Working Paper
Authors
- Philip Nega Lawrence Berkeley National Laboratory ,
- Zhi Li Lawrence Berkeley National Laboratory ,
- Victor Ghosh Bronx High School of Science ,
- Janak Thapa Massachusetts Institute of Technology ,
- Shijing Sun Massachusetts Institute of Technology ,
- Noor Titan Putri Hartono Massachusetts Institute of Technology ,
- Mansoor Ani Najeeb Nellikkal Haverford College ,
- Alexander J. Norquist Haverford College ,
- Tonio Buonassisi Massachusetts Institute of Technology ,
- Emory M. Chan Lawrence Berkeley National Laboratory ,
- Joshua Schrier
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Fordham University
Abstract
We use a data-driven approach to discover the influence of trace amounts of water on perovskite crystal formation. Statistical analysis of 8,470 inverse-temperature crystallization lead iodide perovskite synthesis reactions, performed over 20 months using a robotic system, revealed discrepancies between the empirical crystal formation rate in experiments conducted under different ambient relative humidity conditions. We used the robotic system to conduct 1,296 controlled interventional experiments in which small amounts of water were deliberately introduced to the reactions. Addition of trace amounts of water promotes crystal formation for 4-methoxyphenylammonium lead iodide and iso-propylammonium lead iodide and inhibits crystal formation for dimethylammonium lead iodide and acetamidinium lead iodide. We also performed thin-film syntheses of these four materials and determined the grain size distributions using scanning electron microscopy. Addition of water results in smaller grain sizes for dimethylammonium and larger grain sizes for isopropylammonium, consistent with earlier or delayed nucleation, respectively.
Content
Supplementary material
Supplementary Information (text)
Description of data files and analysis codes; expanded discussion of materials and methods for the ITC and thin-film syntheses and SEM characterization; expanded discussion of sampling strategies; figures illustrating reaction outcomes for the 1296 ITC experiments as a function of composition; expanded version of Figure 3.
