Research Interest

Our research interests are mainly focused on the synthesis and characterization of graphene-semiconductor hybrid nanomaterials. Their applications, such as photocatalysis, bio-molecule sensors, devices, energy storage, photo-panel systems, and others, are also evaluated. We utilize this hybrid system to understand the electron/charge transfer and interactions between graphene and metal oxide semiconductors.

Please contact Prof. Chen if you are interested in joining our research team or collaboration. Comments and questions are welcome as well.

Nanostructured Metal Oxide Semiconductors

Metal oxides are excellent candidates for many technologies due to their simple preparation, low production cost, adjustable properties, and structural variety. We are interested in synthesizing metal oxides with controlled nanostructures to understand how the material performance is affected by the morphologies, sizes, crystal structures, and conductivity. The material performance is evaluated by applications of bio-molecule sensors, catalysis, photocatalysis, energy storage, etc.

Nanostructured Binary Metal Oxides

A general redox method involving metal-containing oxidants was successfully developed for the controlled synthesis of substituted cobalt oxides with hierarchical flower-like nanostructures comprising unique Y-shaped interconnections. The highly homogeneous elemental The synergistically enhancement of Mn substitution and unique nanostructures results in the excellent electrochemical activities for highly efficient sensing of hydrogen peroxide.

Lan, W.-J.; Kuo, C.-C.; Chen, C.-H.* 2013, Chem. Commun.49, 3025-3027 (http://dx.doi.org/10.1039/C3CC40788H)

Hydrogen Peroxide Biosensors

Hydrogen peroxide sensors provide valuable signals of biological interactions, disorders, and developing of diseases. Metal oxides are promising alternatives with low cost, but suffer from issues of low conductivity and activity. We present the redox preparation strategy to successfully synthesize highly homogeneous, noble metal-free hydrogen peroxide sensors of cobalt manganese oxides. High conductivity (1.5 × 10−2 S cm−1) with remarkable sensing activity were observeddue to the homogeneous multiple mixed-valence systems of Co(II)/(III) and Mn(III)/(IV). The results show that manganese species assist the formation of enhancing the H2O2 reduction activities and inhibit the sensing interference. The temperature-dependent properties and nanostructure formation mechanisms based on a reaction rate competition are proposed.

Kuo, C.-C.; Lan, W.-J.; Chen, C.-H.* Nanoscale 2014, 6, 334-341 (http://dx.doi.org/10.1039/C3NR03791F)

CVD graphene

In our recent work (Nanoscale, 2014, 6, 334-341)pdf, it indicated the properties of graphene hybrid material are highly dependent on the number of graphene layers. We focus on how the properties of graphene-semiconductor composites correlate to the thickness of graphene layer. To verification this goal, we utilize chemical vapor deposition (CVD) process to precise control the thickness of graphene stacking on emiconductor panel (TiO2, ZnO), it called graphene-semiconductor hybrid panel (GHP). We design several experiments to verification the effect of graphene stacking layers on their functional performance. First work will carry out with AFM and TEM to find out characterization of single-layer graphene which produced by CVD method.Photocatalysis study of GHP showed the results that graphene enhancement of graphene-hybrid panel depended on the number of graphene layer, 3-layer graphene layer (3L-GHP) have the maximum performance observed in photodegradation of methylene blue. SEM images indicated that gold nanoparticles were synthesized with GHP by photodeposition method, it reveal that graphene thickness affects the density of photocatalytic sites. GHP system with gold nanoparticles are unique, promising substrates for surface enhanced Raman spectra (SERS) study which with the ~108 enhancement factor.