Self‐Assembled Quasi‐3D Nanocomposite: A Novel p‐Type Hole Transport Layer for High Performance Inverted Organic Solar Cells

Abstract

Hole transport layer (HTL) plays a critical role for achieving high performance solution-processed optoelectronics including organic electronics. For organic solar cells (OSCs), the inverted structure has been widely adopted to achieve prolonged stability. However, there are limited studies of p-type effective HTL on top of the organic active layer (hereafter named as top HTL) for inverted OSCs. Currently, p-type top HTLs are mainly 2D materials, which have an intrinsic vertical conduction limitation and are too thin to function as practical HTL for large area optoelectronic applications. In the present study, a novel self-assembled quasi-3D nanocomposite is demonstrated as a p-type top HTL. Remarkably, the novel HTL achieves ≈15 times enhanced conductivity and ≈16 times extended thickness compared to the 2D counterpart. By applying this novel HTL in inverted OSCs covering fullerene and non-fullerene systems, device performance is significantly improved. The champion power conversion efficiency reaches 12.13%, which is the highest reported performance of solution processed HTL based inverted OSCs. Furthermore, the stability of OSCs is dramatically enhanced compared with conventional devices. The work contributes to not only evolving the highly stable and large scale OSCs for practical applications but also diversifying the strategies to improve device performance.

Beyond Metal Oxides: Introducing Low‐Temperature Solution‐Processed Ultrathin Layered Double Hydroxide Nanosheets into Polymer Solar Cells Toward Improved Electron Transport

“…This is because of the similar thicknesses (≈100 nm) of the active layer films atop different CILs. Since optical absorption directly determines the efficiency of exciton generation within the active layer, the comparable optical absorptions of the active layer films atop different CILs is consistent with the slight change of the J sc value obtained for their corresponding devices, as confirmed further by the slight fluctuations of their external quantum efficiency (EQE) responses as well as the integrated J sc values (Figure b, see also Table S4, Supporting Information).…”

“…Polymer solar cells (PSCs) have been attracting considerable attention as a promising renewable energy owing to their advantages of solution‐processability, high‐flexibility, light‐weight, and low‐cost . The state‐of‐the‐art PSC devices are typically constructed by the bulk heterojunction (BHJ) structure with the active layer comprised of low‐bandgap conjugated polymer donors and fullerene/non‐fullerene acceptors, and ever‐growing power conversion efficiency (PCE) exceeding 14% has now been achieved on the basis of not only developing novel active materials but also interface engineering strategy .…”

Robust Inorganic Hole Transport Materials for Organic and Perovskite Solar Cells: Insights into Materials Electronic Properties and Device Performance

“…They showed this improvement due to a higher conductivity and W F of F‐rGO HTL. Similarly, Cheng et al [ 296 ] demonstrated the self‐assembled quasi‐3D GO:NiO x composite as a HTL in an inverted OSC. The remarkable improvement in conductivity led to a high PCE of 12.13% (average PCE was 11.45%), which was at that time the highest reported value for inverted OSCs.…”

Evaporation‐Free Nonfullerene Flexible Organic Solar Cell Modules Manufactured by An All‐Solution Process

“…[3,4,29,49] The donors with deep highest occupied molecular orbital (HOMO) levels, in particular, are incorporated to achieve a high open circuit voltage (V OC ) in NFAs-based inverted structure OSCs. [54][55][56] Furthermore, because a vacuum process is required for efficient modulation of OSCs, productivity decreases. [50][51][52][53] When the BHJ layer is incorporated into an inverted structure OSCs through a solution process, the introduction of an appropriate buffer layer between the BHJ layer and the electrode is necessary to improve the interfacial electronic properties.…”