松果状纳米氧化铁对液晶电光性能的影响

Influence of Pinecone-Like Ferric Oxide on the Electro-Optical Properties of Nematic Liquid Crystals

液晶材料被广泛应用于液晶显示器(LCD)中,但是由于液晶中杂质的存在,导致液晶的应用电压变大,增加了能耗。为了降低应用中的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。本文采用简单的化学沉淀法制备了形貌均一,大小尺寸均匀的松果状氧化铁(P-Fe_2O_3)纳米颗粒。将其掺杂到向列相液晶4-氰基-4'-戊基联苯(4-cyano-4'-pentylbiphenyl,5CB)中,结果表明,掺杂质量分数为0. 5%时,电光性能达到最优,阈值电压和饱和电压分别降低24. 8%和45. 2%,对比度增大46%,响应时间降低至17. 6 ms,此性能优于相同条件下掺杂普通Fe_2O_3纳米颗粒的向列相液晶5CB,其阈值电压和饱和电压分别降低15%和16%。这归因于松果状Fe_2O_3纳米颗粒可以在向列相液晶5CB中均匀分散,其粗糙的表面吸附了液晶中的杂质离子,减少了杂质离子的屏蔽效应,从而提高了电光性能。

Liquid crystal(LC) materials are widely used in LC displays(LCD). However,due to the presence of impurities in liquid crystal,the application voltage of liquid crystal becomes large,which results in the increase of energy consumption. In order to decrease the threshold voltage and saturation voltage,nanoparticles are usually added to LC to improve the electro-optical performance. In this paper,pinecone-like ferric oxide(P-Fe2O3) nanoparticles with uniform shape and size were prepared by a simple chemical precipitation method. Nematic liquid crystal 4-cyano-4’-pentylbiphenyl(5 CB) is doped with pinecone-like Fe2O3 nanoparticles in different doping contents. The results show that the best electro-optical properties of the LC is achieved when the doping mass fraction is 0. 5%. The threshold voltage and saturation voltage decrease by 24. 8% and 45. 2%,respectively,the contrast ratio increases by 46%,and the response time decreases to17. 6 ms. The property is superior to the ordinary Fe2O3 nanoparticles doped in 5 CB with the threshold voltage and saturation voltage decreased by 15% and 16% under the same condition,which is attributed to the uniform dispersion of pinecone-like Fe2O3 in nematic LC 5 CB and the adsorption of impurity ions by the rough surface of pinecone-like Fe2O3 abating the shielding effect.