Synthesis And Charge Transfer Properties Of Subphthalocyanine Green Photodetection Materials

Organic semiconductor photodetector has become a hotspot in image sensing due to its advantages of simple preparation technology and wide material selection.However,organic polymers and most small molecular compounds have a wide spectrum absorption range,and it is difficult to achieve selective absorption of monochromatic light,especially green light,which limits the development and application of high-performance panchromatic organic visible light detectors.In this paper,a series of subphthalocyanine derivatives with different peripheral and axial substituents were synthesized to explore the relationship between molecular structure and properties of the synthesized compounds,providing theoretical basis for molecular design and synthesis of high-performance organic green light detection compounds.In this paper,a series of subphthalocyanine derivatives without peripheral substitution(SubPc 1-4),peripheral phenoxy substitution(SubPc 5-8)and peripheral nitro substitution(SubPc 9-12)were prepared by different phthalonitrile ligands,and their structures were confirmed.The photophysical,charge transfer,electrochemical and thermal stability properties of the synthesized compounds were then tested.The maximum UV-visible absorption wavelength of SubPc 1-12 is between 560-600 nm,which indicates that the synthesized subphthalocyanine compounds have good light absorption to green light.Charge transfer test and calculation showed that SubPc 1,SubPc 5 and SubPc 9 had the strongest charge transfer and separation ability,which indicated that the synthesized compound could effectively separate electrons and holes after absorbing green light.The HOMO and LUMO energy levels of SubPc 1-12ranged from-5.48 to-5.31 e V and from-3.28 to-3.05 e V,indicating that the synthesized subphthalocyanine compounds can be used as electron donor materials for organic semiconductor devices.The T_d value of the synthesized subphthalocyanine was between 200 and 286 ^oC,indicating that the synthesized subphthalocyanine compounds had good stability.Finally,a series of subphthalocyanine compounds were used as photoactive layer to prepare organic green light detectors.Among the devices based on SubPc 1-4,the external quantum efficiency(EQE)of the photodetector with the best performance is31.91%,the photoresponsivity is 0.14 A/W,the specific detection rate(D^*)is 2.4×10¹²,and the response time is 30 ms.Among the devices based on SubPc 5-8,the external quantum efficiency(EQE)of the photodetector with the best performance is 87.10%,the light response is 0.41 A/W,the specific detection rate(D^*)is 1.81×10¹³,and the response time is 33 ms.Among the devices based on SubPc 9-12,the external quantum efficiency(EQE)of the photodetector with the best performance is 78.89%,the light response is 0.36 A/W,the specific detection rate(D^*)is 1.61×10¹³,and the response time is 29 ms,which indicates that the synthesized subphthalocyanine compound shows good green light detection performance.It has potential application prospect in image sensing and other fields.