The authors report a cascade energy transfer based on the long-range dipole-dipole Förster energy transfer between polymer and two fluorescent dyes in solid thin films. The authors studied the fabrication and emission characteristics of a new doubly doped system for color purity and energy transfer efficiency, in which two fluorescent dyes, i. e. TPB and Rubrene were doped into PVK. In the blend film, PVK acted as the energy donor, Rubrene as the fluorescent dye, and the assistant dopant TPB was used to facilitate the energy transfer from PVK to the dye Rubrene. Orange emission comes from Rubrene via a cascade energy transfer from PVK toTPB and then from TPB to Rubrene.