J-aggregates are widely used in studies of light–matter interaction and organic optoelectronic devices. Although J-aggregate films can be fabricated on salt by epitaxial growth method, the size is limited to hundreds of nanometer. In this work, with hexagonal boron nitride (h-BN) as a substrate, highly crystalline J-aggregate ultrathin films of N,N′-ditridecylperylene 3,4,9,10-tetracarboxylic diimide (PTCDI-C₁₃) are achieved by physical vapor transport (PVT) method. Significant bathochromically shifted absorption band and narrowed 0–0 transition are observed in the monolayer PTCDI-C₁₃ crystal on h-BN. The exciton coherence number N_coh of monolayer J-aggregate film extracted from the photoluminescence (PL) spectrum is up to 15 at T = 140 K, which is higher than that of the epitaxially grown layer on salt. Beyond the first molecular layer, the multilayer crystal on h-BN is dominated by H-aggregates. Further study shows that that the first molecular layer on h-BN adopts the highly ordered face-on configuration, while the overlayers adopt the edge-on motif. As a comparison, only H-aggregate PTCDI-C₁₃ ultrathin films are found on SiO₂ substrates, but no J-aggregates. The results suggest that high-quality J-aggregates can be prepared by utilizing appropriate substrates via physical vapor transport.

中文翻译：

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六方氮化硼单层分子晶体中强J聚集体发光的观察。

J-聚集体广泛用于光物质相互作用和有机光电器件的研究。尽管可以通过外延生长法在盐上制造J聚集膜，但其尺寸限于数百纳米。在这项工作中，以六方氮化硼（h-BN）为基底，通过以下方法获得了N，N'-二十三烷基per 3,4,9,10-四羧酸二酰亚胺（PTCDI-C ₁₃）的高结晶J聚集超薄膜。物理蒸气传输（PVT）方法。在h-BN上的单层PTCDI-C ₁₃晶体中观察到显着的红移位移吸收带和狭窄的0-0跃迁。激子相干数N _coh在T = 140 K时，从光致发光（PL）光谱中提取的单层J聚集膜的最大膜厚为15，比盐上外延生长层的膜厚高。除第一分子层外，h-BN上的多层晶体以H-聚集体为主。进一步的研究表明，h-BN上的第一分子层采用高度有序的面对结构，而叠层则采用边缘上的基序。作为比较，在SiO ₂基底上仅发现H-聚集体PTCDI-C ₁₃超薄膜，而没有J-聚集体。结果表明，优质J可以通过物理蒸气传输利用适当的底物来制备骨料。