Status and prospects of ternary all-polymer organic solar cells

Abstract

All-polymer solar cells (all-PSCs) exhibit tremendous potential in fields such as smart and wearable electronic devices due to the benefits of low-cost, flexibility and large-area processability. Researches related to all-PSCs is mushrooming with the development of new polymeric donor and acceptor materials and the continuous optimization of active layer morphology and device performance. It is imperative to further boost the performance of all-PSCs with more productive methods. Ternary blend strategy is widely considered as a straightforward and effective method to optimize the morphology, photovoltaic efficiency and stability. In this review, we present the recent progress in three kinds of ternary blend based all-PSCs, namely, dual-donor and dual-acceptor ternary all-PSCs and the introduction of small-molecules in binary all-PSCs, and discuss in depth how the ternary strategy in all-PSCs can improve cell performance by optimizing film morphology and charge carrier transport properties, helping readers to better understand the morphology-efficiency/stability relationship. Simultaneously, we provide a concise discussion on the challenges and opportunities for the future development of ternary all-PSCs targeting 20% efficiency.