Tzyy-Jiann Wang

• PhD
• Professor (Full) at National Taipei University of Technology

The synthesis of three-dimensional silver nanopopcorns (Ag NPCs) onto a flexible polycarbonate membrane (PCM) for the detection of nitrofurazone (NFZ) on the fish surface by surface-enhanced Raman spectroscopy (SERS) is presented. The proposed flexible Ag-NPCs/PCM SERS substrate exhibits significant Raman signal intensity enhancement with the measu...

An electrochemical sensor is established using an iron titanate (FeTiO3) modified glassy carbon electrode (GCE) to detect nitrofurazone. Various microscopic and spectroscopic analysis was performed to reveal the properties of the prepared FeTiO3 hexagonal nanoplates. The FeTiO3/GCE presents enhanced electrochemical response to nitrofurazone at the...

Developing efficient and robust electrode materials for electrochemical sensors is critical for real-time analysis. In this paper, a hierarchical holmium vanadate/phosphorus-doped graphitic carbon nitride (HoVO4/P-CN) nanocomposite is synthesized and used as an electrode material for electrochemical detection of hydrogen peroxide (H2O2). The HoVO4/...

The development of surface enhanced Raman spectroscopy (SERS) substrates capable of sensing organic pollutants at low concentrations with high sensitivity has always been demanding.

Furaltadone (FLD) as an antibiotic has been widely used in animal husbandry to treat bacterial infection and promote animal growth. Its abnormal usage has threatened human health and the ecological system. The sensitive FLD detection is crucial for the protection of human health and eco-environment. In this study, unique 3D flower-like zinc-chromiu...

Pharmaceutical pollution that imposes a health threat worldwide is making accurate and rapid detection crucial to prevent adverse effects. Herein, binder-free zinc oxide nanograins on carbon cloth (ZnO [email protected]) have been synthesized hydrothermally and employed to fabricate a flexible electrochemical sensor for the quantification of hydrox...

We fabricate a novel hierarchical system of NiFe-layered double hydroxide (LDH)/Mo2C nanocomposite through environmentally friendly deep eutectic solvents (DESs) by the solvothermal method and utilize it as an electrochemical platform for NO2– detection. The NiFe-LDH/Mo2C modified glassy carbon electrode (GCE) demonstrates a low oxidation potential...

The synthesis of manganese cobaltate (MnCo2O4) with the hybrid three-dimensional architecture has been developed as an electrocatalyst for the electrochemical sensing of paraoxon-ethyl (PEL). The detailed physicochemical and structural characterization of MnCo2O4 is meticulously examined. The MnCo2O4-modified screen-printed carbon electrode (SPCE)...

Surface-enhanced Raman spectroscopy (SERS) using the noble-metal/semiconductor hybrid nanostructures are attractive for the real-world detection of organic pollutants due to the unique fingerprint information for analytes and the ultrasensitive detection ability by electromagnetic and chemical mechanisms. In this work, we constructed noble-metal/se...

Semiconductor/noble-metal heterostructures as surface enhanced Raman spectroscopy (SERS) substrates have remarkable recognition due to their synergistic contribution and abundant hotspot generation. Herein, urchin-like α-Fe2O3 and α-Fe2O3/Ag heterostructures were synthesized by the hydrothermal and photoreduction methods for the SERS application. T...

The electrochemical sensor has high promise for applications in the next-generation real-time monitoring devices and technologies. However, the related further development has been hindered by some intractable problems of the electrochemical sensors. In this work, we develop the nanocomposite of TiO2/Au nanofibers (NFs) with O-C3N4 nanosheets (NSs)...

The development of novel electrocatalyst materials with excellent characteristics is inevitably needed to satisfy the practical application of electrochemical sensors. In this study, the 2D ZnCr layered double hydroxide (LDH)/tungsten carbide (WC) composite was prepared by the hydrothermal method and investigated as the electrochemical electrode ma...

This work fabricates a plasmonic lithium niobate substrate with metal nanoparticles (MNPs) to enhance electromagnetic field interaction and diminish lifetime with concentration dependence. The enhanced photoluminescence (PL) from dye molecules in lithium niobate substrate and shortened lifetimes associate with plasmon resonance arising from the met...

