When the tetraazaporphyrin derivative of formula (I) and the porphyrin derivative of formula (II) are doped with an alkali metal, one or more kinds of alkali metals can be employed, and it is preferable that the total number of the atoms of the alkali metal be in a range of 1 to 6 per one molecule of each of the tetraazaporphyrin derivative of formula (I) and the porphyrin derivative of formula (I