Cascade surface modification of colloidal quantum dot inks enables efficient bulk homojunction photovoltaics

Min Jae Choi, F. Pelayo García de Arquer, Andrew H. Proppe, Ali Seifitokaldani, Jongmin Choi, Junghwan Kim, Se Woong Baek, Mengxia Liu, Bin Sun, Margherita Biondi, Benjamin Scheffel, Grant Walters, Dae Hyun Nam, Jea Woong Jo, Olivier Ouellette, Oleksandr Voznyy, Sjoerd Hoogland, Shana O. Kelley, Yeon Sik Jung, Edward H. Sargent*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

191 Scopus citations


Control over carrier type and doping levels in semiconductor materials is key for optoelectronic applications. In colloidal quantum dots (CQDs), these properties can be tuned by surface chemistry modification, but this has so far been accomplished at the expense of reduced surface passivation and compromised colloidal solubility; this has precluded the realization of advanced architectures such as CQD bulk homojunction solids. Here we introduce a cascade surface modification scheme that overcomes these limitations. This strategy provides control over doping and solubility and enables n-type and p-type CQD inks that are fully miscible in the same solvent with complete surface passivation. This enables the realization of homogeneous CQD bulk homojunction films that exhibit a 1.5 times increase in carrier diffusion length compared with the previous best CQD films. As a result, we demonstrate the highest power conversion efficiency (13.3%) reported among CQD solar cells.

Original languageEnglish (US)
Article number103
JournalNature communications
Issue number1
StatePublished - Dec 1 2020

ASJC Scopus subject areas

  • General Chemistry
  • General Biochemistry, Genetics and Molecular Biology
  • General Physics and Astronomy


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