The investigation of the influence of back contact metal and ligand exchanging on the air stability of ambient processed schottky Photovoltaic Cells Based on PbSe CQDs

Abstract

In this work we fabricated and tested nanocrystalline schottky solar cells based on PbSe CQDs. Crystalline and monodisperse PbSe capped oleic acid CQDs were synthesized through hot injection reaction. From absorption peak and narrow photoluminescence peak of QDs in solution, CQDs size (~3 nm) and monodispersity of CQDs were determined. Photovoltaic cell structure is formed from PbSe QDs sandwiched between Al (or Ag) and ITO electrodes as electron and hole transporter layers, respectively. Current-Voltage characteristics showed carrier separation mechanism consistent with schottky device structure. The best efficient cell obtained, without any nanocrystalline film thickness optimization, with ITO\PbSe QDs\LiF\Al structure showed a PCE of 0.55%. Furthermore, oleylamine based devices with Ag as back contact exhibited the most durable cells with the life time of 21 h and survival until 5 days.