基于丝网印刷大面积碳纳米管阴极场发射的研究

Study to Large Area Screen Printing Cathode of Carbon Nanotube

针对碳纳米管(CNT)阴极场发射均匀性这一关键难题,根据CNT场发射理论制备了一种新型碳纳米管阴极印刷浆料.实验表明:质量分数约为20%的纯化CNT与4.2%的导电氧化物粘接材料混合形成的印刷浆料,其阴极具有较佳的发射均匀特性.用丝网印刷技术制作成的大面积(对于线长度大于12.5cm)阴极,再经过快速烧结技术及两步后处理工艺,既能除掉粘接材料又能使CNT很好地与衬底固定,并使碳纳米管部分直立和充分暴露,进一步改善了发射均匀性.该均匀发射的阴极开启场为2.0V/μm,在电场强度为2.5V/μm下,电流密度为35mA/mm2,发光亮度为300cd/m2,场发射电流稳定,其波动性小于4.5%.该阴极可望应用于场致发射显示器,液晶显示的背光源、电光源等器件.

Large area field emission uniformity of carbon nanotube (CNT) cathode prepared by screen printing is studied. A new CNT paste by mixing with oxide-conductive powders is developed based on the theory of CNT field emission, and the paste formation is investigated in detail. It is found that the paste has a fine emission performance when the oxide-conductive powders weight fraction is about 4.2% while that of CNT is 20%. Rapid sintering processing is adopted for fixing CNT to substrate and removing organic binding material. CNT is exposed to erect on the surface through combining two post treatment procedures. Experimental results show the fluctuation is less than 4.5%, the turn-on field of CNT reaches about 2.0 V/μm, the current density amounts to 35 mA/mm2 at the electric field 2.5 V/μm, and the brightness over 300 cd/m2. The method for manufacturing cathode is expected to be applied to field emission display, liquid crystal display and light display devices.