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An effective and versatile room temperature soft chemical route was employed to deposit n-Bi2S3 films followed by p-CuSCN films onto fluorine doped tin oxide (FTO) coated glass substrates. Well optimized preparative parameters led to the formation of a good heterojunction between the n-Bi2S3 and p-CuSCN films without any post-annealing treatment. An interconnected microflake of CuSCN on to the nanocrystalline Bi2S3 film enables a high porous structure in the top layer. The device was completed by ensuring silver as a front and FTO as a back ohmic contact, and exposed to sense the liquefied petroleum gas (LPG) at room temperature (27 °C). The upper porous structure allowed enough room for the gas species to adsorb and de-adsorb easily at the interface. The device exhibited more than 70% response at 1370 ppm of LPG, and the process suggests the possibility to develop a room temperature LPG sensing device with a low cost chemical method.

Nb2O5 layer were deposited on ZnO by using doctor blade method. The preparation of a bilayered ZnO/Nb2O5 photoanode was introduce for dye-sensitized solar cell (DSSC) application. Deposition of Nb2O5 layer on ZnO film improves power conversion efficiency of DSSCs. The ZnO/Nb2O5photoanode-based DSSCs show increase in photocurrent, open circuit voltage and conversion efficiency. The ZnO/Nb2O5 solar cell provides 50 mV increase of open circuit voltage, [Formula: see text] increment in current density and [Formula: see text] increment in efficiency as compare to ZnO-based DSSCs. We further analyzed the electron recombination properties of ZnO and ZnO/Nb2O5 by utilizing electrochemical impedance spectroscopy (EIS). The EIS analysis (Bode Plot) for ZnO/Nb2O5 photoanode show shifting of the peak related to electron recombination towards low frequency as compared to ZnO photoanode. Thus, there is an increase in lifetime of electrons in the ZnO/Nb2O5 photoanode, confirming that the recombination reactions are reduced in ZnO/Nb2O5 photoanode as compared to the ZnO.

Simple wet chemical synthesis of ZnO thin films has been carried out at room temperature (27 °C) from an aqueous alkaline bath followed by annealing in air at 100 °C on fluorine doped tin oxide coated glass substrates. The deposited film showed an optical band gap of 3.28 eV with a thickness of about 40 µm with a hexagonal crystal structure. A flower-like surface morphology consisting of petals was observed. These petals are made up of a fibrous network with interconnected nanoparticles leading to a high surface area. This obliged us to use this structure for dye-sensitized solar cells with lower fabrication process cost than conventional high temperature sintered methods which are commonly used for ZnO and TiO2. It would be advantageous to use a flexible plastic substrate instead of routine glass in future. ZnO showed a current conversion efficiency (η) of 0.34% with chemically adsorbed N3 dye at standard AM 1.5 condition with illumination of light intensity 100 mW cm−2.

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