1：Experimental Design and Method Selection:

The study involved designing OLEDs with a non-doped phosphorescent dye layer inserted in an exciplex forming planar structure. The thickness of the phosphor layer was optimized (0.1, 0.5, and 1 nm) to achieve high efficiency. Devices were fabricated with and without exciplex interfaces for comparison.

2：1, 5, and 1 nm) to achieve high efficiency. Devices were fabricated with and without exciplex interfaces for comparison. Sample Selection and Data Sources:

2. Sample Selection and Data Sources: Indium tin oxide (ITO) coated glass substrates were used as anodes. Organic functional layers and metallic cathodes were thermally evaporated. Two series of devices (A-series without exciplex and B-series with exciplex) were fabricated with specific layer configurations.

3：List of Experimental Equipment and Materials:

Equipment includes ultrasonic cleaners, thermal evaporation systems, quartz crystal oscillators for thickness monitoring, UV-Vis spectrophotometer (SHIMATZU UV-1700), photoluminescence spectrometer (PerkinElmer LS55), EL spectrometer (OPT-2000), PL transient decay measurement system (HORIBA Scientific Single Photon Counting Controller FluoroHub-B with NanoLED-370 and TBX photon detector), and J-V-L measurement system (Keithley 4200 source and ST-86LA luminance meter). Materials include ITO, MoO3, NPB, TCTA, TPBi, Bphen, Mg:Ag, and (tbt)2Ir(acac).

4：Experimental Procedures and Operational Workflow:

Substrates were cleaned and treated with oxygen plasma. Organic layers and cathodes were deposited via thermal evaporation under vacuum. Device configurations were ITO/MoO3(5 nm)/NPB(50 or 40 nm)/(tbt)2Ir(acac)(X nm)/TPBi(10 nm)/Bphen(40 nm)/Mg:Ag(100 nm) for A-series and ITO/MoO3(5 nm)/NPB(40 nm)/TCTA(10 nm)/(tbt)2Ir(acac)(X nm)/TPBi(10 nm)/Bphen(40 nm)/Mg:Ag(100 nm) for B-series. Optical and electrical characterizations were performed at room temperature.

5：Data Analysis Methods:

UV-Vis and PL spectra were analyzed to study material properties. J-V-L characteristics were measured to assess electrical performance. PL transient decay was used to investigate energy transfer mechanisms. Efficiency parameters (PE, CE, EQE) were calculated using standard formulas.