Abstract: An organic electroluminescence device includes: an anode; a cathode; an emitting layer disposed between the anode and the cathode; and a first layer disposed between the anode and the emitting layer, in which the emitting layer contains a delayed fluorescent compound, the first layer contains a first compound, an ionization potential of the first compound Ip(HT1) satisfies a numerical formula (Numerical Formula 1), a hole mobility of the first compound ?h(HT1) satisfies a numerical formula (Numerical Formula 2), and the first layer has a film thickness D1 of 15 nm or more, Ip ? ( HT ? 1 ) ? 5.7 eV ( Numerical ? Formula ? 1 ) ? ? h ? ( H ? T ? 1 ) ? 1 × 1 ? 0 - 5 ? cm 2 / Vs .

Abstract: An organic electroluminescence device may include an anode, a cathode, and an emitting layer provided between the anode and the cathode, in which the emitting layer contains a delayed fluorescent compound M2 and a compound M3 of formula (1) wherein A is a group of formula (11A), (11B)) (11C), (11D), (11E), and/or (11F) and Y1 is O or S. The compound M3 and the compound M2 may be different in structure.

Abstract: A color conversion particle includes a core; and a shell that contains the core and absorbs excitation light, and emits light at the core or at an interface between the core and the shell upon receiving the irradiated excitation light. The shell is composed of a chalcogenide perovskite, and the core and the shell have band alignment that induces a Stokes shift.

Abstract: A color conversion particle includes a core; and a shell that contains the core and absorbs excitation light, and emits light at the core or at an interface between the core and the shell upon receiving the irradiated excitation light. The core is composed of a chalcogenide perovskite, and the core and the shell have band alignment that induces a Stokes shift.