Studies on the Microwave Optics of Ionic Molecular Solids

2002 ◽  
Author(s):  
John R. Hardy
1985 ◽  
Vol 82 ◽  
pp. 153-158 ◽  
Author(s):  
S.P. Velsko ◽  
R.M. Hochstrasser

2019 ◽  
Author(s):  
Shengxian Cheng ◽  
Xiaoxia Ma, ◽  
Yonghe He ◽  
Jun He ◽  
Matthias Zeller ◽  
...  

We report a curious porous molecular crystal that is devoid of the common traits of related systems. Namely, the molecule does not rely on directional hydrogen bonds to enforce open packing; and it offers neither large concave faces (i.e., high internal free volume) to frustrate close packing, nor any inherently built-in cavity like in the class of organic cages. Instead, the permanent porosity (as unveiled by the X-ray crystal structure and CO<sub>2</sub> sorption studies) arises from the strong push-pull units built into a Sierpinski-like molecule that features four symmetrically backfolded (<b>SBF</b>) side arms. Each side arm consists of the 1,1,4,4-tetracyanobuta-1,3-diene acceptor (TCBD) coupled with the dimethylaminophenyl donor, which is conveniently installed by a cycloaddition-retroelectrocyclization (CA-RE) reaction. Unlike the poor/fragile crystalline order of many porous molecular solids, the molecule here readily crystallizes and the crystalline phase can be easily deposited into thin films from solutions. Moreover, both the bulk sample and thin film exhibit excellent thermal stability with the porous crystalline order maintained even at 200 °C. The intermolecular forces underlying this robust porous molecular crystal likely include the strong dipole interactions and the multiple C···N and C···O short contacts afforded by the strongly donating and accepting groups integrated within the rigid molecular scaffold.


MRS Bulletin ◽  
1997 ◽  
Vol 22 (6) ◽  
pp. 46-51 ◽  
Author(s):  
W.R. Salaneck ◽  
J.L. Brédas

Since the discovery of high electrical conductivity in doped polyacetylene in 1977, π-conjugated polymers have emerged as viable semiconducting electronic materials for numerous applications. In the context of polymer electronic devices, one must understand the nature of the polymer surface's electronic structure and the interface with metals. For conjugated polymers, photoelectron spectroscopy—especially in connection with quantum-chemical modeling—provides a maximum amount of both chemical and electronic structural information in one (type of) measurement. Some details of the early stages of interface formation with metals on the surfaces of conjugated polymers and model molecular solids in connection with polymer-based light-emitting devices (LEDs) are outlined. Then a chosen set of issues is summarized in a band structure diagram for a polymer LED, based upon a “clean calcium electrode” on the clean surface of a thin film of poly(p-phenylene vinylene) (PPV). This diagram helps to point out the complexity of the systems involved in polymer LEDs. No such thing as “an ideal metal-on-polymer contact” exists. There is always some chemistry occurring at the interface.


2016 ◽  
Vol 2 (10) ◽  
pp. e1601006 ◽  
Author(s):  
Eric A. Muller ◽  
Benjamin Pollard ◽  
Hans A. Bechtel ◽  
Peter van Blerkom ◽  
Markus B. Raschke

Molecular solids and polymers can form low-symmetry crystal structures that exhibit anisotropic electron and ion mobility in engineered devices or biological systems. The distribution of molecular orientation and disorder then controls the macroscopic material response, yet it is difficult to image with conventional techniques on the nanoscale. We demonstrated a new form of optical nanocrystallography that combines scattering-type scanning near-field optical microscopy with both optical antenna and tip-selective infrared vibrational spectroscopy. From the symmetry-selective probing of molecular bond orientation with nanometer spatial resolution, we determined crystalline phases and orientation in aggregates and films of the organic electronic material perylenetetracarboxylic dianhydride. Mapping disorder within and between individual nanoscale domains, the correlative hybrid imaging of nanoscale heterogeneity provides insight into defect formation and propagation during growth in functional molecular solids.


2004 ◽  
Vol 70 (14) ◽  
Author(s):  
Nichols A. Romero ◽  
Jeongnim Kim ◽  
Richard M. Martin
Keyword(s):  

Sign in / Sign up

Export Citation Format

Share Document