Full‐Color Chemically Modulated g‐C₃N₄ for White‐Light‐Emitting Device

Abstract

And it is widely accepted that its photoluminescence (PL) emission is originated from the radiative transition between conduction band (CB), contributed by the π antibonding orbitals (π*) or δ* related to the sp 2 CN bond and valence band (VB) predominated by the lone pair (LP) in the edge N 2p orbitals. [3] Based on that the PL emission of g-C 3 N 4 in the region of 430-450 nm and 450-500 nm are ascribed to δ*→LP and π*→LP transition, respectively, the PL emission band can be controlled by adjusting π-conjugated polymeric network structure, the size of sp 2 CN clusters, layer packing, and defect degree. [4] However, pristine g-C 3 N 4 had low quantum yield (QY) and narrow range of PL emission (430-550 nm) due to its stable electronic band structure, [5] showing only slight changes in bandgaps upon different condensation precursors and reaction parameters (2.58-2.87 eV). [6] Over a decade, various functionalization strategies (including structural manipulation, [7] atomic/molecular doping, [8] and heterojunction construction [9] ) devoted to the electronic band structure adjustment, mainly aiming for the improvement of g-C 3 N 4 -related catalysis by enhancing their solar light (450-650 nm) is synthesized through the one-step molecular doping during the thermal condensation process of g-C 3 N 4 conjugated framework, which opens up its application beyond the conventional catalysis scopes. By adjusting the doped content of heteromolecules, the modified g-C 3 N 4 with the optical properties controlled according to the demand of practical applications can be facilely and largely obtained. It overcomes the limitation of the narrow adjusting range of conventional g-C 3 N 4 on optical properties and makes it become more promising for applications in solid-state displays. The corresponding multiple-color g-C 3 N 4 -based LED devices and the white-light LEDs with high quality can be obtained as supported by experiments and theoretical calculations. Moreover, the effect of doped molecule on the π-conjugated system of g-C 3 N 4 is systematically studied here, and the tunable luminescence mechanism is proposed. Polymeric g-C 3 N 4 with controllable photoluminescence emission wavelength in the whole visible light range Full-Color PhotoluminescenceThe ORCID identification number(s) for the author(s) of this article can be found under https://doi.

One‐Step Synthesis of Visible Range Luminescent Multicomponent Semiconductor Composites Based on Graphitic Carbon Nitride

“…In general, the spectra contain two distinct broad bands, the peak intensities of which compete with each other in the synthesis temperature range. The band at high energies (3.0–2.2 eV) attributed to recombination processes in g‐C 3 N 4 [ 1,2,7,10 ] shifts to the lower energy range with the increase in the synthesis temperature. Another energy band at low energies (2.4–1.8 eV) is considered as a fingerprint of crystal lattice defects in ZnO and/or ZnS.…”

“…There are some attempts undertaken to fabricate white light‐emitting devices using this material as a luminophore, combining it with oxides (silica), [ 7 ] semiconductors (ZnO), [ 8 ] phosphorus (Y 2 MoO 6 :Eu 3+ ), [ 9 ] and organic compounds (2‐aminothiophene‐3‐carbonitrile). [ 10 ]…”

Rare Earth‐Free Luminescent Materials for WLEDs: Recent Progress and Perspectives

“…However, the PLQY of these materials was relatively low (5.4–1.1%), which led to the low efficiency of the prepared WLEDs (0.3411–0.0895 lm W −1 ). [ 36 ] Yang et al prepared a carbon nitride QD with fluorescent/phosphorescent dual emission through a high‐pressure solid‐phase reaction at 195 °C using urea as the precursor. The overall PLQY (fluorescence and phosphorescence) was as high as 25%.…”

“…Reproduced with permission. [36] Copyright 2019, Wiley-VCH. www.advancedsciencenews.com www.advmattechnol.de…”

Assessment of Crystalline Materials for Solid State Lighting Applications: Beyond the Rare Earth Elements

“…One of the most studied and promising organic materials are carbon nitride-based compounds [81]. Of most interest is the thermal and structural stability (up to 550 • C) as well as the simple and low-cost synthesis procedure.…”