A light-absorbing material contains a compound represented by the composition formula HC(NH.sub.2).sub.2SnI.sub.3 and having a perovskite structure. A solid-state .sup.1H-NMR spectrum, which is obtained by .sup.1H-.sup.14N HMQC measurement in two-dimensional NMR at 25° C., of the compound includes a first peak at 6.9 ppm and a second peak at 7.0 ppm. A peak intensity of the first peak is equal to 80% or more of a peak intensity of the second peak.

A complex has a structure of formula (1A): SnX.sub.n.Math.(m)L, wherein X is at least one type of halogen atoms, L is a polar solvent molecule, n is a value from 1.5 to 2.5, and m is a value from 0.3 to 1.9. A perovskite compound has a structure of formula (2A): RSnX.sub.j, wherein Sn has an oxidation number from 1.5 to 2.5, R is at least one type of a monovalent cation, X is at least one type of halogen atoms, and j is a value from 2.5 to 3.5, and the perovskite compound is free of tin oxide; or a perovskite compound has a structure of formula (2B): R.sub.2M.sup.2BiX.sub.1, wherein R is at least one type of a monovalent cation, X is at least one type of halogen atoms; M.sup.2 is a monovalent metal, and i is a value from 5.0 to 7.0.

A complex has a structure of formula (1A): SnX.sub.n.Math.(m)L, wherein X is at least one type of halogen atoms, L is a polar solvent molecule, n is a value from 1.5 to 2.5, and m is a value from 0.3 to 1.9. A perovskite compound has a structure of formula (2A): RSnX.sub.j, wherein Sn has an oxidation number from 1.5 to 2.5, R is at least one type of a monovalent cation, X is at least one type of halogen atoms, and j is a value from 2.5 to 3.5, and the perovskite compound is free of tin oxide; or a perovskite compound has a structure of formula (2B): R.sub.2M.sup.2BiX.sub.1, wherein R is at least one type of a monovalent cation, X is at least one type of halogen atoms; M.sup.2 is a monovalent metal, and i is a value from 5.0 to 7.0.

A light-absorbing material contains a compound represented by the composition formula HC(NH.sub.2).sub.2SnI.sub.3 and having a perovskite structure. A solid-state .sup.1H-NMR spectrum, which is obtained by .sup.1H-.sup.14N HMQC measurement in two-dimensional NMR at 25? C., of the compound includes a first peak at 6.9 ppm and a second peak at 7.0 ppm. A peak intensity of the first peak is equal to 80% or more of a peak intensity of the second peak.

The present invention relates to novel precursors in the form of metal complexes with 2-substituted 1,3-diketones and to a process for the preparation thereof. The invention furthermore relates to the use thereof for the production of thin metal-oxide layers. The latter are constituents in a very wide variety of electronic components and devices having various functions.

The present application relates to a metal organic framework (MOF) glass composite comprising metal halide perovskite, and a method for its preparation.