Challenges to the Stability of Active Layer Materials in Organic Solar Cells

Abstract

In the past 20 years, organic solar cells (OSCs) have made great progress in pursuing high power‐conversion efficiencies, reaching the application threshold. Instead, device stability is becoming particularly important toward commercialization. There are many factors influencing the stability of OSCs, such as light, heat, humidity, oxygen, as well as device structure. Active layer materials, as the most critical functional layer in the devices, are greatly affected by these factors in terms of both efficiency and stability. Herein, it is desirable and urgent to summarize methods for obtaining active layer materials with long‐term stability, mainly focusing on the chemical structure and blending morphology. Meanwhile, the corresponding degraded mechanism of OSCs is concluded and analyzed. In this outlook, challenges for developing high‐performance and stable OSCs are discussed.

Optimized Stoichiometry for CuCrO2 Thin Films as Hole Transparent Layer in PBDD4T-2F:PC70BM Organic Solar Cells

“…The decrease in current density is more severe in the case of PEDOT: PSS-based devices with a final value around 30% of the original one ( Figure S6b in Supplementary Materials ). On the other hand, the use of CuCrO 2 as HTL leads to the conservation of a J sc around 60% of the initial value after 2 h. The loss in short circuit current found for both the devices is attributed to the chemical degradation or morphological evolution of the AL, with many factors contributing to the deterioration of this material [ 64 , 65 ]. These photoactive polymers undergo a phase separation phenomena, leading to a vertical gradient of the acceptor and donor material, significantly impacting the photogeneration process, charge transport, and carrier recombination [ 66 ], thus, jeopardizing the short-circuit current.…”

Printable and Large‐Area Organic Solar Cells Enabled by a Ternary Pseudo‐Planar Heterojunction Strategy

“…Furthermore, the thermal stability of OSCs is important due to the microstructure of active layer concerned with performance is very sensitive to temperature. [45] The thermal stability curves of BHJ and PPHJ structure ternary films measured at 150 °C are shown in Figure 3d, and relevant parameters are listed in Tables S2 and S3, Supporting Information. It can be observed that the PM6/10%ICBA:IT-4F system with PPHJ structure exhibits better thermal stability as compared with the traditional BHJ structure.…”

Wide bandgap polymer donors for high efficiency non-fullerene acceptor based organic solar cells

“…Solar cells work under various operational stresses such as solar illumination, increased temperature, and exposure to air. 102,[257][258][259][260][261][262] Intrinsic degradation mechanisms of the active layer in OSCs include degradation in dark caused by the morphological changes (rearrangement of donor and acceptor domains) that occur over time and photo-chemical reactions of the organic semiconductor materials in the presence of illumination. [263][264][265][266][267] In terms of morphological stability, all-polymer solar cells have attracted much attention since a polymer donor and a polymer acceptor can be entangled to form a much more metastable blend, leading to superior thermal and mechanical stabilities compared to small moleculebased OSCs.…”