Disclosure of Invention
The invention aims to provide an imide compound, a preparation method thereof and application of a perovskite solar cell, and aims to develop a series of hole transport materials with simple synthesis process and excellent hole transport property.
In view of the above technical problems, the present invention aims to provide an imide compound which has the advantages of simple synthesis, high charge mobility, good stability, etc., and can be applied to perovskite solar cells as a non-doped hole transport material.
The technical scheme of the invention is as follows:
an imide compound having the formula (I):
r1 is selected from C1-C30 substituted or unsubstituted alkyl, C2-C30 substituted or unsubstituted alkenyl, C2-C30 substituted or unsubstituted alkynyl, C3-C30 substituted or unsubstituted cycloalkyl, C6-C60 substituted or unsubstituted aryl, C3-C30 substituted or unsubstituted heterocyclic aryl, C1-C30 substituted or unsubstituted alkoxy, C1-C30 substituted or unsubstituted silyl; r2 is selected from hydrogen, deuterium, halogen, cyano, C1-C30 substituted or unsubstituted alkyl, C2-C30 substituted or unsubstituted alkenyl, C2-C30 substituted or unsubstituted alkynyl, C3-C30 substituted or unsubstituted cycloalkyl, C6-C60 substituted or unsubstituted aryl, C3-C30 substituted or unsubstituted heterocyclic aryl, C1-C30 substituted or unsubstituted alkoxy, C1-C30 substituted or unsubstituted alkylthio, C1-C30 substituted or unsubstituted silyl;
ar is an arylamine structural unit with an electron donating characteristic, and is specifically represented as a substituted or unsubstituted diphenylamine, triphenylamine, carbazole and other structural units.
Preferably, R1 is selected from a C1-C18 linear or branched alkyl group, or an alkyl polyether of the formula:
wherein R3, R4, R5 and R6 are all alkyl groups with the number of C atoms less than 10, and n and m are less than or equal to 10.
Preferably, R2 is selected from hydrogen, fluorine atom, straight chain or branched chain alkyl of C1-C18, methoxy, methylthio.
Preferably, the Ar structural unit is selected from any one of the following structural units:
the imide containing structural formula includes, but is not limited to, the following compounds:
a perovskite solar cell device, at least one functional layer of the perovskite solar cell device contains the imide compound.
Preferably, the functional layer is a hole transport layer.
Compared with the prior art, the invention has the following remarkable advantages: 1. the organic compound based on the structure of the bithiophene imide is developed, the photoelectric characteristic of the compound can be effectively improved by utilizing the molecular design idea that the bithiophene imide has a large pi-conjugated planar structure and D-A-D (donor unit-receptor unit-donor unit), the material is ensured to have good pi-pi accumulation in a film state, and further has good charge transmission characteristic, and simultaneously, the HOMO energy level of the material is further regulated and controlled by introducing an arylamine structure into an end group, so that the hole mobility is improved; 2. the material has the advantages of simple synthesis process and high yield, can be used as an undoped hole transport material to be applied to perovskite solar cells, shows high efficiency and excellent stability, has the potential of replacing the existing hole transport material, and has good industrialization prospect.
Detailed Description
The invention is described in further detail below:
several embodiments will be given below to specifically explain the technical solution of the present invention. It should be noted that the following examples are only for the purpose of facilitating understanding of the present invention, and are not intended to limit the present invention.
The synthesis route of the present invention is as follows:
example 1
Synthesis of Compound C-1
Synthesis of Compounds 1-3:
firstly weighing 2.5g of compound 1-1, glacial acetic acid 20mL and 2.6g of compound 1-2, adding the mixture into a 50mL three-necked bottle, heating and refluxing for reaction for 20 hours, cooling to room temperature, pouring the mixture into a sodium carbonate solution, extracting by dichloromethane, and purifying by a silica gel column to obtain the compound 1-3 with the yield of 78%.
Synthesis of Compounds 1-5:
first, 2g of the compound 1 to 3, the compound 1 to 4(2.2equiv), tetrakistriphenylphosphine palladium (0.05equiv), and 30mL of toluene were weighed and charged into a 100mL two-necked flask, nitrogen was replaced three times with a diaphragm pump, and after heating and refluxing for 20 hours, the mixture was cooled to room temperature, washed with water and extracted with dichloromethane, and purified with a silica gel column to obtain the compound 1 to 5, with a yield of 87%.
Synthesis of Compounds 1-6:
firstly weighing 2g of compound 1-5, chloroform 50mL, glacial acetic acid and adding into a 250mL double-mouth bottle, then adding NBS (2.2equiv) in portions, stirring for 12 hours at room temperature, keeping out of the sun in the process, then pouring into water, extracting with dichloromethane, and purifying with a silica gel column to obtain the compound 1-6, wherein the yield is 80%.
Synthesis of Compounds 1-7:
firstly, 1g of compound 1-6, 250mL of toluene and 5 iodine granules are weighed and added into a 500mL flask, the mixture is stirred for 5 hours at room temperature under 400nm illumination, sodium sulfite solution is poured, dichloromethane is used for extraction, and silica gel column purification is carried out to obtain compound 1-7, wherein the yield is 95%.
