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Study of Electronic and Steric Effects of Different Substituents in Donor–Acceptor Molecules on Multilevel Organic Memory Data Storage Performance
Author(s) -
Han Jinba,
Lian Hong,
Cheng Xiaozhe,
Dong Qingchen,
Qu Yongquan,
Wong WaiYeung
Publication year - 2021
Publication title -
advanced electronic materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.25
H-Index - 56
ISSN - 2199-160X
DOI - 10.1002/aelm.202001097
Subject(s) - triphenylamine , substituent , acceptor , molecule , steric effects , materials science , ternary operation , intermolecular force , conjugated system , active layer , crystallography , layer (electronics) , nanotechnology , stereochemistry , organic chemistry , thin film transistor , chemistry , polymer chemistry , polymer , physics , computer science , condensed matter physics , composite material , programming language
To study the influence of different types of substituent moieties onto the molecular backbones of conjugated donor–acceptor (D–A) molecules on the thin‐film morphology and performance of their memory devices, three new molecules X‐TBT were synthesized, which consist of the same backbone of two triphenylamine (T) groups and benzothiadiazole (BT) group, but have different substituents (X) with different electronic effects, that is, cyano group (CN), tert ‐butyl group ( t Bu), and methoxy group (OMe). Nonvolatile ternary write‐once‐read‐many‐times (WORM) data storage behavior is achieved for the CN‐TBT and t Bu‐TBT based devices as compared to the binary memory characteristic of TBT (X = H). In contrast, OMe‐TBT based device still maintains binary WORM behavior due to its unfavorable molecular packing motif and weak intermolecular charge transfer effect, but exhibits the lowest operating voltage (1.4 V) as a result of the lowest energy barrier between electrode and active layer. Notably, the t Bu‐TBT based device displays the highest I ON2 / I ON1 / I OFF ratio of 10 7 :10 3 :1. Altering the substituents in D–A molecules can adjust the molecular packing, thin film morphology, and electron trap depth of the active layer, which then significantly influence the memory performance.