Research On Preparation And Performance Of Organic Photovoltaic Devices Based On PBDB-T:ITIC System

In recent years,organic photodetectors(OPD)have attracted a lot of attention and research because of their low production cost,spectral tunability,and flexibility.Broadband detection and narrowband detection are widely used in digital cameras,optical sensing,night vision,and wearable or integrated electronic devices.As the active layer of the photodetector,organic semiconductor materials have the advantages of high extinction coefficient,low cost,and large area preparation.The microcavity structure uses the light in the resonant cavity to reflect back and forth several times to expand the optical transmission path.The phase coherence and longness of the light make the amplitude superimpose and produce a powerful amplifying light field.Therefore,it may be a new way to use the advantages of the microcavity structure and organic materials to improve the detection performance of organic photodetectors.Based on this,the main content of this paper first studied the organic photodetector based on the microcavity structure of PBDB-T:ITIC as the active layer,and explored the influence of the microcavity structure on the detection performance of the device.The microcavity is formed by vapor-deposited two layers of Ag with different thicknesses,and the light is continuously reflected between the two Ag mirrors,which expands the optical transmission path in the BHJ,improves the light absorption,and thereby improves the detection rate.Corresponding to the performance test of this device,we analyzed the characteristics of light and dark current,EQE,light response time,lightness and impedance.It has good detection performance,faster response light detection ability,and better light performance.A microcavity detector was also prepared using PET as a substrate.The device has good detection performance,good bending performance and excellent stability.In recent years,organic solar cells(OSC)have made rapid progress,with power conversion efficiency(PCE)reaching more than 17%.However,OSC will still be affected by insufficient light capture by the thin BHJ layer,and the absorption rate and external quantum efficiency are not To 80%,increasing the thickness of the BHJ usually leads to a decrease in efficiency.This is because the increase in the charge transfer distance in the BHJ leads to serious charge recombination inside the device.Based on this,the main content of this paper is to study the organic ternary OSC based on PBDB-T-SF:ITIC-Th:IT-4F.First,the binary and ternary organic OSCs were prepared,and the comparison found that the open circuit voltage of the ternary device was increased,but the Jsc and FF values gradually decreased.The reason is that the energy difference between the HOMOD of the donor and the LUMOA of the acceptor expanded from 1.24 e V to 1.45 e V.At the same time,the ternary mixture shows absorption loss in the near infrared region.In order to solve this problem,we prepared and studied the organic ternary OSC based on the planar microcavity structure of PBDBT-SF:ITIC-Th:IT-4F,discussed its photovoltaic performance,and found the organic ternary structure of the planar microcavity structure.OSC,its corresponding PCE increased from 12.6% to 14.4%.This is because the introduction of the microcavity structure supplements the absorption loss of the ternary blend.Finally,in order to improve the plane microcavity structure part of the incident light is reflected out of the device.Therefore,we have prepared and studied the organic ternary OSC with the cylindrical microcavity structure of PBDB-T-SF:ITIC-Th:IT-4F,which enhances the light scattering of the microcavity device.While the device performance maintains a high open circuit voltage,PCE is increased to 15.5%.