2D MXene-Based Electron Transport Layers for Nonhalogenated Solvent-Processed Stable Organic Solar Cells

Abstract

Implementation of 2D materials is one of the promising routes for improving the efficiency and stability of organic solar cells (OSCs). Due to their tunable optical and electronic properties, MXenes, a family of 2D transition metal carbides and nitrides, have attracted considerable attention and demonstrated their potential for next-generation solar cells. In this work, Ti3C2T x MXene was added into ZnO precursors and applied as a modified composite electron transport layer (ETL) in PM6:N3-based inverted OSCs. The nonhalogenated solvent o-xylene was employed as the active layer solvent for the development of stable, efficient, and eco-friendly OSCs. By optimizing the concentration of Ti3C2T x in the ZnO ETL, the solar cells exhibited power conversion efficiencies (PCEs) of 14.1 and 13.7% for 0.5 and 2 wt % MXene, respectively, as compared to neat ZnO layer devices with a PCE of 14.9%. Interestingly, the MXene-based PM6:N3 OSC devices showed superior device stability compared to the reference cells. It is demonstrated that the MXene introduced in the composite ZnO-based ETL mitigates the photocatalytic decomposition of the organic active layer on the ZnO surface, as analyzed via optical spectroscopy and hard X-ray photoelectron spectroscopy, which appears as a main reason for improved device stability. We thus report on the usage of MXene in green solvent-processed OSCs to enhance the lifetime of solar cells and thus address an important bottleneck in high-performance nonfullerene acceptor solar cells.

2D MXene interface engineering for organic solar cells

“…MXenes have shown potential for use in next-generation solar cells due to their tunability of optical and electrical characteristics. Aryal, Um Kanta, et al 31 created inverted OSCs using the PM6:N3 technology, where the Ti 3 C 2 T x MXene was combined with ZnO precursors and used as a modified composite material for the ETL. Fig.…”

“…It has been proven that solar cells made from the pristine ZnO ETL and PM6:N3 o-xylene can achieve PCE levels of 14.9%. 31 MXene is added to the ZnO ETL (14.1% and 13.7% for addition amounts of 0.5 and 2%, respectively). In the review paper, MXene's function as an ETL and HTL is highlighted.…”

Ti3C2Tx MXene: A New Promising 2D Material for Optoelectronics

“…Ti 3 C 2 T x MXene is explored as an active layer, electron/hole transport layer (ETL/HTL), and electrodes in perovskite solar cells, − silicon solar cells, , organic/polymer solar cells, , and QD sensitized solar cells (QDSSC) . Recently, Zhang et al fabricated the MXene/GaAs Schottky heterojunction solar cell with an efficiency of 9.6% and excellent stability using a one-step drop casting of MXene dispersion for the first time, as illustrated in Figure b.…”

Vitamin C for Photo-Stable Non-fullerene-acceptor-Based Organic Solar Cells

“…39 Recently, Aryal et al demonstrated that 2D Mxene could be embedded with ZnO to reduce this photocatalytic decomposition on ZnO surface. 40 In this work, we investigate the stabilization effect using a naturally occurring antioxidant interlayer between ZnO and active layer.…”

“…This, subsequently, leads to charge accumulation and recombination at the ZnO interface, which both strongly reduce the device stability. ,, Various approaches have been explored to control such interfacial degradation: Su and co-workers utilized nitrogen and sulfur-doped graphene oxide nanosheets (NS-GNSs) as a modifier layer for ZnO; Hu et al used aqueous polyethylenimine as a modifier layer; Liu et al developed modified ZnO layers, Me–ZnO, DMSO-ZnO, and sol–gel-ZnO; and Xu et al used C60 self-assembled monolayer (SAM) as a protective buffer layer . Recently, Aryal et al demonstrated that 2D Mxene could be embedded with ZnO to reduce this photocatalytic decomposition on ZnO surface . In this work, we investigate the stabilization effect using a naturally occurring antioxidant interlayer between ZnO and active layer.…”