Dear Quantumwise staffs,

Recently I have read the paper *Efficient First-Principles Calculation of Phonon-Assisted Photocurrent in Large-Scale Solar-Cell Devices*

. It can be seen phonon plays an important role in calculating photocurrent for inderect energy gap materials. However, phonon calculation using DFT is pretty expensive and time-consuming. So I want to know if there is one material with small difference between direct gap and indirect gap (e.g. direct gap :0.42 eV, indirect gap: 0.38 eV), under low temperature condition (*i.e.* phonon effect is suppressed), is it reasonable to calculate photocurrent not considering EPC? Does the calculated photocurrent mainly come from transition of electrons through direct gap?

Best wishes