Electronic Properties and Photovoltaic Functionality of Zn-Doped Orthorhombic CH₃NH₃PbI₃: A GGA+vdW Study

Attempts have been made to explore the electronic properties and photovoltaic functionality of Zn-doped orthorhombic CH₃NH₃PbI₃ using the generalized gradient approximation method with van der Waals correction (GGA+vdW). Results show that Zn doping effectively decreases the band gap of orthorhombic CH₃NH₃PbI₃, extending the optical absorption into the near-infrared region of solar irradiance. Simultaneously, the incorporation of Zn substantially increases the electron mobility of CH₃NH₃PbI₃, which is expected to assist the dissociation of electron–hole pairs to effectively reduce the probability for their recombination, leading to improved optical absorption. The combined effects of Zn doping on band gap and carrier mobility significantly enhance the photovoltaic functionality of orthorhombic CH₃NH₃PbI₃. The detailed calculation of formation energy for Zn substitution reveals a high favourability to form such doping in orthorhombic CH₃NH₃PbI₃. The outcome of this work offers great promise for widening practical applications of CH₃NH₃PbI₃ for photovoltaic materials or devices.