不同矿化剂对水热法合成ZnO晶体形态的影响

Effects of Different Mineralizers on the Morphology of ZnO Crystal Synthesized by Hydrothermal Method

研究了在350 ℃,填充度为35%时,分别以不同浓度的NaOH和KOH为矿化剂,合成具有不同晶体形态的氧化锌晶体.当以KOH为矿化剂,浓度小于2 mol·L-1时,只能合成出微米级晶体,随着矿化剂浓度增加,开始出现大的晶体,最大晶体的长度为50～100 μm;如以NaOH作矿化剂,当矿化剂浓度为2 mol·L-1时,即可以合成出个体较大的晶体长度,最大晶体的长度达到100 μm.提高矿化剂浓度,有利于合成个体更大的晶体,其长度远远大于以KOH作矿化剂时的晶体长度,最长为200～300 μm,证实在350 ℃, 以NaOH作矿化剂比KOH更易获得个体较大的晶体.

Single crystal ZnO has large number of potential commercial applications, so it is important to get the centimeter-size crystals of high purity, high quality ZnO. The hydrothermal method is a good method to get high quality ZnO crystal. The different mineralizer have different influence on the crystal synthersize. The influence of different mineralizer on the morphology of ZnO crystal synthesized by hydrothermal method have been got. In this paper, ZnO crystal with some kinds of shapes were obtained when KOH or NaOH used as mineralizer at 350 ℃ with the factor of 35%. The concentration of mineralizer were changed within 2 mol · L^-1 to 6 mol · L^-1. When the concentration of KOH was 2 mol · L^-1, the product was only micron-scale crystal. With the increasing of concentration of KOH, the larger crystal began to exist, the lenghth of largest crystal reached 50 - 100 μm. The exposed faces were usually negative polar faces {0001 } , negative cone faces p{1001 } ,hexagonal faces m {1010 }. While NaOH was used as mineralizer,when the concentration of NaOH was 2 mol · L^-1, the larger crystal was present in the product and the length of the largest crystal was about 100 μm. When the concentration of NaOH increased, the length of largest crystal was longer than that with KOH as mineralizer and reached 200 - 300 μm. The exposed faces were integrate hexagonal faces m { 1010 } , but the underside and cone faces of crystals were limited. So we can draw the conclusion, both the kinds and concentration of the mineralizer have obvious influence on the morphology of ZnO crystals, but under the same condition, the length of largest crystal was longer with NaOH as the mineralizer than that with KOH as the mineralizer.