氧化锌荧光粉合成的热力学计算

六面体的ZnO:Zn,因其具有较高的导电率和光电导特性,故在低能的电子激发下就能发光,目前已广泛地被用为低压显示器件的发光层涂料.ZnO:Zn的发光机理,早就有学者提出了一些假设,有的认为它的绿色发光是由过量锌引起的,也有认为是过量的锌和氧的空位存在所致.总之,ZnO:Zn之所以会发光.

SYNTHETIC MECHANISM OF ZnO:Zn PHOSPHOR ON THE BASIS OF THERMODYNAMIC CALCULATION

On Preparing ZnO:Zn Phosphor,many different methods have been reported in the literature. The mechanism of the formation of interstitial Zn, which is considered to be responsible for the performance of luminescence and n-type semiconductor, has thus been proposed in various respects. Thisstudy has placed emphasis on the sulfide method, in which three different systems in the presence of sulfur oxide, zinc sulfide and free sulfur respectively are examined on the basis of thermodynamic calculations.It is found theoretically and verified experimentally that these following changes cannot occur spontaneously in the range of 600~1300℃:ZnO+SO2=Zn+SO3 2ZnO+ZnS=SZn+SO24ZnO+S2(g)=4Zn+2SO2while the last reaction shown above may involve a decrease in free energy under the condition given below, and tends to proceed spontaneously to the right side.2ZnO+S2+O2=2Zn(g)+2SO2(or 2ZnS+O2=2ZnO+S2)It seems clear that trace O2, but not any sulfide or sulfur,has played an important role in the system.