Research On Characteristics Of Narrow-Band Near-Infrared Organic Photodetectors

Narrow-band near-infrared organic photodetectors（NIR-OPDs）have a range of wide application prospects in health monitoring,night vision,optical communication and human infrared vision.With the in-depth research in the field of narrow-band NIR-OPDs,researchers have proposed a variety of effective ways to realize narrow-band near-infrared response,and the performance of NIR-OPDs has been greatly improved.However,it is an urgent problem to prepare near-infrared narrow-band response OPDs with narrower full width at half maxima（FWHm）and further improve the specific detection rate at low voltage.Therefore,the paper carried out narrow-band NIR-OPDs research to solve the current problems.Based on the P3HT:IEICO-4F bulk heterojunction structure,this paper gradually realizes high-performance narrowband NIR-OPDs by combining experimental and theoretical analysis,and studies the change of their photoelectric characteristics.The main research contents are:（1）Study on the influence of structural parameters on the photoelectric characteristics of OPDs:By gradually adjusting the structural parameters of OPDs,the photoelectric characteristics of OPDs are tested,and their influence on the photoelectric characteristics of OPDs is studied.The experimental results show that:When the ratio of active layer P3HT:IEICO-4F is 10:10,the thickness of active layer is 1800nm,and the doping concentration of double-doped C₆₀:C₇₀ is 3wt%:2wt%,the device can achieve high performance narrow-band near-infrared detection with FWHM of 90nm and D*of 5.08×1012Jones at-2V bias.（2）Study on the influence of annealing process on the photoelectric characteristics of OPDs:By adjusting the annealing temperature and annealing time,the photoelectric characteristics of OPDs are tested,and the influence of annealing process on the photoelectric characteristics of OPDs is analyzed.The experimental results show that the best performance of the prepared OPDs is obtained when the annealing temperature is 110℃ and the annealing time is 10min.It is found that the annealing process under appropriate conditions can promote the absorption of the film,improve the interface contact between the film and Al electrode,and increase the doping concentration of trap in active layer.（3）Study on the working mechanism of narrow-band NIR-OPDs:The narrow-band response mechanism and doping multiplication mechanism are analyzed based on the experimental results of narrow-band NIR-OPDs.The results show that with the increase of the thickness of the active layer,carrier collection is limited in the short-wave region,which leads to the contraction of the spectral response region towards the long-wave region.Doped electron traps can assist hole tunneling,and suitable doping concentration can improve the electrical properties of OPDs.Through the above research,high performance narrow-band NIR-OPDs are prepared,which provides a new design method for narrow-band NIR-OPDs and supplements the theories related to the narrow-band self-filtering mechanism and doping doubling mechanism.