In situ Al2O3 Incorporation Enhances the Efficiency of CuIn(S,Se)2 Solar Cells Prepared from Molecular-Ink Solutions

Christopher Muzzillo, Wilman Septina, Craig Perkins, Anne Giovanelli, Thomas West, Kenta Ohtaki, Hope Ishii, John Bradley, Kai Zhu, Nicolas Gaillard

Research output: Contribution to journalArticlepeer-review

9 Scopus Citations


We report an efficiency enhancement of solution-processed CuIn(S,Se)2(CISSe) thin film solar cellsvia in situincorporation of Al2O3. These films were produced using inks containing CuCl, InCl3, AlNO3(Al/Al + In: 0.1) and thiourea dissolved in methanol. After spin coating of these solutions in air, samples were subjected to a selenization process. Auger electron spectroscopy depth-profiling analysis showed that Al is evenly distributed throughout the bulk of the film. Transmission electron microscopy revealed that AlNO3precursor reacted with oxygen to form nanosized amorphous Al2O3grains located within the bulk and grain boundaries of CISSe, as well as at both the top and bottom interfaces. Power conversion efficiency (PCE) as high as 11.6% (JSC: 35.8 mA cm−2,VOC: 518 mV, FF: 62.2%, no anti-reflection coating) was achieved with Al-CISSe solar cell devices integrated with CdS (chemical bath deposition, thickness: 80 nm) and ZnO/ITO bilayers (sputtered, thickness: 300 nm). The average PCE (10.1%, 〈JSC〉: 34.5 mA cm−2, 〈VOC〉: 491 mV, 〈FF〉: 59.8%) was nearly 4% (absolute) higher than that measured on CISSe baseline cells fabricated from solutions without Al (〈PCE〉 = 6.4%, 〈JSC〉: 32.8 mA cm−2, 〈VOC〉: 410 mV, 〈FF〉: 47.3%). Thisin situAl2O3incorporation is speculated to play a role in the enhancement of theVOCand FF of the devices through passivation of defects in CISSe reducing interface and bulk recombination, as evidenced by a reduced defect density and an increased activation energy of the dominant recombination mechanism from capacitance and temperature-dependentVOCmeasurements, respectively.

Original languageAmerican English
Pages (from-to)10419-10426
Number of pages8
JournalJournal of Materials Chemistry A
Issue number16
StatePublished - 28 Apr 2021

Bibliographical note

Publisher Copyright:
© The Royal Society of Chemistry 2021.

NREL Publication Number

  • NREL/JA-5K00-79118


  • Al2O3
  • chalcopyrite
  • molecular ink
  • passivation
  • photovoltaics


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