Insights on the limiting factors of Cu2ZnGeSe4 based solar cells
| Autor: | J.A. Andrade-Arvizu, Maxim Guc, Zouheir Sekkat, Safae Aazou, Ikram Anefnaf, Kunal J. Tiwari, Robert Fonoll-Rubio, Pedro Vidal-Fuentes, Yudania Sánchez, Z. Jehl Li-Kao, Sergio Giraldo, Edgardo Saucedo |
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| Přispěvatelé: | Institut de Recerca en Energía de Catalunya, Universitat Politècnica de Catalunya. Departament d'Enginyeria Electrònica, Universitat Politècnica de Catalunya. MNT - Grup de Recerca en Micro i Nanotecnologies |
| Rok vydání: | 2021 |
| Předmět: |
Solar cells
Materials science Band gap 02 engineering and technology engineering.material 010402 general chemistry 01 natural sciences Band offset law.invention law Solar cell Kesterite Kesterite solar cells Renewable Energy Sustainability and the Environment business.industry Wide-bandgap semiconductor Energies::Energia solar fotovoltaica::Cèl·lules solars [Àrees temàtiques de la UPC] Cu2ZnGeSe4 021001 nanoscience & nanotechnology Copper indium gallium selenide solar cells Recombination Cadmium telluride photovoltaics 0104 chemical sciences Surfaces Coatings and Films Electronic Optical and Magnetic Materials VOC deficit Semiconductor Limitations engineering Optoelectronics Cèl·lules solars 0210 nano-technology business |
| Zdroj: | UPCommons. Portal del coneixement obert de la UPC Universitat Politècnica de Catalunya (UPC) |
| ISSN: | 0927-0248 |
| DOI: | 10.1016/j.solmat.2021.111106 |
| Popis: | Germanium-based wide band gap kesterite semiconductor Cu2ZnGe(S,Se)4 (CZGeSSe) is considered a very promising absorber compound as top cell in tandem devices. Autonomy to tailor the band gap from ~1.47 eV (Cu2ZnGeSe4-CZGeSe) to ~2.2 eV (Cu2ZnGeS4-CZGeS), as well as non-toxic constituents makes this compound a strong candidate for further scientific exploration. However, the record efficiency of Cu2ZnGeSe4 solar cells is still significantly lower than those of its predecessors Cu2ZnSn(SxSe1-x)4 (CZTSSe), Cu(In,Ga)Se2 (CIGS) and CdTe thin-film solar cells. The comprehensive understanding of the factors limiting the performance of Cu2ZnGeSe4 based solar cells is the purpose of this work, by combining a complete characterization of the morphological, structural, compositional and optoelectronic properties of Cu2ZnGeSe4 absorbers and devices. Besides, an in-depth investigation of the main limitations is carried out, specifically focusing on studying the origin of the large VOC deficit, the main recombination mechanisms, electric transport properties, band tails and possible Cu2ZnGeSe4/CdS band offset effects. The champion CZGeSe solar cell device reported in this work shows an efficiency of 6.5%, Voc of 606 mV, JSC of 17.8 mA/cm2 and FF of 60%. The results presented here demonstrate that the large voltage deficit of CZGeSe solar cells could be mainly ascribed to a Fermi level pinning at the interface, while modifications of the buffer layer to induce a “spike” at the p-n junction could be beneficial. Additionally, low carrier diffusion lengths and lifetimes, along with possible back contact recombination, are identified as the main culprits for the limited carrier collection for low-energy photons. Finally, some strategies are proposed to face and overcome most of these issues and to help improving the CZGeSe performance. |
| Databáze: | OpenAIRE |
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