Fig. 1

Optical characterizations of cavity-based organic OLEDs. a Cavity-based F8BT OLEDs with the structure of Bottom DBR/ITO/PEDOT:PSS/F8BT/TPBi/LiF/Al/Top DBR. b Energy diagram for F8BT OLEDs. c Absorption and PL spectra for F8BT thin film. d Reflective spectra at normal incidence angle to bottom DBR used in high-Q, intermediate-Q and low-Q cavity-based OLEDs