Single-step, conformal, and efficient assembly of ligand-exchanged quantum dots for optoelectronic devices via an electric field

Journal Article · 16 January 2025 · Nanoscale

DOI: https://doi.org/10.1039/d4nr04620j · OSTI ID:2507260

Xu, Xiaojie  ^[1]; Nakotte, Tom  ^[1]; Flanders, Bret N. ^[2]; Zhou, Jenny ^[1]; Orme, Christine A.  ^[1]

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1. Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
2. Kansas State University, Manhattan, KS (United States)

Quantum dots (QDs) are promising materials for optoelectronic applications, but their widespread adoption requires controllable, selective, and scalable deposition methods. While traditional methods like spin coating and drop casting are suitable for small-scale deposition onto flat substrates, and ink-jet printing offers precision for small areas, these methods struggle with conformal deposition onto non-planar, large area substrates or selective deposition onto large area chips. Electrophoretic deposition (EPD) is an efficient and versatile technique capable of achieving conformal and selective area deposition over large areas, but its application to QD films has been limited. Previous EPD studies on QD films used QDs with native ligands, which hinder charge transport in optoelectronic devices. Here, we combined in-solution ligand exchange with EPD to deposit dense PbSe QD films. Through solvent engineering, we controlled the growth rate of PbSe QD films and used an in situ quartz crystal microbalance to measure the growth rate as a function of applied potential. We demonstrated the efficacy of this methodology by conformally depositing PbSe QD films onto textured silicon substrates via EPD and fabricating infrared photodetectors. The responsivity of the as-fabricated IR PDs at 1200 nm was ~0.01 A W^-1 and response times were 4.6 ms (on) and 4.7 ms (off).

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
• Sponsoring Organization: USDOE; USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC02-05CH11231; AC52-07NA27344
• OSTI ID: 2507260
• Report Number(s): LLNL--JRNL-2004179
• Journal Information: Nanoscale, Journal Name: Nanoscale Journal Issue: 14 Vol. 17; ISSN 2040-3364
• Publisher: Royal Society of ChemistryCopyright Statement
• Country of Publication: United States
• Language: English