Method for synthesizing perovskite precursor solution of formamidine-based ionic liquid, celldevice, and solar cell

1 . A method for synthesizing a perovskite precursor solution of a formamidine-based ionic liquid, comprising:

adding an organic sodium salt and a formamidine hydrochloride to ethanol, respectively, stirring and dissolving to obtain a formamidine hydrochloride solution and a sodium alkyl carboxylate solution;

dropwise adding the formamidine hydrochloride solution to the sodium alkyl carboxylate solution, and stirring a mixed solution at 25-60° C. for reaction for 24-36 h;

filtering the reacted mixed solution and extracting a filtrate, performing rotary evaporation on an obtained primary filtrate to remove a solvent ethanol, and performing oscillating washing with an organic solvent for 25-35 min;

performing secondary filtration on a washed solution and extracting a filtrate; performing rotary evaporation on an obtained secondary filtrate to remove the organic solvent, to obtain an organic acid formamidine ionic liquid; and

dissolving lead iodide and formamidine hydriodide into the organic acid formamidine ionic liquid for reaction for at least 5 h at 40-80° C. to obtain the perovskite precursor solution of a formamidine ionic liquid.

2 . The method according to claim 1 , wherein a molar ratio of the organic sodium salt to the formamidine hydrochloride is 1:1.5-2.5.

3 . The method according to claim 1 , further comprising:

adding the obtained organic acid formamidine ionic liquid to ethanol for dissolving, removing the ethanol via rotary evaporation repeatedly to obtain a pure product formamidine alkylcarboxylate ionic liquid.

4 . The method according to claim 1 , further comprising:

a molar ratio of a mixture of the organic sodium salt and the formamidine hydrochloride to the ethanol is 1:5-8.

5 . The method according to claim 1 , wherein the organic sodium salt is at least one of sodium alkyl carboxylate, sodium propionate, or sodium butyrate.

6 . A method for preparing a perovskite solar cell device, comprising:

cleaning a conductive glass substrate, spin-coating an electron transport material onto the conductive glass substrate, and spin-coating the perovskite precursor solution of a formamidine-based ionic liquid obtained by the method of claim 1 onto an electron transfer layer of the conductive glass substrate, and annealing to form a formamidine-based perovskite film;

spin-coating a hole transport layer material onto the formamidine-based perovskite film to obtain a hole transport layer, and depositing a modified layer and a metal electrode onto the hole transport layer via vacuum evaporation.

7 . The method according to claim 6 , further comprising:

mixing SnO 2 with deionized water in a mass ratio of 1:3-7 to obtain an electron transfer layer material, a SnO 2 solution;

spin-coating the SnO 2 solution on a conductive substrate for 20-40 s at 3500-4500 r/min by a spin coater for film forming, and annealing at 120-180° C. for at least 30 min; and

performing UV-ozone treatment on an annealed conductive substrate spin-coated with the electron transfer layer for at least 10 min.

8 . The method according to claim 6 , further comprising:

dissolving Spiro-OMeTAD into chlorobenzene, stirring and adding an acetonitrile solution of lithium bis(trifluoromethylsulfonyl)imide and 4-tert-butylpyridine to form the hole transport layer material; and

spin-coating the hole transport layer material on a surface of an FAPbI 3 active layer at 3500-4500 r/min for 20-40 s for film forming, and performing oxidization in the air for at least 24 h.

9 . The method according to claim 6 , wherein the modified layer is MoO 3 having a thickness of 3-7 nm, and the metal electrode is Au or Ag having a thickness of 80-120 nm.

10 . A solar cell, comprising a perovskite solar cell device, wherein the perovskite solar cell device is prepared by a method comprising:

cleaning a conductive glass substrate, spin-coating an electron transport material onto the conductive glass substrate, and spin-coating the perovskite precursor solution of a formamidine-based ionic liquid obtained by the method of claim 1 onto an electron transfer layer of the conductive glass substrate, and annealing to form a formamidine-based perovskite film;

spin-coating a hole transport layer material onto the formamidine-based perovskite film to obtain a hole transport layer, and depositing a modified layer and a metal electrode onto the hole transport layer via vacuum evaporation.

11 . The solar cell according to claim 10 , the method further comprising:

mixing SnO 2 with deionized water in a mass ratio of 1:3-7 to obtain an electron transfer layer material, a SnO 2 solution;

spin-coating the SnO 2 solution on a conductive substrate for 20-40 s at 3500-4500 r/min by a spin coater for film forming, and annealing at 120-180° C. for at least 30 min; and

performing UV-ozone treatment on an annealed conductive substrate spin-coated with the electron transfer layer for at least 10 min.

12 . The solar cell according to claim 10 , the method further comprising:

dissolving Spiro-OMeTAD into chlorobenzene, stirring and adding an acetonitrile solution of lithium bis(trifluoromethylsulfonyl)imide and 4-tert-butylpyridine to form the hole transport layer material; and

spin-coating the hole transport layer material on a surface of an FAPbI 3 active layer at 3500-4500 r/min for 20-40 s for film forming, and performing oxidization in the air for at least 24 h.

13 . The solar cell according to claim 10 , wherein the modified layer is MoO 3 having a thickness of 3-7 nm, and the metal electrode is Au or Ag having a thickness of 80-120 nm.