Polycrystalline tandem photovoltaics
Abstract/Contents
- Abstract
- The future of photovoltaics is defined by benchmarks anticipated through technological breakthroughs (and financing improvements, etc.). To reach projected module efficiencies > 25% and installed system costs of < $1/WDC (translates roughly to 6¢/kWh LCOE), solutions beyond silicon photovoltaics - long thought to have a practical efficiency limit ~25% - are necessary. Tandem photovoltaics, with the potential to shatter the single-junction Shockley-Queisser limit, are a promising path towards breaking the 25% module efficiency barrier. Indeed, tandems have long surpassed 25% efficiency. Traditionally grown as a single crystal, these tandems have not been deployed extensively in terrestrial applications due to the high cost of materials and deposition when growing high-quality single crystals. To achieve both high efficiency as well as low cost, a tandem that operates efficiently as a polycrystalline material is desirable. The metal-halide perovskite fits the ideal criteria for the top absorber in a tandem when either CIGS or Si is used as the bottom absorber. The metal halide perovskite is solution-processable, polycrystalline, has inexpensive input materials, and desirable material properties such as bandgap tunability, high open-circuit voltage, long ambipolar diffusion lengths, and strong absorption make this material very attractive for tandems. In this thesis, I discuss the initial work on perovskite tandems in both mechanically-stacked and monolithically-integrated architectures. With a silver-nanowire transparent electrode, a 12.7% semi-transparent perovskite solar cell improves a CIGS solar cell from 17.0% to 18.6%. With a sputtered ITO electrode, a 12.3% semi-transparent solar cell improves a Si solar cell from 17% to 18%. An initial prototype monolithic tandem using a silicon tunnel junction to enable interconnection shows a 13.7% efficiency with a VOC of 1.65V. I model the cost and performance of perovskite/silicon tandems to identify the economic opportunity finding an opportunity for both single-junction and tandem perovskite modules. I address concerns over the stability of the perovskite by showing enhanced stability with proper encapsulation, observing no measurable degradation at 100 degC for 24h under load in ambient air and full AM1.5G spectrum.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2015 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Bailie, Colin David | |
|---|---|---|
| Associated with | Stanford University, Department of Materials Science and Engineering. | |
| Primary advisor | McGehee, Michael | |
| Thesis advisor | McGehee, Michael | |
| Thesis advisor | Cui, Yi, 1976- | |
| Thesis advisor | Karunadasa, Hemamala | |
| Advisor | Cui, Yi, 1976- | |
| Advisor | Karunadasa, Hemamala |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Colin David Bailie. |
|---|---|
| Note | Submitted to the Department of Materials Science and Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2015. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2015 by Colin David Bailie
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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