An organic light-emitting diode includes: a first electrode, a light-emitting stack thereon including: a hole transport layer (HTL), a blue light-emitting layer including: a blue host material (BHM), and a blue fluorescent dopant (BFD) material, and an electron transport layer (ETL), and a second electrode on the light-emitting stack, wherein BFD LUMO>BHM, BFD HOMO>BHM, BFD singlet energy BHM and BFD, HTL HOMO−BFD HOMO≤0.1 eV, the HTL material LUMO>the BHM, HTL LUMO−BHM LUMO≥0.5 eV, HTL LUMO>BFD, ETL LUMO>BHM and BFD, a difference in LUMO between the ETL material and the BFD material≤0.1 eV, and the HTL material, the ETL material, and the BHM have the following triplet energy relationships: T1,BH