Display and lighting devices comprising phosphorescent excimers with preferred molecular orientation as monochromatic emitters

An organic light emitting diode comprising:

• a substrate;
• a first electrode;
• a hole transporting layer proximate the first electrode;
• a second electrode;
• an electron transporting layer proximate the second electrode;
• and
• an emissive layer between the hole transporting layer and the electron transporting layer, wherein the emissive layer comprises a square planar tetradentate platinum complex represented by one of Formulas I-IX, and excimers formed by two or more of the complexes are aligned such that emitting dipoles of the excimers are substantially parallel to a surface of the substrate:
• wherein, in Formula I:
• M represents Pt(II);
• R1, R3, R4, and R5 each independently represents hydrogen, halogen, hydroxyl, nitro, cyanide, thiol, or optionally substituted C1-C4 alkyl, alkoxy, amino, or aryl;
• each n is independently an integer as limited by valency;
• Y1a, Y1b, Y1c, Y1d, Y1e, Y1f, Y2a, Y2b, Y2c, Y2d, Y2e, Y2f, Y4a, Y4b, Y4c, Y4d, Y4e, Y5a, Y5b, Y5c, Y5d, and Y5e each independently represents C, N, Si, O, S;
• X2 represents NR, PR, CRR′, SiRR′, CRR′, SiRR′, O, S, S═O, O═S═O, Se, Se═O, or O═Se═O, where R and R′ each independently represents halogen, hydroxyl, nitro, cyanide, thiol, or optionally substituted C1-C4 alkyl, alkoxy, amino, aryl, or heteroaryl;
• each of L1 and L3 is independently present or absent, and if present, represents a substituted or unsubstituted linking atom or group, where a substituted linking atom is bonded to an alkyl, alkoxy, alkenyl, alkynyl, hydroxy, amine, amide, thiol, aryl, heteroaryl, cycloalkyl, or heterocyclyl moiety;
• Ar3 and Ar4 each independently represents 6-membered aryl group;
• and
• Ar1 and Ar5 each independently represents a 5- to 10-membered aryl, heteroaryl, fused aryl, or fused heteroaryl;
• and
• wherein, in Formulas II-IX:
• M represents Pt(II);
• each R1, R2, R3, R4, R5, and R6 present independently represents hydrogen, halogen, hydroxyl, nitro, cyanide, thiol, or optionally substituted C1-C4 alkyl, alkoxy, amino, or aryl;
• each n is independently an integer, valency permitting;
• each Y1a, Y1b, Y1c, Y1d, Y2a, Y2b, Y2c, Y3a, Y3b, Y3c, Y4a, Y4b, Y4c, Y4d, Y5a, Y5b, Y5c, Y5d, Y6a, Y6b, Y6e, and Y6d present independently represents C, N, or Si;
• U1 and U2 each independently represents NR, O or S, wherein R represents hydrogen, halogen, hydroxyl, nitro, cyanide, thiol, or optionally substituted C1-C4 alkyl, alkoxy, amino, or aryl;
• U3 and U4 each independently represents N or P;
• and
• X represents O, S, NR, CRR′, SiRR′, PR, BR, S═O, O═S═O, Se, Se═O, or O═Se═O, where R and R′ each independently represents hydrogen, halogen, hydroxyl, nitro, cyanide, thiol, or optionally substituted C1-C4 alkyl, alkoxy, amino, aryl, or heteroaryl.