioselectivity of this transformation. Moreover, this mild and facile protocol is also applicable for gram‐scale preparation of the chiral nitriles.

Excitation-wavelength-dependent persistent luminescence from single-component nonstoichiometric CaGaxO4:Bi for dynamic anti-counterfeiting

Materials capable of dynamic persistent luminescence (PersL) within the visible spectrum are highly sought after for applications in display, biosensing, and information security. However, PersL materials with eye-detectable and excitation-wavelength-dependent characteristics are rarely achieved. Herein, a nonstoichiometric compound CaGaxO4:Bi (x < 2) is present, which demonstrates ultra-long, color-tunable PersL. The persistent emission wavelength can be tuned by varying the excitation wavelength, enabling dynamic color modulation from the green to the orange region within the visible spectrum. Theoretical calculations, in conjunction with experimental observations, are utilized to elucidate the thermodynamic charge transitions of various defect states, thereby providing insights into the relationship between Bi3+ emitters, traps, and multicolored PersL. Furthermore, the utility of color-tunable PersL materials and flexible devices is showcased for use in visual sensing of invisible ultraviolet light, multicolor display, information encryption, and anti-counterfeiting. These discoveries create new opportunities to develop smart photoelectric materials with dynamically controlled PersL for various applications.

Photoelectrochemical sensor based on copper tetraamino phthalocyanine graphene oxide covalent compound for sensitive detection of cefazolin sodium

In the present research, a novel photoelectrochemical (PEC) sensor was built to detect cefazolin sodium. A copper tetraamino phthalocyanine (CuTAPc) covalently linked graphene oxide compound (CuTAPc-GO) was fabricated successfully by covalent bonding of CuTAPc with graphene oxide (GO). The novel PEC sensing platform was prepared using CuTAPc-GO as a photoelectric material. The prepared PEC sensor showed a higher PEC efficiency under red light. In the perfect conditions, the PEC sensor exhibited a linear correlation in detecting cefazolin sodium concentrations between 0.25 and 12.5μM, featuring a detection limit at 0.15μM. Furthermore, the manufacturing sensor was employed to detect cefazolin sodium in a real-world sample, demonstrating commendable sensitivity and stability. Thus, our study provides a new method for cefazolin sodium detection.

The impact of halogens on the structural, electronic, and optical properties of vacancy-ordered double perovskites Rb2SeX6 (X=I, Br, Cl)

Lead-based perovskite materials have become one of the most widely used materials in the field of photovoltaics due to their excellent properties. However, concerns over lead toxicity and the stability of materials have prompted the search for alternative, eco-friendly, and stable perovskite materials. To address this need, our study conducts an in-depth analysis of the electronic and optical properties of the lead-free double perovskite materials Rb2SeX6 (X = Cl, Br, I) using first-principles calculations. The results indicate that Rb2SeX6 perovskites possess an indirect bandgap, with values of 3.26 eV, 2.52 eV and 1.39 eV for Rb2SeCl6/Br6/I6, respectively. Rb2SeI6 has larger dielectric function and superior absorption spectrum across the visible range than the other two materials. Thus, Rb2SeI6 has a promising future as a photoelectric material for solar cells. Rb2SeCl6 and Rb2SeBr6 also have the potential for use in photodetectors, light-emitting diodes and other optoelectronic devices.

Near-infrared light induced cathodic photoelectrochemical biosensor for duplex-specific nuclease mediated detection of miRNA166-a

The photoelectrochemical (PEC) biosensor is a new sensing platform which has the merits of low background signal, low cost, easy miniaturization and so on. However, at present, most PEC biosensors utilize visible light or ultraviolet light as the excitation light source. This type of light has high energy and may cause some light damage to the detected object and some photoelectric materials, thus limiting its application scope. Herein, based on NaYF4:Yb,Tm/BiOBr0.8I0.2 a cathode PEC biosensor that can be excited by near-infrared light was constructed to avoid the occurrence of anode false positives and light damage. Through two cycles of the miRNA cycle assisted by Duplex-Specific Nuclease (DSN) and the dissolved oxygen cycle assisted by gold nanoparticles during the detection process, the detection signal was amplified and miRNA166-a was sensitively detected. By using up-conversion materials, the near-infrared light of 980 nm can be converted into ultraviolet light and visible light, thus exciting the photogenerated carriers of BiOBr0.8I0.2. The photocurrent reaction shows a positive correlation with the quantity of gold nanoparticles present on the electrode surface, which are derived from the reporter molecules produced by the hybridization of miRNA166-a and H1. It has a good linear relationship and selectivity towards miRNA166-a, and the detection limit is 0.32 fM. This sensing method provides a cathode PEC biosensor, which can be excited by near-infrared light. The overall light damage of the system is low, and the possibility of false positive of anode PEC biosensor can be avoided, which has certain significance.