The photodeposition of metallic nanostructures onto ferroelectric surfaces could enable new applications based on the assembly of molecules and patterning local surface reactivity by enhancing surface field intensity. DCJTB (4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran) is an excellent fluorescent dye and dopant m...

Integrating noble-metal and semiconductor nanomaterials for Raman signal enhancement is of great significance in the field of surface enhanced Raman spectroscopy (SERS). In this work, a SERS-active substrate composed of Au nanoparticles (NPs) on Cu2O microspheres is produced by the polyol and photochemical methods for the effective detection of org...

As a novel two-dimensional (2D) material, metal carbide (MXene) has been identified as a hotspot research topic in the field of surface-enhanced Raman spectroscopy (SERS). Herein, we report the increment of SERS activity of titanium carbide (TiC) by incorporation of gold nanoparticles (Au NPs) by a facile photoreduction process for the detection of...

Retraction of ‘Synergistic action of star-shaped Au/Ag nanoparticles decorated on AgFeO 2 for ultrasensitive SERS detection of a chemical warfare agent on real samples’ by Nazar Riswana Barveen et al. , Anal. Methods , 2020, 12 , 1342–1352, DOI: 10.1039/C9AY02347J.

Enormous Raman signal enhancement using gold nanostars (Au NSs) has attracted great attention due to the excitation of strong electric field on the nanostar tips. The synthetic methods of Au NSs mainly utilize specialized shape-directing agents, such as surfactants or polymers, to assist the tip formation. However, these agents passivate nanostar s...

Noble-metal/semiconductor-based nanomaterials have attained high Raman enhancement in the surface-enhanced Raman scattering (SERS) sensor. The fabrication of noble-metal/semiconductor-based SERS substrates with high sensitivity and good reproducibility is a great challenge. Noble-metal nanoparticles on semiconductor have strong capability to resona...

The development of electrode materials with swift response has always been a crucial need for the safety of many foods and environmental applications. Herein, we demonstrate a one-pot hydrothermal approach to synthesize a hybrid nickel cobalt-layered double hydroxide/ functionalized halloysite nanotubes (NiCo-LDH/F-HNTs) composite for the electroch...

Parathion-ethyl (PE) is an organophosphate insecticide frequently used in modern agriculture to enhance food quality. The extensive usage of PE causes ecological damage to the environment and a fatal threat to human health. Therefore, it is essential to develop practical tools for assessing the PE content in aquatic samples. In this study, a flexib...

Dopamine is an essential neurotransmitter for intercellular communication in the living organisms. Miniature sensors for dopamine detection, which rely on the electrochemical sensor with hybrid materials, cannot provide continuous monitoring and comes with several practical limits. High selectivity and sensitivity testified by human samples as well...

Integrated microresonators with low thermal drift of resonant wavelength are imperative photonic devices to provide stable multiplexing/filtering functions on silicon substrates with large thermo-optic coefficient. To realize athermal microresonators with high quality factor and small footprint, we present an undercut Ta2O5-based microdisk resonato...

The composite nanostructure composed of semiconductors and noble-metals have received widespread attention in the field of surface-enhanced Raman scattering (SERS). Herein, one-dimensional (1D) silver/gold/silver-chloride nanowires (Ag/Au/AgCl NWs) are prepared using the facile hydrothermal and photoreduction processes for the SERS detection of ant...

Photoreduction using ferroelectric templates is an emerging green technique for the production of noble-metal nanostructures by a reductant-free process. In this work, anisotropic growth of silver nanostructures is stimulated by a surfactant-assisted photoreduction process on ferroelectric templates. The preferential adsorption of surfactant (polyv...

The construction of novel electrocatalysts for efficient and economic electrochemical sensors is continuously a significant conceptual barrier for the point-of-care technology. Binary metal oxides with heterostructures have gained plenty of attention due to their promising physicochemical properties. Herein, we develop a rapid and sensitive electro...

