The signless Laplacian Estrada index of tricyclic graphs
  The signless Laplacian Estrada index of a graph $G$ is defined as $SLEE(G)=\sum^{n}_{i=1}e^{q_i}$ where $q_1, q_2, \ldots, q_n$ are the eigenvalues of the signless Laplacian matrix of $G$. In this paper, we show that there are exactly two tricyclic graphs with the maximal signless Laplacian Estrada index. 
Ramin Nasiri, Hamid Reza Ellahi, Gholam Hossein Fath-Tabar, Ahmad   Gholami, Tomislav Do\v{s}li\'c
math.CO