title: The necessary length of carbon nanotubes required to optimize solar cells.
abstract: BACKGROUND
  In recent years scientists have been trying both to increase the efficiency of solar cells, whilst at the same time reducing dimensions and costs. Increases in efficiency have been brought about by implanting carbon nanotubes onto the surface of solar cells in order to reduce the reflection of sunrays, as well as through the insertion of polymeric arrays into the intrinsic layer for charge separation.
  
  
  RESULTS
  The experimental results show power rising linearly for intrinsic layer thicknesses between 0-50 nm. Wider thicknesses increase the possibility of recombination of electrons and holes, leading to perturbation of the linear behaviour of output power. This effect is studied and formulated as a function of thickness. Recognition of the critical intrinsic layer thickness can permit one to determine the length of carbon nanotube necessary for optimizing solar cells.
  
  
  CONCLUSIONS
  In this study the behaviour of output power as a function of intrinsic layer thicknesses has been described physically and also simulated. In addition, the implantation of carbon nanotubes into the intrinsic layer and the necessary nanotube length required to optimize solar cells have been suggested.
authors.affiliation: K N Toosi University, Department of Physics, Tehran, Iran. majid@kntu.ac.ir
authors.forename: Majid
authors.initials: M
authors.lastname: Vaezzadeh
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Saeedi
authors.forename: Tirdad
authors.initials: T
authors.lastname: Barghi
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Sadeghi