![Author ORCID: We display the ORCID iD icon alongside authors names on our website to acknowledge that the ORCiD has been authenticated when entered by the user. To view the users ORCiD record click the icon. [opens in a new tab]](https://chemrxiv.org/engage/assets/public/chemrxiv/images/logos/orcid.png)
Abstract
Organic molecules with large gap between the excited singlet/triplet states can be applied in hot exciton emission and singlet fission to beat the spin statistics limit in optoelectronic devices. Herein, a novel strategy is proposed for achieving large triplet-triplet gap (E(T1T2)) and singlet-triplet gap (E(S1T1)) by manipulating the aromaticity of the low-lying excited states. Partially conjugated five-membered heterocyclic rings are found to naturally have low E(T1) owing to high aromaticity obeying Baird’s Rule. Utilizing such ring (pyrazoline) as a bridge and selecting various donor and acceptor moieties, numbers of derivatives have been theoretically designed with tunable emission colors, significantly large E(T1T2) and E(S1T1), and satisfying E(T2)>E(S1)≥2E(T1). The ultrafast spectroscopy and sensitization measurements for one of them with blue fluorescence (named TPA-DBPrz) confirm the calculated prediction. This work opens a new avenue and provides molecular units to develop high-efficiency optoelectronic materials.
Supplementary materials
Title
Searching Building Blocks with Large Excited-State Gaps in Five-memebered Heterocyclic Rings by Aromaticity Strategy
Description
We have proposed a facile strategy to achieve large triple gap by manipulating the aromaticity and the transition properties of the low-lying excited states, then theoretically designed and experimentally verified a series of donor-bridge-acceptor based on partially conjugated five-memebered rings with high aromaticity in T1 state to meet the harsh energy conditions of large triplet energy gap between T2 and T1 (〖∆E〗_(T_1 T_2 )) for hot exciton materials and E(T2)>E(S1)≥2E(T1) for singlet fission materials.
Actions
