Structure-property correlation to assist the design of organic blue emitters with thermally activated delayed fluorescence

Organic light-emitting diodes are constantly developed technologically. An advantageous strategy for efficient work of the devices is the design of emitters exhibiting thermally activated delayed fluorescence (TADF). Efforts are invested, especially towards blue TADF fluorophores. The complex nature of the involved photophysical processes prohibits straightforward prediction of dyes with enhanced TADF potential. Design rules are knowledge-based or derived for specific cases. In the present work, we attempt to establish quantitative structure-property relationships (QSPR) between a key optical property of potential TADF emitters and a set of molecular descriptors. The goal is a statistical model providing better understanding of the molecular factors governing the excited states singlet-triplet energy splitting. We utilise multiple linear regression and principal component analysis to correlate the values of the excited singlet-triplet energy gap to various molecular characteristics. The validated models demonstrate the complexity and collective nature of TADF events and highlight the essential role of the electron-donor fragment.