The complex comprising one or more of the compound represented by general formula: RPbn1Xm1 (wherein R is a cation represented by R1NH3+ (wherein R1 represents a univalent substituted or unsubstituted hydrocarbon group), or the following formula: (wherein R2 represents a hydrogen atom, or a univalent substituted or unsubstituted hydrocarbon group); X is the same or different, and each represents a halogen atom; n1 is 0.8 to 1.2; and m1 is 2.8 to 3.2, or the compound represented by general formula: R2Pbn2Xm2 wherein R and X are as defined above; n2 is 2.8 to 3.2; and m2 is 7.7 to 8.3; and one or more dimethylformamide molecules is capable of decreasing the stirring time upon dissolution in an organic solvent such as DMSO, as well as decreasing the hysteresis and improving the solar cell characteristics (in particular, photoelectric conversion efficiency) when the complex is applied to a perovskite layer.