Methylammonium halide perovskite solar cells have received a tremendous amount of attention in recent years due to their skyrocketing efficiency improvement starting from 4% to 20% within six years. However, the employment of metal electrode, expensive hole-transporting materials (HTM), and particularly, environmentally hazardous material of lead presents a barrier to successful commercialization. In this study, we report on preparation and characterization of perovskite material with PbI₂ partially replaced by SnI₂ or SnCl₂. Moreover, the performances of mixed perovskite solar cells are based on a HTM-free carbon electrode configuration. Noticeably, the case of employing SnCl₂, CH₃NH₃Sn_yPb_(1−y)I_3-xCl_x, which shows completely different energy level trend to CH₃NH₃Sn_yPb_(1−y)I₃ and better photovoltaic performance when more SnCl₂ component in the devices and stability of devices are 70 times more than SnI₂ one. Moreover, the device has the highest powder conversion efficiency (PCE) of 2.15% (CH₃NH₃Sn_0.75Pb_0.25I_3-xCl_x), which shows broad light absorption region up to 1000 nm and highest current density of 15.66 mA cm^-2. In order to further improving device performance, a 20 mol% SnF₂ additive was introduced into CH₃NH₃Sn_0.75Pb_0.25I_3-xCl_x, after that current density can be improved to 23 mA cm^-2, V_OCis 0.35V, FF is 0.52 and PCE will beyond 4.0% with a small effect of hysteresis and excellent long-term stability over 1000 h (storing at glove box).