Polymer, and solar cell manufactured using same

A polymer according to an embodiment has a repeating unit containing a bivalent group represented by formula (1). In formula (1), R1 represents a hydrogen atom or a monovalent group selected from a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkanoyl group, a substituted or unsubstituted aryl group and a substituted or unsubstituted heteroaryl group; X represents an atom selected from an oxygen atom, a sulfur atom and a selenium atom; and Y and Z independently represent a bivalent group selected from a carbonyl group, a sulfinyl group and a sulfonyl group, wherein a case in which each of Y and Z represents a carbonyl group is excluded.