Electronic Structure of Multicomponent Organic Molecular Materials: Evaluation of Range-Separated Hybrid Functionals

Range-separated hybrid (RSH) functionals have become a tool of choice to study the intra- and inter-molecular electronic states in organic materials. These functionals provide the most accurate descriptions of the electronic structure when the range-separation parameter is optimally tuned (OT). However, since the range-separation parameter is molecule dependent, this approach faces consistency issues when applied to the multicomponent systems typically found in the active layers of organic solar cells or organic light-emitting diodes (OLEDs). Here, we investigate the performance of four common RSH functionals in the description of the excited states of three molecular compounds used as components of the active layer in a hyperfluorescence OLED device. Our results indicate that the excited-state energies of the investigated molecules show a very weak dependence on the range-separation parameter value when they are evaluated by means of a screened version of RSH functionals. In this instance, the excited states of all three molecular compounds can be derived accurately and consistently with the exact same functional.