Synthesis of Compound C-1:
1g of Compound 1-7, Compound 1-8(4, 4-dimethoxydiphenylamine (0.82g, 2.5equiv)), NaOtBu (2.5equiv), (t-Bu) were weighed out3P(0.12equiv),Pd2(dba)3(0.06equiv) toluene 20mL, was addedIn a 50mL flask, nitrogen was replaced three times with a diaphragm pump, and after heating reflux reaction for 20 hours, it was cooled to room temperature, washed with water and extracted with dichloromethane, and purified with a silica gel column to obtain compound C-1 with a yield of 85%.
Elemental analysis: theoretical value (C56H55N3O6S 4): c, 67.65; h, 5.58; n, 4.23; s, 12.90; measured value: c, 67.64; h, 5.54; n, 4.26; s,12.88, HRMS (ESI) M/z (M +1)+: theoretical value: 994.29, respectively; measured value: 994.30.
Example 2
Synthesis of Compound C-2
The specific synthetic procedure and operation of compound C-2 were the same as those of compound C-1 except that compound 2-1 was used instead of compound 1-4 in example 1.
Compound C-2: elemental analysis: theoretical value (C58H59N3O8S 4): c, 66.07; h, 5.64; n, 3.99; s, 12.16; measured value: c, 66.05; h, 5.61; n, 4.03; s,12.17, HRMS (ESI) M/z (M +1)+: theoretical value: 1054.31, respectively; measured value: 1054.27.
example 3
Synthesis of Compound C-3
The specific synthetic procedure and operation of compound C-3 are the same as those of compound C-1 except that compound 3-1 is substituted for compound 1-2 and compound 3-3 is substituted for compound 1-4 in example 1.
Compound C-3: elemental analysis: theoretical value (C64H71N3O6S 4): c, 69.47; h, 6.47; n, 3.80; s,11.59 found: c, 69.43; h, 6.51; n, 3.83; s,11.55, HRMS (ESI) m/z (M)+: theoretical value: 1105.42, respectively; measured value: 1105.43.
example 4
Synthesis of Compound C-4
The specific synthetic procedure and operation of compound C-4 are the same as those of compound C-3 except that compound 4-1 is substituted for compound 3-3 in example 3.
Compound C-4: elemental analysis: theoretical value (C74H91N3O6S 4): c, 71.29; h, 7.36; n, 3.37; s, 10.29; measured value: c, 71.27; h, 7.33; n, 3.39; s,10.31, HRMS (ESI) m/z (M)+: theoretical value: 1245.57, respectively; measured value: 1245.58.
examples 5 to 8
Synthesis of synthetic Compounds C-5 to C-8
The specific synthetic steps and operations of the compounds C-5, C-6, C-7 and C-8 are the same as those of the compounds C-1, C-2, C-3 and C-4, except that the compound 5-1 is used instead of the compound 1-8.
Example 9
Synthesis of Compound C-9
Synthesis of Compound C-9:
weighing 1g of Compound 1-7, Compound 9-1(2.5equiv), K2CO3(3equiv),Pd2(PPh3)4(0.1equiv), 10mL of water and 70mL of THF were placed in a 200mL flask, nitrogen was replaced three times with a diaphragm pump, and after heating and refluxing for 20 hours, the reaction mixture was cooled to room temperature, washed with water and extracted with methylene chloride, and purified with a silica gel column to obtain Compound C-9 in a yield of 78%.
Elemental analysis: theoretical value (C68H63N3O6S 4): c, 71.24; h, 5.54; n, 3.67; s, 11.19; measured value: c, 71.21; h, 5.52; n, 3.71; s,11.16, HRMS (ESI) m/z: theoretical value: 1145.36, respectively; measured value: 1146.37 (M +1)+。
Examples 10 to 12
Synthesis of synthetic Compounds C-10 to C-12
The specific synthetic procedures and operations of the compounds C-10, C-11 and C-12 are the same as those of the compound C-9 except that the compounds 2-4, 3-5 and 4-4 are respectively substituted for the compounds 1-7.
Examples 13 to 16
Synthesis of synthetic Compounds C-13 to C-16
The specific synthetic procedures and operations of the compounds C-13, C-14, C-15 and C-16 are the same as those of the compounds C-9, C-10, C-11 and C-12, except that the compound 13-1 is used instead of the compound 9-1.
A hole transport layer in the perovskite solar cell is prepared on the basis of the compound, and is applied to the titanium ore solar cell, and the method specifically comprises the following steps:
and (3) testing a device:
the perovskite solar cell adopts an n-i-p structure, and the specific structure is as follows:
ITO/Electron transport layer (SnO)2PCBM)/perovskite layer (MA)0.7FA0.3PbI2.85Br0.15) Hole transport layer (spiro-OMeTAD or a compound of the invention)/anode (Au)
Device example 1 (comparative example 1)
Substrate cleaning:
the ITO-coated transparent motor substrate is subjected to ultrasonic treatment in a commercial cleaning agent, washed in deionized water, and subjected to ultrasonic treatment in acetone: ultrasonic degreasing is carried out in an ethanol mixed solvent (volume ratio is 1: 1), baking is carried out in a clean environment until water is completely removed, and then ultraviolet light and ozone are used for cleaning.
