title: Multiscale Micro-Nano Nested Structures: Engineered Surface Morphology for Efficient Light Escaping in Organic Light-Emitting Diodes.
abstract: Various micro-to-nanometer scale structures are extremely attractive for light escaping in organic light-emitting diodes. To develop and optimize such structures, an innovative approach was demonstrated for the first time to fabricate multiscale micro-nano nested structures by photolithography with a well-designed mask pattern followed by a controllable thermal reflow process. The experimental and theoretical characterizations verify that these unique nested structures hold the capability of light concentration, noticeable low haze, and efficient antireflection. As a proof-of-concept, the incorporation of this pattern onto the glass substrate efficiently facilitates light escaping from the device, resulting in current efficiency 1.60 times and external quantum efficiency 1.63 times that of a control flat device, respectively. Moreover, compared to a hexagonally arranged microlens array and quasi-random biomimetic moth eye nanostructures, the nested structures proposed here can magically tune the spatial emission profile to comply with the Lambertian radiation pattern. Hence, this novel structure is expected to be of great potential in related ubiquitous optoelectronic applications and provide scientific inspiration to other novel multiscale micro-nanostructure research.
authors.affiliation: Faculty of Mathematics and Physics, Huaiyin Institute of Technology , Huai'an 223003, PR China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhou
authors.affiliation: College of Physics Optoelectronics and Energy, Soochow University , Suzhou 215006, PR China.
authors.forename: Xiaoxuan
authors.initials: X
authors.lastname: Dong
authors.affiliation: College of Physics Optoelectronics and Energy, Soochow University , Suzhou 215006, PR China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Printable Electronics Research Center, Suzhou Institute of Nano-Technology and Nano-Bionics, Chinese Academy of Sciences , Suzhou 215123, PR China.
authors.forename: Wenming
authors.initials: W
authors.lastname: Su
authors.affiliation: Printable Electronics Research Center, Suzhou Institute of Nano-Technology and Nano-Bionics, Chinese Academy of Sciences , Suzhou 215123, PR China.
authors.forename: Xiaolian
authors.initials: X
authors.lastname: Chen
authors.affiliation: Faculty of Mechanical Engineering, Huaiyin Institute of Technology , Huai'an 223003, PR China.
authors.forename: Yufu
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: College of Physics Optoelectronics and Energy, Soochow University , Suzhou 215006, PR China.
authors.forename: Su
authors.initials: S
authors.lastname: Shen
keywords: Fresnel diffraction; microlens array; moth eye nanostructures; organic light-emitting diodes; photolithography; thermal reflow