Loku Singgappulige Rosantha Kumara

Piezoelectric thin films have been widely used in microelectromechanical systems (MEMS), where Pb(Zr _x Ti _{1‐ x} )O ₃ is a representative material. To achieve significant piezoelectric responses, multidomain structural changes under electric fields must be understood via domain‐lattice observations. Here, (100)/(001)‐oriented tetragonal Pb(Zr _x Ti _{1‐ x} )O ₃ epitaxial films with a small (001)‐oriented domain fraction were grown on (100) Si substrates for piezo‐MEMS. Although previous studies have primarily focused on out‐of‐plane piezoelectric responses (33‐mode actuation), in‐plane (31‐mode actuation) is predominantly utilized in piezo‐MEMS devices. Therefore, we investigate the microscopic structural responses associated with both modes. Operando synchrotron x‐ray diffraction under pulsed electric fields applied perpendicular to the film surface was used to probe out‐of‐plane and in‐plane lattice evolution. Domain switching from (100) to (001) was accompanied by in‐plane lattice elongation and out‐of‐plane shrinkage due to substrate‐clamping. Time‐resolved measurements revealed out‐of‐plane lattice dynamics between domain orientations during pulse application. This study provides an operando correlation between ferroelastic domain switching and both out‐of‐plane and in‐plane lattice responses relevant to 33‐ and 31‐mode actuation in Si‐compatible multidomain Pb(Zr _x Ti _{1‐ x} )O ₃ films, providing key insights for optimizing the piezoelectric properties of clamped epitaxial films for MEMS applications.

Efficient photocatalytic water splitting to produce hydrogen using low-cost semiconductor thin films in photoelectrochemical (PEC) cells is a promising approach for harnessing solar energy. In this study, possibility to develop p-type cuprous oxide thin films with a flower-like surface morphology on indium doped tin oxide (ITO) substrates was examined in order to improve the photocatalytic activity of Cu ₂ O photocathodes in a PEC. For this, electrodeposition technique was employed with a novel aqueous peroxide bath containing 0.1 M CuSO ₄ , 0.3 M H ₂ O _2, 0.05 M NaNO ₃ and NaOH solutions. Resulted films were characterised using grazing incidence x-ray diffraction spectra, scanning electron microscopy, x-ray diffraction spectra, and chopped light current–voltage measurements in a PEC. It was revealed that with the condition established in the peroxide bath, Cu and Cu ₂ O crystallite clusters are electrodeposited on ITO surface whereas Cu ₂ O flowers are electrodeposited on Cu ₂ O surface. Thus, we were able to produce p-Cu ₂ O thin films with flower-like surface morphology on ITO substrates using the novel peroxide bath by employing pre-electrodeposited p-Cu ₂ O thin films. Resulted Cu ₂ O flowers have characteristic features (111) preferential orientation, petals of length about 2–3 μ M and thickness about 200 nM. Pristine p-Cu ₂ O photocathodes with a flower-like surface morphology resulted in a 4.5-fold increase in photocurrent in a PEC at 0 V vs RHE. Re-structured Cu ₂ O photocathodes with a flower-like surface morphology will be extremely useful in applications of water splitting devices and in other photocatalytic devices, as well.

The century‐old challenge of isotope separation might be addressed by conductive metal–organic framework (cMOF) thin films featuring ordered nanopores, designable charge‐transport pathways, and potential flexibility. However, resolving and amplifying the microscopic kinetic differences between water isotopologues within such confined spaces remains nontrivial. In this work, proton‐ and electron‐coupled two‐dimensional π‐conjugated cMOF thin films (Cu ₁ TPB _0.1 − x C) are fabricated through controllable layer‐by‐layer growth with oriented narrow pores and flexibility. Correlating electrical‐ and mass‐transduced gas‐sensor technologies, the subtle differences in the interactions of H ₂ O and D ₂ O with the framework were identified, revealing a complex multistage mass transport. Comparison of cMOFs with different pore sizes shows that this identification originates from distinct conduction mechanisms. Notably, the Cu ₁ TPB _0.1 − x C thin film with a strong space‐confined effect exhibits a complex multistage electrical response due to its unique proton–electron‐coupled conduction characteristics, thereby enabling further differentiation of the transport processes of H ₂ O and D ₂ O on the outer surface and within the confined spaces. The oriented cMOF films therefore provide a real‐time platform for resolving and amplifying subtle isotope‐dependent transport dynamics in confined pores, offering mechanistic guidance for the design of porous materials with controlled water‐isotopologue transport.

The century‐old challenge of isotope separation might be addressed by conductive metal–organic framework (cMOF) thin films featuring ordered nanopores, designable charge‐transport pathways, and potential flexibility. However, resolving and amplifying the microscopic kinetic differences between water isotopologues within such confined spaces remains nontrivial. In this work, proton‐ and electron‐coupled two‐dimensional π‐conjugated cMOF thin films (Cu ₁ TPB _0.1 − x C) are fabricated through controllable layer‐by‐layer growth with oriented narrow pores and flexibility. Correlating electrical‐ and mass‐transduced gas‐sensor technologies, the subtle differences in the interactions of H ₂ O and D ₂ O with the framework were identified, revealing a complex multistage mass transport. Comparison of cMOFs with different pore sizes shows that this identification originates from distinct conduction mechanisms. Notably, the Cu ₁ TPB _0.1 − x C thin film with a strong space‐confined effect exhibits a complex multistage electrical response due to its unique proton–electron‐coupled conduction characteristics, thereby enabling further differentiation of the transport processes of H ₂ O and D ₂ O on the outer surface and within the confined spaces. The oriented cMOF films therefore provide a real‐time platform for resolving and amplifying subtle isotope‐dependent transport dynamics in confined pores, offering mechanistic guidance for the design of porous materials with controlled water‐isotopologue transport.

Zinc oxide (ZnO) films were electrodeposited at −1.2 V vs. Ag/AgCl in 0.3 M Zn (NO ₃ ) ₂ with Polyethylene glycol (PEG (4000)) additive to investigate the impact of the deposition temperature. Grazing incidence X-ray diffraction (GIXRD), scanning electron microscopy (SEM) analyses and raman spectroscopy confirmed that increased deposition temperature led to the growth of larger crystallites. Electron density contour mapping further revealed that at 60 ⁰ C exhibited the maximum electron density of ∼24.8 electrons/Å ³ . The potential of electrodeposited ZnO films for application in natural dye-sensitized solar cells (DSSCs) was initially investigated. A higher electron density and minimum band gap and internal resistance contributed to the improved DSSC performance at 60 °C.

Precisely engineered nanoarchitectures can unlock new catalytic active sites. We introduce nanomace, a ceria (CeO₂) nanostructure integrating cubic and rod-like domains within a single framework. The chemically coherent interface generates highly active oxygen sites, enabling faster CO conversion than conventional morphologies and surpassing physically mixed rods and cubes. Enhanced lattice oxygen reactivity is confirmed by facile redox cycling in in situ Raman and synchrotron-based ambient-pressure XPS, and fast lattice oxygen exchange in isotopic studies. As a support, nanomace amplifies activity across multiple reactions: Au-, Pd-, and Rh-loaded nanomace outperform commercial, rod, and cube CeO₂ by up to 14.4-fold in water gas shift, CH₄ combustion, and N₂O decomposition. Molecular dynamics simulations reveal preferential lattice oxygen activation at the integrated interface. By establishing interface sites as uniquely reactive, nanomace demonstrates structural integration as a powerful strategy for next-generation redox catalysis.