Carbon nanodots (CDs) have emerged as an alternative option for traditional nanocrystals due to their excellent optical properties and low toxicity. Nevertheless, high emission efficiency is a long-lasting pursuit for CDs. Herein, CDs with near-unity emission efficiency are prepared via atomic condensation of doped pyrrolic nitrogen, which can highly localize the excited states thus lead to the formation of bound excitons and the symmetry break of the 𝝅-electron conjugation. The short radiative lifetimes (<8 ns) and diffusion lengths (<50 nm) of the CDs imply that excitons can be efficiently localized by radiative recombination centers for a defect-insensitive emission of CDs. By incorporating the CDs into polystyrene, flexible light-converting films with a high solid-state quantum efficiency of 84% and good resistance to water, heating, and UV light are obtained. With the CD-polymer films as light conversion layers, CD-based white light-emitting diodes (WLEDs) with a luminous efficiency of 140 lm W −1 and a flat-panel illumination system with lighting sizes of more than 100 cm 2 are achieved, matching state-of-the-art nanocrystal-based LEDs. These results pave the way toward carbon-based luminescent materials for solid-state lighting technology.

Hydrogen peroxide (H2O2) is an important product generated in the body and related to many pathophysiological processes and glucose metabolism disorder can cause many fatal diseases in living bodies. Therefore, the sensing of H2O2 and glucose is of great significance in disease diagnostics and treatment. Fluorescent carbon dots (CDs) are one new class of nanoprobes for H2O2 and glucose. Nevertheless, the CD-based sensor is always based on its fluorescence response, which is influenced by the auto-fluorescent interference. Herein, efficient fluorescent CDs were synthesized by one-pot solvothermal method, and the CDs exhibit bright and persistent deep-red (DR) chemiluminescence (CL) in bis(2,4,6-trichlorophenyl) oxalate and H2O2 solution with a CL quantum yield of (8.22 ± 0.30) × 10−3, which is amongst the highest values in ever reported nanomaterials for chemical analysis. Employing the CDs as CL nanoprobes, sensitive sensing for H2O2 has been achieved with a detection limit of 11.7 μM, and further for glucose detection with a detection limit of 12.6 μM. The DR CL CDs is promising to be applied in blood glucose analysis or in vivo biosensor.

Localized excitons are expected to achieve high-performance electroluminescence and have been widely investigated in GaN-based light-emitting diodes (LEDs). Although carbon nanodot (CD) based LEDs have been achieved with the radiative recombination of electrons and holes, localized excitonic electroluminescence has been not reported before. In this Letter, localized excitonic electroluminescent devices have been fabricated using fluorescent CDs as an active layer. The CDs show strong localized excitonic yellow emission with a fluorescence quantum yield of 76% and Stokes shift of 2.1 eV. The CD-based LEDs present a sub-bandgap turn-on voltage of 2.4 V and a maximum luminance of 60.2 cd m–2, which is the lowest driving voltage among the CD-based electroluminescent devices. Localized centers trap carriers effectively, resulting in sub-bandgap light emission. The current results manifest that localized excitons may furnish a promising approach to boost the development of CD-based LEDs.

Carbon nanogels (CNGs) with dual ability of reactive oxygen species (ROS) imaging and photodynamic therapy have been designed with selfassembled chemiluminescent carbonized polymer dots (CPDs). With efficient deep-red/near-infrared chemiluminescence (CL) emission and distinctive photodynamic capacity, the H 2 O 2 -driven chemiluminescent CNGs are further designed by assembling the polymeric conjugate and CL donors, enabling an in vitro and in vivo ROS bioimaging capability in animal inflammation models and a high-performance therapy for xenograft tumors. Mechanistically, ROS generated in inflammatory sites or tumor microenvironment can trigger the chemically initiated electron exchange luminescence in the chemical reaction of peroxalate and H 2 O 2 , enabling in vivo CL imaging. Meanwhile, part of the excited-state electrons will transfer to the ambient H 2 O or dissolved oxygen and in turn lead to the type I and type II photochemical ROS production of hydroxyl radicals or singlet oxygen, endowing the apoptosis of tumor cells and thus enabling cancer therapy. These results open up a new avenue for the design of multifunctional nanomaterials for bioimaging and antienoplastic agents.

Room‐temperature phosphorescence has received much attention owing to its potential applications in information encryption and bioelectronics. However, the preparation of full‐color single‐component‐derived phosphorescent materials remains a challenge. Herein, a facile in situ confining strategy is proposed to achieve full‐color phosphorescent carbon dots (CDs) through rapid microwave‐assisted carbonization of citric acid in NaOH. By tuning the mass ratio of citric acid and NaOH, the obtained CDs exhibit tunable phosphorescence wavelengths ranging from 483 to 635 nm and alterable lifetimes from 58 to 389 ms with a synthesis yield of up to 83.7% (>30 g per synthesis). Theoretical calculations and experimental results confirm that the formation of high‐density ionic bonds between cations and CDs leads to efficient afterglow emission via the dissociation of CD arrangement, and the evolution of the aggregation state of CDs results in redshifted phosphorescence. These findings provide a strategy for the synthesis of new insights into achieving and manipulating room‐temperature phosphorescent CDs, and prospect their applications in labeling and information encryption.