You Do Need power plug adapter while traveling from Aruba to Slovenia.

Here is Why You Need An Adapter

The outlet and plug type used in Slovenia are C and F and in Aruba are A, B and F. This is how they look like.

Aruba

In Aruba, outlets of type A, B and F are in use.

Type A

Type B

Type F

Slovenia

In Slovenia, outlets of type C and F are in use.

Type C

Type F