Perovskite solar cells

Published papers:

• G. A. Nemnes, Cristina Besleaga, Andrei Gabriel Tomulescu, Alexandra Palici, Lucian Pintilie, Andrei Manolescu and Ioana Pintilie,
  "How measurement protocols influence the dynamic J-V characteristics of perovskite solar cells: theory and experiment",
  Solar Energy 173, 976 (2018)
  
• G. A. Nemnes, Cristina Besleaga, Viorica Stancu, Daniela Emilia Dogaru, Lucia Nicoleta Leonat,
  L. Pintilie, K. Torfason, M. Ilkov, A. Manolescu, Ioana Pintilie,
  "Normal and inverted hysteresis in perovskite solar cells",
  J. Phys. Chem. C 121, 11207 (2017)
  (arXiv:1704.03300)
  
• G. A. Nemnes, Cristina Besleaga, A. G. Tomulescu, Ioana Pintilie, L. Pintilie, K. Torfason, A. Manolescu,
  "Dynamic electrical behavior of halide perovskite based solar cells",
  Sol. Energy Mater. Sol. Cells 159, 197 (2017)
  
• N. Plugaru, G. A. Nemnes, L. Filip, Ioana Pintilie, L. Pintilie, K. T. Butler and Andrei Manolescu,
  "Atomistic Simulations of Methylammonium Lead Halide Layers on PbTiO3 (001) Surfaces",
  J. Phys. Chem. C 121, 9096 (2017)
  
• Cristina Besleaga, Laura Elena Abramiuc, Viorica Stancu, A. G. Tomulescu, M. Sima, Liliana Trinca, N. Plugaru,
  L. Pintilie, G. A. Nemnes, Mihaiela Iliescu, H. G. Svavarsson, A. Manolescu and Ioana Pintilie,
  "Iodine Migration and Degradation of Perovskite Solar Cells Enhanced by Metallic Electrodes",
  J. Phys. Chem. Lett. 7, 5168 (2016)
  
• Adela Nicolaev, T. L. Mitran, Sorina Iftimie, G. A. Nemnes,
  "Optimization of halide perovskite solar cells based on nanocolumnar ZnO",
  Sol. Energy Mater. Sol. Cells 158, 202 (2016)
• G. A. Nemnes, C. Goehry, T. L. Mitran, Adela Nicolaev, L. Ion, S. Antohe, N. Plugaru, A. Manolescu,
  "Band alignment and charge transfer in rutile-TiO2/CH₃NH₃PbI_3-xCl_x interfaces",
  Phys. Chem. Chem. Phys. 17, 30417 (2015)
• C. Goehry, G. A. Nemnes and Andrei Manolescu,
  "Collective Behavior of Molecular Dipoles in CH₃NH₃PbI₃",
  J. Phys. Chem. C 119, 19674 (2015)

Finalized research project:

• The PERPHECT project
  

Ongoing research:

• DFT simulations of hybrid perovskite layers on ferroelectric PbTiO3(001) surfaces
  
• Band alignment of Cu2O/perovskite interface
  
• Normal and inverted hysteresis
  

Main results:

1. Modeling hysteresis in perovskite solar cells -- Dynamic Electrical Model (DEM)
   
   • Pre-poling bias is causing the current overshoot in reverse J-V characteristics
   • The hysteresis is minimal at low and high bias scan rates, which is explained by the dynamic electrical model (DEM)
   
   G. A. Nemnes, Cristina Besleaga, A. G. Tomulescu, Ioana Pintilie, L. Pintilie, K. Torfason, A. Manolescu,
   "Dynamic electrical behavior of halide perovskite based solar cells",
   Sol. Energ. Mater. & Sol. Cells 159, 197 (2017)
   arXiv:1606.00335
   
   ***Citations:
   • S. Ravishankar, O. Almora, C. Echeverria-Arrondo, E. Ghahremanirad, C. Aranda, A. Guerrero,
     F. Fabregat-Santiago, A. Zaban, G. Garcia-Belmonte, and J. Bisquert,
     "Surface Polarization Model for the Dynamic Hysteresis of Perovskite Solar Cells",
     J. Phys. Chem. Lett. 8, 915 (2017)
     
   
   
2. Degradation is enhanced by the presence of metalic electrodes
   • Aged structures without metallic electrodes behave as fresh ones when adding the back contact
   • Iodine migration is confirmed by XPS experiments
   
   Cristina Besleaga, Laura Elena Abramiuc, Viorica Stancu, A. G. Tomulescu, M. Sima, Liliana Trinca, N. Plugaru,
   L. Pintilie, G. A. Nemnes, Mihaiela Iliescu, H. G. Svavarsson, A. Manolescu and Ioana Pintilie,
   "Iodine Migration and Degradation of Perovskite Solar Cells Enhanced by Metallic Electrodes",
   J. Phys. Chem. Lett. 7, 5168 (2016)
   
   
   
3. Nanocolumnar ZnO perovskite solar cells
   • AZO interfacial layer produces a spike-less band diagram
   • Optimized structures based on the Perovskite/AZO/ZnO layer sequence have enhanced PCEs
   
   Adela Nicolaev, T. L. Mitran, Sorina Iftimie, G. A. Nemnes,
   "Optimization of halide perovskite solar cells based on nanocolumnar ZnO",
   Sol. Energy Mater. Sol. Cells 158, 202 (2016)
   
   
   
4. Chlorine effect on the band alignment in rutile-TiO2/CH₃NH₃PbI_3-xCl_x interfaces
   • A certain concentration of chlorine is needed for optimal band offsets
   • Large chlorine concentrations may significantly decrease the valence band offset
   
   G. A. Nemnes, C. Goehry, T. L. Mitran, Adela Nicolaev, L. Ion, S. Antohe, N. Plugaru, A. Manolescu,
   "Band alignment and charge transfer in rutile-TiO2/CH₃NH₃PbI_3-xCl_x interfaces",
   Phys. Chem. Chem. Phys. 17, 30417 (2015)
   
   
   
5. Microscopic ferroelectricity in hybrid perovskite
   • Ab initio evidence of microscopic ferroelectricity, which elegantly explains the lack of macroscopic ferroelectricity
   • Rotational relaxation times of dipoles is of the order of a few tens of ps
   
   C. Goehry, G. A. Nemnes and Andrei Manolescu,
   "Collective Behavior of Molecular Dipoles in CH₃NH₃PbI₃",
   J. Phys. Chem. C 119, 19674 (2015)