Transparent conductors as solar energy materials: A panoramic review

Electrochromic tungsten oxide films: Review of progress 1993–1998

Methods that fix atmospheric nitrogen to ammonia under mild conditions could offer a more environmentally benign alternative to the Haber–Bosch process. Now, a Ru-loaded electride, [Ca24Al28O64]4+(e−)4, is reported that acts as an efficient electron donor and reversible hydrogen store, and is demonstrated to function as an efficient catalyst for ammonia synthesis.

Ammonia synthesis using a stable electride as an electron donor and reversible hydrogen store

We removed approximately 100% of clathrated oxygen ions from the crystallographic cages in a single crystal of 12CaO.7Al2O3, leading to the formation of high-density (approximately 2 x 10(21) cm-3) electrons highly localized in the cages. The resulting electron forms a structure that we interpret as an F+ center and migrates throughout the crystal by hopping to a neighboring cage with conductivity approximately 100 siemens per centimeter, demonstrating that the encaged electron behaves as an anion. The electron anions couple antiferromagnetically with each other, forming a diamagnetic pair or singlet bipolaron. The resulting [Ca24Al28O64]4+(4e-) may be regarded as a thermally and chemically stable single crystalline "electride."

https://science.sciencemag.org/content/sci/301/5633/626.full.pdf

High-density electron anions in a nanoporous single crystal: [Ca24Al28O64]4+(4e-).

Recent progress in transparent oxide semiconductors: Materials and device application

An inorganic electride, 12CaO·7Al2O3:e-, synthesized by exclusively replacing oxygen ions in the sub-nanometer-sized cages of 12CaO·7Al2O3 crystal with electrons exhibits a superconducting transition at a temperature (Tc) of ∼0.4 K. Tc varies in the range of 0.14−0.4 K with the concentration of anionic electrons, which are primarily distributed over crystallographic spaces without occupying any particular framework ions. The precursor of electride is composed of representative metal oxides, which are electrical insulators. Thus, the exotic crystal structure of electrides provides an insight for a material platform to realize a new superconductor.

Superconductivity in an Inorganic Electride 12CaO·7Al2O3:e-

Electrides are ionic compounds in which electrons act as anions These compounds are expected to have interesting properties arising from their exotic structure The fatal drawbacks of the thermal and chemical instability of organic electrides were resolved by the synthesis of a room temperature (RT) stable electride using single crystalline 12CaO·7Al2O3 (C12A7) with a nanoporous structure and the chemical treatments for a long duration However, an innovative fabrication method is obviously required for practical applications such as cold electron-emitter and thermionic devices Herein we report a simple synthesis for polycrystalline C12A7 electrides with a moderate electronic conductivity via a strongly reducing C12A7 “melt”, ie, direct solidification of the melt or crystallization of the transparent glass Generation of carrier electrons and precipitation of the C12A7 phase from the strongly reducing melt and glass are likely associated with the incorporation of carbon-related anions for stabilizing 

Simple and Efficient Fabrication of Room Temperature Stable Electride: Melt-Solidification and Glass Ceramics

12CaO·7Al2O3 electride (C12A7:e-) is a promising material for the cathode of organic light-emitting diodes (OLEDs), because it has a low work function (φWF = 2.4 eV), comparable to metal potassium,...

Masashi Miyakawa

Papers

High-density electron anions in a nanoporous single crystal: [Ca24Al28O64]4+(4e-).

Superconductivity in an Inorganic Electride 12CaO·7Al2O3:e-

Simple and Efficient Fabrication of Room Temperature Stable Electride: Melt-Solidification and Glass Ceramics

Photoelectron Spectroscopic Study of C12A7:e - and Alq3 Interface: The Formation of a Low Electron-Injection Barrier

Fabrication of Highly Conductive 12CaO·7Al2O3 Thin Films Encaging Hydride Ions by Proton Implantation