Ray Tracing of Perovskite Thin Films for Solar Windows

In this work, OPAL 2 is used to perform ray tracing simulation on perovskite thin films based on methylammonium lead triiodide (CH3NH3PbI3) and methylammonium lead tribromide (CH3NH3PbBr3) for solar windows. The thicknesses of both perovskite materials are varied between 100 nm and 500 nm. The ray tracing is carried out within 300-1000 nm wavelength region with AM1.5G solar spectrum as the illumination source. Perovskite solar cells based on CH3NH3PbI3 demonstrate absorption edge up to wavelength of 800 nm. The short-circuit current density (Jsc) improves from 11.71 mA/cm2 to 21.07 mA/cm2 due to the increased perovskite thickness from 100 nm to 500 nm. On the contrary, the average visible transmission (AVT) drops from 45% to 13%. For perovskite solar cells based on CH3NH3PbBr3, the absorption edge is shifted to wavelength of 550 nm due to the increased band gap. The Jsc increases from 3.49 mA/cm2 to 7.25 mA/cm2 when the thickness is increased from 100 nm to 500 nm. However, the AVT drops from 74% to 59%. The findings from this work show that a trade-off is required when maximizing the Jsc of the solar cells while maintaining reasonable transparencies through the solar windows.