A photoelectrochemical sensor based on polydopamine membrane-coated CdS@C core-shell heterostructure for curcumin detection

Curcumin has been widely employed in various fields, but excessive intake may cause tissue necrosis and pose a serious threat to people’s lives and health. Hence, it is crucial to rapidly and precisely detect the content of curcumin. In present research, CdS@C heterostructure materials were successfully prepared through a one-pot solvothermal reaction strategy, utilizing glucose as the carbon source. Simultaneously, polydopamine thin films (ePDA) were successfully deposited on the surface of CdS@C-modified electrodes by the cyclic voltammetry (CV) method. A photoelectrochemical sensor based on the polydopamine membrane-coated CdS@C core–shell heterostructure (ePDA/CdS@C) was designed for curcumin detection. Furthermore, scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible spectrophotometers (UV-vi) techniques were applied to characterize the structure and morphology of the synthesized photoelectric materials. The ePDA coating enhances the stability of the CdS@C material, and the CdS@C core-shell heterostructure accelerates electron transfer. Consequently, the ePDA/CdS@C material generates an outstanding and steady photocurrent response. Under ideal conditions, the novel sensor exhibits a satisfactory linear response to curcumin detection within the concentration range of 0.025–370 μM, with a detection limit as low as 0.0165 μM. Additionally, the ePDA/CdS@C-based photoelectrochemical aptasensor displays remarkable reproducibility, stability, and selectivity. This innovative sensing platform accurately detects curcumin in human serum and urine samples, with an excellent recovery range (99.47 %–103.60 %) and relatively low RSD values (1.49 %–3.56 %). In conclusion, this work offers a novel approach for curcumin detection.

(Co, S)-Codoped BiOBr as a novel signal probe coupled with LAMP (H+)-pH responsive photoelectrochemistry biosensor for ultrasensitive detection of microRNA

Herein, Co/S-BiOBr as a novel photoelectric material with excellent photoelectric property was prepared by cation–anion co-doping method with LAMP (H+)-pH responsive as signal amplification to construct a photochemical (PEC) biosensor for ultrasensitive detection of microRNA-221 (miRNA-221) related to triple-negative breast cancer (TNBC). Notably, not only the lattice distortion caused by S doping could elevate the photo-generated electron-hole separation efficiency, but also the tune of electronic structure by Co doping promoted electron transfer and decreased recombination rate, thus significantly improving the photoelectric performance. Furthermore, in the aid of Loop-mediated isothermal amplification (LAMP), a few miRNA-221 could be converted to abundant LAMP(H+) for changing the configuration of the Fc-DNA probe, which made the ferrocene (Fc) approach to electrode via pH-responsive for hindering the transmission of electrons, resulting in a significantly reduced photocurrent signal to enhance the sensitivity of the biosensor. The proposed PEC biosensor performed a wide range from 1 fM to 10 nM with a detection limit of 0.24 fM. This work prepared a novel material with efficient photoelectric efficiency for sensitive detection of biomolecules and exhibited enormous potential in disease diagnosis.

Development of an Ion Mobility Spectrometer Based on a Pulsed Photoelectric Effect Ionization Source.

Ion mobility spectrometry (IMS) is a compact and sensitive trace gas analysis instrument that ionizes the sample into ions for detection. Typically, an ion gate is used to cut the continuous ion beam into ion packets for separation and detection. However, commonly used ion gates suffer from complex structures or low ion transmission rates, making the gateless IMS a viable alternative. In this study, an IMS based on a pulsed photoelectric effect ionization source was designed. The photoelectrons were generated by irradiating a photoelectric material with a back-illuminated pulsed xenon lamp. This allows for low-energy photoelectron generation and the production of simple reactant ions (O2-(H2O)n) and thus negative product ions. The photoelectron current generated by this ionization source was analyzed, which can reach an intensity of a few microamperes and can be converted into an ion signal exceeding 10 nA. The introduction of the pulsed photoelectric effect ionization source makes it possible to generate separate ion packets and complete ion injection when a constant electric field is maintained in the ionization region. And with an assisted pulsed electric field in the ionization region, the resolving power of the system can be effectively improved to 1.85 times that of the constant electric field. The IMS developed in this study was used for the detection of common volatile hazardous chemicals, yielding effective results. The detection limit for phenol was below 1 ppb, and the dynamic response range exceeded 1 order of magnitude, which implies the potential applications of this IMS to detect substances with high electron affinity, such as explosives detection in public safety.

