Homogeneous application liquid and production method for same, light-absorbing layer for solar cell and production method for same, and solar cell and production method for same

Provided is a homogeneous application liquid used to form a light-absorbing layer of a solar cell, wherein the homogeneous application liquid contains: at least one metal or metal compound selected from the group consisting of Group 11 metals, Group 13 metals, Group 11 metal compounds, and Group 13 metal compounds; a Lewis base solvent; and a Lewis acid.