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Inkjet Printing All Inorganic Halide Perovskite Inks for Photovoltaic Applications
Published on: January 22, 2019
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Low threshold and efficient multiple exciton generation in halide perovskite nanocrystals
Mingjie Li1, Raihana Begum2, Jianhui Fu1
1School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore, Singapore.
Nature Communications
|October 12, 2018
Summary
Perovskite nanocrystals exhibit enhanced multiple exciton generation (MEG), a process boosting solar cell efficiency. Their unique properties overcome limitations of conventional nanocrystals, paving the way for advanced optoelectronics.
Area of Science:
- Materials Science
- Nanotechnology
- Photovoltaics
Background:
- Multiple exciton generation (MEG) promises to surpass the Shockley-Queisser limit in solar cells by creating multiple electron-hole pairs per photon.
- Conventional semiconductor nanocrystals struggle with rapid hot-carrier cooling, hindering efficient MEG.
- Perovskite nanocrystals offer a potential solution due to an intrinsic phonon bottleneck that slows hot-carrier cooling.
Purpose of the Study:
- To demonstrate enhanced MEG in intermediate-confined colloidal formamidinium lead iodide (FAPbI3) nanocrystals.
- To investigate the potential of perovskite nanocrystals in overcoming limitations of traditional materials for optoelectronic applications.
Main Methods:
- Fabrication of intermediate-confined colloidal formamidinium lead iodide nanocrystals.
- Characterization of MEG properties, including threshold energy and slope efficiency.
- Analysis of hot-carrier cooling dynamics and the underlying inverse Auger process.
Main Results:
- Achieved enhanced MEG with a threshold of 2.25Eg and a slope efficiency of 75% in FAPbI3 nanocrystals.
- Demonstrated efficient MEG via inverse Auger process occurring within 90 fs, attributed to slow hot-carrier cooling.
- Showcased superior performance compared to strongly confined lead sulfide (PbS) or lead selenide (PbSe) nanocrystals.
Conclusions:
- Formamidinium lead iodide nanocrystals effectively overcome the fast hot-carrier cooling issue plaguing conventional materials.
- The observed efficient MEG in perovskites offers a pathway to circumvent challenges like enhanced Coulombic coupling and reduced density of states.
- These findings pave the way for next-generation solar cells and efficient optoelectronic devices.
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