Band Alignment and Performance Optimization in Organic Solar Cells with Quantum Dot Hole-Transport Layers
- Publicada
- Servidor
- Preprints.org
- DOI
- 10.20944/preprints202609.2558.v1
Organic solar cells provide fascinating solutions for sustainable energy conversion. However, inefficient hole transport layers limit their performance by restricting charge extraction and facilitating interfacial charge recombination. This study provides a comprehensive simulation-based performance analysis of organic photovoltaic cells using PbS, PbSe, and PbS-TBAI quantum dots as alternative HTLs in the AZO/PM6:Y6/QD solar cell architecture. We used numerical simulations to carefully evaluate the effect of QD type, thickness, doping concentration, and defect density on photovoltaic parameters. PbS QDs-based devices surpass PbSe-based (21.23%) and PbS (QD)-TBAI-based devices (19.71%) due to their greater intrinsic material proper-ties, superior interfacial chemistry, better tolerance to defects and thermal stress, and perfect band alignment with the PM6:Y6 active layer, resulting in a notable power conversion efficiency of 22.19%. The PbS-based devices displayed acceptable thermal stability and trap tolerance, keeping 92.5% of their original PCE even at high defect densities (~1020 cm-3). A thorough band alignment study demonstrated that flat-band conditions at the PbS/PM6:Y6 interface reduce non-radiative recombination, but the insulating TBAI ligand layer in PbS-TBAI devices creates tunnelling barriers and Fer-mi-level pinning. This study presents essential design concepts for choosing and de-veloping QD-based HTLs, establishing PbS QDs as the best choice for high-efficiency, stable, solution-processed OPV cells, with important implications for next-generation photovoltaic technologies.