Abstract Transitions from the singlet electronic excited states higher than S1 level (S2) to the fundamental state (S0) are unlikely, although such transitions are observed for perylene derivative compounds. This rareness led us to investigate the role of the molecular structure of two perylene derivatives (bis(butylimido) – BuPTCD and bis(phenetylimido) – PhPTCD), as well as their supramolecular arrangements, such as molecular organization, crystallinity, and molecular aggregates (before and after thermal treatment) on the radiative transition S2→S0. The emission spectra of BuPTCD and PhPTCD solutions (monomers) indicated that differences in their molecular structures (lateral groups) do not influence such transitions. Besides, it was verified that the relative intensity (RI) S1→S0 over S2→S0 (RI = IS1–S0/IS2–S0) obtained for BuPTCD and PhPTCD PVD films increases around 15 and 1.5, respectively (in comparison to their respective solutions). However, it was surprising to observe a decrease of RI = IS1–S0/IS2–S0 by a factor of 88 for both BuPTCD and PhPTCD PVD films after their thermal treatment at 200 °C for 2 h. The latter led to an increase of the emission intensity from S2→S0 transition in relation to S1→S0. The decrease of H aggregates, presence of J aggregates and formation of other types of molecular aggregates, induced by thermal treatment, seem to be the cause of the S2→S0 emission increase, which is supported by theoretical calculations.

中文翻译：

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苝衍生物薄膜：来自较高单线激发态的发射

摘要 从高于 S1 能级 (S2) 的单重电子激发态跃迁到基本态 (S0) 是不太可能的，尽管在苝衍生物化合物中观察到了这种跃迁。这种稀有性促使我们研究了两种苝衍生物（双（丁基亚氨基）-BuPTCD 和双（苯乙酰亚胺）-PhPTCD）的分子结构的作用，以及它们的超分子排列，如分子组织、结晶度和分子聚集体（热处理前后）辐射跃迁 S2→S0。BuPTCD 和 PhPTCD 溶液（单体）的发射光谱表明，它们的分子结构（侧基）的差异不会影响这种转变。除了，经验证，BuPTCD 和 PhPTCD PVD ​​薄膜获得的相对强度 (RI) S1→S0 相对于 S2→S0（RI = IS1–S0/IS2–S0）分别增加了约 15 和 1.5（与其各自的溶液相比） . 然而，令人惊讶的是，在 200°C 下热处理 2 小时后，BuPTCD 和 PhPTCD PVD ​​薄膜的 RI = IS1-S0/IS2-S0 降低了 88 倍。后者导致从 S2→S0 转变相对于 S1→S0 的发射强度增加。热处理诱导的 H 聚集体的减少、J 聚集体的存在和其他类型分子聚集体的形成似乎是 S2→S0 排放增加的原因，这得到了理论计算的支持。令人惊讶的是，在 200°C 下热处理 2 小时后，BuPTCD 和 PhPTCD PVD ​​薄膜的 RI = IS1-S0/IS2-S0 降低了 88 倍。后者导致从 S2→S0 转变相对于 S1→S0 的发射强度增加。热处理诱导的 H 聚集体的减少、J 聚集体的存在和其他类型分子聚集体的形成似乎是 S2→S0 排放增加的原因，这得到了理论计算的支持。令人惊讶的是，在 200°C 下热处理 2 小时后，BuPTCD 和 PhPTCD PVD ​​薄膜的 RI = IS1-S0/IS2-S0 降低了 88 倍。后者导致从 S2→S0 转变相对于 S1→S0 的发射强度增加。热处理诱导的 H 聚集体的减少、J 聚集体的存在和其他类型分子聚集体的形成似乎是 S2→S0 排放增加的原因，这得到了理论计算的支持。