Numerical Simulations to Understand the Role of DIO Additive in PTB7:PC71BM Solar Cell

This paper presents a simulation analysis of bulk heterojunction (BHJ) photovoltaic (PV) cell containing the PTB7 (donor) and PC
₇₁
BM (acceptor) polymer with and without 1,8-diiodooctane (DIO) additive. Presence of DIO significantly increases the available photocurrent for the wavelength of approximately > 400 nm, which leads to large singlet exciton density inside the device. Recombination profile also shows a lower recombination rate inside the DIO additive device due to superior charge collection (due to high mobility) compared to without DIO based device. Superior photon absorption and lower recombination rates led to an improvement in overall power conversion efficiency (PCE) from 3.6% to 9.1%.