Aquaculture and farming industries have been seriously threatened by the illegal use of antibiotics as feed-additives to benefit the animal growth. Although various conventional chemical sensing approaches have been widely explored for the trace-level detection of antibiotics, effective and accurate monitoring techniques are still highly demanded....

We report the rational design of nanocomposite with zirconium phosphate encapsulated on graphene oxide (ZrP/GO) for the highly sensitive and selective analysis of fenitrothion (FT). The characteristics of ZrP/GO nanocomposite are systematically analyzed by various in-depth electron microscopic, spectroscopic and analytical techniques. The ZrP/GO na...

Rapid-monitoring of drugs has attracted tremendous consideration owing to robust global demand for cost-effective and high effectiveness. Binary metal oxides with various morphology have been reported as electrodes for electrochemical sensor to fulfilling the clinical and enviromental requirements. In this study, strontium tungstate (SrWO4) nanofla...

Developing cost-effective approaches for the fabrication of electrochemical devices is instantly needed for transferring from basic research to point-care technology. Herein, we report an electrochemical sensing platform based on iron...

Recently, a great deal of research has been stepped forward to implement real-time detection of multiple targets using surface-enhanced Raman spectroscopy (SERS). Herein, a novel incorporation of silver nanoparticles (AgNPs) on silver nanoflowers (AgNFs) via the in-situ process offers high SERS enhancement by its unique plasmonic resonance. The ele...

A reliable and accurate sensing of synthetic dyes in foodstuffs is highly significant to prevent health risks. Recently, various heterogeneous structures are used predominantly to explore the distinguished enhancement action of surface-enhanced Raman scattering (SERS) for ultrasensitive detection of multiple food colorants. Herein, we construct a s...

An attractive strategy for effective Raman signal enhancement is to employ the synergistic action of electromagnetic and chemical mechanisms by using semiconductor/noble-metal nanostructures in the SERS substrates. This work presents the utilization of ferroelectric templates to synthesize the ZnO/Ag heterogeneous nanostructures photochemically for...

Aquatic contamination from the accumulation of pharmaceuticals has induced severe toxicological impact to the ecological environment, especially from non-steroidal anti-inflammatory drugs (NSAIDs). Real-time monitoring of flutamide, which is a class of NSAIDs, is very significant in environmental protection. In this work, we have synthesized the he...

High-efficiency electro-optic tuning of microresonators both for TE and TM polarizations is important for versatile advanced photonic applications. This work demonstrates a new device design to realize on-chip lithium niobate microresonators with excellent dual-polarized electro-optic tuning efficiency. The electrode structure is designed such that...

Two-dimensional (2D) nanomaterials are considered a rising star in diverse electrochemical technologies due to their special characteristics. We report here the design and synthesis of 2D titanium carbide/boron nitride nanocomposite via the sonochemical method. The successfully produced TiC/BN nanocomposites were characterized by in-depth electron...

The design and construction of efficient nanostructure-based electrocatalyst are the keys to advance in the field of electrochemical sensors. Herein, we synthesize the samarium molybdate (SmM) on a large scale via a straightforward approach. The structure of the as-prepared SmM was investigated using the in-depth electron microscopic and spectrosco...

Two-dimensional (2D) MXene-based electrode materials have recently gained attention in the field of electrochemical sensors. Herein, we report the first titanium carbide (TiC)-based electrochemical sensor for the detection of 4-nitroquinoline N-oxide (4-NO). X-ray diffraction, field emission scanning electron microscopy, elemental mapping, and ener...

Electro-optic tuning by using lithium niobate (LiNbO3) possesses the unique features of sub-picosecond response time, low power consumption, reduced thermal noise, and combination of nonlinear-optic applications. Here, we demonstrate a new device design and fabrication to realize on-chip electro-optically tunable LiNbO3 microresonators with high pe...

We report a simple and rapid synthesis of hexagonal boron nitride/halloysite-nanotube (h-BN/HNTs) nanocomposite and its potential application towards highly selective electrochemical determination of furazolidone (FZ). The as-prepared h-BN/HNTs nanocomposite was characterized by using field emission scanning electron microscopy, electron dispersive...

