Two spiro-configured phenyl acridophopsphine-based oxide and sulfide host materials, named 5-phenyl-5H-spiro[acridophosphine- 10,9′-fluorene]-5-oxide (PSAFO) and 5-phenyl-5H-spiro [acridopho-sphine-10,9′-fluorene]5-sulfide (PSAFS), were synthesized by convenient method. The lowest unoccupied molecular orbital (LUMO) energy level and electron mobility could be decreased and improved as the S-atom replaced O-atom, respectively. Then, the electron injecting/transporting ability of PSAFS is expected to be enhanced. Moreover, the S-atom would provide PSAFS with better electron-donating capability and heavier molecular weight compared with that of PSAFO. Thus, a higher HOMO (the highest occupied molecular orbital) energy level and thermal stability can be achieved due to the shallower onset of oxidation potential and increased molecular weight. Consequently, a narrower energy gap between HOMO and LUMO of PSAFS would be obtained, and its thermal stability could be improved, which is beneficial to constructing high performance device. Although the frontier molecular orbitals and thermal stability were finely controlled by molecular modification, the high triplet (T₁) energy level was still retained due to the limited π-conjugation. With the high T₁, HOMO and LUMO energy levels of 2.83/2.82, −6.19/-5.66 and −2.12/-2.19 eV, PSAFO and PSAFS based blue TADF OLEDs with low driving voltages of 2.9/3.1 V and maximum EQEs of 12.4/13.8% are successfully realized.

两种螺构型苯基吖啶膦基氧化物和硫化物主体材料，命名为 5-苯基-5H-螺[acridophosphine-10,9'-芴]-5-氧化物（PSAFO）和 5-苯基-5H-螺[吖啶磷- spine-10,9'-芴]5-硫化物（PSAFS）通过简便的方法合成。随着 S 原子取代 O 原子，最低未占分子轨道 (LUMO) 能级和电子迁移率可以分别降低和提高。然后，预计PSAFS的电子注入/传输能力将得到增强。此外，与PSAFO相比，S原子将为PSAFS提供更好的给电子能力和更大的分子量。因此，由于更浅的氧化电位起始和增加的分子量，可以实现更高的 HOMO（最高占据分子轨道）能级和热稳定性。因此，PSAFS 的 HOMO 和 LUMO 能隙更窄，热稳定性得到提高，有利于构建高性能器件。虽然前沿分子轨道和热稳定性通过分子修饰得到了很好的控制，但高三重态 (T₁ ) 由于有限的 π 共轭，能级仍然保留。具有2.83/2.82、-6.19/-5.66 和 -2.12/-2.19 eV的高 T ₁、HOMO 和 LUMO 能级，基于 PSAFO 和 PSAFS 的蓝色 TADF OLED 具有 2.9/3.1 V 的低驱动电压和 124 的最大 EQE。 /13.8% 成功实现。