A Chemically Orthogonal Hole Transport Layer for Efficient Colloidal Quantum Dot Solar Cells

Margherita Biondi, Min Jae Choi, Olivier Ouellette, Se Woong Baek, Petar Todorović, Bin Sun, Seungjin Lee, Mingyang Wei, Peicheng Li, Ahmad R. Kirmani, Laxmi K. Sagar, Lee J. Richter, Sjoerd Hoogland, Zheng Hong Lu, F. Pelayo García de Arquer, Edward H. Sargent*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

51 Scopus citations


Colloidal quantum dots (CQDs) are of interest in light of their solution-processing and bandgap tuning. Advances in the performance of CQD optoelectronic devices require fine control over the properties of each layer in the device materials stack. This is particularly challenging in the present best CQD solar cells, since these employ a p-type hole-transport layer (HTL) implemented using 1,2-ethanedithiol (EDT) ligand exchange on top of the CQD active layer. It is established that the high reactivity of EDT causes a severe chemical modification to the active layer that deteriorates charge extraction. By combining elemental mapping with the spatial charge collection efficiency in CQD solar cells, the key materials interface dominating the subpar performance of prior CQD PV devices is demonstrated. This motivates to develop a chemically orthogonal HTL that consists of malonic-acid-crosslinked CQDs. The new crosslinking strategy preserves the surface chemistry of the active layer beneath, and at the same time provides the needed efficient charge extraction. The new HTL enables a 1.4× increase in charge carrier diffusion length in the active layer; and as a result leads to an improvement in power conversion efficiency to 13.0% compared to EDT standard cells (12.2%).

Original languageEnglish (US)
Article number1906199
JournalAdvanced Materials
Issue number17
StatePublished - Apr 1 2020


  • chemical orthogonality
  • colloidal quantum dots
  • hole transport layers
  • solar cells
  • surface ligands

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering


Dive into the research topics of 'A Chemically Orthogonal Hole Transport Layer for Efficient Colloidal Quantum Dot Solar Cells'. Together they form a unique fingerprint.

Cite this