Synthesis of Ni-poor NiO nanoparticles for DSSC-p applications

Over the last decade, p-type semiconductors (SC) have known a renewed interest. Indeed these materials may have potential applications for light-emitting diodes, transistors, solar cells, etc. Since the achievement of the first Dye Sensitized Solar Cells (DSSC) by Gratzel in 1991 a new generation of solar cells has been developed where the n-type SC is replaced by a p-type one. This leads to the photo-injection of holes instead of electrons in the circuit. To date nickel oxide (NiO) is the reference p-type semiconductor. However yields are still far from those of n-DSSC and many studies aim to replace NiO by other systems such as CuAlO2 , CuGaO2, CuCrO2 or NiCo2O4 nanoparticles. Following our recent synthesis of N doped ZnO with stabilization of p-type charge carriers, we focus now on the preparation of N doped NiO nanoparticles to improve the p-type conductivity of NiO. We study here the chemical reactivity of a nickel oxyhydroxide precursor under air and ammonia that conducts to nanostructured Ni-poor NiO.