Study Of Organic Optoelectronic Integrated Device Based On Doping Phosphorescent Dye

Organic optoelectronic integrated devices(OIDs)with organic light-emitting diode(OLED)and ultraviolet organic photodetector(OPD)dual functions have attracted lots of research interests,since the integration of the two functions is helpful to reduce the device size and simplify the fabrication process.Although OIDs have showed greatly enhanced detection performance,the electroluminescent performance is still low when compared to the common OLED.In this work,the effect of a new-type thermally activated delayed fluorescence(TADF)featured host material on the performance of several typical phosphorescent dyes doped OIDs is studied in detail.(1)OIDs with UV photodetectivity and different color emitting were constructed by using two pure TADF materials,4CzIPN and 2CzPN,as active layers.It was found that the devices could achieve high electroluminescent performance under forward bias through reverse intersystem crossing.Meanwhile,TADF materials are intramolecular charge transfer complex so as to dissociate photo-induced excitons directly under a reverse bias.By doping with phosphorescent dye(tbt)2Ir(acac),we studied the effects of different kinds of TADF host materials on the performance of doped structures.The 2CzPN based OID shows the maximum luminanceof 88776 cd/m2,current eff-iciency of 42.18 cd/A and power efficiency of 25.16 lm/W,which was ascribed to effective energy transfer from 2CzPN to(tbt)2Ir(acac).(2)The 2CzPN based OIDs doping with typical red phosphorescent dye Ir(piq)3,orange phosphorescent dye(tbt)2Ir(acac),and blue phosphorescent dye FIr6 were investigated and compared.As a result,the(tbt)2Ir(acac)doped orange devices show better performance than those of red and blue devices,and we got the reason for the difference of device performance from analyzing the spectra of the device and the energy levels of the materials.(3)Sine the(tbt)2Ir(acac)doped device shows the highest OLED performances among the three phosphorescent dyes,four different doping concentrations of 1 wt%,3 wt%,5 wt%,and 7 wt%are chosen to analyze the influence of the(tbt)2Ir(acac)doping concentration on the OLED and UV OPD performance.At a low dopant concentration of 3 wt%,the(tbt)2Ir(acac)doped OID shows the maximum luminance of 70786 cd/m2,current efficiency of 39.55 cd/A and power efficiency of 23.92 lm/W.It is obvious that the device not only shows high luminance and efficiency,but also has decent OPD performance.In conclusion,doping suitable phosphorescent dye with low concentration into TADF host materials could significant enhance electroluminescent performance,and it can also insure stable detection performance.This work may arouse widespread interest in constructing high efficiency and luminance OIDs based on doping phosphorescent dye.