Novel II-VI compound based organic-inorganic hybrid semiconductors: intrinsic properties, defects, and long-term stability*

The hybrid structures in this study are a family of sub-nanoscale II-VI layers or chains interconnected or coordinated with smaller organic linkers.[1] They were shown to exhibit a very high degree of structural ordering (e.g., the most perfect man-made semiconductor superlattices), and a number of extraordinary properties such as much-greater-than-kT exciton binding energy, exceedingly strong excitonic absorption, and zero thermal expansion.[2,3] Comparison between Raman, PL and XPS spectra of freshly made and approximately 15-year old samples of a prototype hybrid structure β-ZnTe(en)0.5 have revealed defect related spectroscopy signatures that appear in both newly made defective samples and aged samples. Although the old samples typically show varying degree of degradation, some are found to be as pristine as high-quality freshly made samples. The study suggests that the initial state of the defect level is pertinent to the material’s long-term stability. This is a rare example of hybrid materials exhibiting recorded long-term stability. This study has a broad impact on the long-term stability of a wide range of hybrid materials, including perovskites.
[1]Huang,JACS 125,7049(03). [2]Zhang,PRL96,26405(06). [3]Zhang,PRL99,215901(07).