Synthesis,preparation And Photoelectric Property Of Organic Single Crystals

As the core material of a new generation of electronic devices, organic semiconductor material has been paid much attention to,and a variety of material systems have been reported. However, research of the relation between structure and properties of organic semiconductor materials is still not enough. For example, the understanding of the discipline of the carrier transportation in the organic semiconductor is not clear. Structure of organic single crystal field-effect transistor is more suitable for studying the carrier behavior in organic semiconductor. In the study of organic field-effect transistor, exploration of the thin film transistor is more than the others, however, the inevitable structure defects(like the grain boundary and so on) in the structure of film could not reflect the intrinsic properties of the organic semiconductor. Compared with the film,impurity and defect density of organic single crystal both reduce a lot. As a consequence, field effect transistor devices manufactured using organic single-crystal as a semiconductor material provide the effective tool to study the relationship between the structure-performance of organic semiconductor and the transmission mechanism of the carrier. Firstly, we should pay attention to the preparation methods of organic crystals and the growth mechanism of organic crystals during the process of researches. After that, we can understand the information of structure by x-ray crystallographic analysis, thus we could have a deeper understanding of the material. Finally, we can analyze the carrier transport properties using a transistor device structure. In addition to the devices, organic crystals also have unique features on the laser properties, piezallochromy and so on. In this paper, we designed and synthesized two molecules: PBNA and BP-CNDSB and prepared the high quality organic single crystals in thin sheet shape. We then studied the photophysical property of these two kinds of crystals in detail and obtained the accurate single crystal structure by the XRD single crystal diffraction. Under the pump laser light, two kinds of single crystals both showed the excellent amplified spontaneous emission(ASE) properties: the ASE threshold value of PBNA crystal is 88KW/cm2 and the minimum peak width at half height value is 4.41 nm; the ASE threshold value gained by the tests of BP-CNDSB crystal is 18.25 KW/cm2 and the minimum peak width at half height value is 3.92 nm. Besides, PBNA crystals have a special piezochromism pressure phenomenon under the pressure, it has phase transformation in the process of the piezochromism process and this behaves as that the shape and intensity of the optical spectrum have a saltation with the change of pressure. In this paper, we would elaborate the relationship of this unique phenomenon with the material structure. Finally, using PBNA and BP- CNDSB single crystals, we prepared the asymmetric electrode field effect transistor devices, studying the nature of carrier transmission. Results show that PBNA crystal reveal the bipolar features, the highest electron and hole mobility value is 2.77 cm2 V-1 s-1 and 2.9 cm2 V- 1 s-1, and the BP-CNDSB crystal also show bipolar transmission characteristics,the highest mobility of electrons and hole is 1.21 cm2 V-1 s-1 and 0.21 cm2 V-1 s-1.