An electrochemical sensor is described for the determination of catechol (CT) based on the nanocomposite of lanthanum cobaltite supported on graphene nanosheets (LaCo/GNS). The nanocomposite was systematically examined by various analytical and spectroscopic methods. The LaCo/GNS-modified electrode exhibites good electrochemical activity towards CT...

It is a great challenge to design and fabricate a cost-effective surface-enhanced Raman spectroscopy (SERS) substrate with excellent reproducibility and sensitivity for reliable environmental analysis. In this work, we have synthesized silver ferrite (AgFeO2) interlinked with star-shaped gold/silver (Au/Ag) bimetallic (BM) nanoparticles (NPs) by a...

Recently, two-dimensional nanomaterials have received great attention in the field of electrochemical applications due to their outstanding physicochemical properties. In this research, we developed vanadium carbide entrapped on graphitic carbon nitride nanosheets (VC/g-CN NSs) as a highly efficient electrocatalyst for determination of furazolidone...

Prostate cancer is one of the primary causes of death around the world. As an important drug, flutamide has been used in the clinical diagnosis of prostate cancer. However, the over dosage and improper discharge of flutamide could affect the living organism. Thus, it necessary to develop the sensor for detection of flutamide with highly sensitivity...

The proper architecture of supporting electrode materials is the most promising strategy for improving the catalytic activity and chemical stability of the electrochemical sensors. Herein, we have successfully synthesized the 3D hierarchical flower-like cerium vanadate (CeVO4) nanostructure by a simple hydrothermal approach. A sequence of scanning...

Nanotips made of metal and semiconductor have been widely utilized in versatile applications to strengthen the electric field through lightning rod effect and localized surface plasmon resonance (LSPR) effect. Here, we present the utilization of ferroelectric nanotips to assist photoreduction of silver nanostructures for surface enhanced Raman scat...

The present work reports a highly sensitive electrochemical sensor based on manganese cobaltite entrapped reduced graphene oxide (MnCo2O4-rGO) modified glassy carbon electrode (GCE) for the efficient determination of tryptopan (Trp). The MnCo2O4-rGO nanocomposite was prepared by simple hydrothermal method. As synthesized nanocomposite was systemati...

It is a great challenge to design and develop a new kind of cost-effective electrode with excellent activity and high stability for the electrochemical sensors. In this presented research, an eco-friendly sonochemical route was utilized to synthesize the flower-like nickel oxide entrapped on boron doped carbon nitride (NiO/BCN) nanocomposite for th...

The rapid quantification of drugs in biological samples has turned the hottest issue and ongoing challenge to protect human health. To address this issue, we designed and synthesized a tin phosphate entrapped graphene flakes (SnP/GRF) nanocomposite for the trace level electrochemical detection of antituberculosis drug isoniazid (ISZ). Moreover, the...

This study used the sol-gel reaction to synthesize an erbium oxide precursor. The precursor was coated on a hydrophilic SiO2/Si substrate by using spin coating technology, which was then processed at the temperature of 600-1100°C for 45min to form erbium oxide and erbium silicate thin films. The film obtained from a 600°C reaction is smooth and cra...

This work presents the effects of erbium content on the morphological, structural, and photoluminescent properties of erbium-doped yttrium oxide film prepared by water-added-free gelation and spin coating. Crack-free annealed films with uniform thickness and good adhesion are obtained by spin-coating the precursor solutions synthesized by the water...

This work studies the interdiffusion effect of Er ions in Er2O3 and Si ions in SiO2 on the photoluminescent (PL) properties of Er2O3/SiO2 films. Er2O3 layers are deposited on thermally oxidized Si substrates by reactive radio-frequency magnetron sputtering. Different interdiffusion behaviors are observed by thermally treating films with rapid therm...

It is desirable to extend the surface-enhanced Raman scattering (SERS) from the conventionally used visible range into the infrared region, because the fluorescence background is lower in the long-wavelength regime. To do this, it is important to have a SERS substrate suitable for infrared operation. In this work, we report the near infrared SERS o...

