Improved Doping and Optoelectronic Properties of Zn-Doped Cspbbr₃ Perovskite through Mn Codoping Approach

Reducing the toxic Pb component in perovskites is an important step to realize environment-friendly perovskite optoelectronic devices. Herein, the structural, electronic, and optical properties of Zn and Mn codoped CsPbBr₃ have been investigated based on first-principle calculations and experimental verifications. Although the Zn dopant could reduce the optical band gap and exciton binding energy and enhance the optical absorption and defect tolerance for CsPbBr₃, the maximum reduction of the toxic Pb component was just about 12.5% in the experiment because the Zn dopant enlarges the formation energy of CsPb_1-ZnBr₃. For the stable CsPb_1-MnZnBr₃ perovskite, the largest y and corresponding (x + y) could reach up to 25% and 83% respectively, since the Mn dopant could reduce the structural disorder. Especially when (x + y) < 50%, CsPb_1-MnZnBr₃ exhibits a comparable carrier lifetime and exciton binding energy with a lower band gap to those of the CsPbBr₃, since the Zn dopant supplies a charge to CsPbBr₃ to counteract the variation of Pb-Br bonds induced by the Mn dopant. Meanwhile, the d orbitals of the dopant increase the optical absorption. These suggest that a 50% reduction of toxic Pb could be realized for stable CsPb_1-MnZnBr₃ with negligibly deteriorated optoelectronic properties. This work provides an alternative approach to achieve a Pb-less perovskite with a high performance.