An organic electroluminescent device comprising: (A) an anode layer A; (B) a light-emitting layer B comprising at least one host material H B and at least one thermally activated delayed fluorescence (TADF) emitter compound E B , wherein the light-emitting layer B does not comprise more than 20 % by weight of an electron transport material ETM D ; (C) an exciton quenching layer C comprising at least one emitter compound E C and at least 80 % by weight of at least one electron transport material ETM D ; (D) an electron-transport layer D comprising at least one electron transport material ETM D ; and (E) a cathode layer K, wherein the layers are arranged in the sequential order in the following order (A) - (B) - (C) - (D) - (E), wherein optionally one or more additional layers may be present between the anode layer A and the light-emitting layer B, between electron-transport layer D and the cathode layer K, or each between the anode layer A and the light-emitting layer B and between electron-transport layer D and the cathode layer K, wherein the exciton quenching layer C is adjacent to both the light-emitting layer B and the electron-transport layer D, and characterized in that the at least one emitter compound E C has a lowest excited singlet state energy level S1(E C ) and the at least one electron transport material ETM D has a lowest excited singlet state energy level S1(ETM D ), wherein S 1 ETM D > S 1 E C , wherein the at least one emitter compound E B exhibits an emission with an emission maximum λ max (E B ) and a full width at half maximum FWHM(E B ) and the at least one emitter compound E C exhibits an emission with an emission maximum λ max (E C ) and a full width at half maximum FWHM(E C ), wherein λ max E B ≥ λ max E C . (A) an anode layer A; (B) a light-emitting layer B comprising at least one host material H B and at least one thermally activated delayed fluorescence (TADF) emitter compound E B , wherein the light-emitting layer B does not comprise more than 20 % by weight of an electron transport material ETM D ; (C) an exciton quenching layer C comprising at least one emitter compound E C and at least 80 % by weight of at least one electron transport material ETM D ; (D) an electron-transport layer D comprising at least one electron transport material ETM D ; and (E) a cathode layer K, wherein the layers are arranged in the sequential order in the following order (A) - (B) - (C) - (D) - (E), wherein optionally one or more additional layers may be present between the anode layer A and the light-emitting layer B, between electron-transport layer D and the cathode layer K, or each between the anode layer A and the light-emitting layer B and between electron-transport layer D and the cathode layer K, wherein the exciton quenching layer C is adjacent to both the light-emitting layer B and the electron-transport layer D, and characterized in that the at least one emitter compound E C has a lowest excited singlet state energy level S1(E C ) and the at least one electron transport material ETM D has a lowest excited singlet state energy level S1(ETM D ), wherein S 1 ETM D > S 1 E C , wherein the at least one emitter compound E B exhibits an emission with an emission maximum λ max (E B ) and a full width at half maximum FWHM(E B ) and the at least one emitter compound E C exhibits an emission with an emission maximum λ max (E C ) and a full width at half maximum FWHM(E C ), wherein λ max E B ≥ λ max E C . <EOS>