Loading...

Fabrication and Optimization of Copper-Based Multicomponent Chalcogenide Layers Using Colloidal Ink Aimed to Apply in Nanostructured Solar Cells

Heidari Ramsheh, Maryam | 2022

204 Viewed
  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 55449 (48)
  4. University: Sharif University of Technology
  5. Department: Institute for Nanoscience and Nanotechnology
  6. Advisor(s): Mahdavi, Mohammad; Taghavinia, Nima
  7. Abstract:
  8. The aim of this thesis was to study and fabricate stable inks of Cu2SnS3 (CTS), Cu2ZnSnS4 (CZTS) and Cu3SbS4 (CAS) copper-based chalcogenide nanoparticles (NPs) and their application in solar cells. Inorganic semiconductors with p-type conductivity, high stability, high hole mobility (compared to organic type), and the ability to synthesize and deposition by simple low temperature solution-based methods have the potential to provide suitable alternative for hole-transporting material (HTM) in perovskite solar cells (PSCs) and the photo-absorbers in thin film solar cells (TFSCs). The ability to adjust energy levels and optoelectrical properties is another advantage of these compounds. In addition to the colloidal stability of the related inks, the deposition capability with large-scale methods was also considered, which were successfully deposited by the “meniscus blade” method. First, stable inks were synthesized and characterized by heating-up method using Oleylamine (OLAM) solvent. Among the different dispersion media, chloroform and chlorobenzene were found to be suitable dispersants for maximizing the colloidal stability of HTM inks. The presence of OLAM ligands at the NPs surface provides the ability to disperse in non-polar environments, which is important not only in terms of chemical compatibility with perovskite, but also by promoting the hydrophobicity of HTM surface, helping cell stability when exposed to moisture.In the section of evaluating CTS performance as HTM, the critical role of crystal phase in photovoltaic performance was observed. The solar cell made with wurtzite-CTS showed an optimal efficiency of 13.1% compared to 7.87% for zincblende-CTS. This improvement was due to the suitability of the valance band energy level and the uniform coverage of the perovskite surface by wurtzite-CTS ink. In the next step, the optoelectrical properties of quaternary NPs of CZTS by changing the Zn/Sn ratio. (0, 0.9, 1.1, 1.3, 1.5 and 1.7) were investigated. CZTS NPs have been confirmed to be a potential HTM for carbon-based PSCs that can achieve photovoltaic performance of up to 40% (9.34%, Avg PCE for Zn:Sn1.3) and up to 100%. (13.09% average PCE for Zn:Sn1.5) compared to HTM free device (6.52% average PCE). The best photovoltaic performance of 14.86% is related to Zn:Sn1.5, which reaches 15.49% after 25 days of ageing. Zn/Sn ratio control allows adjusting the energy level and photovoltage, which leads to improved photovoltaics performance. Finally, copper-based chalcogenides were evaluated as appropriate and promising options for replacement with organic materials due to their greater stability and lower cost. Application the simple composition of CTS and optimizing the Zn/Sn ratio of the CZTS composition for use as HTM were some of the innovative aspects of this thesis.In addition to HTM, the role of these materials as an absorber layer in TFSCs with a superstrate configuration was also investigated. CZTS-based inks with different Zn/Sn ratio were deposited by large-scale “meniscus blade” method and then a low-temperature selenization treatment was applied to improve the crystallinity of the layer. CTSe and CZTSe based TFSCs indicated the best efficiencies of 4.18% and 2.56%, respectively. The return of 4.18% is a record of its kind. Antimony-based layers did not show photovoltaic feedback. The photovoltaic yield of 6.37% was achieved for CTSe layers as counter-electrode in DSSCs. Another aspect of innovation was the deposition of stable inks by large-scale "meniscus blade" method and their application in these structures
  9. Keywords:
  10. Counter Electrode ; Perovskite-Based Solar Cell ; Dye Sensitized Solar Cells ; Hole Transporter Layer ; Thin Film Chalcogenide Solar Cell ; Stable Colloidal Ink ; Chalcogenide Semiconductor

 Digital Object List

 Bookmark

No TOC