ZnO:Ga-graded ITO electrodes to control interface between PCBM and ITO in planar perovskite solar cells

Hae Jun Seok, Azmat Ali, Jung Hwa Seo, Hyun Hwi Lee, Na Eun Jung, Yeonjin Yi, Han Ki Kim

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


Ga-doped ZnO (GZO)-graded layer, facilitating electron extraction from electron transport layer, was integrated on the surface of transparent indium tin oxide (ITO) cathode by using graded sputtering technique to improve the performance of planar n-i-p perovskite solar cells (PSCs). The thickness of graded GZO layer was controlled to optimize GZO–indium tin oxide (ITO) combined electrode for planar n-i-p PSCs. At optimized graded thickness of 15 nm, the GZO–ITO combined electrode showed an optical transmittance of 95%, a resistivity of 2.3 × 10−4 Ohm cm, a sheet resistance of 15.6 Ohm/square, and work function of 4.23 eV, which is well matched with the 4.0-eV lowest unoccupied molecular orbital of [6,6]-phenyl-C61-butyric acid methyl ester. Owing to enhanced extraction of electron by the graded GZO, the n-i-p PSC with GZO–ITO combined electrode showed higher power conversion efficiency (PCE) of 9.67% than the PCE (5.25%) of PSC with only ITO electrode without GZO-graded layer. In addition, the GZO integrated-ITO electrode acts as transparent electrode and electron extraction layer simultaneously due to graded mixing of the GZO at the surface region of ITO electrode.

Original languageEnglish
Pages (from-to)389-400
Number of pages12
JournalScience and Technology of Advanced Materials
Issue number1
StatePublished - 31 Dec 2019


  • 107 Glass and ceramic materials; 201 Electronics / Semiconductor / TCOs
  • 209 Solar cell / Photovoltaics
  • 306 Thin film / Coatings
  • 50 Energy Materials
  • Ga-doped ZnO
  • ITO
  • electron extraction layer (EEL)
  • graded sputtering
  • perovskite solar cells


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