Photoelectrocaloric effect in ferroelectric oxide.

The enhanced electrocaloric (EC) effect in solid-state-based lead-free ferroelectric Ba0.875(Bi0.5Li0.5)0.125TiO3 system is investigated under light as an external stimulus. The sample exhibits an analogous value of maximum change in entropy at Curie temperature, extracted from the two different measurements process. Notably, the sample depicts maximum value of adiabatic change in temperature (ΔT) as 1.27 K and isothermal entropy change (ΔS) as 2.05 J/K kg along with the EC coefficient value of 0.426 K mm/kV, under dark conditions. In addition, the sample exhibits > 0.5 K adiabatic temperature change over a broad temperature range (~ 35 K). Remarkably, the EC parameters display ~ 27% enhancement upon 405 nm light illumination. The demonstrated photoelectrocaloric effect is found to be in accordance with theoretical formalism. The present work elucidates the light as an additional degree of freedom to widen the potential of solid-state-based technologies for advanced environment-friendly cooling devices.

Physical vapor deposited organic ferroelectric diisopropylammonium bromide film and its self-powered photodetector characteristics.

Organic diisopropylammonium bromide (DIPAB) is a promising material with superior ferroelectric characteristics. However, the DIPAB continuous film, which is essential to explore its application potential, is challenging because its crystallization kinetics favors island-like microcrystalline growth. In this work, the continuous and uniform deposition of organic ferroelectric DIPAB film on a single crystalline Si(100) substrate is demonstrated by a thermal evaporation process. Structural and optical studies reveal that the film is c-axis oriented with an optical bandgap of 3.52 eV. The topographic image displays well-connected grain-like surface morphology with ∼2 nm roughness. The ferroelectric domain studies illustrate the in-plane orientation of the domains, which is in accordance with c-axis oriented film where polarization is along the in-plane b-axis. The phase and amplitude responses of the domains display hysteresis and butterfly characteristics, respectively and thereby endorse the ferroelectric nature of the film. Importantly, it is demonstrated that the DIPAB film exhibits remarkable self-powered UV-Vis photodetector characteristics with responsivity of 0.66 mA W-1 and detectivity of 2.20 × 109 Jones at 11.45 mW cm-2 light intensity. The fabricated DIPAB film reported in this work can widen its application potential in self-powered photodetector and other optoelectronic devices.

Antibacterial activity of two plant extracts on eight burn pathogens.

Antibacterial activity of crude alcoholic extract of Datura alba and Celosia argentea leaves were studied against pathogens isolated from infected burn patients. The disc-diffusion method showed significant zone of lysis against all the pathogens studied and the results are comparable to the conventional antibiotic cream namely Silver Sulphadiazine (SSD). On comparing the efficiency of the two extracts, extract of D. alba exhibited more than 50% increase in antibacterial activity compared to C. argentea.

Healing potential of Datura alba on burn wounds in albino rats.

Datura alba Nees (Solanaccae) is popular all over the world for its medicinal uses in asthma, muscle spasm, whooping cough, hemorrhoids, skin ulcers, etc. In India, it is widely used traditionally for the relief of rheumatism and other painful affections. Ayurveda and Siddha practitioners use oil based preparations of this plant from ancient days to till date for all types of wounds. Hence, the present study was chosen to evaluate its scientific validity. The alcohol extract of the D. alba leaves were investigated for the evaluation of its healing efficiency on burn wound models in rats. The crude alcohol extract and one of the fractions exhibited antimicrobial effect against all the pathogens studied. A 10% (w/w) formulation of alcoholic extract was topically applied on thermal wounds. Complete wound closure was observed within 12 days in treated rats. The effect produced by the ointment, in terms of wound contracting ability, wound closure time, tissue regeneration at the wound site and histopathological characteristics were significant in treated rats. Collagen, hexosamine and gelatinase expressions were also well correlative with the healing pattern observed. The present study thus provides a scientific rationale for the traditional use of this plant in the management of wounds.