Research On Characteristics Of Quaternary Broad-spectrum Organic Photodetectors Based On Dualacceptors

The organic photodetector has the advantages of easy adjustment of response spectrum,simple preparation process and low production cost,etc.,which has attracted the attention of many researchers.Most of the current research on organic photodetectors is focused on improving the light response in a certain range,However,few studies have explored the wavelength range from visible to near infrared.In order to solve the above problems,this thesis studies the broad-spectrum OPDs with the non-fullerene acceptor IEICO-4F as the third or fourth component.The thesis first studied the active layer P3HT:IEICO-4F:PC6iBM ternary device(the first group).Study the effect of different IEICO-4F doping concentration on the optical and electrical properties of the device.Experiments have found that when the doping ratio of IEICO-4F is 10wt%,the device has good performance.The specific detection rate D*at 650nm of red light is 4.86×1011 Jones,which successfully broadens the response spectrum range of the device,but the characteristics of red band are relatively poor.In order to further improve the red light absorption,Then,ternary devices with two active layers of red light materials(PTB7:IEICO-4F:PC61BM)were fabricated(the second group).The effects of different doping concentrations of IEICO-4F on the optical and electrical properties of the device are studied.Experiments have found that when the doping ratio of IEICO-4F is 4wt%,the device has good red light response characteristics,and D*is 1.61×1012 Jones at 650nm,indicating that two red light absorbing materials containing PTB7 and IEICO-4F can improve the red light response of the device.Finally,the study of the Quaternary bulk heterojunction with the active layer of P3HT:PTB7:IEICO-4F:PC61BM was carried out(the third group),and the influence of different doping concentrations on the optical and electrical properties of the device is studied.When the doping ratios of PTB7 and IEICO-4F are 10wt%and 5wt%,respectively,the device shows good photoelectric performance.At 650nm in red light,D*increases from 4.86×1011 Jones of single red light material to 1.1 ×1012 Jones,which increases By an order of magnitude.Meanwhile,the D*at green and blue(530nm and 460nm)reaches 1.4×1012 Jones and 1.07×1012 Jones,respectively,and both have been significantly improved.It shows that double doping is beneficial to the formation of an interpenetrating network structure in the active layer and improves the mobility of carriers.The research results show that the double doping method can effectively increase the mass ratio of additives,from 10wt%and 4wt%of single doping to 15wt%,so as to increase the absorption intensity of the active layer in the red wavelength band;The doping form of one donor and one acceptor forms an exciton dissociation effect between the double donor and the double acceptor,which increases the dissociation surface in the system and improves the efficiency of exciton dissociation;Using the doping form of one donor and one receptor,the morphology of the active layer is optimized to form a good interpenetrating network structure,and the carrier mobility is improved.In summary,using two long-wave absorbing material components with different properties to replace a single component can increase the mass ratio of the added components,broaden the response spectrum of the device,improve the exciton dissociation efficiency and mobility,and reduce the compound loss in the system.This provides a theoretical basis and experimental method for realizing OPDs with broad spectrum and high detection rate by using multiple components.