Perovskite solar cell and preparation method therefor and power consuming device

1 . A perovskite solar cell, comprising a bottom electrode, a perovskite layer and a top electrode, wherein the perovskite layer comprises several layers of sub-perovskite films arranged in stack, and band gaps of two adjacent layers of the sub-perovskite films are different.

2 . The perovskite solar cell of claim 1 , wherein band gaps of the several layers of the sub-perovskite films sequentially vary from large to small.

3 . The perovskite solar cell of claim 1 , wherein the bottom electrode is a transparent electrode, and band gaps of the several layers of the sub-perovskite films sequentially vary from large to small in the direction from the bottom electrode to the top electrode.

4 . The perovskite solar cell of claim 1 , wherein the sub-perovskite films have a number of layers of 2-10.

5 . The perovskite solar cell of claim 1 , wherein a band gap difference between two adjacent layers of the sub-perovskite films is 0.01 eV-0.5 eV.

6 . The perovskite solar cell of claim 1 , wherein the several layers of sub-perovskite films include at least one wide-band-gap layer and one narrow-band-gap layer, wherein the wide-band-gap layer has a band gap G w of 1.2 eV-2.0 eV, the narrow-band-gap layer has a band gap G n of 0.8 eV-1.8 eV, and G n ≤G w .

7 . The perovskite solar cell of claim 1 , wherein the sub-perovskite films are evaporated films.

8 . The perovskite solar cell of claim 1 , wherein the sub-perovskite films have a thickness of 200 nm-2 μm.

9 . The perovskite solar cell of claim 1 , wherein the sub-perovskite films comprise a material selected from one or more of compounds represented by following structural formula (I):

ABX 3   (I)

wherein:

A represents first one or more mixed cations;

B represents second one or more mixed cations; and

X represents one or more mixed halide anions.

10 . The perovskite solar cell of claim 1 , wherein the perovskite solar cell is a thin film cell.

11 . A power consuming device, comprising the perovskite solar cell of claim 1 .

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

preparing a perovskite layer on a surface of the bottom electrode, the perovskite layer comprising several layers of sub-perovskite films arranged in stack, and band gaps of two adjacent layers of the sub-perovskite films being different; and

preparing a top electrode on the surface of the perovskite layer.

13 . The method of claim 12 , wherein the sub-perovskite films are prepared by means of an evaporation method.

14 . The method of claim 13 , wherein when the sub-perovskite films are prepared by means of the evaporation method, at least one of following characteristics is satisfied:

(1) an evaporation temperature is 100° C.-300° C.;

(2) an evaporation distance is 10 cm-50 cm;

(3) a degree of vacuum is (0.5-3)×10 −6 mbar;

(4) during the evaporation, the substrate is rotated, at a substrate temperature of 15° C.-30° C.; and

(5) after the evaporation of several layers of perovskite films is completed, an annealing step is performed.

15 . The method of claim 12 , wherein band gaps of the several layers of the sub-perovskite films sequentially vary from large to small.

16 . The method of claim 12 , wherein the sub-perovskite films have a number of layers of 2-10.

17 . The method of claim 12 , wherein a band gap difference between two adjacent layers of the sub-perovskite films is 0.01 eV-0.5 eV.

18 . The method of claim 12 , wherein the several layers of sub-perovskite films comprise at least one wide-band-gap layer and one narrow-band-gap layer, wherein the wide-band-gap layer has a band gap G w of 1.2 eV-2.0 eV, the narrow-band-gap layer has a band gap G n of 0.8 eV-1.8 eV, and G n ≤G w .

19 . The method of claim 12 , wherein the sub-perovskite films have a thickness of 200 nm-2 μm.

20 . The method of claim 12 , wherein the sub-perovskite films comprise a material selected from one or more of compounds represented by following structural formula (I):

ABX 3   (I)

wherein:

A represents first one or more mixed cations;

B represents second one or more mixed cations; and

X represents one or more mixed halide anions.