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 CsPb1-xZnxBr3. For the stable CsPb1-x-yMnxZnyBr3 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%, CsPb1-x-yMnxZnyBr3 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 CsPb1-x-yMnxZnyBr3 with negligibly deteriorated optoelectronic properties. This work provides an alternative approach to achieve a Pb-less perovskite with a high performance.