Characterization of CBO and defect states of CZTSe solar cells prepared by using two-step process
| Autor: | Myeung-Hoi Kwon, SeongYeon Kim, Kang-Woo Kim, Tanka Raj Rana, JunHo Kim |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Materials science
business.industry Two step Energy conversion efficiency General Physics and Astronomy 02 engineering and technology engineering.material 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Buffer (optical fiber) 0104 chemical sciences law.invention law Sputtering Solar cell engineering Optoelectronics General Materials Science Kesterite 0210 nano-technology business p–n junction Conduction band |
| Zdroj: | Current Applied Physics. 18:191-199 |
| ISSN: | 1567-1739 |
| DOI: | 10.1016/j.cap.2017.12.004 |
| Popis: | We fabricated kesterite Cu2ZnSnSe4 (CZTSe) solar cells and studied device characteristics, where CZTSe absorbers were made by using two-step process. First, we deposited precursor CZTSe films with spin-coating or sputtering, and performed sulfurization and subsequent selenization. To complete the device, we applied In2S3 as a buffer layer. We obtained power conversion efficiency (PCE) of 4.18% with spin-coated CZTSe absorber and 5.60% with sputtered CZTSe absorber. Both devices showed deep defects in the bulk and strong interface recombinations near the pn junction. In addition, we observed red-kinks in the current density-voltage (J-V) curves for both devices under the filtered light illumination (>660 nm), which is attributed to large conduction band offset (CBO) between the CZTSe absorber and the buffer layer and defect states in the buffer/CZTSe absorber or in the buffer. The red-kink was also observed in CZTSe (PCE of 7.76%) solar cell with CdS buffer. Hence, to enhance the PCE with CZTSe absorber, along with suppression of deep defects which act as recombination center, optimization of CBO between absorber and buffer is also required. |
| Databáze: | OpenAIRE |
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