Solar cells based on PbSe nanorod-quantum dot heterostructures: Multiple exciton generation with record photo conversion efficiencies

Date

2023-08-17

Author

Kolay, İrem
Asil Alptekin, Demet

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Multiple-exciton generation (MEG) process has critical importance due to its high potential in increasing photocurrent and theoretical photoconversion efficiency (PCE) of the solar cells beyond the theoretical limits. In this respect, PbSe quantum dot-QDs and PbSe nanorods-NRs are considered as one of the most promising candidates due to their outstanding MEG yields. Unfortunately, the number of solar cells with MEG capability is limited because demonstrating this unique feature in a functional solar cell has been challenging. In this sense, we utilized a light absorbing layer which combines the advantages of using two different nanostructures known to have high MEG yields together and created a donor-acceptor type bulk nano heterojunction (BNHJ) to facilitate the carrier separation. We discovered that the type of hole transport layer has a profound impact on MEG characteristics and cell efficiency.In this study, different materials with varying degrees of conduction band offset values (PbSe QDs, PbS QDs and bis(triisopropylsilylethynyl)pentacene (TIPS-Pentacene) molecules) were utilized as the electron-blocking/hole-extraction layer. We found that the HTL prepared from PbSe QDs offers an optimum interface by reducing the electron back injection and enhancing the MEG yield. A record PCE of 4.09% and peak internal quantum efficiencies greater than 100% were demonstrated for cells with 0.97 eV NR-donor band gap. We believe that this study, outperforming previously reported MEG-based solar cells using only quantum dots or nanorods as the light absorption layer, will form the basis for future studies aimed at exceeding the theoretical solar cell efficiency limits.

URI

https://hdl.handle.net/11511/113683

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Department of Chemistry, Conference / Seminar