Quantum size effect of poly(o-phenylenediamine) quantum dots: From controllable fabrication to tunable photoluminescence properties

•The polymer quantum dots with excellent PL performance were synthesized for the first time.•The tunable photoluminescence properties was strongly influenced by the significant quantum size effect.•Experiments and theoretic calculation suggested the existence of quantum size effect in amorphous structures.•These polymer quantum dots have application perspective of fluorescent bio-imaging.

In this paper, poly(o-phenylenediamine) quantum dots (PoQDs) with amorphous structures were synthesized via a simple hydrothermal treatment. The size of PoQDs can be easily controlled by changing the reaction time. All these quantum dots show excellent photoluminescent (PL) performance. The p–π* transition between N and conjugated system in PoQDs increased the quantum yield significantly. Further experiments suggested the existence of quantum size effect in amorphous structures for the first time. The controllable PL performance were closely related to the significant quantum size effect. What’s more, these PoQDs were low cost and have high anti-jamming performance, good stability and application perspective of fluorescent bio-imaging.