Quantum　dot　photodiodes　(QLEDs)　hold　promising　potential　for　next-generation　display　and　lighting　devices　due　to　their　high　emission　efficiency,　high　color　purity　in　the　visible　region,　tunability　of　emission　wavelengths,　and　low　manufacturing　costs.　However,　QLEDs　confine　a　large　number　of　photons　inside　the　device　that　cannot　be　utilized,　leading　to　low　external　quantum　efficiency.　In　this　paper,　a　simple　and　efficient　strategy　to　construct　bilayer　light　extraction　structures　is　developed　based　on　the　self-assembled　polystyrene　(PS)　microspheres　embedded　in　polyvinyl　butyral　(PVB)　film　with　excellent　thermoplasticity.　The　maximum　external　quantum　efficiency　(EQE)　of　blue-QLED,　green-QLED　and　red-QLED　increased　from　8.18%　to　13.51%,　12.96%　to　19.61%　and　21.7%　to　25%,　respectively.　It　is　found　that　bilayer　light　extraction　structure　does　not　change　the　light　intensity　angular　distribution　of　Lambertian　emission　mode.　The　bilayer　optically　coupled　structure　proposed　in　this　work　provides　an　efficient　and　stable　way　for　the　improvement　of　QLED　performance.　©　1980-2012　IEEE.