Graphene oxide enhanced the photocatalytic performance of one-dimensional porous carbon/ZnO hybrids

In order to improve the dispersion and photocatalytic performance of ZnO particles, one-dimensional graphene oxide/ZnO/carbon (GOZC) hybrid was prepared in situ by calcining zinc-based organometallic frameworks (Zn-MOFs) under nitrogen condition, and the structure and photocatalytic performance of the resultant GOZC were analyzed. The experimental results showed that one-dimensional corn-like ZnO/carbon (ZC) hybrid composed of porous carbon and ZnO nanoparticles was synthesized by carbonization, and GO was embedded in one-dimensional ZC hybrid with porous structure. The photocatalytic property of ZC material was improved by GO significantly, which the degradation rate of GOZC was 1.75 times higher than that of one-dimensional corn-like ZC. The enhancement for photocatalytic property originates that the incorporation of GO composites effectively reduces resistance and accelerates the separation of excited electron-hole pairs. This will provide an effective method for the preparation of porous carbon/metal oxides, and the resultant products possess very broad applications in the photoelectric materials, fuel cells, absorbing materials, ultraviolet light detectors, and piezoelectric materials.

Donor-acceptor-donor type AIEgens based on thieno[3.4-c]pyrrole-4,6-dione: Synthesis, electropolymerization, and electrochromism.

Photoelectric functional materials with electrochemical reversible activity and fluorescence intensities have attracted significant interest due to their wide range of applications in optoelectronic devices. In this work, a series of photoresponsive and electroactive monomers based on thieno[3.4-c]pyrrole-4,6-dione (TPD) are synthesized and characterized. They possess planar geometry with smaller dihedral angles owing to the existence of a noncovalent conformation lock coming from the S atoms and the O atoms. Crystallographic, spectroscopic, and computational results reveal that the introduction of the TPD unit can endow the monomers with aggregation-induced emission (AIE), reduced energy levels, and increased electrochemical activity. The monomers were successfully polymerized through the electrochemical method, and the corresponding polymers displayed reversible electrochemical activity and stability. Moreover, polymer films based on 3,3-dimethyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine (ProE)-TPD have electrochromic properties in the near-infrared field with a high value of optical contrast ratio (∆T) of 27.1% at 1000 nm.

Anchoring Cu2O onto WO3 by adsorption-ascorbic acid reduction: A p-n junction with improved photocatalytic and photoelectrochemical properties

Tungsten trioxide is a promising photoelectric material owing to its abundant structures and unique properties, but the serious photogenerated charge recombination limits its photocatalytic and photoelectrochemical performance. Herein, 0D Cu2O was anchored onto 3D WO3 in-situ via a facile adsorption-ascorbic acid reduction method at room temperature. The coupling of WO3 with Cu2O produces improved charge separation efficiency, thereby the photocatalytic degradation rate and transient photocurrent of optimal WO3/Cu2O are 2.7 and 1.6 times higher than those of WO3, respectively. The enhanced performance is ascribed to the formation of a p-n heterojunction, which was demonstrated by experimental characterizations and theoretical calculation.

Spectrum Reconstruction Model Based on Multispectral Electrochromic Devices.

Reconstructing the visible spectra of real objects is critical to the spectral camouflage from emerging spectral imaging. Electrochromic materials exhibit unique superiority for this goal due to their subtractive color-mixing model and structural diversity. Herein, a simulation model is proposed and a method is developed to fabricate electrochromic devices for dynamically reproducing the visible spectrum of the natural leaf. Over 20 kinds of pH-dependent leuco dyes have been synthesized/prepared through molecular engineering and offered available spectra/bands to reconstruct the spectrum of the natural leaf. More importantly, the spectral variance between the device and leaf is optimized from an initial 98.9 to an ideal 10.3 through the simulation model, which means, the similarity increased nearly nine-fold. As a promising spectrum reconstruction approach, it will promote the development of smart photoelectric materials in adaptive camouflage, spectral display, high-end encryption, and anti-counterfeiting.

