As a member of the polycyclic aromatic hydrocarbon family, pyrene has high fluorescence efficiency, carrier mobility, and excimer emission efficiency, and has the characteristics of electron richness, macrocyclic conjugation, easy chemical modification, and good crystallinity. Pyrene-based π-conjugated materials are ideal organic optoelectronic materials for semiconductor devices. The pyrene ring has many functionalization sites, which makes the synthesis methods of pyrene derivatives diverse. At present, the following three strategies are often used to construct pyrene-based semiconductor materials: (1) regulating the number of substituents; (2) introduce electron-rich or electron-withdrawing substituents to prepare p-type and n-type semiconductors to achieve tunability of energy levels and carriers; (3) The pyrene unit is cyclized with different fused ring units to construct π-conjugated molecules with different structures. Through various molecular manipulations, the photophysical and electrochemical properties of perylene semiconductor materials have been improved, expanding their applications in the field of organic electronics.
Figure 1. Chemical structures of pyrenes
- Organic Light Emitting Diode (OLED): Pyrene exhibits strong blue fluorescence, high quantum yield, and excellent optical properties in solution. In OLEDs, pyrene-based materials exhibit the advantages of good thermal stability, high carrier mobility, solution processability, and high luminous efficiency. Moreover, chemical modification of pyrene compounds can avoid fluorescence quenching in the condensed state and improve the performance of their optical and optoelectronic devices.
- Organic Field Effect Transistor (OFET): The tetra-substituted pyrene molecule has a certain steric hindrance effect, which can avoid the aggregation of small molecules and improve the mobility of carriers. The small molecule with tetra-substituted pyrene as the core is a good organic semiconductor material with good carrier transport properties and is widely used in the field of OFETs.
- Organic Solar Cells (OSC): The larger conjugation length of pyrene-based molecules can extend the absorption band of pyrene-based semiconductor materials to the visible light region. As a light-harvesting molecule, pyrene-based molecules can improve the photon utilization rate of OSC and improve the photoelectric conversion efficiency. And pyrene materials have good stability, generate stable current, and improve the stability of OSC.
- Minglun Liu, Xiaojie Gong, Chaoyue Zheng, Deqing Gao. Development of Pyrene Derivatives as Promising n-Type Semiconductors: Synthesis, Structural and Spectral Properties [J]. Asian J. Org. Chem., 2017, 6, 1903-1913.