Date

2022-7-22

Author

Kolay, İrem

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Multiple exciton generation (MEG) process has received a great deal of attention in solar energy research due to its high potential in improving photocurrent. In this respect, PbSe NRs are considered as one of the most promising candidates due to their remarkable MEG yield. However, limited number of solar cell studies based on PbSe NRs and their poor performances have been limiting their utilization in photovoltaic (PV) technologies. In this thesis, previously introduced solar cell design, where covalently bonded PbSe QDs and PbSe NRs in a BNHJ layer were utilized as light absorbing layer, were further optimized and the direct roles of solar cell components and processing conditions are disclosed for the first time in literature. High quality QDs and NRs with low polydispersity were synthesized with hot injection method and characterized by techniques such as UV-Vis spectroscopy, TEM and UPS. Solar cells with inverted architecture were fabricated and characterized by I-V and EQE techniques. Performance of the solar cells was enhanced by optimizing the cell components such as light absorbing active layer, electron transport and hole transport layers. Optimization of the thicknesses of the active and electron transport layers, and heat treatment were found to be the key factors for improving the performance of the solar cells in terms of PCE and EQE/IQE values at energies where the MEG is expected to take place. Additionally, we found that the type of the HTL has a profound affect in cell performance. In this sense, PbSe QDs with 1.4 eV band gap, PbS QDs with 1.3 eV band gap and TIPSPentacene molecule were utilized as HTLs. We found that PbSe QDs with 1.4 eV band, gap leads to the best performing cells. Furthermore, we found that the structure of the ligand that holds NRs and QDs together in BNHJ layer has a drastic affect in cell performance. The optimized BNHJ devices lead to the best performing cells comprising PbSe NRs in literature; >100% EQE/IQE and 4.09% PCE.

Subject Keywords

Quantum Dot, Nanorod, Multiple Exciton Generation, Bulk Nano - Heterojunction Solar Cells

URI

https://hdl.handle.net/11511/98553

Collections

Graduate School of Natural and Applied Sciences, Thesis