Integration of TiO2/ZnIn2S4 p‐n Heterojunction with Titanium Defects to Boost PEC Oxygen Production

AbstractTiO2 is a widely used photoelectric conversion semiconductor material. However, due to its native defects, such as the selective absorption of ultraviolet light and high recombination rate of photogenerated carriers, it exhibits poor photoelectrochemical (PEC) water splitting performance. In this study, intrinsic defect titanium vacancy and semiconductor recombination agents ZnIn2S4 were introduced into an anodization‐annealed TiO2 film (TiO2 NT) to enhance the photoanode activity. The activity‐enhanced TiO2 photoanode (ZIS@TiO2 NT‐EA) was characterized by surface analyses and photoelectrochemical measurements. Mott‐Schottky measurement indicated that the introduction of titanium vacancies into the TiO2 NT changed its semiconductor type from n to p, and significantly reduced its apparent activation energy if compared with the TiO2 NT. In addition, after the ZnIn2S4 nanoparticles were loaded on the TiO2 NT‐EA film, the carrier concentration of the ZIS@TiO2 NT‐EA was nearly 12 times higher than the pristine TiO2 NT. Due to the higher carrier separation efficiency resulting from the formation of p‐n heterojunction between TiO2 and ZnIn2S4, the photocurrent density of the ZIS@TiO2 NT‐EA reached 3.89 mA cm−2 at 1.23 V (vs. RHE), nearly 3 times higher than that of the original TiO2 NT. Amazingly, the maximum applied bias photon‐to‐current efficiency (ABPE) value of the ZIS@TiO2 NT‐EA photoanode reached 2.15 % at 0.496 V (vs. RHE), which is very competitive if compared with all the reported TiO2 film electrodes in the PEC water splitting application. The incident photon‐to current efficiency (IPCE) of the ZIS@TiO2 NT‐EA photoanode was approximately 40.9% at 300 nm, which was about 3 times higher than that of the TiO2 NT (13.6%). To understand these impressive improvements in water splitting, further analyses were conducted on the effect of the increased titanium vacancy concentration in the TiO2 lattice and the formation of p‐n junction between the TiO2 and ZnIn2S4 on the PEC behaviour, as well as on the charge transfer resistance and separation efficiency of carriers.

Ligand-free Cs2PdBr6 perovskite microcrystals with narrow bandgap and high photoelectrochemical performance in aqueous solution

The exploration of efficient lead-free perovskite photoelectric active materials to develop high-performance photoelectrochemical (PEC) systems in aqueous solution is crucial to expand their PEC applications. Herein, we successfully constructed a high-performance PEC platform using ligand-free perovskite Cs2PdBr6 microcrystals (MCs) as the photoactive substance. The Cs2PdBr6 MCs showed narrow bandgap, wide absorption range, high electronic mobility and good stability in aqueous solutions. Particularly, the Cs2PdBr6 MCs exhibited an excellent photoresponse, the photocurrent density could reach as high as 98 μA/cm2 under 10.18 mW/cm2 light irradiation in the absence of other electron acceptors. In addition of the extremely wide range of response wavelength, wide pH range and accelerated interfacial carrier transfer, the Cs2PdBr6 MCs demonstrated the significant potential of photocathode active material for applications in PEC sensors and optoelectronic devices. Therefore, this work indicates that Cs2PdBr6 MCs design is a highly efficient way to solve the intrinsic issues of perovskite material, predicting a promising strategy for high performance PEC application in aqueous ambience.

Planar and ridged waveguide preparation on erbium pre-implanted fused silica by multi-energy helium ion implantation and femtosecond laser ablation

Ion implantation stands as a highly competitive technique for fabricating optical waveguide structures within photoelectric materials. In this work, both planar and ridge waveguides have been successfully realized on fused silica. The fabrication process begins with the implantation of erbium ions into fused silica, utilizing an energy of 400 keV and a fluence of 5×1015ions/cm2 to produce a fluorescence effect. Following this, helium ions are implanted at varying energies −450, 500, and 550 keV-with a consistent fluence of 3.2×1016ions/cm2 to create a planar waveguide structure. Subsequently, the ridge waveguide is meticulously prepared through the application of laser ablation, leveraging the pre-existing planar waveguide as a foundation. The guide mode of the planar waveguide is characterized at a wavelength of 632.8 nm using the prism coupling method. Additionally, the near-field light intensity distribution at the same wavelength is assessed via the end-face coupling technique and further analyzed using the finite-difference beam propagation method. To substantiate the practical utility of these waveguides, measurements of the propagation loss and fluorescence properties are conducted.

Two new selenidostannates TM-Sn-Se (TM = transition metal) photoelectrocatalytic materials

In recent decades, chalcogenides have appealed extensive attention due to potential applications in photoelectric materials. Two selenidostannates, [Fe1.11Zn0.89(en)3]2Sn2Se6 (1, en = ethylenediamine) and [Co1.24Zn0.76(en)3]2Sn2Se6 (2) were synthesized by solvothermal method with ethylenediamine and ethylene glycol as the solvents, both consisting of complexes in which the two different transition metals occupied the same position and [Sn2Se6]4− anions. Transition metal complexes (TMCs) can combine photoelectric properties with inorganic skeletons to extend their compound properties. Therefore, we investigated the photocurrent response of both compounds and found higher transient photocurrent densities. The band gaps of compounds 1 and 2 were calculated to be 2.31 eV and 2.17 eV, respectively, indicating that two compounds have potential semiconductor properties. In addition, we also studied the photodegradation efficiency of compounds 1 and 2 and found that the degradation efficiency of two compounds could be achieved 84.5 % and 55.9 %, which indicated that the compounds have excellent photocatalytic properties. The field of photoelectrocatalytic research on selenidostannates is broadened.

