The article discusses the development of lead-free organic-inorganic tin halide perovskite solar cells, which are a promising alternative to lead-based perovskites. Lead, a key component in traditional perovskites, poses potential toxicity issues, leading researchers to explore tin as a substitute. However, tin's instability in its 2+ oxidation state has been a significant challenge. The authors report the first completely lead-free, CH3NH3SnI3 perovskite solar cell processed on a mesoporous TiO2 scaffold, achieving efficiencies of over 6% under 1 sun illumination and open-circuit voltages exceeding 0.88 V. The material's bandgap is estimated to be 1.23 eV. Despite the short electron lifetime and low diffusion length, the solar cells show unexpectedly high open-circuit voltages, suggesting that further optimization could lead to even higher efficiencies. The study highlights the potential of tin-based perovskites as a non-toxic, abundant, and low-cost alternative to lead-based perovskites, with the possibility of surpassing the performance of state-of-the-art lead-based perovskites in the near future.The article discusses the development of lead-free organic-inorganic tin halide perovskite solar cells, which are a promising alternative to lead-based perovskites. Lead, a key component in traditional perovskites, poses potential toxicity issues, leading researchers to explore tin as a substitute. However, tin's instability in its 2+ oxidation state has been a significant challenge. The authors report the first completely lead-free, CH3NH3SnI3 perovskite solar cell processed on a mesoporous TiO2 scaffold, achieving efficiencies of over 6% under 1 sun illumination and open-circuit voltages exceeding 0.88 V. The material's bandgap is estimated to be 1.23 eV. Despite the short electron lifetime and low diffusion length, the solar cells show unexpectedly high open-circuit voltages, suggesting that further optimization could lead to even higher efficiencies. The study highlights the potential of tin-based perovskites as a non-toxic, abundant, and low-cost alternative to lead-based perovskites, with the possibility of surpassing the performance of state-of-the-art lead-based perovskites in the near future.