Compositions for solution processing of perovskites and methods of making the same
The present disclosure relates to a composition that includes a perovskite crystal, where the perovskite crystal is in the form of a powder, and the perovskite crystal is semiconducting and photovoltaically active.
1. A method comprising:
metering a first amount of a first salt comprising a methylammonium halide (MAX);
metering a second amount of a second salt comprising at least one of a formamidinium halide (FAX) or a cesium halide (CsX);
metering a third amount of a third salt comprising a PbI 2 ; and
combining at least two of the first amount, the second amount, or the third amount resulting in a first solid mixture, wherein:
X comprises at least one of iodide or bromide,
the first solid mixture is substantially free of dimethylammonium formate (DMAF),
each of the first salt, the second salt, and the third salt are in a solid form,
the first salt, the second salt, and the third salt provide a stoichiometry corresponding to a perovskite comprising Cs 1-x-y MA x FA y Pb(I 1-w Br w ) 3 , and
0<x<1, 0<y<1, and 0≤w≤1.
2. The method of claim 1 , further comprising:
mixing the first solid mixture, wherein:
the mixing converts at least a portion of the first solid mixture to a second solid mixture comprising the perovskite.
3. The method of claim 2 , wherein the second solid mixture has a particle size between 1 μm and 1 mm.
4. The method of claim 2 , wherein the mixing provides to the first solid mixture a specific grinding energy between 0.001 kWhr/kg and 1.0 kWhr/kg.
5. The method of claim 2 , further comprising after the mixing:
adding a solvent to the second solid mixture to produce a liquid mixture.
6. The method of claim 5 , wherein the liquid solvent comprises dimethylformamide.
7. The method of claim 5 , further comprising after the adding, storing the liquid mixture for a first period of time.
8. The method of claim 7 , wherein the first period of time is between twelve hours and six months.
9. The method of claim 7 , wherein after the storing of the liquid mixture, the liquid mixture is substantially free of DMAF.
10. The method of claim 7 , further comprising, after the storing of the liquid mixture:
coating a substrate with the liquid mixture to produce a liquid film comprising the liquid mixture on the substrate, and
treating the substrate and the liquid layer to produce a solid film comprising the perovskite.
11. The method of claim 1 , further comprising, after the combining, storing the first solid mixture for a second period of time.
12. The method of claim 11 , wherein the second period of time is between about twelve hours and six months.