A Molecular Engineering Strategy for Achieving Blue Phosphorescent Carbon Dots with Outstanding Efficiency above 50%

Abstract

n, π*) and β π 3 (π, π*) to promote and accelerate ISC process and further bring in a slow quenching/non-radiative rate (K q and K nr ).

Thermally Enhanced and Long Lifetime Red TADF Carbon Dots via Multi‐Confinement and Phosphorescence Assisted Energy Transfer

“…[36,37] Note that the seed CDs possess an average size of 2.2 nm, the increased particle size of these two CDs might originate from further crosslinking reactions with part of urea during the reaction. [45] XRD pattern of the uCDs@SiO 2 (Figure 3d) reveals the existence of amorphous silica phase owing to the large broadening of the SiO 2 peak at ≈21.6°. [45] In the XRD pattern of uCDs@SiO 2 /NaOH, except for the weak amorphous SiO 2 peak, the NaCNO related crystalline peaks appear prominently, indicating that the CDs particles have been embedded in NaCNO crystal.…”

“…First, after modifying seed CDs with urea, plenty of functional groups (such as NH 2 and CO/CN) contributing to (n, π*) transitions are introduced in the uCDs@SiO 2 system, which is beneficial to promote the ISC from singlet to triplet excited states. [43,45] In addition, the formed covalent and hydrogen bonds between the CDs and matrix can suppress the non-radiative transition of triplet excited states, thus also promoting the RTP (Figure 3g). [18] It should be noted that a fast RISC rate from triplet to singlet states to outcompete non-radiative decay and quenching process of T 1 is a critical factor to obtain TADF.…”

Colorful Triplet Excitons in Carbon Nanodots for Time Delay Lighting

“…Especially, light‐emitting diodes (LEDs) based on emissive CNDs have been receiving enormous attention as light sources because of their eco‐friendly feature and easily tunable fluorescence wavelength. [ 13–15 ] Time delay LEDs can stay lit for other illumination time, which can give eyes a buffer time to reduce transient blindness because of the abrupt darkness of switching off. However, time delay LEDs based on CNDs have rarely been investigated, due to the challenging phosphorescence wavelength regulation and limited emission lifetimes.…”

“…Especially, lightemitting diodes (LEDs) based on emissive CNDs have been receiving enormous attention as light sources because of their ecofriendly feature and easily tunable fluores cence wavelength. [13][14][15] Time delay LEDs can stay lit for other illumination time, which can give eyes a buffer time to reduce efficient multicolor emitters within CNDs, enhancing the corresponding density of triplet excitons, and minimizing the dissipation channels of triplet excitons by constructing a reasonable matrix can achieve colorful triplet excitons.…”

Intense Circularly Polarized Fluorescence and Room-Temperature Phosphorescence in Carbon Dots/Chiral Helical Polymer Composite Films

“…It is well-known that the generation of triplet excitons is crucial for endowing C-dots with the RTP feature, which can be realized by the intersystem crossing (ISC) process from the lowest singlet state to the lowest triplet state. Nowadays, scientists have developed many efficient strategies to promote the ISC process, such as restricting C-dots in solid-state host matrixes, − doping heteroatoms, − and designing new synthetic methods, , leading to numerous RTP C-dots with broad applications in photoelectric display, biological imaging, and information encryption, etc. − Meanwhile, the lifetimes of RTP C-dots have significantly improved from several hundreds of microseconds to tens of seconds at room temperature under air conditions in the past few years. However, although great progress has been made to obtain RTP C-dots, RTP C-dots with a circularly polarized luminescence (CPL) property have been rarely reported so far …”