Desai Netaji K, Mahajan Prasad G, Mali Sawanta S, Kolekar Govind B, Patil Shivajirao R
Fluorescence Spectroscopy, Research Laboratory, Department of Chemistry, Shivaji University, Kolhapur, 416 004, India.
Thin Film Materials Laboratory, Department of Physics, Shivaji University, Kolhapur, 416 004, India.
J Fluoresc. 2018 Jul;28(4):897-903. doi: 10.1007/s10895-018-2252-1. Epub 2018 Jun 27.
The present work reports on the preparation of thin films of pyrene luminophors doped by varying amounts of perylene by spin coating technique. The structural, morphological, and photophysical properties of pyrene thin films have been investigated as a function of perylene contents. X-ray diffraction studies of doped thin films show well-defined peaks, and estimated crystallite size decreases with increasing perylene content, due to the formation of closed packed crystal structure. SEM images of pure pyrene revealed smooth, and compact and separated crystals with amounts of perylene. The result of absorption spectra showed decrease in intensity with perylene content. However, the fluorescence spectra of pyrene containing higher amounts of perylene showed broad and structureless exciplex emission at 510 nm. The emission colour of pyrene luminophors tuned from blue to green by controlling the concentration of perylene. The phenomenon of change in colour was seen due to efficient excitation energy transfer from pyrene to perylene in thin films. It also found that the intensity of exciplex emission increases with increasing concentration of perylene is of high demand in fluorescent lamp as well as green organic light emitting diodes.
本工作报道了通过旋涂技术制备不同含量苝掺杂的芘发光体薄膜。研究了芘薄膜的结构、形态和光物理性质随苝含量的变化。掺杂薄膜的X射线衍射研究显示出清晰的峰，由于形成了密堆积晶体结构，估计的微晶尺寸随苝含量的增加而减小。纯芘的扫描电子显微镜图像显示出光滑、致密且分离的晶体以及一定量的苝。吸收光谱结果表明强度随苝含量降低。然而，含有较高含量苝的芘的荧光光谱在510nm处显示出宽的且无结构的激基复合物发射。通过控制苝的浓度，芘发光体的发射颜色从蓝色调至绿色。由于薄膜中从芘到苝的有效激发能量转移，观察到了颜色变化现象。还发现激基复合物发射强度随苝浓度的增加而增加，这在荧光灯以及绿色有机发光二极管中具有很高的需求。
