We have synthesized a series of PPV copolymers and investigated the relationships between their chemical structures, thermal stabilities, and optoelectronic properties. Initially, we monitored the effects of the end group and the molecular weight on the behavior of polymer light emitting diodes (PLEDs) prepared from a series of oligo(phenylenevinylene) (OPV)-fluorene luminescent copolymers. We found that the nature of the end-capping group was an important factor affecting the luminescence properties of devices, which were improved especially when applying a triphenylamine end group. The molecular weight mainly affected the film quality of the manufactured device; that is, it improved to a certain degree when the molecular weight increased. Based on the luminescence conversion mechanism, we used a simple spin-coating process to fabricate a high-efficiency LED displaying white-light CIE 1931 (coordinates of 0.31, 0.34). The device exhibited a high current-efficiency of 3.5 cd/A and a brightness of 973 cd/m(2). (c) 2007 Wiley Periodicals, Inc.