Fermions Entropy of Vaidya-Bonner Black Hole

Using the membrane model which is based on brick-wall model, the authors calculated the free energy and entropy of the Vaidya-Bonner black hole due to fermions fields. The result shows that the entropy of the Vaidya-Bonner black hole is exactly proportional to the area of its event horizon. The relationship between entropy and event horizon in such non-static case is just the same as that in the static or stationary case.