Vacancy defect modulation in hot-casted NiOx film for efficient inverted planar perovskite solar cells

Aili WANG, Zhiyuan CAO, Jianwei WANG, Shurong WANG, Chengbo LI, Nuo LI, Lisha XIE, Yong XIANG, Tingshuai LI*, Xiaobin NIU, Liming DING, Feng HAO

*Corresponding author for this work

Research output: Journal PublicationsJournal Article (refereed)peer-review

45 Citations (Scopus)

Abstract

Nickel oxide (NiOx) has exhibited great potential as an inorganic hole transport layer (HTL) in perovskite solar cells (PSCs) due to its wide optical bandgap and superior stability. In this study, we have modulated the Ni2+ vacancies in NiOx film by controlling deposition temperature in a hot-casting process, resulting the change of coordination structure and charge state of NiOx. Moreover, the change of the HOMO level of NiOx makes it more compatible with perovskite to decrease energy losses and enhance hole carrier injection efficiency. Besides, the defect modulation in the electronic structure of NiOx is beneficial for increasing the electrical conductivity and mobility, which are considered to achieve the balance of charge carrier transport and avoid charge accumulation at the interface between perovskite and HTL effectively. Both experimental analyses and theoretical calculations reveal the increase of nickel vacancy defects change the electronic structure of NiOx by increasing the ratio of Ni3+/Ni2+ and improving the p-type characteristics. Accordingly, an optimal deposition temperature at 120 °C enabled a 36.24% improvement in the power conversion efficiency compared to that deposited at room temperature (25 °C). Therefore, this work provides a facile method to manipulate the electronic structure of NiOx to improve the charge carrier transport and photovoltaic performance of related PSCs.

Original languageEnglish
Pages (from-to)426-434
Number of pages9
JournalJournal of Energy Chemistry
Volume48
Early online date4 Mar 2020
DOIs
Publication statusPublished - Sept 2020
Externally publishedYes

Bibliographical note

This work was financially supported by the National Natural Science Foundation of China NSFC (51702038) and the Recruitment Program for Young Professionals. L. Ding thanks the National Key Research and Development Program of China (2017YFA0206600) and the National Natural Science Foundation of China (51773045, 21772030, 51922032, 21961160720) for financial support. We thank Prof. Qinye Bao from East China Normal University for the UPS measurements and fruitful discussions, and Prof. Feng Yang from Comprehensive training platform of specialized laboratory, College of Chemistry, Sichuan University for the thickness measurements.

Keywords

  • Conductivity
  • Electronic structure
  • Energy level
  • Hole transport layer
  • Mobility
  • Vacancy

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