Ultra-stable nanoparticles in A(II)B(VI), (A(II) = Cd, Zn; BVI, = S, Se, Te) compounds

Laser ablation on binary A(II)B(VI) compounds exhibits in time-of-flight mass spectra abundant peaks at stoichiometric (A(II)B(VI)),n with n = 13, 19, 33 and 34 measured on bulk powders of CdSe, CdS, CdTe, ZnS and ZnSe. Investigation on solution grown nanometer size particles of CdSe shown an existence of ultra-stable stoichiometric clusters (CdSe)13, (CdSe)19, (CdSe)33, (CdSe)34 and (CdSe)48. This set of n has not been predicted as particularly stable particles in previous bulk fragment models based on either zinc-blende or wurtzite, and a different type of structures is required to explain our experimental results. Present investigation shows that nanoparticles formed in vacuum as magic numbers above are found in solution as preferentially grown species in CdSe, and possibly in other A(II)B(VI). It is suggested that the high stability of the observed magic clusters originates from their specific structure as endohedral binary fullerenes, supposedly. These molecular-like particles composed of few tens of atoms lie between atom and solid, and exhibit novel materials functions not realizable in the bulk.