Abstract: A thin film for an optoelectronic device includes a layered 2D perovskite material. The thin film including the layered 2D perovskite material forms a substantially or nearly single-crystalline highly uniform thin film with strongly preferential out-of-plane alignment of the inorganic perovskite layers. This single-crystalline, highly uniform, and highly aligned thin film of the layered 2D perovskite material may thereby facilitate efficient charge transport in an optoelectronic device.

Abstract: According to an embodiment of the present disclosure, a thermionic cathode includes: a cathode body having an outer surface, and a sealing layer including one or more graphene sheets on the outer surface of the cathode body. According to another embodiment of the present disclosure, a method for manufacturing a thermionic cathode includes: depositing a sealing layer including one or more graphene sheets on an outer surface of a cathode body.

Abstract: According to an embodiment of the present disclosure, a photocathode may include: a mesh having a first surface and a second surface facing away from the first surface, and including metallic, semiconductor or ceramic mesh grid with micron-sized openings in the mesh; a photosensitive film on the first surface of the mesh and extending at least partially into the openings of the mesh; and a graphene layer including one or more graphene sheets on the second surface of the mesh.

Abstract: According to an embodiment of the present disclosure, a photocathode may include: a mesh having a first surface and a second surface facing away from the first surface, and including metallic, semiconductor or ceramic mesh grid with micron-sized openings in the mesh; a photosensitive film on the first surface of the mesh and extending at least partially into the openings of the mesh; and a graphene layer including one or more graphene sheets on the second surface of the mesh.

Abstract: Hybrid organic-inorganic perovskite thin films with average grain sizes of at least 50 micrometers were prepared and employed in solar cells. The PCE values of the solar cells did not degrade with the direction or the scan-rate of the applied voltage. The larger average grain sizes are believed to assist in reducing the influence of defect states on carrier recombination. The tunability of PCE with substrate temperature may be correlated to the quality of the crystalline perovskite formed using the hot-casting procedure. The larger average grain sizes lead to good crystalline quality, low defect density, and high carrier mobility. The process for growing hybrid organic-inorganic perovskites may be applicable to the preparation of other materials to overcome problems related to polydispersity, defect formation, and grain boundary recombination.