A kind of preparation method of the thin-film solar cells based on narrowband gap conjugated polymer
Technical field
The invention belongs to technical field of thin-film solar, be specially a kind of preparation method of the thin-film solar cells based on narrowband gap conjugated polymer.
Background technology
Polymer thin-film solar cell have lightweight, flexibility, with low cost, technology simple, be easy to large tracts of land processing, plurality of advantages such as easy for installation, thereby has very application prospects.Yet the energy conversion efficiency of conjugated polymer thin films solar cell is lower at present, can not satisfy business-like requirement.The band gap that a key factor of limit polymerization thing solar battery efficiency is exactly a light absorbent is wide, and absorption spectrum and solar spectrum do not match, thereby has caused the loss of energy.
Novel narrowband gap conjugated polymer: poly-[2, and 6-(4,4-two-(2-ethylhexyl)-cyclopenta two thiophene-4, the 7-diazosulfide] the electrochemistry band gap be 1.75 electron-volts of (Advanced Materials, 2006,18,2884-2889), optical band gap is 1.46 electron-volts of (Advanced Functional Materials, 2007,17,632-636), can fully absorb sunlight, improve the utilization ratio of sunlight.PCPDTBT has become light absorption and the electron donor material that has potentiality in the conjugated polymer thin films area of solar cell.In the conjugated polymer thin films solar battery structure, electron donor material needs and electron acceptor material forms the inierpeneirating network structure with the yardstick that necessarily is separated, to realize exciton dissociation and charge-trapping.But, for by narrowband gap conjugated polymer poly-[2,6-(4,4-two-(2-ethylhexyl)-cyclopenta two thiophene-4,7-diazosulfide] and [6,6]-2-phenyl-C
61The bulk heterojunction thin-film solar cells that-2-butyric acid formicester is formed because the yardstick that is separated of two-phase is less, is unfavorable for the transmission and the collection of photogenerated charge, has limited the raising of energy content of battery conversion efficiency.
Summary of the invention
The objective of the invention is to have gathering in the photosensitive layer that exists in the thin-film solar cells in order to solve [2,6-(4,4-two-(2-ethylhexyl)-cyclopenta two thiophene-4,7-diazosulfide] and [6,6]-2-phenyl-C
61The yardstick that is separated of two kinds of components of-2-butyric acid formicester is less, the problem that causes the energy conversion efficiency of battery not to be further improved.The present invention is by containing poly-[2,6-(4,4-two-(2-ethylhexyl)-cyclopenta two thiophene-4,7-diazosulfide] (being called for short PCPDTBT) and [6,6]-2-phenyl-C
61Add high boiling solvent 1 in the chlorobenzene solution of-2-butyric acid formicester (being called for short PCBM), 3-dimethyl-imidazolinone (being called for short DMI), play a role in the solvent evaporates process of DMI after spin-coating film, two of control PCPDTBT and PCBM be separated yardstick and then the short circuit current and the energy conversion efficiency of raising battery.
A kind of preparation method of the thin-film solar cells based on narrowband gap conjugated polymer, its Step By Condition is as follows:
The structure formation of described solar cell comprises the glass substrate 1 that connects in turn, indium tin oxide anode layer 2, by poly-(3,4-epidioxy ethylthiophene) and the anode modification layer 3 that constitutes of poly styrene sulfonate, photosensitive layer 4 and the aluminium cathode layer 5 that constitutes by the blend of narrowband gap conjugated polymer and fullerene derivate; Narrowband gap conjugated polymer wherein is poly-[2,6-(4,4-two-(2-ethylhexyl)-cyclopenta two thiophene-4,7-diazosulfide], and it is [6,6]-2-phenyl-C that fullerene is inhaled derivative
61-2-butyric acid formicester.
In inert-atmosphere glove box, will gather [2,6-(4,4-two-(2-ethylhexyl)-cyclopenta two thiophene-4,7-diazosulfide] and [6,6]-2-phenyl-C
61-2-butyric acid formicester is dissolved in the chlorobenzene solvent with 1: 3 mass ratio, obtains mixed solution I, and wherein, the concentration of poly-[2,6-(4,4-two-(2-ethylhexyl)-cyclopenta two thiophene-4,7-diazosulfide] is 7 mg/ml, [6,6]-2-phenyl-C
61The concentration of-2-butyric acid formicester is 21 mg/ml, and 50 ℃ added thermal agitation after 2 hours, stops heating, continuing to stir 12 hours, then, is to add 1 of 20-70 milliliter among every milliliter of mixed solution I in proportion, the 3-dimethyl-imidazolinone continues to stir 12 hours, obtains mixed solution I I;
To be etched into fine strip shape at the indium tin oxide anode layer 2 on the glass substrate 1, the workpiece of the indium tin oxide of the good fine strip shape of etching is cleaned up, put into baking oven, 120 ℃ of oven dry, again this workpiece is placed on the carriage of film applicator, filtering head by 0.45 micron, to gather (3,4-epidioxy ethylthiophene) and the solution of poly styrene sulfonate (be called for short PEDOT:PSS) evenly be coated with completely whole slice, thin piece, spin-coating film, rotating speed are that per minute 3000 changes, and the film that forms one deck 40 nanometer thickness in this this work piece surface is an anode modification layer 3, put into baking oven again, 120 ℃ were heated 30 minutes;
The preparation that baking is good has the workpiece of anode modification layer 3 to transfer in the glove box, place it in after the cooling on the carriage of film applicator, the filtering head of the mixed solution I I that stirs by 0.45 micron be evenly coated in anode modification layer 3 above, spin-coating, rotating speed is that per minute 900 changes, and obtaining thickness is the photosensitive layer 4 of 100 nanometers;
The workpiece that scribbles photosensitive layer 4 is taken out from glove box with shifting bottle, put into vacuum coating equipment, vacuumize, when vacuum degree reaches 4 * 10
-4During Pascal, evaporate the aluminium cathode layer 5 of 80 nanometer thickness; Obtain a kind of thin-film solar cells based on narrowband gap conjugated polymer.
