5. In an equilateral $\triangle A B C$ with side length 1 cm, $P_{0}$ is a point on side $B C$. Draw $P_{0} P_{1} \perp C A$ at point $P_{1}$, draw $P_{1} P_{2} \perp A B$ at point $P_{2}$, and draw $P_{2} P_{3} \perp B C$ at point $P_{3}$. If point $P_{3}$ coincides with point $P_{0}$, then the area of $\triangle P_{1} P_{2} P_{3}$ is $\qquad$ square centimeters.
5. $\frac{\sqrt{3}}{12}$