Electroluminescent devices

A consumer product comprising an organic light-emitting device (OLED) having an emission spectrum, the OLED comprising:

• an anode;
• a cathode;
• and
• an organic emissive layer, disposed between the anode and the cathode, comprising:
• a first host material having a highest occupied molecular orbital (HOMO) energy and a lowest unoccupied molecular orbital (LUMO) energy;
• and
• an emitter material having a HOMO energy and a LUMO energy;
• wherein,
• all materials in the organic emissive layer are mixed together;
• the emitter material is a phosphorescent metal complex;
• High HOMO energy is the highest HOMO energy among all materials in the organic emissive layer;
• Low LUMO energy is the lowest LUMO energy among all materials in the organic emissive layer;
• a≤ET−ΔE≤b, wherein ET is triplet energy T1 of the emitter material, which is the lowest T1 energy among all materials in the organic emissive layer, ΔE is the energy gap between the High HOMO energy and the Low LUMO energy, a is 0.00 up to 0.15 eV, and b is 0.05 up to 0.45 eV;
• and
• wherein root mean squared function (RMSD) value for the emission spectrum of the OLED and an emission spectrum of a reference OLED, whose organic emissive layer consists of the emitter material and an inert host, is not greater than 0.05,
• wherein RMSD value is a single value that represents the average difference between the emission spectrum of the OLED and the emission spectrum of the reference OLED at all wavelengths obtained by the following equation:
• R
• ⁢
• M
• ⁢
• S
• ⁢
• D
• =
• 1
• n
• ⁢
• ∑
• 1
• n
• (
• I
• 1
• (
• λ
• )
• -
• I
• 2
• (
• λ
• )
• )
• 2
• ,
• wherein n is the number of points on the two emission spectrums being compared, and I1 and I2 are the normalized intensity spectrums as a function of wavelength, λ.