Geometries, stabilities and electronic properties of photo sensitized (CdS)2n (n=5-27) nanoclusters

As advanced materials for energy storage or conversion applications, metal sulfides with hollow structures are as widely used as supercapacitors and sensors. The geometries and electronic properties of (CdS)2n (n = 5-27) nanocages are calculated by density functional theory with the gradient corrected Perdew-Burke-Ernzerh of exchange-correlation functional and including the relativistic effect. The obtained results showed that the inner radius and charge-transfers, surface stabilities along with ionic semiconductor and metallic properties of the hollowed (CdS)2n are increased as cage size being increased. The distinct metallic features in large-size (CdS)2n are revealed. Particularly, the calculated energy gaps for (CdS)2n are generally decreased as the size of (CdS)2n being increased, together with absorption spectra moving from short to long wavelength. The photon to current conversion efficiency related energy conversion is discussed. Interestingly, the encapsulated double-layer CdS nanocages have bigger capacity for energy conversion than the monolayer nanocages.