Testing trap states in polymer solar cells
Zesheng Liu, Yuze Lin
Abstract
Polymer/organic solar cells (PSCs) are one promising candidate for sustainable technologies of converting solar energy to electricity, making impressive progress with the power conversion efficiencies of single-junction devices exceeding 18–19%. The trap density of states (tDOS) of polymer/organic semiconductors ranging from 1016∼1018 cm−3 are much higher than those traditional inorganic/hybrid semiconductors, thus PSCs continue to face a remaining challenge to achieve close efficiency levels as approaching Shockley-Queisser limit or their inorganic counterparts, such as single-crystal silicon solar cells. Hence, comprehending the sources and distributions of tDOS in PSCs is of utmost importance to implement appropriate approaches to mitigate the defects in devices. Here we summary the understanding of defect origin in PSCs and elucidate the techniques employed for evaluating the spatial and energetic distribution of tDOS and offer a perspective and outlook in the field of PSCs from the view of trap suppression.