ScholarWorks@성균관대학교

초록

Phosphor-sensitized fluorescent (PSF) is a promising strategy for achieving high-efficiency and stable OLEDs, but the independent assessing Förster resonance energy transfer (FRET) and dexter energy transfer (DET) from the phosphor-sensitizer has been a challenge. Here, we present a multiscale energy transfer (MET) model that quantifies FRET and DET rate constants by connecting molecular and macroscopic approaches with experimental data. Through the combination of DFT calculation, Monte Carlo modeling, and numerical fitting, the proposed MET model successfully analyzed FRET and DET rates by resolving the long-standing multiple-solution problem in the exciton dynamics equation. We validated the model using PtON7-dtb and a newly designed phosphor-sensitizer, Pt-BS. It is unraveled that Pt-BS PSF system showed a 31.8% reduction in DET compared to PtON7-dtb PSF system. Attributed to the suppressed DET in Pt-BS PSF system, Pt-BS PSF OLEDs showed a 120% increase in exciton utilization efficiency (EUE) compared to PtON7-dtb PSF OLED. The optimized Pt-BS PSF OLED achieved a record-high EQE of 21.1% (CIE y = 0.100, λmax = 465 nm, FWHM = 24 nm) among deep-blue PSF devices.