NOVELTY - A solid-state dye-sensitized solar cell comprises a p-type semiconductor material (copper delafossite material), an n-type semiconductor material, a dye, and a pair of electrodes. At least one electrode is optically transparent, and the n-type semiconductor material, p-type semiconductor material, and dye are between the pair of electrodes.    USE - Solid-state dye-sensitized solar cell, thin film solar cell. The transparent p-type semiconductor material can also be used for transparent p-n diodes, visible and UV photodetectors, devices used for photoelectrolysis for hydrogen production, and other devices used for displays and low-E glazing applications.    ADVANTAGE - The solid-state dye-sensitized solar cell uses a p-type material which is transparent throughout the visible spectrum, where the dye absorbs light (in other words the semiconductor has a large band gap). The p-material can be deposited without dissolving or degrading the monolayer of dye on the titania nanocrystallites (n-type semiconductor). The excited level of the dye is located above the bottom of the conduction band of titanium and the ground level is below the upper edge of the valence band of the p-type material. This condition is essential for ensuring the separation of photo-generated electron-hole pairs. The solar cell has excellent energy conversion efficiency.    DETAILED DESCRIPTION - A solid-state dye-sensitized solar cell comprises a p-type semiconductor material (copper delafossite material CuB'O2, where B' is aluminum, gallium or indium), an n-type semiconductor material, a dye, and a pair of electrodes. At least one electrode is optically transparent, and the n-type semiconductor material, p-type semiconductor material, and dye are between the pair of electrodes. INDEPENDENT CLAIMS are included for the following:    (1) fabrication of solid-state dye-sensitized solar cell;    (2) fabrication of copper-boron oxide thin film on a substrate; and    (3) transparent thin film transistor.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic cross-sectional view of a single-junction p-i-solar cell with a copper delafossite p-layer.    Substrate (310)    Transparent conductive layer (320)    P-type copper boron oxide (330)    Amorphous silicon absorber (340)    N-type amorphous silicon thin film (350)