Organic Solvent Dispersible MXene for Band Alignment and Interface Engineering of Colloidal Quantum Dot Photovoltaics

Abstract

Despite the recent developments in colloidal quantum dot (CQD) photovoltaics the unfavorable energy band for hole collection and the surface cracks lowers the device performance. To address these issues, we developed polycatechol functionalized MXene (PCA-MXene), which act as an interlayer and a dopant and an interlayer in CQD photovoltaics. PCA-MXene achieves a consistently dispersed mixture in a butylamine solvent, which makes MXene and CQDs work together effectively. As a result, the energy band alignment is modulated and the work function of CQDs is altered, which eventually leads to improved hole extraction. Furthermore, the surface cracks in the thiol-treated CQD layer eliminated by the PCA-MXene interlayer. Owing to these benefits, the PCA-MXene-integrated CQD device shows a 13.6% power conversion efficiency (PCE) compared to the reference device, which has a PCE of 12.8%.