Tailored Band Alignment for Improved Carrier Transport in Composition-Controlled Sb2(S,Se)3
Geumha Lim1, Ha Kyung Park1, Yazi Wang2
1Department of Physics, Ewha Womans University, Seoul 03760, Republic of Korea.
The Journal of Physical Chemistry Letters
|March 14, 2024
Summary
This study enhances antimony sulfo-selenide solar cells by optimizing the sulfur/selenium ratio and passivating defects. This approach boosts efficiency through improved bandgap grading and reduced carrier recombination, leading to higher performance.
Area of Science:
- Materials Science
- Renewable Energy
- Semiconductor Physics
Background:
- Antimony sulfo-selenide (Sb2(S,Se)3) is a promising, earth-abundant material for solar cells.
- Bandgap tunability via S/Se ratio adjustment offers efficiency gains, but open-circuit voltage (VOC) limitations persist.
- Defect passivation is crucial for reducing carrier recombination and enhancing VOC.
Purpose of the Study:
- To investigate the relationship between S/Se ratio, defect concentration, and VOC in Sb2(S,Se)3 solar cells.
- To explore defect passivation strategies for improving solar cell performance.
- To achieve simultaneous enhancement of short-circuit current (JSC) and VOC.
Main Methods:
- Fabrication of Sb2(S,Se)3 solar cells with varying S/Se ratios and surface treatments.
- Surface composition analysis using Raman spectroscopy.
- Characterization of defect states via photoluminescence and conductive atomic force microscopy.
- Quantification of defect concentration using surface photovoltage measurements.
Main Results:
- Surface composition differences were confirmed by Raman spectroscopy.
- Complex subdefect states in S-rich Sb2(S,Se)3 were identified.
- A significant decrease in defect concentration was observed after surface treatment.
- Bandgap grading improved JSC, while defect passivation enhanced VOC.
Conclusions:
- Optimizing the S/Se ratio and implementing defect passivation are effective strategies for enhancing Sb2(S,Se)3 solar cell performance.
- Simultaneous improvement in JSC and VOC was achieved, leading to more efficient devices.
- This work provides a pathway for developing high-performance, low-cost solar cells based on Sb2(S,Se)3.
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