Charge Carrier Dynamics in Perovskite-based Nanomaterials
Srinivasan, Dhanushi (2026)
2026
Master's Programme in Photonics Technologies
Tekniikan ja luonnontieteiden tiedekunta - Faculty of Engineering and Natural Sciences
Hyväksymispäivämäärä
2026-03-19
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202603193366
https://urn.fi/URN:NBN:fi:tuni-202603193366
Tiivistelmä
The demand for high-performing, affordable optoelectronic devices has expanded the world of semiconductor nanomaterials. In particular, colloidal caesium lead bromide (CsPbBr3) nanocrystal films are attractive materials due to high photoluminescence quantum yield, tunable bandgap and narrow emission linewidths, making them ideal for optoelectronic devices.
Efficient thin-film devices using colloidal nanocrystals are often fabricated by processing them into inks. Long-chain organic ligands are used during synthesis to stabilize the NCs and prevent aggregation. Although essential for stability, these ligands hinder charge transport between neighbouring NCs and reduce device performance. Hence, different washing treatments were employed to remove excess ligands. However, this is a very complex process as insufficient removal of ligands affects charge transport and transfer but too much removal creates surface defects that could form trap states and further reduce the performance of optoelectronic devices.
Furthermore, the 2D Cs2Br5 phase often emerges during the synthesis and processing of CsPbBr3 NCs. The optoelectronic properties and behaviour of this hybrid material are not fully understood. This thesis explores the relationship between these two phases and how different ligand washing treatments affect their charge carrier dynamics.
Efficient thin-film devices using colloidal nanocrystals are often fabricated by processing them into inks. Long-chain organic ligands are used during synthesis to stabilize the NCs and prevent aggregation. Although essential for stability, these ligands hinder charge transport between neighbouring NCs and reduce device performance. Hence, different washing treatments were employed to remove excess ligands. However, this is a very complex process as insufficient removal of ligands affects charge transport and transfer but too much removal creates surface defects that could form trap states and further reduce the performance of optoelectronic devices.
Furthermore, the 2D Cs2Br5 phase often emerges during the synthesis and processing of CsPbBr3 NCs. The optoelectronic properties and behaviour of this hybrid material are not fully understood. This thesis explores the relationship between these two phases and how different ligand washing treatments affect their charge carrier dynamics.