High-performance assaying cardiac troponin I using Bi-doped tin-based heterojunction in photoelectrochemical biosensing with the quencher of yolk-shell nanostructure

Cardiac troponin I (cTnI), a protein regulating myocardial contraction, stands the premier biomarker for diagnosing acute myocardial infarction and stratifying heart disease risk. Photoelectrochemical (PEC) biosensing combines traditional PEC analysis with high bioconjugation specificity, rendering a prospective avenue for disease biomarker analysis. However, the performance of sensors often falls short due to inadequate photoelectric materials. Hence, designing heterojunctions with proper band alignment, effective transport and separation of photogenerated carriers is highly expected for PEC sensors. Meanwhile, doping as a synergistic strategy to tune the energy band edges and improve carrier transport in heterojunctions, can also enhance the sensing performance. In this work, bismuth-doped tin oxide and tin disulfide heterojunction (Bi–SnOS) was prepared via a simple one-step hydrothermal method and utilized as a highly sensitive platform. Integrating copper sulfide-coated nano-gold (Au@CuS), a yolk-shell shaped nanocomposites, as the double quenching probe, an excellent PEC biosensor was fabricated to assay cTnI via sandwich immunorecognition. Under optimal conditions, the proposed biosensor displayed a high-performance for cTnI in the range from 0.1 pg/mL to 5.0 ng/mL with a low detection limit (44.7 fg/mL, 3σ). The strong photocurrent response, high stability and suitable selectivity point out that the synergistic effect between heterojunction and doping provides a promising prospect for the design of new PEC materials.

Oxygen intercalation in 2D layered PtSe2 for tunable bandgap infrared photoelectric materials

Infrared materials play a pivotal role in driving societal advancement across various domains. Bilayer PtSe2 with bandgap of 0.2 eV is an ideal material for infrared applications. However, the inherent limitation of the untunable bandgap in bilayer PtSe2 restricts its utility, particularly in the context of state-of-the-art two-color infrared detectors. Therefore, by introduction of quantum confinement effect, PtSe2[O]y superlattice was constructed via intercalating O atoms into interlayer space of PtSe2, and kinetic stability was confirmed by ab initio molecular dynamics. Considering van der Waals interactions of interlayer, PtSe2[O]y superlattice can be exfoliated into few-layer PtSe2[O]y. By employing density functional theory, optical and electrical properties of PtSe2[O]y superlattice and few-layer PtSe2[O]y were calculated. Tunable bandgaps were achieved by manipulating the O composition y, ranging from 0 eV to 0.21 eV (covering wavelengths > 5.9 μm) for the PtSe2[O]y superlattice and from 1.12 eV to 0.15 eV (covering wavelengths from 1.1 μm to 8.3 μm) for monolayer PtSe2[O]y. Considering the continuously tunable bandgap covering from near-infrared to mid-infrared absorption spectrum, PtSe2[O]y could be a promising candidate with a wide-application in the field of infrared photoelectric materials.

Porous two-dimensional CuSe@BiOI isotype heterojunction with highly exposed (1 0 2) facets for efficient photoelectrocatalytic CO2 reduction and photodetection

Using photoelectrochemical technology to construct efficient photoelectric materials has aroused extensive research interest. In this study, we propose a two-dimensional porous CuSe@BiOI isotype heterojunction photocathode for CO2 reduction to formic acid. The heterojunction was constructed by the epitaxial growth of high-quality oriented BiOI nanosheets onto the porous CuSe framework. The CuSe framework as a template to ensure the formation of the (102) facets of BiOI and the isotropic charge transport characteristics of the (102) surface greatly improve the efficiency of charge separation and transfer. This CuSe@BiOI isotype heterojunction electrode can efficiently reduce CO2 to formic acid with a selectivity of up to 80.5 % in 0.5 M potassium bicarbonate aqueous solution. Meanwhile,the performance of the photodetector based on CuSe@BiOI heterostructure is 6.97 × 1011 Jones and a response rate of 87.13 mA W−1. This finding provides a new approach to designing stable heterojunction photoelectrocatalysts with isotropy.