Effect of the air humidity on the chlorine treatment for CdTe thin films solar cells

Nanoscale Characterization of Photocurrent and Photovoltage in Polycrystalline Solar Cells

“…The higher power conversion efficiency in the optimized CdTe cell is mainly caused by the highest photocurrent as shown in Table . Despite degraded photogenerated voltage, Figure illustrates that the grain boundaries can contribute to increasing photogenerated current by more effectively collecting carriers when CdTe solar cells are exposed to Cl and annealed at an appropriate temperature. ,,, It is apparent that the grain boundaries lead to two counteracting contributions: a built-in electric field helps to collect more photogenerated carriers, while the enhanced recombination impairs the photovoltage, as can be confirmed with Figure c,f. Thus, we need to combine all information we obtain (i.e., photocurrent and photovoltage maps obtained by NSPM and KPFM) to more accurately evaluate the role of CdTe grain boundaries and their impact on the overall device performance such as the power conversion efficiency.…”

Toward Development of CdZnTe and CdMnTe Thin Film‐Based Solar Cells: Optimized Properties and a Comparative Performance Exploration

“…Due to front reflection and absorption in the window or substrate layers, the device losses as determined by QE measurement may be optical owing to recombination losses in the absorber layers. [ 7,43,44 ]…”

“…Due to front reflection and absorption in the window or substrate layers, the device losses as determined by QE measurement may be optical owing to recombination losses in the absorber layers. [7,43,44] The quantum efficiency for both CZT and CMT PV cells demonstrated the PV active nature of the devices in the wavelength range of 300 to 900 nm, with the highest QE at 640 (51%) and 660 nm (42%), respectively, for CZT and CMT PV cells. It drops rapidly after 720 nm, which could be attributed to recombination and optical losses due to transmission and reflection, as well as indicating a high degree of recombination in the CdZnTe and CdMnTe with CdS layers by forming a CdZnTe 1-x S x and CdMnTe 1-x S x alloys close to the interface, which reduces nonradiative recombination centers.…”

“…Few micrometers of CdTe can absorb more than 90% of the light spectrum due to its superior absorption coefficient (>10 5 cm −1 ) and near‐optimal direct energy bandgap of 1.45 eV. [ 7 ] For CdTe solar cells, where the cadmium sulfide (CdS) layer is exploited as an n‐type window layer in conventional heterojunctions, the superstrate structure is the proper device structure. According to First Solar Inc., CdTe solar cells in superstrate design have achieved a superior efficiency of 22.1%.…”