Nonconventional luminogens with persistent room temperature phosphoresce (p-RTP) are attracting increasing attention owing to their momentous significance and diverse technical applications in optoelectronic and biomedical. So far, the p-RTP emission of some amorphous powders or single crystals has been studied in depth. The p-RTP emission of amorphous and fully crystalline states and their emission properties are widely divergent, while the difference of their p-RTP emission mechanism is still controversial. The relevance between crystallinity change and p-RTP properties is rarely studied. Furthermore, there is almost no research on the photoluminescence (PL) property change and emission mechanism under the crystal form transformation of semi-crystalline polymer. Herein, microcrystalline cellulose (MCC) is chosen as a model compound to explore its crystallinity and the change in luminescence during the crystal form transformation to make up for this gap. By precisely adjusting the crystallinity and crystal cellulose conversion of MCC, the changing trend of quantum efficiency, and p-RTP lifetime is consistent with the change of crystallinity, and the cellulose I may be more beneficial to PL emission than cellulose II. Clustering-triggered emission mechanism can reasonably explain these interesting photophysical processes, which also can be supported by single-crystal analysis and theoretical calculations.

中文翻译：

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逐渐改变结晶度和晶型的微晶纤维素的可调光致发光特性

具有持久室温磷光 (p-RTP) 的非常规发光体由于其在光电和生物医学中的重要意义和多样化的技术应用而引起越来越多的关注。到目前为止，已经深入研究了一些非晶粉末或单晶的 p-RTP 发射。非晶态和全晶态的 p-RTP 发射及其发射性质差异很大，而其 p-RTP 发射机制的差异仍存在争议。结晶度变化与 p-RTP 特性之间的相关性很少被研究。此外，几乎没有关于半结晶聚合物晶型转变下的光致发光（PL）性质变化和发射机制的研究。在此处，选择微晶纤维素 (MCC) 作为模型化合物来探索其结晶度和晶型转变过程中的发光变化，以弥补这一差距。通过精确调节MCC的结晶度和结晶纤维素转化率，量子效率和p-RTP寿命的变化趋势与结晶度的变化一致，纤维素I可能比纤维素II更有利于PL发射。聚类触发的发射机制可以合理地解释这些有趣的光物理过程，这也可以得到单晶分析和理论计算的支持。量子效率和p-RTP寿命的变化趋势与结晶度的变化一致，纤维素I可能比纤维素II更有利于PL发射。聚类触发的发射机制可以合理地解释这些有趣的光物理过程，这也可以得到单晶分析和理论计算的支持。量子效率和p-RTP寿命的变化趋势与结晶度的变化一致，纤维素I可能比纤维素II更有利于PL发射。聚类触发的发射机制可以合理地解释这些有趣的光物理过程，这也可以得到单晶分析和理论计算的支持。