We present an electrostatic-field-tunable ferroelectric template to produce photoreduced silver nanostructures for Raman scattering enhancement. The intensity and distribution of the surface electrostatic field in the ferroelectric template determine the morphology of the photoreduced silver nanostructures and thus the degree of the Raman signal en...

The first LiNbO3 microtoroid resonators with high quality factor are produced by gravity-assisted surface tension reshaping. The original microdisk is produced by selective ion implantation and chemical etching. It is transformed into the microtoroid by thickening its rim through stretching the melted surface region by gravity force. The used therm...

We present a novel fragmented-film surface-enhanced Raman scattering (SERS) substrate produced by nanosphere lithography and direct peel-off for SERS efficacy enhancement. The 2D hexagonally close-packed polystyrene nanospheres on the polydimethylsilozane (PDMS) substrate are covered with silver film and then directly peeled off using sticky tape....

The electrically tunable liquid crystal (LC) optical channel waveguide with strong polarization-dependent mode tunability is demonstrated for the first time. When the applied voltage increases, the LC molecules encapsulated in the semicircular groove on the fused silica substrate gradually tilt upward and twist toward two sides. For TE polarization...

This paper reports strategies of sensitivity enhancement for magneto-optic surface plasmon resonance (MOSPR) sensors using metal heterostructure for two types of measured signals, ordinary and normalized reflectivity changes (ΔRPP and ΔRPP/RPP). The sensitivities using the ΔRPP and ΔRPP/RPP signals are effectively enhanced with the improvement as l...

The efficient tuning of microring resonator with the radially realigning nematic liquid crystal (NLC) cladding is presented. By applying the voltage on the in-plane annular electrodes, the produced electric field realigns the homeotropically-aligned NLC in the radial direction. Under the voltage sufficient for 90° NLC reorientation, the guided mode...

We report electrically tunable liquid-crystal-core channel waveguides, in which the lightwave guiding can be tuned among cut-off, single-mode, and multi-mode. Ultrasonic-assisted chemical etching is used to produce semicircular grooves on the optical glass substrate for encapsulating liquid crystal as the waveguide core. The liquid-crystal-core wav...

A method of forming an undercut microstructure includes: forming an etch mask on a top surface of a substrate; forming, on a top surface of the etch mask, an ion implantation mask having a top surface that is smaller than the top surface of the etch mask and that does not extend beyond the top surface of the etch mask; ion implanting the substrate...

We report ultra-smooth LiNbO3 microdisk resonators fabricated by selective ion implantation, chemical etching, and thermal treatment. The undercut microdisk structure is produced by chemically etching the buried lattice damage layer formed by selective ion implantation. By thermal treatment, surface tension smoothes and reshapes microdisk surface t...

We present wide electrical tuning of microring resonators with auto-realigned nematic liquid crystal (NLC) cladding. By applying electric field, homeotropically-aligned negative Δε NLC with non-rubbed alignment layers is auto-realigned along the microring waveguide due to the protruding of the ridge structure. The consistent cladding index distribu...

A new integrated-optic polarization rotator with anisotropic cladding formed by oblique angle deposition is presented. Optical anisotropy with tilt principal axes in the obliquely deposited columnar thin film induces hybrid polarization modes in the waveguide and thus produces polarization rotation. The dependence of device characteristics on colum...

The authors demonstrate a localized surface plasmon resonance (LSPR) biosensing technique based on electro-optically modulated attenuated total reflection. Electro-optic effect is utilized to modulate the wavevector of the light for exciting LSPR with the initial wavevector specified by setting the incident angle. The power variation of the attenua...

We present a new fabrication technique to produce three-dimensional (3D) microstructures on crystalline substrate using selective ion implantation and chemical etching. Localized lattice-damage layers at the specified depth beneath the substrate surface are formed by selective ion implantation. After etching out the partial surface regions and the...

This study presents a surface plasmon resonance biosensing technique based on electro-optically modulated attenuated total reflection. The initial wavevector of the light for exciting surface plasmons is specified by setting the incident angle and is then modulated by electro-optic effect. The light power which is attenuated-total-reflected from th...

