Abstract: An organometallic compound represented by Formula 1: M1(L1)n1(L2)n2??Formula 1 wherein, M1 is a transition metal, L1 is a ligand represented by Formula 1A, L2 is a ligand represented by Formula 1B, and n1 and n2 are each independently 1 or 2, wherein X1 is C or N, and X2 is C or N, b1 is an integer from 1 to 6, b2 is an integer from 1 to 8, * and *? each indicate a binding site to M1 in Formula 1, and the remaining substituent groups are as described herein.

Abstract: An organometallic compound represented by Formula 1: wherein M1 is a transition metal, L1 is a ligand represented by Formula 1A, L2 is a ligand represented by Formula 1B, and n1 and n2 are each independently 1 or 2, wherein Formulae 1A and 1B are as described herein.

Abstract: An organometallic compound represented by Formula 1: wherein, Y1 to Y4 are each independently C or N, one of Y1 to Y4 is N bonded to Ir in Formula 1, and one of the remaining Y1 to Y4 is C bonded to ring CY2 in Formula 1, Y9 is O, S, N(R19), C(R19a)(R19b), or Si(R19a)(R19b), X2 is C, ring CY1 and ring CY2 are each independently a C5-C30 carbocyclic group or a C1-C30 heterocyclic group, Z1 is a group represented by —Si(Q3)(Q4)(Q5) or a group represented by —Ge(Q3)(Q4)(Q5), a1 is an integer from 0 to 2, a2 is an integer from 0 to 20, b1 and b2 are each independently an integer from 1 to 10, and R1, R19, R19a, R19b, R2, R30a, R30b, R37, and Z2 are as described herein.

Abstract: A photoresist underlayer composition comprising a first polymer comprising a first structural unit derived from an N-(alkoxymethyl) (meth)acrylic amide monomer; a second structural unit comprising an aromatic group, a heterocyclic group, an ester group, an amide group, or a combination thereof, wherein the second structural unit further comprises a crosslinkable group; wherein the first polymer comprises the second structural unit, the photoresist underlayer composition further comprises a second polymer comprising the second structural unit, or a combination thereof, a thermal acid generator; and a solvent.