We present an investigation of inverted polymer light-emitting diodes (PLEDs) with an alcohol-soluble conjugated starburst macromolecule TrOH as an interlayer. The introduction of a TrOH interlayer between the light-emitting polymer layer and ZnO has been shown to significantly enhance the device efficiency due to efficient electron injection as well as efficient blocking of exciton quenching. It was found that the thickness of the TrOH interlayer is an important factor impacting the device performance. As a result, an efficient inverted PLED with a maximum luminous efficiency of 1.43 cd A⁻¹ was achieved using a blue polymer poly(9,9-dioctylfluorene) (PFO) as the emitting layer.