Thiophene-based donor–acceptor conjugated polymer as potential optoelectronic and photonic material
作者:MALUVADI G MURALI、UDAYAKUMAR DALIMBA、VANDANA YADAV、RITU SRIVASTAVA、K SAFAKATH
DOI:10.1007/s12039-013-0377-y
日期:2013.3
In this paper, we report the synthesis, characterization and optical properties of a donor–acceptor conjugated polymer, PTh-CN, containing 3,4-didodecyloxythiophene and cyanovinylene units. The polymer possesses a low band gap of 1.75 eV as calculated from the onset absorption edge. From the electrochemical study, the HOMO and LUMO energy levels of the polymer are figured out to be −5.52 eV and −3.52 eV, respectively. Polymer light-emitting diodes are fabricated using PTh-CN as the emissive layer with a device configuration of ITO/PEDOT:PSS/PTh-CN/Al. The device showed stable saturated red electroluminescence with CIE coordinate values (0.65, 0.32) at 12 V, which are very close to the values for standard red demanded by the NTSC. In addition, the device showed good colour stability under different bias voltages and the threshold voltage of the PLED device is found to be as low as 3.1 V. Further, a nanocomposite of the polymer and TiO2 nanoparticles is prepared by the dispersion method. The nonlinear optical properties of PTh-CN and PTh-CN/TiO 2 nanocomposite are studied using z-scan technique. The polymer solution, polymer film and polymer/TiO2 nanocomposite film show a strong saturable absorption behaviour. The value of saturation intensity (Is) is found to be of the order 1011–1012 W/m2, indicating that the materials are useful candidates for photonic applications.
在本文中,我们报告了一种供体-受体共轭聚合物PTh-CN的合成、表征和光学特性,该聚合物包含3,4-二十二烷氧基噻吩和氰乙烯单元。根据起始吸收边缘计算,该聚合物具有低带隙1.75 eV。通过电化学研究,聚合物的HOMO和LUMO能级分别为−5.52 eV和−3.52 eV。利用PTh-CN作为发光层,采用ITO/PEDOT:PSS/PTh-CN/Al的器件结构制造了聚合物发光二极管(PLED)。该器件在12 V下显示出稳定的饱和红色电致发光,CIE坐标值为(0.65, 0.32),非常接近NTSC标准红色的要求。此外,该器件在不同偏压下表现出良好的颜色稳定性,PLED器件的阈值电压低至3.1 V。此外,通过分散法制备了聚合物和TiO2纳米颗粒的纳米复合材料。使用z-scan技术研究了PTh-CN和PTh-CN/TiO2纳米复合材料的非线性光学特性。聚合物溶液、聚合物薄膜和聚合物/TiO2纳米复合膜表现出强饱和吸收行为。饱和强度(Is)的值约为10^11–10^12 W/m²,表明这些材料是光子应用的良好候选者。