High T_g Polymer Insulator Yields Organic Photovoltaic Blends with Superior Thermal Stability at 150 ^oC

Abstract

Main observation and conclusion Record‐breaking organic solar cells (OSCs) based on blends of polymer donors and small molecule acceptors often show undesirable degradation, which severely precludes their practical use. Herein, we demonstrate a facile and cost‐effective approach to construct thermally stable OSCs at 150 oC by incorporating a small amount of a polymer insulator polyacenaphthylene (PAC) with high glass‐transition temperature over 230 oC into polymer:acceptor blends. The model PTB7‐Th:EH‐IDTBR blend with 10 wt% PAC maintained above 85% of its initial efficiency upon continuous heating at 150 oC for over 800 h, while the efficiency of the blend without PAC sharply dropped by 70% after ~300 h. Owing to high miscibility with acceptors, PAC confines the motion of the acceptor molecules and suppresses the acceptor crystallization at elevated temperatures, leading to significantly improved stability. Importantly, the effectiveness of this blending approach was also validated in many other OSC systems, showing great potential for achieving high‐performance thermally stable electronics.

Thermally stable poly(3‐hexylthiophene): Nonfullerene solar cells with efficiency breaking 10%

“…[15,16] Particularly, thermal degradation is inevitable throughout the operation of OSCs since the prolonged exposure to light results in high working temperatures (50 • C-80 • C, even reaching 100 • C) during outdoor applications. [17,18] Many highly efficient OSCs are extremely sensitive to thermal stress, [19,20] for instance, the PM6:BTP-C3-4F binary cell can maintain 80% of the initial PCE after the storage of 600 h at room temperature, while the PCE dramatically degrades to 66% of the initial value with the continuous aging at 80 • C. [21] Evidently, thermal stability is one of the important hindrances for the practical applications of OSCs, which has drawn abundant attention. [17,19,21] Thermal stress during outdoor operation generally has a great impact on morphological stability, which usually does not involve chemical reactions such as decomposition and photooxidation.…”

“…Many highly efficient OSCs are extremely sensitive to thermal stress, [ 19,20 ] for instance, the PM6:BTP‐C3‐4F binary cell can maintain 80% of the initial PCE after the storage of 600 h at room temperature, while the PCE dramatically degrades to 66% of the initial value with the continuous aging at 80°C. [ 21 ] Evidently, thermal stability is one of the important hindrances for the practical applications of OSCs, which has drawn abundant attention.…”

Efficient and Ultraviolet‐Durable Nonfullerene Organic Solar Cells: From Interfacial Passivation and Microstructural Modification Perspectives

“…[ 3–5 ] The stability of the NFA‐OSCs is closely associated with the intrinsic material properties, thermodynamic factors, stratification of donor and acceptor in the bulk heterojunction (BHJ), interfacial reaction, photo‐degradation in the functional layers, and the built‐in potential across the BHJ. [ 6–8 ] Ultraviolet (UV) light‐induced photo‐degradation is one of the main reasons responsible for the undesired degradation process in OSCs. [ 9 ] An obvious improvement in the operational stability of the OSCs has been observed when the UV portion of the incoming light is filtered out.…”

Recent advances in small molecular design for high performance non-fullerene organic solar cells

“…The best PCE of solar cells based on PTB7-Th/IDT-2BR/1% PDI-2DTT is 10.1%, which is one of the highest for single junction solar cells with small energy loss (<0.6 eV) and high V OC (>1.0 V). Ye et al 113 provided a facile and cost-effective method to construct thermally stable organic solar cells. They added 10 wt% polyacenaphthylene (PAC, Fig.…”