Precursor effects of citric acid and citrates on ZnO crystal formation.
We have studied the precursor effects of citric acid and various citrates-including triethyl citrate, tripotassium citrate, trisodium citrate and triammonium citrate-on the formation of ZnO crystals in alkaline solution. These citrate-related chemicals could be divided into three groups (group A, triethyl citrate; group B, tripotassium citrate and trisodium citrate; and group C, citric acid and triammonium citrate) based on their activity for modifying the ZnO growth direction and solution pH dependency on their concentration. We could obtain ZnO structures with various distinct morphologies by simply changing the concentration of citric acid or citrate additive dissolved in the alkaline reaction solution. On the basis of the results, we propose the growth mechanisms underlying the formation of the various ZnO structures in the absence and presence of citric acid or citrate additives.
Cho
Seungho
S
Department of Chemical Engineering, Pohang University of Science and Technology, and National Center for Nanomaterials Technology, San 31, Hyoja-Dong, Nam-Gu, Pohang, Gyungbuk, Korea 790-784.
Jang
Ji-Wook
JW
Jung
Seung-Ho
SH
Lee
Bo Ram
BR
Oh
Eugene
E
Lee
Kun-Hong
KH