Optical Nanomaterials Lab

In this study, we report the rapid, room-temperature synthesis of red/near-infrared (NIR) dual-emissive carbonized polymer dots (RCPDs) via successive oxidative aromatic coupling of 1,3-dihydroxynaphthalene in isopropanol, catalyzed using iron nitrate and nitric acid. The resulting RCPDs exhibit two well-defined emission bands centered at approximately 610 and 750 nm. These emissions can be rationalized within a framework involving proposed molecular fluorophores based on a fused aromatic motif, represented by 1,3,7,9,11,13-hexahydroxyacenaphthyleno[1,2-b]perylene (HHAP), and their excimer states formed through π–π stacking, respectively. Remarkably, these RCPDs achieve a quantum yield of over 85%, among the highest reported for long-wavelength-emitting CPDs. Integration of the RCPDs into polymer matrices enables the fabrication of red/NIR-emitting light-emitting devices, demonstrating their practical utility. This study presents an efficient synthetic strategy for producing structurally defined, long-wavelength-emitting CPDs and provides mechanistic insights that can guide the rational design of next-generation luminescent carbon nanomaterials. This work has been published in Chemical Engineering Journal (IF = 13.2). 

In this study, in situ formed silica nanoparticles (SNPs) emitting second-level phosphorescence at room temperature without a phosphorescent dopant have been achieved for the first time. This phosphorescence is achieved through the simple in situ formation of carbonaceous defects (CDs) within the SNPs, followed by passivation of the CDs by a robust silica matrix. The CD in the SNPs, termed CD@SNPs, are synthesized by cross-linking tetraethyl orthosilicate (TEOS) and (3-aminopropyl)triethoxysilane (APTES), and these cross-linked components create a porous structure within the silica matrix. Upon calcination, the carbon-related structures within the pores deform, leading to the formation of CDs. Confined within a robust silica matrix, the molecular motion of the CD is restricted, facilitating the generation of a stable triplet state and suppressing nonradiative decay. Moreover, the robust silica matrix passivates the CD confined in the SNPs at a nanoscale. These comprehensive effects enable prolonged phosphorescence emission from the SNPs. In addition, these phosphorescence-emitting SNPs have been applied as dopants in the emissive layer of organic light-emitting diodes to realize blue light emission. This feature suggests the possibility of utilizing luminescent SNPs as light emitters in display technologies.  This work has been published in ACS Applied Materials & Interfaces (IF = 8.3).