TY - GEN
T1 - Nanojunction solar cells based on polycrystalline CdTe films grown on ZnO nanocones
AU - Lee, Sang Hyun
AU - Xu, Jun
AU - Zhang, X. G.
AU - Parish, Chad M.
AU - Smith, Barton
PY - 2011
Y1 - 2011
N2 - We report the nanojunction effect on nanocone based solar cell consisting of 5 μm thick CdTe thin film as a p-type absorption layer and n-type ZnO nanocones as a minority electron collector. The morphology of the nanojunction, with embedding depth ∼ 100 nm into CdTe matrix, was clearly revealed by transmission electron microscopy (TEM) and scanning TEM (STEM). The characteristics of nanojunction solar cell were compared with those of planar ZnO/CdTe structure in dark and under 100 mW (AM 1.5) illumination using a solar simulator. The nanojunction cell showed small reverse saturation current density in dark. Lower capacitance of the nanojunction from capacitance-frequency (C-f) measurement implies the existence of low defects at near the junction interfaces, which enables to lowerer junction recombination. The small junction area and low defects produces the higher open circuit voltage (V oc) and fill factor (ff) than those of planar under light illumination. The fact that the performance of nanojunction based solar cell is not critically affected by interfacial defects will be very useful for polycrystalline or nanoparticle CdTe with many crystal defects. Our current conversion efficiency of ∼ 3.2 % nanocone was achieved by decreasing CdTe grain size, which is different from planar polycrystalline solar cells.
AB - We report the nanojunction effect on nanocone based solar cell consisting of 5 μm thick CdTe thin film as a p-type absorption layer and n-type ZnO nanocones as a minority electron collector. The morphology of the nanojunction, with embedding depth ∼ 100 nm into CdTe matrix, was clearly revealed by transmission electron microscopy (TEM) and scanning TEM (STEM). The characteristics of nanojunction solar cell were compared with those of planar ZnO/CdTe structure in dark and under 100 mW (AM 1.5) illumination using a solar simulator. The nanojunction cell showed small reverse saturation current density in dark. Lower capacitance of the nanojunction from capacitance-frequency (C-f) measurement implies the existence of low defects at near the junction interfaces, which enables to lowerer junction recombination. The small junction area and low defects produces the higher open circuit voltage (V oc) and fill factor (ff) than those of planar under light illumination. The fact that the performance of nanojunction based solar cell is not critically affected by interfacial defects will be very useful for polycrystalline or nanoparticle CdTe with many crystal defects. Our current conversion efficiency of ∼ 3.2 % nanocone was achieved by decreasing CdTe grain size, which is different from planar polycrystalline solar cells.
UR - http://www.scopus.com/inward/record.url?scp=84861067057&partnerID=8YFLogxK
U2 - 10.1109/PVSC.2011.6186362
DO - 10.1109/PVSC.2011.6186362
M3 - Conference contribution
AN - SCOPUS:84861067057
SN - 9781424499656
T3 - Conference Record of the IEEE Photovoltaic Specialists Conference
SP - 2078
EP - 2081
BT - Program - 37th IEEE Photovoltaic Specialists Conference, PVSC 2011
T2 - 37th IEEE Photovoltaic Specialists Conference, PVSC 2011
Y2 - 19 June 2011 through 24 June 2011
ER -