1：Experimental Design and Method Selection:

The study involved the synthesis of a bipolar host material, CzPN, by combining carbazole and phthalonitrile as donor and acceptor units, respectively. The photophysical, electrochemical, and charge transporting properties of CzPN were characterized.

2：Sample Selection and Data Sources:

The materials used included carbazole and 4-fluorophthalonitrile for the synthesis of CzPN. The characterization involved UV-vis absorption, photoluminescence, and phosphorescence spectra, cyclic voltammetry, and device fabrication.

3：List of Experimental Equipment and Materials:

Equipment included a Bruker Ascend 400 spectrometer for NMR, a TA instrument Q600 for thermogravimetric analysis, and a Perkin-Elmer Lambda-900 spectrophotometer for UV-vis absorption. Materials included carbazole, 4-fluorophthalonitrile, and various solvents.

4：Experimental Procedures and Operational Workflow:

The synthesis of CzPN was carried out under nitrogen and anhydrous conditions. The characterization involved measuring thermal stability, photophysical properties, and electrochemical properties. OLED devices were fabricated and their performance was evaluated.

5：Data Analysis Methods:

The data were analyzed using Gaussian 09 for DFT calculations, and device performance was evaluated based on current density, luminance, and external quantum efficiency.