Enhanced Open-Circuit Voltage in Colloidal Quantum Dot Photovoltaics via Reactivity-Controlled Solution-Phase Ligand Exchange

Jea Woong Jo, Younghoon Kim, Jongmin Choi, F. Pelayo García de Arquer, Grant Walters, Bin Sun, Olivier Ouellette, Junghwan Kim, Andrew H. Proppe, Rafael Quintero-Bermudez, James Fan, Jixian Xu, Chih Shan Tan, Oleksandr Voznyy*, Edward H. Sargent

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

The energy disorder that arises from colloidal quantum dot (CQD) polydispersity limits the open-circuit voltage (VOC) and efficiency of CQD photovoltaics. This energy broadening is significantly deteriorated today during CQD ligand exchange and film assembly. Here, a new solution-phase ligand exchange that, via judicious incorporation of reactivity-engineered additives, provides improved monodispersity in final CQD films is reported. It has been found that increasing the concentration of the less reactive species prevents CQD fusion and etching. As a result, CQD solar cells with a VOC of 0.7 V (vs 0.61 V for the control) for CQD films with exciton peak at 1.28 eV and a power conversion efficiency of 10.9% (vs 10.1% for the control) is achieved.

Original languageEnglish
Article number1703627
JournalAdvanced Materials
Volume29
Issue number43
DOIs
StatePublished - 20 Nov 2017

Keywords

  • colloidal quantum dots
  • open-circuit voltage
  • photovoltaics
  • polydispersity
  • solution-phase ligand exchange

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