不同光滑度立方体氧化铁对液晶电光性能的改善

向列相液晶被广泛应用于液晶显示中,但是由于杂质的存在,会导致液晶的驱动电压变大,增加能耗。为了降低阈值电压和饱和电压,通常向液晶中添加纳米颗粒来提高电光性能。本文利用水热法制备了表面粗糙和光滑的两种立方体Fe2O3纳米颗粒,其形貌均匀,尺寸约550nm。将二者分别掺杂到向列相液晶E7中,结果表明,粗糙立方体Fe2O3/E7复合体系具有比光滑立方体Fe2O3/E7复合体系和向列相液晶E7更优的电光性能,且在掺杂质量分数为0.4%时,其电光性能达到最优,阈值电压和饱和电压分别降低9.9%和11.6%,对比度增大80%,响应时间降低至6.0ms。这归因于粗糙立方体Fe2O3具有足够的表面积和表面所带电荷更多,所以会更易吸附体系中的杂质离子和减弱杂质离子的屏蔽作用,从而提高了电光性能。

Improvement of Electro-optical Properties of Liquid Crystal by Cubic Ferric Oxide with Different Roughness

Nematic liquid crystals(NLC) materials are widely used in liquid crystal display. However, due to the presence of impurities, the driving voltage of the liquid crystal becomes large, which results in the increasing energy consumption. In order to decrease the threshold voltage and saturation voltage, nanoparticles are usually added to liquid crystal to improve the electro-optical performance. In this paper, rough and smooth cubic ferric oxide nanoparticles with uniform shape and size of ~550 nm were prepared by a hydrothermal method. NLC E7 was doped with cubic Fe₂O₃ nanoparticles in different doping mass percent. Compared with the smooth Fe₂O₃/E7 composite and NLC E7, the rough Fe₂O₃/E7 composite has superior electro-optical properties. When the doping mass percent is 0.4%, the electro-optical properties reach the best. The threshold voltage and saturation voltage decrease by 9.9% and 11.6%, respectively, the contrast ratio increases by 80%, and the response time decreases to 6.0 ms. The superior electro-optical properties can be attributed to the sufficient surface area and more charge on the surface of rough cubic Fe₂O₃, which is beneficial to absorb the impurity ions in the NLC system and weaken the shielding effect of impurity ions, thus improving the electro-optical properties.