“…The application of pressure promotes the molecular modication from a non-planar to a planar state, which was observed on other nonplanar metal-organic frameworks in previous studies. 41,42 To further study the effect of compression on the grain boundary, we performed high-resolution transmission electron microscopy (TEM) on Alq 3 , which can directly inspect detailed atomic information, and hence is reliable to identify the grain boundaries. Fig.…”