This paper presents the first lead-free perovskite solar cell based on methylammonium tin triiodide (CH₃NH₃SnI₃), achieving power conversion efficiencies of over 6% under 1 sun illumination. The material is processed on a mesoporous TiO₂ scaffold and exhibits an open circuit voltage of over 0.88 V, with a band gap of 1.23 eV. The study addresses the concern of lead toxicity in perovskite solar cells by demonstrating that tin-based perovskites can be viable alternatives. However, the instability of tin in its 2+ oxidation state remains a challenge. The material shows good semiconducting behavior but requires careful handling to prevent degradation in ambient conditions. The research highlights that while lead-based perovskites have high efficiency, tin-based materials can also achieve high performance with appropriate optimization. The study also investigates the optical and electrical properties of the material, including its THz mobility and charge-carrier lifetime, which suggest that with further optimization, tin-based perovskites could become a viable, non-toxic alternative to lead-based solar cells. The results indicate that the efficiency of tin-based perovskite solar cells could potentially match or exceed that of lead-based ones, with the added benefit of reduced toxicity. The study also discusses the challenges of stabilizing the material and the potential for future improvements in performance through better control of doping and processing techniques.This paper presents the first lead-free perovskite solar cell based on methylammonium tin triiodide (CH₃NH₃SnI₃), achieving power conversion efficiencies of over 6% under 1 sun illumination. The material is processed on a mesoporous TiO₂ scaffold and exhibits an open circuit voltage of over 0.88 V, with a band gap of 1.23 eV. The study addresses the concern of lead toxicity in perovskite solar cells by demonstrating that tin-based perovskites can be viable alternatives. However, the instability of tin in its 2+ oxidation state remains a challenge. The material shows good semiconducting behavior but requires careful handling to prevent degradation in ambient conditions. The research highlights that while lead-based perovskites have high efficiency, tin-based materials can also achieve high performance with appropriate optimization. The study also investigates the optical and electrical properties of the material, including its THz mobility and charge-carrier lifetime, which suggest that with further optimization, tin-based perovskites could become a viable, non-toxic alternative to lead-based solar cells. The results indicate that the efficiency of tin-based perovskite solar cells could potentially match or exceed that of lead-based ones, with the added benefit of reduced toxicity. The study also discusses the challenges of stabilizing the material and the potential for future improvements in performance through better control of doping and processing techniques.