Defect engineering in wide bandgap perovskites for efficient and stable fully textured perovskite-silicon tandem solar cells
View Patent ↗Described herein are perovskite ink solutions comprising a composition of Formula I (APbI 3-z Br z ), a tribromide salt, and a solvent, wherein z is defined herein. Further described are perovskite films prepared using the ink solutions, methods for preparing the perovskite films, and use of the films in wide band gap single junction and tandem solar cells. As shown herein, solar cells fabricated using the perovskite films prepared from ink solutions comprising a tribromide salt achieve enhanced efficiency compared to solar cells comprising a perovskite film prepared without the tribromide salt.
1 . An ink solution, comprising:
(i) a perovskite precursor composition of Formula I:
APbI 3-z Br z (I),
wherein,
A is a cation selected from the group consisting of methylammonium (MA), tetramethylammonium (TMA), formamidinium (FA), cesium (Cs), rubidium (Rb), potassium (K), sodium (Na), butylammonium (BAH), phenethylammonium (PEA), phenylammonium (PHA), and guanidinium (GU), or a combination thereof; and
z is between 0.01 and 1.0;
(ii) a tribromide salt;
and
(iii) a solvent.
2 . The ink solution of claim 1 , wherein the tribromide salt is present in the ink solution at a molar ratio of about 0.05 to about 1.0% relative to the composition of Formula I.
3 . The ink solution of claim 2 , wherein the tribromide salt is present in the ink solution at a molar ratio of about 0.1 to about 0.5% relative to the composition of Formula I.
4 . The ink solution of claim 2 or 3 , wherein the tribromide salt is present in the ink solution at a molar ratio of about 0.2% relative to the composition of Formula I.
5 . The ink solution of claim 1 , wherein the tribromide salt is selected from the group consisting of tetrabutylammonium tribromide, tetramethylammonium tribromide, trimethylphenylammonium tribromide, hexamethylenetetramine tribromide, pyridinium tribromide, 4-(dimethylamino)pyridinium tribromide, boron tribromide, phosphorus tribromide, aluminum tribromide, and benzyltrimethylammonium tribromide.
6 . The ink solution of claim 1 , wherein the tribromide salt is an ammonium tribromide salt.
7 . The ink solution of claim 6 , wherein the ammonium tribromide salt is trimethylphenylammonium tribromide.
8 . The ink solution of claim 1 , wherein:
A is selected from the group consisting of Cs, FA, and MA, or a combination thereof, and
z is between 0.3 and 0.6.
9 . The ink solution of claim 8 , wherein:
A is Cs, FA, and MA, wherein the molar ratio of Cs to FA to MA is about 0.1:0.2:0.7; and
z is 0.45.
10 . The ink solution of claim 1 , wherein the solvent is selected from the group consisting of dimethyl sulfoxide, dimethylformamide, dichloromethane, tetrahydrofuran, γ-butyrolactone, 2-methoxyethanol, N,N′-Dimethylpropyleneurea, N-methyl-2-pyrrolidone, and acetonitrile, or a combination thereof.
11 . The ink solution of claim 1 , wherein:
the composition of Formula I is Cs 0.1 FA 0.2 MA 0.7 PbI 2.55 Br 0.45 ; and
the tribromide salt is trimethylphenylammonium tribromide, wherein the tribromide salt is present in the ink solution at a molar ratio of about 0.2% relative to the composition of Formula I.
12 . A method for preparing a perovskite film using the ink solution of claim 1 , comprising:
contacting the ink solution using a fast coating process onto a substrate to form a film, wherein the fast coating process is selected from the group consisting of blade coating, slot die coating, shear coating, gravure coating, brush coating, syringe coating, and screen printing.
13 . The method of claim 12 , wherein the fast coating process is blade coating.
14 . The method of claim 12 , wherein the perovskite film prepared has a thickness of about 300 nm to about 2000 nm.