A wavelength-tunable microring resonator with integrated microheater on lithium niobate is presented. Ridge structure on lithium niobate is formed by a wet-etching technique for enhancing the lateral index contrast of the waveguide. The resonant wavelength of the microring resonator is tuned through thermooptic effect by injecting current into the...

A resolution-tunable localized surface plasmon resonance (LSPR) biosensor employing electro-optically modulated phase interrogation is presented. This biosensor modulates the analyte-dependent LSPR phase characteristic through electro-optic effect by varying the wave vector of lightwave for exciting surface plasmon. The induced LSPR phase change is...

A novel electro-optically modulated surface plasmon resonance (EOMSPR) biosensor based on phase detection by collinear heterodyne interferometry is presented. Its operation is by means of modulating the SPR-induced phase variation by electro-optic effect. Because the relation between the phase change and the applied voltage is highly sensitive to a...

Electro-optical tuning of a microring resonator fabricated on lithium niobate ( LiNbO 3 ) is presented. The device structure, including microring resonator and couplers, is designed in detail and is produced by titanium diffusion on the wet-etched LiNbO 3 ridge surface. The resonance wavelengths for TM and TE polarizations can be tuned by electro-o...

We present a new integrated-optic surface plasmon resonance (SPR) biosensor based on electro-optical modulation. The SPR characteristics for the analyte concentration detection can be electro-optically modulated by applying the voltage on the electrodes of the biosensor fabricated on lithium niobate, which is an excellent electro-optic material. Tw...

An integrated-optic wavelength demultiplexer produced by double proton exchange on z-cut lithium niobate is demonstrated. The mode sorting effect and waveguide dispersion characteristics are utilized to demultiplex the optical fields at the wavelengths 980 nm and 1550 nm. The opposite waveguide dispersion in the two output waveguides can be obtaine...

An integrated-optic biosensor based on electro-optically modulated localized surface plasmon resonance (LSPR) is demonstrated. This biosensor utilizes the electro-optic effect to modulate the wave vector of incident lightwave used to excite localized surface plasmons. Electro-optically modulated LSPR results in the analyte-dependent variation of ou...

Single-mode non-ridge benzocyclobutene optical waveguides fabricated by excimer laser illumination are presented. The induced index change is about 0.003 after 50 shots of laser pulse exposure. The propagation loss at 1548nm is about 0.6dB/cm.

The resonant-wavelength tuning of integrated-optic microring filters in silicon nitride using oxygen plasma treatment is demonstrated. During the treatment, high-energy oxygen ions in the plasma enter into the device surface such that the material composition is converted to SiO_xN_y. The corresponding index variation results in...

A new integrated-optic surface-plasmon-resonance (SPR) biosensor using gold nanoparticles with the ability of bipolarization interrogation is demonstrated. Although the previous SPR biosensor using gold nanoparticles can excite the surface plasma wave by the TM- and the TE-polarized lightwave, the sensitivity to the environmental index change for t...

A new wavelength-tunable polarization converter utilizing the strain induced by proton exchange is demonstrated in x-cut LiNbO3. The light polarization is converted by the strain-optic effect through the phase-matched coupling of two orthogonal polarizations. The stress-applying structure is designed to be composed of several proton-exchanged strip...

A new electrooptically wavelength-tunable polarization converter by strain-optic effect on LiNbO₃ is presented. The polarization conversion is achieved by the tilt of waveguide principal axis caused by the stress induced by the proton-exchanged region on the single side of the waveguide. Simply increasing the proton-exchange time can enl...

This paper presents a novel wet etching method for LiNbO₃ using electric-field-assisted proton exchange. By applying voltage with appropriate polarity on designed electrodes placed on both sides of substrate, the induced electric-field distribution can effectively suppress or enhance proton diffusion in the lateral and depth directions....

A new surface-plasmon-resonance (SPR) waveguide biosensor with the capability of bipolarization wavelength interrogation is presented. In the conventional SPR biosensors, only the transverse magnetic (TM)-polarized lightwave can couple with the surface plasma wave. The proposed SPR biosensor can make both the TM- and the transverse electric (TE)-po...