Stereoisomer-Independent Stable Blue Emission in Axial Chiral Difluorenol.

Mengna Yu,Xue Du,Linghai Xie,Wei Huang,Dong Jin,Ying Wei,Dongqing Lin,Xiong Jia

doi:10.3389/fchem.2021.717892

Abstract

Bulky conjugated molecules with high stability are the prerequisite for the overall improvement of performance in wide-bandgap semiconductors. Herein, a chiral difluorenol, 2,2′-(9,9′-spirobi[fluorene]-2,2′-diyl)bis(9-(4-(octyloxy)phenyl)-9H-fluoren-9-ol) (DOHSBF), is set as a desirable model to reveal the stereoisomeric effects of wide-bandgap molecules toward controlling photophysical behavior and improving thermal and optical stability. Three diastereomers are obtained and elucidated by NMR spectra. Interestingly, the effect of modifying the stereo-centers is not observed on optical properties in solutions, pristine films, or post-treated film states. All three diastereomers as well as the mixture exhibit excellent spectral stability without undesirable green emission. Therefore, this stereoisomer-independent blue-emitting difluorenol will be a promising candidate for next-generation wide-bandgap semiconductors that would have extensive application in organic photonics.

Highlights

Organic wide-bandgap blue-emitting semiconductors have attracted more attentions in industrial and fundamental research in information display and solid lighting (Friend et al, 1999; Xie et al, 2012)
Inspired by the supramolecular steric hindrance (SSH) effect (Li et al, 2018), we try to propose a novel strategy based on the molecular integration of steric bulk groups and axial chiral synthons into one functional molecule
We present difluorenol (DOHSBF), which consist of an axial chiral spirobifluorene and two chiral sp3 carbon atoms bearing a phenyl ring and a hydroxyl moiety

Summary

INTRODUCTION

Organic wide-bandgap blue-emitting semiconductors have attracted more attentions in industrial and fundamental research in information display and solid lighting (Friend et al, 1999; Xie et al, 2012). Axial chiral molecules have been widely used in organic reactions, such as kinetic resolution, asymmetric catalysis, cyclamation/addition, direct aromatization, and chiral recognition, and exhibit promising application in optoelectronic fields like molecular electronic devices, semiconductors, light-emitting devices, and solar cells Inspired by the supramolecular steric hindrance (SSH) effect (Li et al, 2018), we try to propose a novel strategy based on the molecular integration of steric bulk groups and axial chiral synthons into one functional molecule. DOHSBF shows three different stereoisomers, which display stereoisomer-independent stable blue emission

AND DISCUSSION

CONCLUSION

Findings

DATA AVAILABILITY STATEMENT