[Ca24Al28O64]4+(4e−) electrides ceramic with high-electron concentration rapidly fabricated by spark plasma sintering of Ca, Al organic powder precursor in spark plasma sintering

[Ca24Al28O64]4+(4e−) are directly and quickly synthesized by self‐reduction of C12H10Ca3O14 + Al2O3 without any reducing agent

“…The electron density of C12A7:e − synthesized at 1050°C is analyzed by Equation (), and its value is 2 × 10 21 cm −3 . This is close to the theoretical electron density (2.33 × 10 21 cm −3 ) of C12A7:e − 14 . Also, the conductivity and electron density of the samples synthesized at 950°C and 1000°C were analyzed by using a comprehensive physical property test system and ultraviolet absorption spectroscopy.…”

“…The UV absorption peak of the synthesized sample at 0.45 eV corresponds to the transition of free electrons between the cages (inter‐cage transition) 16 . The UV absorption peak at 2.48 eV corresponds to the electronic transition from the 1S ground state to the 1P excited state (intra‐cage transition) 14 . Combined with the abscissa value of the UV peak of the sample at 2.48 eV, the electron density can be analyzed using Equation () 11…”

“…This makes its electrical conductivity up to 1500 S/cm 13 . C12A7:e − has a cage conduction band (CCB) that passes through the fermi surface and is partially occupied by electrons, and the bandgap between the CCB and the frame conduction band (FCB) is extremely small (0.68 eV) 14,15 . This also makes it have excellent electrical transport characteristics.…”

“…13 C12A7:e − has a cage conduction band (CCB) that passes through the fermi surface and is partially occupied by electrons, and the bandgap between the CCB and the frame conduction band (FCB) is extremely small (0.68 eV). 14,15 This also makes it have excellent electrical transport characteristics. The free electrons in the cage cavity of C12A7:e − form a structure similar to the F + center, and the binding of these electrons is much weaker than the binding of the electrons in the typical F + center in MgO.…”

Enhancing the injected electron concentration and thermionic emission property in C12A7:e− ceramic via Al site Zr doping

“…12,13 Khan et al significantly improved the conductivity and catalytic performance of C12A7:e − by doping Fe, Ga, Si, Sn, and V. [14][15][16][17] Xiao et al enlarged the size of the cage of polycrystalline C12A7 using the partial substitution of Sr and Ba on the Ca site, which facilitated the replacement of internal free O 2− and the migration of free e − . [18][19][20][21][22] Thus, homovalent cationic substitution helped to improve electrical transport properties and reduce the work function of the C12A7:e − . To better understand the doping phenomenon, Huang et al used density functional theory (DFT) to explore the effect of cationic (Mg 2+ , Cu 2+ , Sr 2+ , Fe 3+ , Ir 4+ , P 5+ , and V 5+ ) substitution on C12A7:e − structure, electronic characteristics, and electrical properties.…”