Preparing a device:
spin coating 15nm SnO on ITO2(annealing at 180 ℃ for 1 hour) transferring the substrate into a glove box, and spin-coating 10nm PCBM (annealing at 100 ℃ for 10 minutes) as an electron transport layer; spin-coating 600nm perovskite layer (prepared by mixing MAI (0.7 mmol), FAI (0.3mmol), PbI2(0.925mmol),PbBr2(0.075mmol),DMSO(71μL),Pb(SCN)2(9.22mg) was dissolved in DMF (1mL) to make a spin-on solution), annealed at 100 ℃ for 5 minutes; the 40nm hole transport layer spiro-OMeTAD evaporated with 80nm gold as anode.
Device example 2 (comparative example 2)
This embodiment differs from device embodiment 1 in that: doping the hole transport layer spiro-OMeTAD of the perovskite solar cell device (doping with 4-tert-butylpyridine, lithium bis (trifluoromethanesulfonyl) imide).
Device example 3
This embodiment differs from device embodiment 1 in that: the hole transport material of the perovskite solar cell device is replaced by the compound C-1 (without doping) of the invention.
Device example 4
This embodiment differs from device embodiment 1 in that: the hole transport material of the perovskite solar cell device is replaced by the compound C-2 (without doping) of the invention.
Device example 5
This embodiment differs from device embodiment 1 in that: the hole transport material of the perovskite solar cell device is replaced by the compound C-3 (without doping) of the invention.
Device example 6
This embodiment differs from device embodiment 1 in that: the hole transport material of the perovskite solar cell device is replaced by the compound C-5 (without doping) of the invention.
Device example 7
This embodiment differs from device embodiment 1 in that: the hole transport material of the perovskite solar cell device is replaced by the compound C-9 (without doping) of the invention.
Device example 8
This embodiment differs from device embodiment 1 in that: the hole transport material of the perovskite solar cell device is replaced by the compound C-10 (without doping) of the invention.
Device example 9
This embodiment differs from device embodiment 1 in that: the hole transport material of the perovskite solar cell device is replaced by the compound C-11 (without doping) of the invention.
Device example 10
This embodiment differs from device embodiment 1 in that: the hole transport material of the perovskite solar cell device is replaced by the compound C-15 (without doping) of the invention.
Device example 11
This embodiment differs from device embodiment 1 in that: the hole transport material of the perovskite solar cell device is replaced by the compound C-17 (without doping) of the invention.
Device example 12
This embodiment differs from device embodiment 1 in that: the hole transport material of the perovskite solar cell device is replaced by the compound C-18 (without doping) of the invention.
Test example 1
Testing the photovoltaic performance of the device: the effective area of the device is 0.4cm2. And (3) testing conditions are as follows: spectral distribution AM1.5G, illumination intensity 100mW/cm2AAA solar simulator (tokoro, tokyo), J-V curve was measured with Keithly model 2400 digital source meter, all devices were simply packaged with uv glue and tested for normal measurement in atmospheric environment.
The results are shown in Table 1.
Table 1 device example corresponding performance table
From the performances of the device examples, it can be seen that compared with the comparative examples, the hole transport material designed by the invention has better photoelectric conversion efficiency and better stability compared with the undoped spiro-OMeTAD without doping, the efficiency is comparable to or even exceeds that of the doped spiro-OMeTAD, and the stability is more than one order of magnitude, which indicates that the material disclosed by the invention has obvious performance advantages compared with the current hole transport material.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.
In conclusion, the organic compound based on the bithiophene imide structure and the arylamine unit is synthesized, and in the molecules, the bithiophene imide structure unit has good conjugation property and planarity, so that the prepared material can form effective pi-pi accumulation in a thin film, and further has good charge mobility. And by a molecular design strategy of D-A-D, an arylamine structure is modified at the end group of the bithiophene imide structural unit, the HOMO energy level of the material is further regulated and controlled, the hole characteristic of the material is improved, and the good hole transmission characteristic of the material is finally realized. The material has good thermal stability, simple synthesis, easily obtained raw materials and solution processing. The hole transport material is applied to perovskite solar cells, and has good hole transport characteristics, excellent stability and excellent material performance. The imide structure can further passivate a perovskite layer, so that the stability of the battery can be effectively improved while high photoelectric conversion efficiency is realized. The hole transport material based on the invention can obtain high photoelectric conversion efficiency without doping, has obvious advantage in stability compared with the current commonly used hole transport material Spiro-OMeTAD, has the potential of replacing the current hole transport material, and has good industrialization prospect.