On the spectral radius and the energy of a digraph

The energy of a digraph (Formula presented.) is defined as (Formula presented.) , where (Formula presented.) are the (possibly complex) eigenvalues of (Formula presented.). In this paper, we obtain an improved lower bound on the spectral radius of (Formula presented.). Considering this result, we present an upper bound on the energy of (Formula presented.). We also show that our results generalize and improve some known results for graphs and digraphs.