Make the polymer thin-film solar cell that structure is ITO/PEDOT:PSS/PCPDTBT:PCBM/Al by above step, the effective area of battery is 12 square millimeters.
Be the performance of the narrowband gap conjugated polymer thin-film solar cells of test the inventive method preparation under the AM 1.5G simulated solar irradiation of 100 milliwatt/square centimeters in intensity, comprise open circuit voltage, short circuit current, energy conversion efficiency and fill factor, curve factor.
Table 1 has been listed DMI: the volume proportion of mixed solution I is respectively 0,2: 100,4: 100,7: the performance parameter of the polymer thin-film solar cell of preparation in 100 o'clock.As can be seen from Table 1; Along with the increase of the content of DMI, the short circuit current of battery increases thereupon, and as DMI: when the volume proportion of mixed solution I reached 4: 100, it is maximum that short circuit current reaches, and is 10.42 milliamperes/square centimeter, and at this moment, it is maximum that energy conversion efficiency also reaches: 2.64%.When DMI content continued to increase, short circuit current and energy conversion efficiency all descended to some extent.And open circuit voltage and fill factor, curve factor are little with the DMI content.
Beneficial effect: the preparation method who the present invention relates to a kind of high efficiency thin-film solar cells based on narrowband gap conjugated polymer.Be specially at poly-[2,6-(4,4-two-(2-ethylhexyl)-cyclopenta two thiophene-4,7-diazosulfide] and [6,6]-2-phenyl-C
61Add boiling point in the-2-butyric acid formicester blend solution and be 224 ℃ 1,3-dimethyl-imidazolinone, poly-in the photosensitive layer in order to improve [2,6-(4,4-two-(2-ethylhexyl)-cyclopenta two thiophene-4,7-diazosulfide] and [6,6]-2-phenyl-C
61Two of-2-butyric acid formicester the yardstick that is separated improves the transmission path in light induced electron and hole, thereby has reduced the series resistance of battery, has improved the collection efficiency of photogenerated charge, improves the short circuit current and the energy conversion efficiency of battery.To not add 1, the battery of 3-dimethyl-imidazolinone is compared with the battery that has added DMI (DMI: the volume proportion of mixed solution I is 4: 100): the series resistance of battery drops to 12.55 ohm by 24.9 ohm, has reduced 50%; Short circuit current increases to 10.42 milliamperes/square centimeter by 7.68 milliamperes/square centimeter, has improved 36%; Energy conversion efficiency is increased to 2.64% by 1.88%, has improved 40%.
Description of drawings
Fig. 1 is the battery structure schematic diagram that the present invention adopts.
Fig. 2 is the molecular formula of material therefor among the present invention.Wherein: a is poly-[2,6-(4,4-two-(2-ethylhexyl)-cyclopenta two thiophene-4,7-diazosulfide]; B is [6,6]-2-phenyl-C
61-2-butyric acid formicester; C is 1, the 3-dimethyl-imidazolinone.
Fig. 3 is that Comparative Examples 1 is the current-voltage characteristic curve figure that tests under the AM 1.5G simulated solar irradiation of 100 milliwatt/square centimeters in intensity.
Fig. 4 is that embodiment 1 is the current-voltage characteristic curve figure that tests under the AM 1.5G simulated solar irradiation of 100 milliwatt/square centimeters in intensity.
Fig. 5 is that embodiment 2 is the current-voltage characteristic curve figure that tests under the AM 1.5G simulated solar irradiation of 100 milliwatt/square centimeters in intensity.
Fig. 6 is that embodiment 3 is the current-voltage characteristic curve figure that tests under the AM 1.5G simulated solar irradiation of 100 milliwatt/square centimeters in intensity.
