Reduced hysteresis in perovskite solar cells using metal oxide/organic hybrid hole transport layer with generated interfacial dipoles

Fan Wu, Rajesh Pathak, Chong Chen, Yanhua Tong, Haibin Xu, Tiansheng Zhang, Ronghua Jian, Xiaoyi Li, Qiquan Qiao

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Herein, we report a facile method to reduce the J–V hysteresis using nickel oxide(NiOx)/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS) double hole transport layer (DHTL) fabricated p-i-n perovskite solar cells. The device using the NiOx/PEDOT:PSS DHTL shows a reduced hysteresis with an average hysteresis index of 0.020. This is smaller than a single NiOx device (0.142) or single PEDOT:PSS (0.093). First-principles calculations reveal that O and S in PEDOT:PSS couple with the Ni in NiOx, and PSS forms hydrogen bonds with O on NiOx. This coupling generates an interfacial dipole moment directed toward the PEDOT: PSS layer, evidenced by dark current-voltage plots. Electrochemical impedance spectroscopy (EIS) indicates that these dipoles lead to kinetically-favorable charge extraction and contribute to the suppressed hysteresis. Kelvin probe force microscopy indicates that the generated dipoles dispel the accumulated iodine ion vacancies at the hole transport layers side that enhanced charge collection and thereby decreased the hysteresis. Intensity modulated photocurrent spectroscopy demonstrates that the device with the NiOx/PEDOT:PSS DHTL shows faster charge transport rate ktrans than that of device with single PEDOT:PSS or NiOx, and further demonstrates that a more efficient outward charge flow in PSCs with the NiOx/PEDOT:PSS DHTL reduces hysteresis.

Original languageEnglish (US)
Article number136660
JournalElectrochimica Acta
Volume354
DOIs
StatePublished - Sep 10 2020
Externally publishedYes

Keywords

  • Charge transport
  • Hysteresis
  • Interfacial dipoles
  • Perovskite solar cells

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Electrochemistry

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