Polymers, formulations, organic optoelectronic devices, and applications thereof

A polymer, comprising a repeating unit of formula I:

• wherein n is an integer greater than or equal to 1, X is selected from O, S, CR1R2, SiR1R2, or NR3, and a repeating structural unit E is selected from a structural unit of formula (1) or (2):
• wherein:
• each of Ar1, Ar2, and Ar3 is independently an aromatic group containing 5 to 24 ring atoms, or a heteroaromatic group containing 5 to 24 ring atoms;
• each of Ar4 and Ar5 is independently null, an aromatic group containing 5 to 24 ring atoms, or a heteroaromatic group containing 5 to 24 ring atoms;
• each of Ya and Yb is independently B, P═O, C(R9), or Si(R9);
• when neither Ar4 nor Ar5 is null, each of Xa and Xb is independently selected from the group consisting of N, C(R9), and Si(R9);
• when Ar4 and/ or Ar5 is null, each of the corresponding Xa and Yb is independently selected from the group consisting of N(R9), C(R9R10), Si(R9R10), C═O, O, C═N(R9), C═C(R9R10), P(R9), P(═O)R9, S, S═O, and SO2;
• each of X1 and X2 is independently null or a bridging group;
• R1 to R10 are independently selected from the group consisting of -H, -D, -F, -Cl, -Br, -I, —CN, —NO2, —CF3, a C1-C20 linear alkyl group, a C1-C20 linear haloalkyl group, a C1-C20 linear alkoxy group, a C1-C20 linear thioalkoxy group, a C3-C20 branched/ cyclic alkyl group, a C3-C20 branched/ cyclic haloalkyl group, a C3-C20 branched/ cyclic alkoxy group, a C3-C20 branched/cyclic thioalkoxy group, a C3-C20 branched/ cyclic silyl group, a C1-C20 ketone group, a C2-C20 alkoxycarbonyl group, a C7-C20 aryloxycarbonyl group, a cyano group, a carbamoyl group, a haloformyl group, a formyl group, an isocyano group, an isocyanate group, a thiocyanate group, an isothiocyanate group, a hydroxyl group, a nitro group, a CF3 group, Cl, Br, F, a crosslinkable group, a substituted/ unsubstituted aromatic/ heteroaromatic group containing 5 to 40 ring atoms, an aryloxy/ heteroaryloxy group containing 5 to 40 ring atoms, an arylamine/heteroarylamine group containing 5 to 40 ring atoms, and a disubstituted unit in any position of the above substituents or any combination thereof, wherein one or more of the substituent groups can form a monocyclic or polycyclic aliphatic or aromatic ring system with each other and/ or with the ring bonded to the groups.