Facile synthesis of graphitic carbon-nitride supported antimony-doped tin oxide nanocomposite and its application for the adsorption of volatile organic compounds.

Antimony-doped tin oxide (ATO) nanoparticles with an average size of ~ 6 nm were prepared by co-precipitation and subsequent heat treatment. Graphitic carbon nitride (g-CN)/ATO hybrid nanocomposite was designed by the combination of thermally synthesized g-CN and ATO nanoparticles by ultrasonication. The materials were characterized using N2 adsorption/desorption (BET), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). A mixture of five volatile organic compounds (VOCs, chloroform, benzene, toluene, xylene and styrene) was used to compare the adsorption capacity of the samples. The adsorption capacity of ATO nanoparticles was improved by the addition of g-CN. Experimental data showed that, among the five VOCs, chloroform was the least adsorbed, regardless of the samples. The g-CN/ATO showed nearly three times greater adsorption capacity for the VOC mixture than pure ATO. The unchanged efficiency of VOC adsorption during cyclic use demonstrated the completely reversible adsorption and desorption behavior of the nanocomposite at room conditions. This economically and environmentally friendly material can be a practical solution for outdoor and indoor VOC removal.

50 nm sized spherical TiO2 nanocrystals for highly efficient mesoscopic perovskite solar cells.

Single crystalline TiO2 nanoparticles (NPs) with spherical morphology are successfully synthesized by a hydrothermal reaction under basic conditions. TiO2 NPs, selectively controlled to the sizes of 30, 40, 50, and 65 nm, are then applied to a mesoporous photoelectrode of CH3NH3PbI3 perovskite solar cells. In particular, a spherical TiO2 NP of 50 nm size (NP50) offers the highest photovoltaic conversion efficiency (PCE) of 17.19%, with JSC of 21.58 mA cm(-2), VOC of 1049 mV, and FF of 0.759 while the enhancement of PCE mainly arises from the increase of VOC and FF. Furthermore, the fabricated photovoltaic devices exhibit reproducible PCE values and very little hysteresis in their J-V curves. Time-resolved photoluminescence measurement and pulsed light-induced transient measurement of the photocurrent indicate that the device employing NP50 exhibits the longest electron lifetime although the electron injection from perovskite to TiO2 is less efficient than the devices with smaller TiO2 NPs. The extended electron lifetime is attributed to the suppression of electron recombination due to optimized mesopores generated by the spherical NP50.