Small molecule semiconductor building blocks have special optoelectronic properties that are different from inorganic or polymer semiconductor materials. Compared with inorganic semiconductor materials, there are many types of small-molecule semiconductor materials, and there is a lot of room for the choice of material types. Secondly, molecular synthesis and modification can be used to achieve regulation at the molecular scale. In the assembly process of nanostructures, small molecule semiconductor materials are easy to solubilize, easy to realize large area, and the process is simple. In addition, small molecule nanostructures have good flexibility and are compatible with lightweight and flexible substrates, making them ideal materials for flexible electronics and printed electronics. Compared with polymer materials, the structure of small molecules is clear, easy to purify, the prepared nanostructures have good crystallinity, and it is easy to prepare high-performance devices. Small molecule semiconductor materials are used as active materials in electronic devices, mainly in two forms: thin film structure and single crystal structure. The application in the field of optoelectronic devices is very important, such as electroluminescent devices, field effect transistors and solar cells.
Figure 1. Small molecule semiconductor building blocks are used in OLED screens
- Solar cell: Small molecule semiconductor building blocks have clear molecular structure, simple synthesis and purification, and stronger crystallinity, which can effectively reduce energy loss and improve device efficiency. For solar cells, small molecule semiconductor building blocks can be used as donor materials to become active layer materials for organic solar cells with their excellent properties.
- Organic photodetector: The principle of the photodetector is a type of instrument that changes the electrical conductivity of the irradiated material caused by radiation, thereby transmitting a change in electrical signal. Photodetectors play an important role in the fields of machine vision, fluorescence microscopy, remote monitoring and environmental detection, and communications. Organic photodetectors using small molecular semiconductor building blocks have the advantages of solution processability, light weight, good flexibility, and adjustable spectral response, and have received widespread attention.
- Organic Light-Emitting Diode (OLED): Small molecule semiconductor materials are driven by an electric field to produce organic light-emitting devices through carrier injection and recombination leading to light-emitting technology. Compared with polymer semiconductors, small molecule semiconductors have the advantages of easy colorization, simple production, stable properties, easy material synthesis and purification, and can improve the luminous efficiency of OLEDs or change the luminous color of devices.
- Minkyu Kyeong, Yuri Park, Ayeong Gu, Heejoo Kim, Sukwon Hong. Small molecule semiconductors for organic photovoltaics: a truncation approach [J]. Synthetic Metals, 2018, 245, 10-17.