Strong Linearly Polarized Photoluminescence and Electroluminescence from Halide Perovskite/Azobenzene Dye Composite Film for Display Applications

Abstract

Polarization emission from halide perovskite is expected to bring a lot of benefits for next‐generation displays, such as cost down, wide color gamut, and structure simplification. In this work, strong linearly polarized luminescence from emissive halide perovskites modulated by photoaligned azobenzene dye AD1 is demonstrated. The azobenzene dye functionalized halide perovskite thin films not only exhibit exceptionally high degree of polarization (DOP) of 86.2–93.1% for red, green, and blue emission, but also promise an improved environmental stability originating from the hydrophobic nature of the azobenzene dye. When these perovskite/AD1 composite films are applied in liquid crystal display panels to replace the conventional thick polarizer, the energy efficiency can be doubled and the color gamut can be extended to >120% NTSC. Furthermore, the AD1 functionalized strategy is successfully employed to generate linearly polarized electroluminescence from an inverted perovskite light‐emitting diode, showing a high DOP of 47%.

High-Luminance Microsized CH3NH3PbBr3 Single-Crystal-Based Light-Emitting Diodes via a Facile Liquid-Insulator Bridging Route

“…Thus, we infer that the polarized edge emissions of the PSC-LEDs should result from the multiple reflections of the emission light between the top and bottom crystal surfaces (Figure S21). According to the definition of the DOP (DOP = ( I max – I min )/( I max – I min ), where I max and I min are the maximal and minimal polarization components of the EL emission, respectively), a considerable DOP of 0.69 is achieved for the edge emission of the device, which is much higher than those of previously reported perovskite-based LEDs such as polycrystalline MAPbBr 3 film-based LED (∼0.5), CsPbBr 3 nanowires-based LED (0.5), and halide perovskite/azobenzene dye composite film-based LED (0.47) . Such an excellent DOP is ascribed to the absence of grain boundaries, high refractivity, and large aspect ratio of the high-quality microflakes.…”

Luminescent, Wide-Band Gap Solar Cells with a Photovoltage up to 1.75 V through a Heterostructured Light-Absorbing Layer

“…Indeed, the preferred orientation of perovskite growth from AVA-doped CH 3 NH 3 PbI 3 has been reported, which was caused by an oriented interface where the 3D phase had a marked preferential growth direction . This is possible because the bifunctional amino acid of AVA + can crosslink perovskite grains via the Pb–COO – bond and ionic bond between the NH 3+ and [PbX 6 ] unit. , The detailed modeling and explanation are out of the scope of this work. In the material with an orientated crystal structure, the numbers of the grain boundaries are largely reduced, which is beneficial for the carrier transport.…”

“…19 This is possible because the bifunctional amino acid of AVA + can crosslink perovskite grains via the Pb−COO − bond and ionic bond between the NH 3+ and [PbX 6 ] unit. 20,21 The detailed modeling and explanation are out of the scope of this work. In the material with an orientated crystal structure, the numbers of the grain boundaries are largely reduced, which is beneficial for the carrier transport.…”

Polarized Photoluminescence from Lead Halide Perovskites

“…The dielectric confinement of optical electric field in polymer matrix leads to linearly polarized photoluminescence from the stretched films of perovskite nanocrystal composites, as shown in Figure 9c. [99][100][101] Li et al introduced the dichroic dye that aligned in a fixed direction under polarized excitation into the perovskite films, [102] which could serve as a built-in optical filter to polarize the photoluminescence. As a result, high degree of polarization (86.2-93.1%) was obtained in the spectral range of red, green, and blue from the photoluminescence of these perovskite composites.…”