采用聚合物poly(N-vinylcarbazole) (PVK)掺 杂小分子蓝色荧光材料 N,N′-bis(naphthalen-1-y)-N,N′-bis(phenyl) benzidine (NPB)作为蓝色发光层, 将PbS量子点与环氧树脂的混合 物涂覆在ITO导电玻璃背面作为波长转换膜,制备了结构为PbS QDs/Glass/ITO/PVK:NPB /Al的近红外波 长转换有机电致发光器件(OLED)。蓝色发光层中,NPB发出峰值位于445nm的蓝光。通过控制前驱体S/Pb比例调节PbS量 子点的粒径,正向电场下获得900~1600nm范 围可调节峰值的近红外光发射。经过优化波长转换膜中PbS量 子点比例,增强了波长转换膜对蓝光的吸收,当PbS量子点比例为10%左右时器件发射强 度最高。
Novel near-infrared (NIR) light-emitting devices with a structure of PbS quantum dots (QDs)/glass/indium-tin oxide (ITO)/poly (N-vinylcarbazole) (PVK) :N,N ′-bis(naphthalen-1-y)-N,N′-bis(phenyl) benzidine (NPB)/Al are fabricated. A hybrid system consisting of small molecular blue fluorescent material of NPB a nd polymer material of PVK is employed as the blue light emitting layer,and the near-infrared wavelength convers ion film is prepared by dispersing PbS quantum dots into the mixture of the A,B epoxy resin.The blue light emitti ng layer has a emission around 445nm,and the emission comes from the NPB.With various size of PbS quantum dots which were synthesized with different precursor molars of S/Pb,the EL spectrum shows tunable emission peaks at 900-1600nm in the near-infrared range under forward bias.The NIR emission intensity is improved by optimizing the ratio of PbS quantum dots in the wavelength conversion film.The increased ratio of PbS quant um dots can enhance the probability of blue light absorption.When the ratio reaches 10%,the emission int ensity tends to be the highest.