Multicolor Photoluminescence from Nonconjugated Poly(3,4-dihydropyran) Nanoparticles
Lorenzo Vallan, Anh Thy Bui, Gediminas Jonušauskas, Nathan D. McClenaghan, Emin Istif, Daniele Mantione, Eleni Pavlopoulou, Cyril Brochon, Georges Hadziioannou, Éric Cloutet
Abstract
In recent years, nonconjugated organic luminophores are receiving considerable interest from the scientific community, offering a new conceptual basis for the development of alternative photoluminescence-based technologies. In this work, the polymerization of 3,4-dihydropyran was exploited for the preparation of nonconjugated photoluminescent polymer nanoparticles. Remarkably, excitation-dependent multicolor emission ranging from blue to yellow was observed in both solid and solution. In contrast with similar materials, this behavior was not attributed to aggregation-induced emission, but rather to the presence of independent, noninteracting chromophores located on the polymer structure. Structural and optical characterizations along with further chemical modifications suggest that the emission is related to the presence of acetal groups formed by ring-opening polymerization. In addition, it was shown that the removal of unsaturated structures could enhance the photoluminescence quantum yield of the polymer (QY) up to 0.20 (λ ex = 355 nm). This work provides a new type of nonconjugated organic luminophore with both high QY and multicolor emission.