1：Experimental Design and Method Selection:

The study involved the synthesis of two electron-transporting materials (ETMs) by combining spirobifluorene with di(pyridine-3-yl)phenyl and di(pyridine-4-yl)phenyl, respectively. The photophysical, thermal, and electrochemical properties were characterized, and their performance in PhOLEDs was evaluated.

2：Sample Selection and Data Sources:

The materials were synthesized and characterized using various spectroscopic and analytical techniques. Single-carrier devices and PhOLEDs were fabricated to evaluate the materials' electron-transporting properties and device performance.

3：List of Experimental Equipment and Materials:

Instruments used include Bruker Solarix XR Fourier Transform Ion Cyclotron Resonance Mass Spectrometer, Bruker 500 MHz NMR spectrometer, PerkinElmer Diamond DSC Pyris, SEIKO EXSTAR 6000 TG/DTA 6200 unit, Perkin-Elmer Lambda 35 spectrometer, Hitachi F7000 fluorescence spectrophotometer, and others.

4：Experimental Procedures and Operational Workflow:

The synthesis involved multiple steps including Suzuki coupling reactions, purification by silica-gel column chromatography, and characterization by NMR, mass spectrometry, and elemental analysis. Device fabrication involved thermal evaporation of organic and cathode layers under vacuum.

5：Data Analysis Methods:

The performance of the devices was analyzed based on current density-voltage characteristics, luminance, power efficiency, current efficiency, and external quantum efficiency.