采用沉淀法制备In/ZnO纳米粉, 通过XRD和光致发光谱等分析手段, 详细讨论了不同In掺杂浓度、 煅烧温度、 反应物配比, 以及沉淀剂种类对In/ZnO纳米粉微结构及光致发光特性的影响。 实验结果表明, 随着In掺杂浓度的增加, In/ZnO纳米粉的结晶性能和紫外发光强度因杂质缺陷的增多而逐渐减弱; 同时观察到该发光峰位从389 nm红移至419 nm, 这可能是由于施主能级和导带的合并, 以及杂质能级的潜在波动因素的影响所致。 当煅烧温度从500 ℃升至600 ℃时, 晶粒尺寸逐渐变大, 紫外发射强度也因结晶性的增强而逐渐增大; 当温度继续升高至800 ℃时, 结晶性的进一步提高导致紫外发射强度增强, 同时由于温度的升高使得ZnO晶格中离子动能变大而更易于产生氧空位, 从而导致525 nm绿光发射也大大增强; 当温度升高至1 000 ℃时, 紫外发射强度由于过多的氧空位而被极大抑制, 此时525 nm绿光发射成为了发光主成份。 随着反应物NH4HCO3/Zn(NO3)2摩尔比的增加, 由于反应速率的加快, 使得In/ZnO纳米粉晶粒变小, 紫外发光强度下降。 沉淀剂种类(NH4HCO3或NaOH)对前驱体粉末的结晶性能有着显著的影响, 但对最终纳米粉产物的发光性能影响不大。

In-doped ZnO nanopowders were prepared by precipitation. The influence of the processing parameters, such as In doping concentration, calcination temperature, reactant ratio and type of precipitant on the grain size, structure and photoluminescence (PL) of In/ZnO nanopowders was detailed analyzed by using X-ray diffraction (XRD) and photoluminescence spectrum. The experimental results indicated that with the increase in the In doping level (the molar ratio of In3+/Zn2+ increased from 0% to 5%), the crystallization and the UV emission of ZnO nanopowders were reduced because of the increase of impurity defects. And the UV emission band would have a red-shift from 389 to 419 nm, which could be resulted from the effects of merging of donor and conduction bands, and potential fluctuations of impurity energy level. The calcination temperature will play an important role in synthesis of luminescence materials. When the calcination temperature was raised from 500 to 600 ℃, the grain size of In/ZnO nanopowder increased gradually, and the dominated UV emission band was improved due to the enhanced crystallization of the nanopowder. If the temperature was raised up to 800 ℃, the crystallization of the sample was further improved, leading to an enhanced intensity of UV emission. Additionally, near this temperature, the oxygen vacancy is easier to be produced owing to the improvement of the kinetic energy for the ions in lattice, which induces in the enhancement of the green emission band peaking at 525 nm. For the temperature up to 1 000 ℃, the UV emission band was suppressed due to the production of excessive oxygen vacancy, and the In/ZnO nanopowder exhibited a dominated green emission. The luminescence performance of the In/ZnO nanopowder is also much affected by the reactant ratio. The reaction rate is improved by the increase of the NH4HCO3/Zn(NO3)2 molar ratio, which will decrease both grain size of In/ZnO nanopowder and emission intensity of UV band. Furthermore, the effect of the precipitant on the luminescence was examined. It is obviously that the NH4HCO3 and NaOH precipitants will remarkably affect the crystallization of the precursor powder, but nearly have no effect on the luminescence property of the final nanopowder products.