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Title: Increased Voltage in CdSe Solar Cells by Mitigation of Charge Carrier Trapping Due to Se Vacancies
Abstract Cadmium selenide (CdSe), with a 1.7 eV bandgap, is a promising high‐bandgap semiconductor for tandem solar cells, yet device efficiencies are hindered by rapid minority carrier recombination. Here, polycrystalline CdSe solar cells are investigated using radiative emission spectroscopy, time‐resolved photoluminescence, and density functional theory, revealing fast (sub‐nanosecond) minority carrier trapping by selenium vacancy‐related defect states with densities of (5–50) × 1017 cm−3, limiting carrier mobility and increasing recombination. By reducing absorber thickness to ≈0.5 µm, trapping effects are mitigated, achieving a record open‐circuit voltage of 917 mV, a 165 mV improvement over prior reports. These findings clarify the role of Se vacancies in limiting CdSe solar cell performance and provide insights applicable to CdSe and CdSeTe thin‐film photovoltaics. This work advances understanding of defect‐mediated losses in II–VI semiconductors and suggests pathways for improving solar cell performance through defect control.  more » « less
Award ID(s):
2308979
PAR ID:
10662821
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  
Publisher / Repository:
WILEY
Date Published:
Journal Name:
Advanced Materials Technologies
ISSN:
2365-709X
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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