Perovskite tandem solar cells
Abstract/Contents
- Abstract
- Solar cells are an energy source of the future - clean, renewable, and with the promise of increasing energy access globally. A promising way to speed up the shift of global energy production toward renewable sources is to make highly efficient and inexpensive solar cells. Ten years ago, a new family of semiconductors was discovered to work well as solar cell absorbers - organic-inorganic metal halide perovskites. These materials absorb light strongly and have long carrier lifetimes and diffusion lengths. They can be processed quickly and inexpensively into high-performing solar cells. Perovskite band gaps can be tuned by simple compositional substitution - and this enables them to be used in two-junction tandem solar cells, which get past theoretical efficiency limits on single junction solar cells. This thesis begins with an overview of the main materials properties of perovskites that are relevant to their use in efficient solar cells. We then present a study identifying the chemical mechanisms band gap tuning in halide perovskites, based on molecular orbital theory and measurements of absorption spectra, X-ray diffraction and photoelectron spectroscopy across a range of perovskite compositions. This work helps identify a mixed tin-lead perovskite whose band gap is appropriate for the rear subcell in a two-junction tandem solar cell. A persistent concern with tin-containing perovskites has been that they are unstable to oxidation - this has hampered the development of all-perovskite tandems. We describe our study of the chemistry of how this oxidation occurs. The conclusions of this study lead to a chemical strategy to suppress oxidation in low band gap perovskite semiconductors. Practically building an efficient tandem solar cell requires designing perovskite compositions, contact and electrode layers, and a recombination layer to connect the subcells together and protect the first cell while fabricating the second cell on top of it. The fourth chapter shows our work that led to a monolithic tandem solar cell whose efficiency is a record for all-perovskite tandems. Finally, tin-lead perovskites present unique challenges to stability when integrated into full solar cells. The last chapter presents work on understanding how these solar cells degrade, and strategies that we developed to ensure that tin-lead perovskite solar cells, which are critical to high-efficiency all-perovskite tandems, can be designed to successfully retain their performance through 1000-hour tests under heat, light, and atmospheric exposure.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2019; ©2019 |
| Publication date | 2019; 2019 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Prasanna, Rohit |
|---|---|
| Degree supervisor | McGehee, Michael |
| Degree supervisor | Salleo, Alberto |
| Thesis advisor | McGehee, Michael |
| Thesis advisor | Salleo, Alberto |
| Thesis advisor | Lindenberg, Aaron Michael |
| Degree committee member | Lindenberg, Aaron Michael |
| Associated with | Stanford University, Department of Materials Science and Engineering. |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Rohit Prasanna. |
|---|---|
| Note | Submitted to the Department of Materials Science and Engineering. |
| Thesis | Thesis Ph.D. Stanford University 2019. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2019 by Rohit Prasanna
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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