A display device (4, 8, 9, 10), comprising: a base; a light emitting device on a first surface of the base; and a plate-like inorganic layer on a second surface of the base, the plate-like inorganic layer including first plate-like inorganic particles with a first horizontal size and second plate-like inorganic particles with a second horizontal size different from the first horizontal size, wherein the plate-like inorganic layel includes a first plate-like inorganic layer disposed directly on the second surface of the base and including the first plate-like inorganic particles; and a second plate-like inorganic layer disposed directly on the first plate-like inorganic layer and including the second plate-like inorganic particles, wherein the first and second plate-like inorganic particles have a horizontal size greater than a vertical size, have no polarity and are substantially neutral, characterized in that the first plate-like inorganic layer and the second plate-like inorganic layer each comprise a different graphene oxide particle from one another, wherein the first plate-like inorganic particle is a graphene oxide particle that contains carbon atoms, hydrogen atoms, and oxygen atoms and is free of nitrogen atoms, and the second plate-like inorganic particle is a graphene oxide particle that contains carbon atoms and hydrogen atoms and further contains nitrogen atoms, wherein the first horizontal size ranges from 20.0 μm to 50.0 μm, and the second horizontal size ranges from 0,5 μm to 8 μm. a base; a light emitting device on a first surface of the base; and a plate-like inorganic layer on a second surface of the base, the plate-like inorganic layer including first plate-like inorganic particles with a first horizontal size and second plate-like inorganic particles with a second horizontal size different from the first horizontal size, wherein the plate-like inorganic layel includes a first plate-like inorganic layer disposed directly on the second surface of the base and including the first plate-like inorganic particles; and a second plate-like inorganic layer disposed directly on the first plate-like inorganic layer and including the second plate-like inorganic particles, wherein the first and second plate-like inorganic particles have a horizontal size greater than a vertical size, have no polarity and are substantially neutral, characterized in that the first plate-like inorganic layer and the second plate-like inorganic layer each comprise a different graphene oxide particle from one another, wherein the first plate-like inorganic particle is a graphene oxide particle that contains carbon atoms, hydrogen atoms, and oxygen atoms and is free of nitrogen atoms, and the second plate-like inorganic particle is a graphene oxide particle that contains carbon atoms and hydrogen atoms and further contains nitrogen atoms, wherein the first horizontal size ranges from 20.0 μm to 50.0 μm, and the second horizontal size ranges from 0,5 μm to 8 μm. a first plate-like inorganic layer disposed directly on the second surface of the base and including the first plate-like inorganic particles; and a second plate-like inorganic layer disposed directly on the first plate-like inorganic layer and including the second plate-like inorganic particles, wherein the first and second plate-like inorganic particles have a horizontal size greater than a vertical size, have no polarity and are substantially neutral, characterized in that the first plate-like inorganic layer and the second plate-like inorganic layer each comprise a different graphene oxide particle from one another, wherein the first plate-like inorganic particle is a graphene oxide particle that contains carbon atoms, hydrogen atoms, and oxygen atoms and is free of nitrogen atoms, and the second plate-like inorganic particle is a graphene oxide particle that contains carbon atoms and hydrogen atoms and further contains nitrogen atoms, wherein the first horizontal size ranges from 20.0 μm to 50.0 μm, and the second horizontal size ranges from 0,5 μm to 8 μm.