Intrinsic Polarization and Tunable Color of Electroluminescence from Organic Single Crystal-based Light-Emitting Devices

Abstract

A single crystal-based organic light-emitting device (OLED) with intrinsically polarized and color-tunable electroluminescence (EL) has been demonstrated without any subsequent treatment. The polarization ratio of 5:1 for the transversal-electric (TE) and transversal-magnetic (TM) polarization at the emission peak of 575 nm, and 4.7:1 for the TM to TE polarization at the emission peak of 635 nm, respectively, have been obtained. The emitting color is tunable between yellow, yellow-green and orange by changing the polarization angle. The polarized EL and the polarization-induced color tunability can be attributed to the anisotropic microcavity formed by the BP3T crystal with uniaxial alignment of the molecules.

Two-Dimensional Stretchable Organic Light-Emitting Devices with High Efficiency

“…A template stripping technique was used to fabricate the free-standing ultrathin OLEDs. OTS modification was performed on a precleaned silicon (Si) substrate to realize a hydrophobic surface with lowered surface energy (Figure S2), which was beneficial to the template stripping process. , An ultrathin polymer film was obtained by spin-coating a photopolymer on the OTS-treated Si support and curing with ultraviolet (UV) exposure (Figure a, left). Its thickness is only 2.8 μm, which makes it very flexible.…”

Molecular Orientation of Conjugated Polymer Chains in Nanostructures and Thin Films: Review of Processes and Application to Optoelectronics

“…Therefore, as summarized in Figure 4, tuning the emission properties and color of PLEDs could be easily achieved through specific relative orientations active layers or thin films containing more than one active molecule. Furthermore, the generation of PLEDs exhibiting two perpendicular preferential molecular orientations also represents a simple but efficient strategy to fabricate bicolor emitting devices in which the emission color can be easily selected through the rotation of a polarizer [16,17]. Additionally, orientation of the molecules with respect to the substrate in light-emitting devices may lead to enhanced light-outcoupling properties which, in turn, could generate higher performances devices [35].…”

“…This may be due to the inadequate stacking orientation in the single crystals for vertical device architectures. Nevertheless, some single crystal devices display very peculiar optical properties (bipolarity) [16] which also represents one of the major advantages of directional organization of organic molecules (including conjugated polymers) as we will discuss in the following section.…”

“…Polarized light is widely used for applications such as lenses for sunglasses (UV-polarized) or fabrication of next-generation 3D displays or liquid crystal Journal of Nanomaterials displays but also as polarized light sources in analytical scientific equipment. Therefore, a particular effort has been given over the past few years to fabricate low power consumption highly polarized organic or inorganic light sources [13][14][15][16]. In polymer conjugated systems, which can be easily oriented, polarized electroluminescence has been demonstrated for around two decades [17].…”

Recent developments on organic single crystal-based light-emitting devices

“…Ding等人 [59] 在有机晶体中引入了"双掺 [59] . Copyright © 2019 Wiley-VCH 有各向异性特点 [60] . 进一步通过计算模拟了微腔吸收 光谱图, 模拟的TE和TM模式峰值与实验得到的TE和 TM峰值基本重合, 充分说明了偏振发光可归因于各向 异性的微腔 [61,62] .…”