Embodiment
Comparative Examples 1
In inert-atmosphere glove box, PCPDTBT and PCBM are dissolved in the chlorobenzene solvent with 1: 3 mass ratio, obtain mixed solution I, wherein, the concentration of PCPDTBT is 7 mg/ml, the concentration of PCBM is 21 mg/ml.50 ℃ added thermal agitation after 2 hours, closed heating, continued to stir 24 hours.
To be etched into fine strip shape at the indium tin oxide anode layer 2 on the glass substrate 1, the workpiece of the indium tin oxide of the good fine strip shape of etching is cleaned up, put into baking oven, 120 ℃ of oven dry, again this workpiece is placed on the carriage of film applicator, filtering head by 0.45 micron, the solution of PEDOT:PSS evenly is coated with completely whole slice, thin piece, spin-coating film, rotating speed is that per minute 3000 changes, the film that forms one deck 40 nanometer thickness in this this work piece surface is an anode modification layer 3, puts into baking oven again, and 120 ℃ were heated 30 minutes;
The preparation that baking is good has the workpiece of anode modification layer 3 to transfer in the glove box, after the cooling, place it on the carriage of film applicator, with the mixed solution I that the stirs filtering head by 0.45 micron be evenly coated in anode modification layer 3 above, spin-coating, rotating speed is that per minute 900 changes, and obtaining thickness is the photosensitive layer 4 of 100 nanometers;
The workpiece that scribbles photosensitive layer 4 is taken out from glove box with shifting bottle, put into vacuum coating equipment, vacuumize, when vacuum degree reaches 4 * 10
-4During Pascal, evaporate the aluminium cathode layer 5 of 80 nanometer thickness; Obtain a kind of thin-film solar cells.
Embodiment 1
In inert-atmosphere glove box, PCPDTBT and PCBM are dissolved in the chlorobenzene solvent with 1: 3 mass ratio, obtain mixed solution I, wherein, the concentration of PCPDTBT is 7 mg/ml, the concentration of PCBM is 21 mg/ml.50 ℃ added thermal agitation after 2 hours, closed heating, continued to stir 12 hours.Then, add DMI, ratio is that every ml soln adds 20 microlitre DMI, and the volume proportion of DMI and mixed solution I is 2: 100.Continue to stir 12 hours, obtain mixed solution I I;
To be etched into fine strip shape at the indium tin oxide anode layer 2 on the glass substrate 1, the workpiece of the indium tin oxide of the good fine strip shape of etching is cleaned up, put into baking oven, 120 ℃ of oven dry, again this workpiece is placed on the carriage of film applicator, filtering head by 0.45 micron, the solution of PEDOT:PSS evenly is coated with completely whole slice, thin piece, spin-coating film, rotating speed are that per minute 3000 changes, and form the film of one deck 40 nanometer thickness in this this work piece surface, as anode modification layer 3, put into baking oven again, 120 ℃, heated 30 minutes;
The preparation that baking is good has the workpiece of anode modification layer 3 to transfer in the glove box, after the cooling, place it on the carriage of film applicator, with the mixed solution I I that the stirs filtering head by 0.45 micron be coated in equably anode modification layer 3 above, spin-coating, rotating speed is that per minute 900 changes, and obtaining thickness is the photosensitive layer 4 of 100 nanometers;
The workpiece that scribbles photosensitive layer 4 is taken out from glove box with shifting bottle, put into vacuum coating equipment, vacuumize, when vacuum degree reaches 4 * 10
-4During Pascal, evaporate the aluminium cathode layer 5 of 80 nanometer thickness; Obtain a kind of thin-film solar cells based on narrowband gap conjugated polymer.
Embodiment 2
Preparation of devices method and condition are with embodiment 1, and different is when configuration solution, adds 40 microlitre DMI in every milliliter of mixed solution I, and DMI and mixed solution I volume proportion are 4: 100;
Embodiment 3
Preparation of devices method and condition are with embodiment 1, and different is when configuration solution, adds 70 microlitre DMI in every milliliter of mixed solution I, and the volume proportion of DMI and mixed solution I is 7: 100.
The technical parameter of a kind of thin-film solar cells based on narrowband gap conjugated polymer that a kind of thin-film solar cells of Comparative Examples 1 and embodiment 1-3 obtain sees Table 1.
Table 1
|
DMI: mixed solution I (volume proportion) |
Open circuit voltage (V) |
Short circuit current (mA/cm
2)
|
Fill factor, curve factor |
Energy conversion efficiency (%) |
Series resistance (Ω) |
Comparative Examples 1 |
0 |
0.68 |
7.68 |
0.36 |
1.88 |
24.90 |
Embodiment 1 |
2∶100 |
0.67 |
8.91 |
0.34 |
2.00 |
19.64 |
Embodiment 2 |
4∶100 |
0.66 |
10.42 |
0.38 |
2.64 |
12.55 |
Embodiment 3 |
7∶100 |
0.66 |
9.36 |
0.35 |
2.17 |
12.51 |