Optical anisotropy plays an indispensable role in a variety of optical components. Organic halide perovskites often rely on artificially oriented nanostructures to enhance optical anisotropy due to their in-plane isotropic crystal structure, which results in unnecessary optical losses and fabrication difficulties. Here, we report the large optical anisotropy in two-dimensional perovskite [CH(NH₂)₂][C(NH₂)₃]PbI₄ crystals. Without specially designing their morphology, we achieved a large photoresponse linear dichroic ratio of 2 and a photoluminescence linear dichroic ratio of 4.7. Furthermore, we identified that the polarization orientation is parallel to the corrugated inorganic layers on every crystal plane by density functional theory calculations. The anisotropy of the ab-plane and ac-plane changes in opposite trend with temperature, suggesting that the perovskite can selectively generate polarized light or unpolarized light from different crystal planes by tuning the temperature. Our studies provide a new platform toward two-dimensional perovskite-based optical polarization devices.

中文翻译：

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带有波纹无机层的二维钙钛矿[CH（NH ₂）₂ ] [C（NH ₂）₃ ] PbI _4的大光学各向异性

光学各向异性在各种光学组件中起着不可或缺的作用。有机卤化物钙钛矿由于其面内各向同性的晶体结构，常常依赖于人工取向的纳米结构来增强光学各向异性，这导致不必要的光学损失和制造困难。在这里，我们报道了二维钙钛矿[CH（NH ₂）₂ ] [C（NH ₂）₃ ] PbI _4中的大光学各向异性。晶体。无需特别设计它们的形态，我们获得了2的大光响应线性二向色比和4.7的光致发光线性二向色比。此外，通过密度泛函理论计算，我们确定偏振方向与每个晶体平面上的波纹无机层平行。Ab平面和ac平面的各向异性随温度呈相反的趋势变化，这表明钙钛矿可以通过调节温度从不同的晶面选择性地产生偏振光或非偏振光。我们的研究为基于二维钙钛矿的光学偏振设备提供了新的平台。