Long-acting and stable perovskite solar cell and preparation method thereof

A perovskite solar cell, characterized in that a structure of the perovskite solar cell comprises:

• a substrate, an anode layer, a hole-transporting layer, a perovskite multi-protective layer, a composite electron-transporting layer, a hole blocking layer, and a metal cathode layer that are arranged sequentially from bottom to top of the structure of the perovskite solar cell;
• wherein the perovskite multi-protective layer comprises:
• a perovskite light-absorbing layer and a multifunctional protection layer, the perovskite multi-protective layer is configured to improve a stability of the perovskite solar cell through triple protection, and the triple protection comprises:
• an ion exchange reaction, a hydrophobic effect and hydrogen bonding based on raw materials of the perovskite solar cell, and passivation of perovskite defects;
• and
• wherein a preparation method of the perovskite solar cell comprises the following steps:
• preparing the anode layer on the substrate by using transparent glass as the substrate, and spin-coating a poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) solution on the anode layer to obtain the hole-transporting layer;
• spin-coating a perovskite precursor solution on the hole-transporting layer by using a one-step anti-solvent method;
• wherein the perovskite precursor solution is prepared by dissolving formamidinium iodide (FAI), methylammonium bromide (MABr), lead(II) bromide (PbBr2), and lead(II) iodide (PbI2) in a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) with a volume ratio of the DMF to the DMSO being 4:1 to obtain a first mixed solution, then dissolving cesium iodide (CsI) in DMSO to obtain a second mixed solution, and mixing the first mixed solution and the second mixed solution before spin-coating the perovskite precursor solution;
• and a speed of spin-coating the perovskite precursor solution is in a range of 5,000 revolutions per minute (rpm) to 10,000 rpm, and a time for spin-coating the perovskite precursor solution is 55 seconds (s);
• dropwise adding an anti-solvent of ethyl acetate (EA) containing ammonium hexafluorophosphate (NH4PF6) during spin-coating the perovskite precursor solution, wherein a concentration of the NH4PF6 in the anti-solvent of EA containing NH4PF6 is 1 milligram per milliliter (mg/mL), a time for dropwise adding the anti-solvent of EA containing the NH4PF6 is 15 s before finishing spin-coating the perovskite precursor solution, and an addition amount of the anti-solvent of EA is 150 microliters (μL);
• placing the hole-transporting layer coated with the perovskite precursor solution on a heating stage for an annealing reaction after finishing spin-coating the perovskite precursor solution, and obtaining the perovskite multi-protective layer after the annealing reaction is finished;
• wherein a lower portion of the perovskite multi-protective layer is a perovskite crystal with a composition of (Cs0.05FA0.81MA0.14)Pb(Br0.14I0.86)3 and an upper portion of the perovskite multi-protective layer is an ion-exchanged perovskite crystal with a composition of (Cs0.05FA0.81MA0.14)Pb(Br0.14I0.86-x(PF6)x)3 that together constitute the perovskite light-absorbing layer of the perovskite multi-protective layer, and a top surface of the perovskite multi-protective layer is the multifunctional protection layer made from the NH4PF6;
• spin-coating a [6,6]-phenyl C61 butyric acid methyl ester (PC61BM) solution on the multifunctional protection layer to obtain a PC61BM layer, and then depositing fullerene (C60) on the PC61BM layer to construct the composite electron-transporting layer;
• and
• wherein a lower layer of the composite electron-transporting layer is the PC61BM layer, and an upper layer of the composite electron-transporting layer is the C60;
• evaporating lithium fluoride (LiF) on the composite electron-transporting layer as the hole blocking layer, and then evaporating a metal material on the hole blocking layer to form the metal cathode layer, thereby obtaining the perovskite solar cell.