The Synthesis And Photoelectric Properties Research Of Schiff Base Derivatives

With the maturity of organic light-emitting device(OLED)commercial technology,OLED displays have been used in various industries,and gradually become an integral part of people’s lives.OLED light-emitting materials are the core part of OLED technology,and therefore attract much attention.At present,organic light-emitting materials are mainly divided into red,green and blue light-emitting materials,among which the efficiency and luminous purity of red light-emitting materials are relatively backward.To solve this problem,a series of donor-acceptor-donor(D-A-D)type red fluorescent Schiff base materials were synthesized,and the following results were obtained by preparing the corresponding devices.1.The D-A-D red fluorescent Schiff base material DMT-t Bu TPA was designed and synthesized,and the photophysical and electrochemical tests were carried out.The D-AD structure allows for a larger conjugation system inside the DMT-t Bu TPA molecule,which theoretically makes it easier to obtain a smaller energy gap to achieve red light emission.The luminescence peak of the OLED device prepared based on DMT-t Bu TPA is 623 nm,the maximum current efficiency(CE)is 11.0 cd/A,and the maximum external quantum efficiency(EQE)is 6.56%,when the DMT-t Bu TPA doping concentration is increased appropriately,the maximum EQE of the device was 4.04%,which decreased the efficiency but achieved the deep red light emission at 645 nm.To further improve the device efficiency,the TADF material 4CZIPN or SAF-2NP sensitized DMT-t Bu TPA was introduced in the emitting layer.the emitting peak of the OLED device based on 4CZIPN sensitized DMT-t Bu TPA was 630 nm with the maximum CE of 23.7 cd/A and the maximum EQE of 14.9%.The peak of the OLED device based on SAF-2NP sensitized DMT-t Bu TPA was 627 nm,the CE maximum was 20.8 cd/A,and the EQE maximum was14.3%.2.In order to prepare high-purity red light devices,red fluorescent Schiff base materials 4a and BDPMB with narrow half-peak width(Full-Width at Half-Maximum,FWHM)were selected,and the materials were tested photophysically and electrochemically.The FWHM of the OLED devices prepared based on 4a and BDPMB were 56 nm and 50 nm,with EQE of 2.6% and 4.15%,respectively,and luminescence peaks of 608 nm and 620 nm.To improve the efficiency of the devices,TADF-sensitized materials 4CZIPN or SAF-2NP were also introduced into the luminescence layer.Based on 4CZIPN-sensitized 4a and BDPMB,the FWHM of the OLED devices were 58 nm and53 nm,respectively,with EQE of 6.3% and 12.6%,and luminescence peaks of 616 nm and 625 nm,respectively.The OLED devices based on SAF-2NP sensitized 4a and BDPMB with FWHM of 64 nm and 50 nm,EQE of 16.1% and 15.9%,and luminescence peaks of 602 nm and 620 nm,respectively,yielded red light devices with both efficiency and luminescence purity.