A fluorene-based photoinitiator, wherein said fluorene-based photoinitiator has a structure represented by Formula I:
- or said fluorene-based photoinitiator comprises a structure represented by Formula V:
- wherein in said Formula I,
- the R1 and the R1′ are each independently selected from hydrogen, a halogen, a C1-C20 linear alkyl group, a C1-C20 branched alkyl group, a C3-C8 cycloalkyl group, a C2-C20 alkenyl group, or a C1-C10 alkyl group substituted with a C3-C8 cycloalkyl group;
- the R2 and the R3 are each independently selected from a C1-C20 linear alkyl group, a C1-C20 branched alkyl group, a C3-C8 cycloalkyl group, a C1-C10 alkyl group substituted with a C3-C8 cycloalkyl group, or a C6-C20 aryl group;
- or the R2 and the R3 are connected to form a C3-C8 cycloalkyl group;
- the X is -A-(X′)n, wherein A is selected from a heteroatom which is selected from O, N, or S, X′ is selected from a C1-C20 linear alkyl group, a C1-C20 branched alkyl group, a C3-C8 cycloalkyl group, a C1-C10 alkyl group substituted with a C3-C8 cycloalkyl group, or one or more of carbon atoms in the X′ are substituted with the heteroatom, and n is 1 or 2;
- and
- the R4 is a hydroxy group or a N-morpholinyl group;
- or
- in Formula V,
- the R5 and the R6 are each independently selected from one of a hydrogen atom, a halogen, or a chain group, wherein the chain group is a C1-C20 linear alkyl group, a C1-C20 branched alkyl group, a C1-C20 cycloalkyl group, a C4-C20 cycloalkylalkyl group, a C4-C20 alkylcycloalkyl group, or a C2-C20 alkenyl group, or the R5 and R6 form a ring by using one or two of the chain groups, and —CH2— in the one or two chain groups can be substituted with —O—, —C(═O)O—, a halogen, or a phenyl group;
- Ar is a substituent containing an aromatic ring or a heteroaromatic ring;
- the R8 has n external linkages and is a C1-C60 linear alkyl group, a C1-C60 branched alkyl group, or the C1-C60 linear or branched alkyl group having any carbon or hydrogen in the C1-C60 linear or branched alkyl group substituted with oxygen, sulfur, or a phenyl grow;
- the A represents a repeating unit having a structure of -(Q-CHR9)m—, wherein the R9 is hydrogen, a methyl group, or an ethyl group, the Q represents O or a hyphen wherein the hyphen means that —(CHR9)m is directly connected to O, and m is an integer of 1 to 6;
- and
- the n represents an integer of 1 to 20.