Easy and cost-effective production of high-quality photonic crystals (PCs) remains challenging but attractive, not just because they are a type of gemstone but more for their scientific applications (e.g., serving as lossless waveguides, visual sensors, novel pigments and novel separation media). Herein presented is a separation-cooperated assembly (SCA) strategy able to organize cheap polydisperse particles into PCs. Its feasibility was validated through sink-induced SCA of poorly disperse (size variation up to 56%) particles into iridescent liquid PCs in 3 days or more. Strikingly, with a sharp photonic band gap down to 10 nm (ca. 1/7 of the reported 66 nm), the liquid PCs are able to cyclically recover their iridescent color in ca 20 s after agitation, and keep their structural order after dryness, making them practicable to write and paint directly. Also significant is that SCA yielded uniform particles with size variation down to 0.7%. It is thus an easy way to isolate homogeneous particles from disperse ones.

中文翻译：

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从多分散粒子中分离合作组装液态光子晶体†

简便且经济高效地生产高质量光子晶体（PC）仍然具有挑战性，但仍具有吸引力，这不仅是因为它们是宝石类型，而且还更多地用于科学应用（例如，用作无损波导，视觉传感器，新型颜料和新型光子晶体）。分离介质）。本文介绍了一种能够将廉价的多分散颗粒组织到PC中的分离协同组装（SCA）策略。通过水槽诱导的SCA在3天或更长时间内将分散不良（尺寸变化高达56％）的颗粒分散到虹彩液体PC中，验证了其可行性。引人注目的是，用锋利的光子带隙向下至10nm（约在所报道的66 nm的1/7中，液体PC能够在搅拌后约20 s内周期性地恢复其虹彩色，并在干燥后保持其结构有序，从而使它们可以直接书写和绘画。同样重要的是，SCA产生的颗粒均匀，粒径变化低至0.7％。因此，这是从分散颗粒中分离出均匀颗粒的简便方法。