Creating Fluorescent Perovskite Nanocrystals from Hardware Store Chemicals: A Synthesis Journey
0:00 Introduction to Perovskites: Introduces perovskites, highlighting their use in solar cells and their potential for high fluorescence. Mentions the efficiency and degradation challenges of perovskite solar cells, especially those containing lead.
2:18 Focus on Perovskite Nanocrystals: Shifts focus to perovskite nanocrystals, explaining how they fluoresce and how their color can be tuned by changing the halide anion.
3:10 Mechanosynthesis Approach: Explains the chosen synthesis method, mechanosynthesis (ball milling), using a 2018 paper as a guide. This method involves grinding bulk perovskite into fluorescent nanocrystals.
3:45 Hardware Store Chemicals: Emphasizes the goal of using readily available chemicals, outlining the starting materials: lead metal (from hardware store flashing or potentially found objects), nitric acid, sodium bromide (bromine pool chemical), and cesium carbonate (from the lab).
5:23 Hydrobromic Acid Synthesis: Describes the need to synthesize hydrobromic acid from sulfuric acid (drain cleaner) and sodium bromide. Discusses the decision to use older sulfuric acid samples for this step.
7:22 Hydrobromic Acid Distillation: Shows the process of distilling hydrobromic acid, emphasizing the importance of minimizing sulfuric acid carryover.
12:55 Testing for Sulfate Contamination: Demonstrates a test for sulfate contamination in the distilled hydrobromic acid using calcium chloride.
15:02 Cesium Bromide Synthesis: Prepares cesium bromide by reacting cesium carbonate with the synthesized hydrobromic acid.
16:55 Lead Bromide Synthesis: Starts with lead metal, showing the process of melting and solidifying it (potentially to remove copper from copperized lead flashing). Dissolves the lead in nitric acid and precipitates lead bromide by adding sodium bromide.
24:27 Lead Waste Disposal: Highlights the importance of responsible lead waste disposal, mentioning the use of sulfide ions to precipitate insoluble lead sulfide.
26:08 DMSO as a Solvent: Introduces dimethyl sulfoxide (DMSO) as a key solvent, discussing its properties, availability, and ethical concerns related to its use in alternative medicine.
31:33 Dissolving Lead and Cesium Bromides: Dissolves the lead bromide and cesium bromide in DMSO, observing unexpected early fluorescence.
33:55 Growing Perovskite Crystals: Attempts to grow cesium lead bromide crystals by heating the DMSO solution, noting the lack of initial success.
35:40 Copper in Lead Flashing: Revisists the copperized lead flashing, discussing concerns about copper contamination and performing a test to assess the copper content.
41:20 Ethanol Antisolvent Method: Explores the use of ethanol as an antisolvent to precipitate perovskite from the DMSO solution, observing promising results.
Note: The transcript ends before the final attempt to precipitate and potentially grow perovskite crystals using the ethanol antisolvent method. The outcome of this attempt is not documented in the provided text.