Dataset on the absorption of PCDTBT:PC70BM layers and the electro-optical characteristics of air-stable, large-area PCDTBT:PC70BM-based polymer solar cell modules, deposited with a custom built slot-die coater

The data presented in this article is related to the research article entitled “Fabrication of air-stable, large-area, PCDTBT:PC70BM polymer solar cell modules using a custom built slot-die coater” (D.I. Kutsarov, E. New, F. Bausi, A. Zoladek-Lemanczyk, F.A. Castro, S.R.P. Silva, 2016) [1]. The repository name and reference number for the raw data from the abovementioned publication can be found under: https://doi.org/10.15126/surreydata.00813106. In this data in brief article, additional information about the absorption properties of PCDTBT:PC70BM layers deposited from a 12.5 mg/ml and 15 mg/ml photoactive layer dispersion are shown. Additionally, the best and average J-V curves of single cells, fabricated from the 10 and 15 mg/ml dispersions, are presented.


Specifications
PCDTBT:PCBM-based single cells were fabricated from different photoactive layer inks to investigate the effect of the dispersion concentration on the device characteristics.
The data can be used as a comparison and a benchmark for other researchers, who work on the field of fabrication of large-area polymer solar cells.

Thin film characterization
The dataset in this article shows a dependence of the PCDTBT:PCBM layer properties on the deposition temperature. This is directly related to an alteration of the optical density of the deposited film and hence, the thickness of the films in Figs. 1 and 2. The measured thickness for photoactive inks with concentrations of 10, 12.5, and 15 mg/ml, which were deposited at 50, 70, and 90°C, are reported by Kutsarov et al. [1], whereas the raw data, used for the compiling of the graph, is furthermore included in the excel spread sheet in the public repository.

Solar cell characterization
The J-V characteristics of PCDTBT:PC 70 BM based devices, which were fabricated from a 10 and 15 mg/ml photoactive layer dispersion, are shown in Figs. 3 and 4, respectively. The detailed device characteristics are shown in Supplementary information Table S1 and S2 by Kutsarov et al. [1]. It can be seen that the average characteristics of the cells are reduced, compared to the characteristics of the best performing cell. This is due to fabrication defects, as reported by Kutsarov et al. [1].

Materials
For the optical characterization in this data in brief, PCDTBT:PC 70 BM layers were deposited with a custom built slot-die coater on glass substrates. The photoactive layer ink consisted of the donor material PCDTBT (SOL 4280, Solaris Chem Inc.) and [6]-Phenyl-C71-butyric acid methyl ester (PC 70 BM, Solenne BV) as the acceptor material. PCDTBT and PC 70 BM were mixed in a 1:4 wt ratio and dispersed in a 3:1 solvent mixture by volume of anhydrous o-DCB and CB (1,2-dichlorobenzene and chlorobenzene) to achieve a total concentration of 35 mg/mL [1]. The donor-acceptor mixture was stirred at room temperature until complete dissolution and then diluted to a desired concentration (10, 12.5, or 15 mg/ml).

Sample and solar cell fabrication
Prior to the deposition of the PCDTBT:PC 70 BM dispersion, the glass substrates were cleaned in an ultrasonic bath sequentially for 5 min in Decon 90 detergent solution with deionized water (DI), DI, acetone, and methanol. Then, the substrates were blown dry with a nitrogen gun and treated with an oxygen plasma for 5 min (100 W, 15 sccm O2, Emitech K1050X plasma cleaner). The PCDTBT:PC 70 BM layers were deposited under ambient conditions on top of the glass substrate, at a substrate temperature of 50°C, 70°C, or 90°C. A flow rate of 100 ml/min, coating speed of 18 mm/s, and a screw gap of 200 mm were used. After the deposition, the layers were annealed for 10 min at 70°C to ensure the evaporation of any excess solvents. The complete devices comprised an inverted structure of glass-ITO/ZnO/PCDTBT:PC 70 BM/MoO3/Al and were fabricated according to the experimental details reported by Kutsarov et al. [1].

Methods
To characterize the PCDTBT:PC 70 BM layers absorption spectra, UV-visible (UV-vis) spectroscopy was used (Varian Cary 5000 UV-vis-NIR spectrophotometer). The spectra were recorded through a shadow mask with a circular opening (diameter of 5 mm), which was placed at the center of the slotdie coated layer as reported by Kutsarov et al. [1]. The reported spectra represent the average of two spectra, measured for each sample in the wavelength range from 300 nm to 900 nm relative to a glass reference. Current-voltage (I-V) characterization was conducted using a Keithley 2400 source measurement apparatus in a four-wire setup in ambient atmosphere with an ORIEL solar simulator (class ABA) at AM 1.5 G. A silicon reference cell (PV Measurements, Inc. 20 mm Â 20 mm) was used for the calibration of the illumination source to 1 Sun (100 mW/cm 2 ).