Da Como Enrico, Loi Maria Antonietta, Murgia Mauro, Zamboni Roberto, Muccini Michele
Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), Consiglio Nazionale delle Ricerche, Bologna, Italy.
J Am Chem Soc. 2006 Apr 5;128(13):4277-81. doi: 10.1021/ja056060s.
We report on the observation of J-aggregates in submonolayer films of alpha-sexithiophene grown on silicon dioxide. Photoluminescence spectroscopy reveals that submonolayers are formed by molecules lying flat on the substrate with a head to tail configuration. Excitation energy dependence of photoluminescence shows a red-shifted absorption with respect to isolated molecules and a negligible Stokes shift between absorption and emission. The pronounced structural order of J-aggregates is reflected in the fwhm of the emission bands. From time-resolved and low-temperature photoluminescence experiments, we infer a quantum yield of the J-aggregate between 0.6 and 1. The demonstration of spontaneous formation of J-aggregates of pi-conjugated systems on amorphous silicon-based substrates can be relevant for the development of organic-inorganic hybrid photonic devices.
我们报告了在二氧化硅上生长的α-六噻吩亚单层薄膜中J聚集体的观察结果。光致发光光谱表明，亚单层是由分子以头对尾的构型平躺于基底上形成的。光致发光的激发能量依赖性显示，相对于孤立分子，吸收发生红移，且吸收与发射之间的斯托克斯位移可忽略不计。发射带的半高宽反映了J聚集体明显的结构有序性。通过时间分辨和低温光致发光实验，我们推断J聚集体的量子产率在0.6到1之间。在非晶硅基衬底上π共轭体系J聚集体的自发形成的证明可能与有机-无机混合光子器件的发展相关。
