title: Low-temperature solution-processed solar cells based on PbS colloidal quantum dot/CdS heterojunctions.
abstract: PbS colloidal quantum dot heterojunction solar cells have shown significant improvements in performance, mostly based on devices that use high-temperature annealed transition metal oxides to create rectifying junctions with quantum dot thin films. Here, we demonstrate a solar cell based on the heterojunction formed between PbS colloidal quantum dot layers and CdS thin films that are deposited via a solution process at 80 °C. The resultant device, employing a 1,2-ethanedithiol ligand exchange scheme, exhibits an average power conversion efficiency of 3.5%. Through a combination of thickness-dependent current density-voltage characteristics, optical modeling, and capacitance measurements, the combined diffusion length and depletion width in the PbS quantum dot layer is found to be approximately 170 nm.
authors: Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
authors: Liang-Yi
authors: LY
authors: Chang
authors: Richard R
authors: RR
authors: Lunt
authors: Patrick R
authors: PR
authors: Brown
authors: Vladimir
authors: V
authors: Bulović
authors: Moungi G
authors: MG
authors: Bawendi