Highly Photosensitive Colloidal Quantum Well Based Nanocrystal Skins Assisted by Orientation Control.

Isik, Furkan; Bozkaya, Taylan; Bozkaya, Iklim; Delikanli, Savas; Canimkurbey, Betul; Demir, Hilmi Volkan · Nano Lett · 2025

basic_science · Level V

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Abstract

Colloidal quantum wells (CQWs) exhibit superior optical characteristics, including giant oscillator strengths and high absorption cross sections, making them attractive for light-sensing applications. In this study, we fabricated light-sensitive nanocrystal skin (LS-NS) devices using a single-layer edge-up oriented CQW film as the active absorber and achieved a significant enhancement in the performance by leveraging the controlled orientation of the self-assembled CQWs. The LS-NS devices with edge-up oriented CQW film show eight times higher sensitivity and three times higher voltage build-up compared to LS-NS devices with spin-coated CQW films. Such enhancements are due to the trapping of the holes on the edges of the CQWs because of defect-ridden edges, which helps hopping of the holes localized within close proximity to the metal-CQW interface. The LS-NS device with edge-up CQW film exhibited a record-high photovoltage buildup of 600 mV, three times greater than the highest previously reported value for similar LS-NS architectures.