Stable and Efficient Hole Selective Contacts for Silicon Photovoltaics via Solution-Processed Luminescent Small Molecules

Li Jung Kuo, Li Yu Li, Yu Chun Chang, Tong Ke Lin, Han Chen Chang, Yu Chiao Shieh, Shih Wei Chen, Jia Min Shieh, Li Yin Chen, Peichen Yu*, Yu Chiang Chao*, Hsin Fei Meng*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


We report an organic luminescent small molecule, Bis(1-phenylisoquinoline) (acetylacetonate) iridium(III) or Ir(piq)2(acac), that can function as a stable and efficient hole selective contact (HSC) for crystalline silicon (c-Si) solar cells. The devices with the Ir(piq)2(acac) HSC exhibit superior charge transport properties and high stability for up to 30 days in the air without packaging. The photovoltaic characteristics with the solution-processed Ir(piq)2(acac) HSC exhibit little dependence on the blade coating speed and film thickness, demonstrating tolerance to coating and thickness variations. Moreover, the series resistance of the solar cells and the surface work function of the Ir(piq)2(acac) HSCs exhibit analogous correlations to the annealing temperature, suggesting that the fill factor (FF) enhancement originates from an upward energy band bending and a reduced barrier height which facilitates hole transport and collection. The conventional c-Si solar cell incorporating an Ir(piq)2(acac) HSC achieves a 17.8% power conversion efficiency (PCE) with a 78.9% FF, both exceeding the reference counterpart with a 16.9% PCE and 76.8% FF. This work opens up possibilities for exploring a variety of organic luminescent small molecules as efficient hole selective contacts in high-efficiency and low-cost silicon photovoltaics. Graphic Abstract: [Figure not available: see fulltext.].

Original languageEnglish
Pages (from-to)2708-2717
Number of pages10
JournalJournal of Electronic Materials
Issue number4
Publication statusPublished - 2023 Apr


  • Carrier selective contacts
  • luminescent small molecules
  • organic silicon interface
  • silicon solar cells

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Materials Chemistry
  • Electrical and Electronic Engineering


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