Morphology and Optical Properties of Fluorene-Based Ladder-type Poly(para-phenylenes): Origin of Low-Energy Emission

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• 作者：Linlin Liu ; Song Qiu ; Baoling Wang ; Huan Wang ; Zengqi Xie ; Yuguang Ma*
• 刊名：Journal of Physical Chemistry C
• 出版年：2009
• 出版时间：April 9, 2009
• 年：2009
• 卷：113
• 期：14
• 页码：5799-5804
• 全文大小：281K
• 年卷期：v.113,no.14(April 9, 2009)
• ISSN：1932-7455

文摘

The stability of fluorene-based compounds and polymers, especially at the bridged C-9 position, under photoirradiation and thermal treatment has widely claimed attention. The real chromophore group of low-energy emission in fluorene-based compounds and polymers is debatable for fluorenone, and the aggregate is difficult to distinguish. We report the morphology and optical properties of two fluorene-based ladder-type poly(p-phenylene)s (LPFs) with the target to explore the real chromophore group of low-energy emission. The basic comparison of LPFs with different substitutions and degraded degree testify the low-energy emission is relating to oxidized products but not packing order. The molecular distance is then adjusted by doping degraded LPF into an inert matrix, which shows that the low-energy emission is as strong as in bulk when the average molecular distance is larger than 1.2 nm. These results suggest fluorenone is the chromophore group of low-energy emission and rule out aggregate, especially fluorenone-based aggregates that require a molecular distance smaller than 0.4 nm.