An A-site mixed-ammonium solid solution perovskite series of [(NH2 NH3 )x (CH3 NH3 )1-x ][Mn(HCOO)3 ] (x=1.00-0.67).

An A-site mixed-ammonium solid solution perovskite series of [(NH2 NH3 )x (CH3 NH3 )1-x ][Mn(HCOO)3 ] (x=1.00-0.67).