Sensitized organic light emitting device

A consumer product comprising an OLED, comprising:

• an anode;
• a cathode;
• and
• an emissive region, disposed between the anode and the cathode;
• wherein the emissive region comprises a first compound (S1), a second compound (A1), and a host;
• wherein the first compound is capable of phosphorescent emission at room temperature, and has a peak emission wavelength in the range from 540 nm to 750 nm;
• wherein the second compound is capable of fluorescent or delayed fluorescent emission at room temperature, and has a peak emission wavelength in the range from 580 nm to 750 nm;
• wherein the host has a first triplet excited state energy T1 that is higher in energy than the first triplet excited state of the first compound;
• wherein the first compound has the formula M(LA)x(LB)y(LC)z;
• wherein the metal M is selected from the group consisting of Ir, Rh, Re, Ru, Os, Pt, Pd, Ag, Au, and Cu;
• wherein x is 1, 2, or 3;
• wherein y and z are each independently 0, 1, or 2;
• wherein x+y+z is equal to the oxidation state of M;
• wherein LA, LB, and LC are optionally joined to form a tridentate, tetradentate, pentadentate, or hexadentate ligand;
• wherein the first ligand LA comprises a structure of Formula I,
• wherein:
• each of moiety A and moiety B is independently a monocyclic ring or a polycyclic fused ring system, wherein the monocyclic ring or each ring of the polycyclic fused ring system is independently a 5-membered to 10-membered carbocyclic or heterocyclic ring;
• if M is Ir, then at least one of moiety A or moiety B is a polycyclic fused ring system comprising at least two fused rings;
• each of Z1, Z2, Z3, and Z4 is independently C or N;
• L is selected from the group consisting of a direct bond, BR, BRR′, NR, PR, P(O)R, O, S, Se, C═O, C═S, C═Se, C═NR′, C═CRR′, S═O, SO2, CR, CRR′, SiRR′, and GeRR′;
• K is selected from the group consisting of a direct bond, O, S, N(Rα), P(Rα), B(Rα), C(Rα)(Rβ), and Si(Rα)(Rβ);
• RA and RB each independently represent mono to the maximum allowable substitution, or no substitution;
• each R, R′, Rα, Rβ, RA and RB is independently hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, germyl, boryl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, selenyl, and combinations thereof;
• any two substituents can be joined or fused to form a ring;
• if M is Ir, then at least one of the following statements is true:
• (1) at least one RA or one RB substituent comprises deuterium, silyl, germyl, an electron-withdrawing group, an alkyl group comprising at least 5 carbon atoms, or a cycloalkyl group comprising at least 5 carbon atoms;
• (2) Z1 is N, L and K are both direct bonds, and moiety A comprises at least three fused rings;
• (3) L is not a direct bond;
• or
• (4) Z1 is N, Z4 is C, K is a direct bond, and moiety B comprises at least two fused rings, with the proviso that moiety B does not comprise or
• with the proviso that the first compound does not comprise: