Exploring the optical limiting, photocatalytic and antibacterial properties of the BiFeO3-NaNbO3 nanocomposite system

Thin films of BiFeO3-NaNbO3 composites were fabricated in a PMMA matrix. XRD and HRTEM were used for structural investigations. The grain size and surface morphology of samples were analysed through HRTEM images. The self-cleaning property of any material accelerates its industrial applications. Hence, along with the optical limiting performance, the photocatalytic and antibacterial activity of BiFeO3-NaNbO3 composite samples were also studied. BiFeO3-NaNbO3 films fabricated in the PMMA matrix exhibit strong optical nonlinearity when excited by 5 ns laser pulses at 532 nm. The origin and magnitude of the observed optical nonlinearity were explained on the basis of the weak absorption saturation and strong excited state absorption. The photocatalytic performance of samples was analysed by dye degradation method using Methyl Orange dye. The dye degradation rate in the presence of the catalyst is heeded in a particular time interval, which exhibits the photocatalytic performance of the samples. The destruction of microbial organisms that are in contact with the material was contemplated, which could prove its antibacterial activity. The effect of the particle size on the photocatalytic activity was also investigated.Peer reviewe

Twin peak distribution of electron emission profile and impact ionization of ambient molecules during laser ablation of silver target

Laser-induced plasma generated from a silver target under partial vacuum conditions using the fundamental output of nanosecond duration from a pulsed Nd:yttrium aluminum garnet laser is studied using a Langmuir probe. The time of flight measurements show a clear twin peak distribution in the temporal profile of electron emission. The first peak has almost the same duration as the laser pulse while the second lasts for several microseconds. The prompt electrons are energetic enough ('60 eV) to ionize the ambient gas molecules or atoms. The use of prompt electron pulses as sources for electron impact excitation is demonstrated by taking nitrogen, carbon dioxide, and argon as ambient gases.Cochin University of Science & Technolog

Evaluating shrub architectural performance in sun and shade environments with the 3-D model Y-plant: Are there optimal strategies?

The wavelength dependence of thermal lens signal from organic dyes are studied using dual beam thermal lens technique. It is found that the profile of thermal lens spectrum widely differ from the conventional absorption spectrum in the case of rhodamine B unlike in the case of crystal violet. This is explained on the basis of varying contribution of nonradiative relaxations from the excited vibronic levels.Cochin University of Science & Technolog

Time resolved study of CN band emission from plasma generated by laser irradiation of graphite

Time and space resolved studies of emission from CN molecules have been carried out in the plasma produced from graphite target by 1.06 urn pulses from a Q-switched Nd:YAG laser. Depending on the laser pulse energy, time of observation and position of the sampled volume of the plasma, the features of the emission spectrum are found to change drastically. The vibrational temperature and population distribution in the different vibrational levels have been studied as functions of distance, time, laser energy and ambient gas pressure. Evidence for nonlinear effects of the plasma medium such as self focusing which exhibits threshold-like behaviour are also obtained. Temperature and electron density of the plasma have been evaluated using the relative line intensities of successive ionization stages of carbon atom. These electron density measurements are verified by using Stark broadening method.Cochin University of Science and Technolog

Not Available

Not AvailableNot AvailableNot Availabl