Photophysical properties of ZnS quantum dots

ZnS nanoparticles of less than or equal to 3 nm average diameter were synthesized by a solvothermal reaction with zinc acetate [Zn(CH3COO)(2). 2H(2)O] and thiourea at 120 degrees C, Their photophysical propel ties were investigated. The UV-Vis spectrum showed an absorption shoulder at 276 nm, corresponding to the bandgap energy of 4.49 eV, and a weak shoulder at 320 nm (3.875 eV). The photoemissions at 365 nm (lambda(ex) = 280 nm), 325 nm and 333 nm (lambda(ex) = 220 nm) were observed, which may result from point defects in these ZnS quantum dots. (C) 1998 Elsevier Science Ltd. All rights reserved.