Theoretical insights into tunable optical and electronic properties of graphene quantum dots through phosphorization

Theoretical Understanding of Structure–Property Relationships in Luminescence of Carbon Dots

“…Heteroatom doping has a unique effect on the PL properties of CDs, they are the dominant factor in adjusting their LUMO–HOMO gap. Theoretical research results indicate that electron-rich atoms (such as N, O, P, and S) increase the HOMO energy, while electron-deficient atoms (such as B) reduce the LUMO energy, resulting in a redshift of the emission spectrum. − This is conjectured to be because heteroatoms participate in the formation of the carbon structure during the synthesis process, introducing vacancies (p-type) or electrons (n-type) and significantly changing the electronic structure and surface chemical activity, thereby affecting their optical properties. In general, single-atom doping alters the electronic and optical properties of CDs, thereby greatly improving the PL performance of the CDs.…”

“…The P = O bond in C 2 PO 2 and C 3 PO configurations induces multiple absorption peaks, and the P bond configuration in the sp 3 state has a stronger effect on the electronic transition than in the sp 2 state. Further, the doping of the P-bond structure with tetrahedral geometry has a more marked effect than the conical geometry. , …”

“…Further, the doping of the P-bond structure with tetrahedral geometry has a more marked effect than the conical geometry. 37,50 Chauhan et al evaluated the S-doping in CDs (S-CDs). The enhancement of the optical properties of S-CDs after doping is considered to arise from the increased contribution of s and p orbitals of S atoms close to the Fermi level based on the DFT calculated DOS results.…”

Outstanding Graphene Quantum Dots from Carbon Source for Biomedical and Corrosion Inhibition Applications: A Review

“…GQDs keep the center of graphene and indeterminate chemical groups on their surface, so the graphene center and neighboring chemical groups coordinate photoluminescence. Furthermore, the basic characteristics of GQDs depend mainly on shape and size which represent the main factors in the localization of absorption peaks [106]. Moreover, the edge structure, functional groups, solvents, and temperature plays an important part which is affected by the fundamental properties and other determining factors [107].…”

Theoretical Insights into Enhanced Electrocatalytic Activity of Oxygen Reduction Reactions on N/S-Codoped Graphene Quantum Dots

“…However, slow kinetics of ORRs at the cathode have hindered broad commercial applications of fuel cells. , In acidic media, Pt and its alloys exhibit high efficiency and have been the catalysts of choice for the ORRs . However, high cost and poor stability of Pt catalysts have limited extensive applications of fuel cells in energy production. − Consequently, researchers are seeking alternative metal-free electrocatalysts which are more efficient and environmentally friendly, such as carbon nanotubes, graphene, fullerenes, and graphene quantum dots. − In addition, heteroatom doping can endow metal-free materials with outstanding physicochemical and structural properties. − For example, since Dai et al reported catalytic performance of N-doped carbon nanotubes, heteroatom-doped carbon materials (e.g., N, B, S, and P) have been investigated as efficient electrocatalysts to enhance ORR performances. , In recent years, graphene quantum dots (GQDs) have demonstrated excellent electrocatalytic activities due to chemical inertness, quantum confinements, and edge effects . For instance, Qu et al reported N-doped GQDs with ORR electrocatalytic activity comparable to Pt catalysts in alkaline medium .…”