A highly efficient third generation catalyst, CaCu₃Ti₄O₁₂ (CCTO) shows excellent photoelectrochemical (PEC) and photocatalytic ability. As only 4% part of the solar spectrum covers UV light, thus it is highly desirable to develop visible light active photocatalyst materials like CCTO for effective solar energy conversion. A direct band transition with a narrow band gap (1.5 eV) was observed. Under light irradiation, high photocurrent density was found to be 0.96 mA/cm², indicating the visible light induced photocatalytic ability of CCTO. Visible light mediated photocatalytic and photoelectrocatalytic degradation efficiency of CaCu₃Ti₄O₁₂ pellets (CCTO) was investigated for three classes of pharmaceutical waste: erythrosin (dye), ciprofloxacin (antibiotic) and estriol (steroid). It is found that the degradation process follows first order kinetic reaction in electrocatalysis, photocatalysis and photoelectrocatalysis and high kinetic rate constant was observed in photoelectrocatalysis. This was quite high in comparison to previously reported methods.

This study systematically investigates the phenomenon of internal clamping in ferroelectric materials through the formation of glass-ceramic composites. Lead-free 0.715Bi_0.5Na_0.5TiO₃−0.065BaTiO₃−0.22SrTiO₃ (BNT-BT-ST) bulk ferroelectric ceramic was selected for the course of investigation. 3BaO − 3TiO₂ − B₂O₃ (BTBO) glass was then incorporated systematically to create sintered samples containing 0%, 2%, 4% and 6% glass (by weight). Upon glass induction features like remnant polarization, saturation polarization, hysteresis losses and coercive field could be varied as a function of glass content. Such effects were observed to benefit derived applications like enhanced energy storage density ∼174 kJ/m³ to ∼203 kJ/m³ and pyroelectric coefficient 5.7x10⁻⁴ Cm⁻²K⁻¹ to 6.8x10⁻⁴ Cm⁻²K⁻¹ by incorporation of 4% glass. Additionally, BNT-BT-ST depolarization temperature decreased from 457K to 431K by addition of 4% glass content. Glass incorporation could systematically increases diffuse phase transition and relaxor behavior temperature range from 70 K to 81K and 20K to 34 K, respectively when 6% and 4% glass content is added which indicates addition of glass provides better temperature stability. The most promising feature was observed to be that of dielectric response tuning. It can be also used to control (to an extent) the dielectric behavior of the host ceramic. Dielectric permittivity and losses decreased from 1278 to 705 and 0.109 to 0.107 for 6% glass, at room temperature. However this reduction in dielectric constant and loss increases pyroelectric figures of merit (FOMs) for high voltage responsivity (F_v) high detectivity (F_d) and energy harvesting (F_e) from 0.018 to 0.037 m²C⁻¹, 5.89 to 8.85 μPa^−1/2 and 28.71 to 61.55 Jm⁻³K⁻², respectively for 4% added ceramic-glass at room temperature. Such findings can have huge implications in the field of tailoring ferroelectric response for application specific requirements.

A perfectly compliant substrate would allow the monolithic integration of high-quality semiconductor materials such as Ge and III-V on Silicon (Si) substrate, enabling novel functionalities on the well-established low-cost Si technology platform. Here, we demonstrate a compliant Si substrate allowing defect-free epitaxial growth of lattice mismatched materials. The method is based on the deep patterning of the Si substrate to form micrometer-scale pillars and subsequent electrochemical porosification. The investigation of the epitaxial Ge crystalline quality by X-ray diffraction, transmission electron microscopy and etch-pits counting demonstrates the full elastic relaxation of defect-free microcrystals. The achievement of dislocation free heteroepitaxy relies on the interplay between elastic deformation of the porous micropillars, set under stress by the lattice mismatch between Ge and Si, and on the diffusion of Ge into the mesoporous patterned substrate attenuating the mismatch strain at the Ge/Si interface.

In order to investigate the optical properties of wurtzite (Wz) InP nanowires grown on Si(001) by solid source molecular beam epitaxy with the vapour-liquid-solid method, the growth temperature and V/III pressure ratio have been optimized to remove any zinc-blende insertion. These pure Wz InP nanowires have been investigated by photoluminescence (PL), time-resolved PL and PL excitation. Direct observation of the second and third valence band in Wz InP nanowires using PL spectroscopy at high excitation power have been reported and, from these measurements, a crystal field splitting of 74 meV and a spin-orbit interaction energy of 145 meV were extracted. Based on the study of temperature-dependent optical properties, we have performed an investigation of the thermal escape processes of carriers and the electron-phonon coupling strength.