Conjugated polymers are an important class of organic semiconductors that can be deposited from solution to make optoelectronic devices. Among them, poly(9,9′-dioctylfluorene) (PFO) has distinctive optical properties arising from its ability to adopt an ordered planar conformation (β phase) from a disordered glassy phase (α phase). The β phase has attractive optical properties, but the precise mechanism of its formation in solution remains unknown. Here, we have combined specifically tailored polymer synthesis and surface-passivation strategies to provide the first spectroscopic characterization of single PFO chains in solution at room temperature. By anchoring PFO molecules at one end on an anti-adherent surface, we show that isolated chains can adopt the β-phase conformation in a solvent-dependent manner. Furthermore, we find that individual PFO chains can reversibly switch multiple times between phases in response to solvent-exchange events. The methodology presented here for polymer synthesis and immobilization is widely applicable to investigate other luminescent polymers.

共轭聚合物是一类重要的有机半导体，可以从溶液中沉积以制造光电器件。其中，聚（9,9'-二辛基芴）（PFO）具有独特的光学特性，这是由于其能够从无序玻璃态相（α相）中采用有序的平面构象（β相）。β相具有吸引人的光学性质，但是在溶液中形成它的精确机理仍然未知。在这里，我们结合了专门定制的聚合物合成和表面钝化策略，以提供室温下溶液中单个PFO链的首次光谱表征。通过将PFO分子的一端锚定在抗粘附表面上，我们证明了分离的链可以以溶剂依赖的方式采用β相构象。此外，我们发现，响应溶剂交换事件，单个PFO链可以在相之间可逆地切换多次。本文介绍的用于聚合物合成和固定化的方法学广泛适用于研究其他发光聚合物。