“Steric Armor” Strategy of Blue Fluorescent Emitters against Photooxidation‐Induced Degradation

• Published in: Chinese journal of chemistry Vol. 42; no. 11; pp. 1223 - 1229
• Main Authors: Wang, Sha‐Sha, Zhang, Jing‐Rui, Wang, Kuan‐De, Li, Hao‐Ran, Meng, Peng‐Hui, Zhou, Yang, Yu, Xiang, Wei, Ying, Feng, Quan‐You, Kan, Yu‐He, Xie, Ling‐Hai
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY‐VCH Verlag GmbH & Co. KGaA 01-06-2024; Wiley Subscription Services, Inc
• Subjects: Armor; Crystal engineering; Crystallization; Emitters; Fluorene; Fluorescence; Molecular structure; Organic semiconductor; Oxidation; Oxygen; Photoelectric effect; Photoelectric properties; Photoelectricity; Photoluminescence; Photons; Photooxidation; Photosensitivity; Semiconductor devices; Service life; Spirocyclic aromatic hydrocarbons
• ISSN: 1001-604X; 1614-7065
• DOI: 10.1002/cjoc.202300638

Comprehensive Summary
Stability against oxygen is an important factor affecting the performance of organic semiconductor devices. Improving photooxidation stability can prolong the service life of the device and maintain the mechanical and photoelectric properties of the device. Generally, various encapsulation methods from molecular structure to macroscopic device level are used to improve photooxidation stability. Here, we adopted a crystallization strategy to allow 14H‐spiro[dibenzo[c,h]acridine‐7,9′‐fluorene] (SFDBA) to pack tightly to resist fluorescence decay caused by oxidation. In this case, the inert group of SFDBA acts as a “steric armor”, protecting the photosensitive group from being attacked by oxygen. Therefore, compared with the fluorescence quenching of SFDBA powder under 2 h of sunlight, SFDBA crystal can maintain its fluorescence emission for more than 8 h under the same conditions. Furthermore, the photoluminescence quantum yields (PLQYs) of the crystalline film is 327% higher than that of the amorphous film. It shows that the crystallization strategy is an effective method to resist oxidation.