In this article, room temperature ethanol sensing behavior of p-type Ce doped SnO₂ nanostructures are investigated successfully. Interestingly, it is examined that the abnormal n to p-type transition behavior is caused by Ce doping in SnO₂ lattice. In p-type Ce doped SnO₂, Ce ion substituting the Sn is in favor of generating excess holes as oxygen vacancies, which is associated with the improved sensing performance. Although, p-type SnO₂ is one of the important materials for practical applications, it is less studied as compared to n-type SnO₂. Pure and Ce doped SnO₂ nanostructures were successfully synthesized by chemical co-precipitation method. The structure, surface morphology, unpaired electrons (such as free radicals), and chemical composition of obtained nanoparticles were studied by various kinds of characterization techniques. The 9% Ce doped SnO₂ sensors exhibit maximum sensor response of ~382 for 400 ppm of ethanol exposure with fast response time of ~5 to 25 sec respectively. Moreover, it is quite interesting that such enhancement of ethanol sensing is unveiled at room temperature, which plays a key role in the quest for better ethanol sensors. These remarkably improved sensing results are attributed to uniformly distributed nanoparticles, lattice strain, complex defect chemistry and presence of large number of unpaired electrons on the surface.

To overcome the parasitic absorption of UV light in the transparent conductive oxide layer of flexible CIGS solar cells, a CsPbBr ₃ perovskite nanocrystal based luminescent down-shifting layer was integrated on flexible CIGS solar cells.