Extracts from roots of Beta vulgaris were used as natural sensitizers of a wide-bandgap semiconductor (CeO2–TiO2) in photoelectrochemical solar cells. The natural dye, adsorbed onto the semiconductor surface, absorbs visible light and promotes electron transfer across the dye/semiconductor interface. We have applied CeO2–TiO2 to natural dye sensitizer solar cells as a photoelectrode to reduce the charge recombination rate by providing energy barrier at the interface between the photoanode and electrolyte which offers an improvement of photovoltaic efficiency. Short-circuit current density (J sc) and open-circuit voltages (V oc) of 9.0 mA cm−2 and 680 mV, respectively, were obtained, and an effective energy conversion efficiency of 3.5 % was achieved. This simple and cheap technique of cell preparation opens up a perspective of commercial feasibility for inexpensive and environment-friendly dye cells.

The present paper describes the modification and solar hydrogen production studies employing a new semiconductor-septum (SC-SEP) photoelectrode ns-TiO 2 /In 2 O 3 based photoelectrochemical solar cell. The current-voltage characteristics of the above SC-SEP cell revealed that an enhancement in short-circuit current (I SC ) up to three times (5 ∼ 14.6 mA cm −2 ). The optimum hydrogen production rate was found to be 11.8 lh −1 m −2 for 5M H 2 SO 4 and with a further increase in H 2 SO 4 concentration, the hydrogen production rate was found to be invariant. In yet another part of our study instead of using new SC-SEP solar cell design, we used another new oxide material form such as ns-TiO 2 /WO 3 . The ns-TiO 2 /WO 3 exhibited a high photocurrent and photo-voltage of 15.6 mA cm −2 , 960 mV, respectively. The ns-TiO 2 /WO 3 electrode exhibited a higher hydrogen gas evolution rate of 13.8 lh −1 m −2 . Evidences and arguments are put forward to show that, whereas for the bare ns-TiO 2 electrode, the improvement in the performance of this photo-electrode compared with its original form was due to the higher quantum yield. In the case of ns-TiO 2 /In 2 O 3 and ns-TiO 2 /WO 3 photo-electrodes, the improvement is due to the improved spectral response resulting from decrease of energy band gap.

Development and characterization of Poly vinyl alcohol (PVA) based nano composite polymer electrolytes comprising of (PVA-NH4I):SiO2 is reported. Sol-gel derived silica powder of nano dimension has been used as ceramic filler for development of nano composite electrolyte. Formation of nano composites, change in the structural and microscopic properties of the system have been investigated by X-ray differaction, SEM and conductivity.

We have explored the application of natural dyes extracted from beetroot in Dye sensitized solar cell (DSSC). The main pigment is betacyanin which was obtained by separation and purification from the extract. The photo electrochemical performance of the DSSC based on these dyes showed that the photo voltage and photocurrent 435 mV, 9.86 mA, respectively. The overall conversion efficiency of nano WO3 coated TiO2 dye-sensitized solar cells exhibits a higher conversion efficiency of 2.2%. The photo electrochemical performance of beetroot extract demonstrate that betacyanin dye was the most effectual component of the sensitizer for DSSC because of the simple preparation technique, widely available and low cheap cost.

Multi drug resistant pathogenic bacteria are posing a serious problem for the current world. Thus in the search for novel antibiotics traditional plants have been proved to be potent source for antimicrobial agents. Zingiberaceae family constitutes a vital group of rhizomatous medicinal and aromatic plants characterised by the presence of volatile oils and oleoresins of export value. Since the middle ages, essential oils have been widely used for bactericidal, fungicidal, medicinal and cosmetic applications. The aim of this review article is to elucidate major constituents present in essential oils of some medicinally important plants of Zingiberaceae family and to explain their antimicrobial activities.

In the present paper, photovoltaic studies of dye-sensitized solar cells (DSSCs) based on betacyanin/TiO2 and betacyanin/WO3–TiO2 have been done. The cell performances were compared through I–V curves and wavelength dependant photocurrent measurements for the two new types of DSSCs. The TiO2-coated DSSC showed the photovoltage and photocurrent of 300 mV and 4.96 mA/cm2, whereas the cell employing WO3–TiO2 photoelectrode showed the values 435 mV and 9.86 mA/cm2, respectively. The conversion efficiency of TiO2 based dye-sensitized solar cell was found to be 0.69 %, while WO3–TiO2-based cell exhibited a higher conversion efficiency of 2.2 %. The better performance of the WO3–TiO2 dye-sensitized solar cell photoelectrode is thought to be due to an inherent energy barrier at the electrode/electrolyte interface leading to the reduced recombination of photoinduced electrons.

We studied a new type of TiO2-WO3 admixed septum-based semiconductor photo-electrochemical (SC-SEP, PEC) solar cell for photo-electro chemical measurement and hydrogen production. The SC-SEP cell in the configuration of SCE/1 M NaOH/TiO2 (ns)/Ti/H2SO4 + K2SO4/Pt-CE, Pt-WE showed photo-voltage and photo-current of 0.72V and 8.6 mA/cm(2), respectively, whereas the SC-SEP cell employing WO3 admixed TiO2 (ns) photo-electrode with the configuration: SCE/1 M NaOH/TiO2(ns)-WO3/Ti/H2SO4 + K2SO4/Pt-CE, Pt-WE, showed photo-voltage and photo-current of 0.96V and 15.6 mA/cm(2), respectively. The hydrogen gas evolution for the SC-SEP cell based on TiO2 (ns)/Ti photo-electrode was found to be 8.2 l/h/m(2), while the WO3-modified ns-TiO2 exhibited a higher hydrogen gas evolution rate of 13.8 l/h/m(2). The improved performance of new photo-electrode is due to improved spectral response of WO3 for the hydrogen gas evolution kinetics.