ZnSe nanoparticles were synthesized using a facile solvothermal reaction of zinc nitrate hexahydrate with Se powder, and two types of solvent: (i) ethylene glycol (EG), and (ii) triethanolamine (TEA). The ZnSe nanoparticles obtained using EG solvent, referred to as ZnSe nanoparticles (EG), were measured around 20 nm, while their TEA counterparts, referred to as ZnSe nanoparticles (TEA), were slightly smaller at around 18 nm. The effects of the two solvents on the growth mechanism of the nanoparticles were observed and analyzed. The ZnSe nanoparticles (EG) displayed a weak defect-related emission spectrum between 520 and 580 nm. In contrast, the ZnSe nanoparticles (TEA) displayed a much wider stronger deep defect-related emission spectrum extending from 470 to 630 nm. The photocatalytic activity results demonstrated that ZnSe nanoparticles (TEA) exhibited stronger photocatalytic activity than their EG counterparts by measuring the degradation of Rhodamine B dye under UV light conditions. (C) 2014 Elsevier Ltd. All rights reserved.