PF8Cz: High - Performance Hole - Transporting Material

is a carbazole - fluorene alternating copolymer jointly developed by the research groups of Yizheng Jin and Linjun Wang from Zhejiang University and the team of Fei Huang and Lei Ying from South China University of Technology. It serves as a core hole - transporting material in quantum - dot light - emitting diodes (s). This material effectively addresses the charge leakage problem at the organic/inorganic interface through the design of a rigid molecular framework and high - molecular - weight regulation, enabling significant performance breakthroughs in blue and green QLEDs.

Material Design Background and Molecular Structure

The molecular structure of PF8Cz consists of rigid copolymer units of carbazole and fluorene, which are alternately copolymerized to form a conjugated main chain. It has the following characteristics:

• The planar conjugated structure enhances the π - π stacking ability and reduces the structural disorder of the material.

• High molecular weight (Mw > 100 kDa) is achieved through the Suzuki coupling reaction, improving the film continuity.

• The HOMO energy level (-5.4 eV) and LUMO energy level (-2.3 eV) are precisely regulated to match the energy levels of the quantum - dot emitting layer.

Core Performance Advantages

• Efficient Electron - Blocking Ability: The LUMO energy level is 0.2 eV higher than that of traditional materials (such as TFB), creating an electron injection barrier that suppresses the leakage of electrons from the quantum - dot layer to the hole - transporting layer. This is particularly suitable for blue quantum dots with high conduction - band energy levels.

• Low Energy Disorder: The energy disorder degree σ≈0.03 eV, which is 40% lower than that of traditional polymers. This reduces the distribution of tail - states and carrier trapping in traps, enhancing the charge - transport efficiency.

• Excellent Thermal Stability: The glass transition temperature (Tg) > 150°C, ensuring the stability of the film structure during long - term device operation.

Application Performance in QLED Devices

The prototype blue and green QLED devices based on the PF8Cz hole - transporting layer have achieved several performance breakthroughs:

Material Compatibility: It supports solution spin - coating/ink - jet printing processes and is compatible with various light - emitting material systems such as CdSe/ZnS quantum dots and perovskite quantum dots.