Unravelling the crystal structure and optoelectronic properties of C3H3MI3 (M = Sn, Pb) for solar cell applications

Abstract

Solar cells made up of hybrid halide perovskites possess excellent power conversion efficiency due to the presence of remarkable optoelectronic properties of their photoactive layer. Herein, for the first time, we predict the ground state crystal structures of cyclopropenium metal iodide (C3H3MI3, (M = Sn, Pb)) in this class and discern their optoelectronic properties through first-principles calculations. Also, it is found that van der Waals interactions included ab initio calculations are essential for the correct prediction of the ground state crystal structure and their properties. Furthermore, the calculated formation energy values confirm their phase stability. Also, from COHP analyses we have characterized the nature of the bonding and antibonding states present in these materials. Our electronic structural studies reveal their semiconducting behavior with a direct band gap of 0.452 eV and 1.733 eV, when M is Sn and Pb, respectively. The calculated carrier effective mass values imply that C3H3SnI3 has high carrier mobility than C3H3PbI3, and their absorption coefficient peak values are same, but is shifted to higher energy value for C3H3PbI3 than C3H3SnI3 due to the increase in its band gap value. However, the calculated power conversion efficiency show that C3H3PbI3 than C3H3SnI3 will be more promising material for solar cell applications.