Data related to the PC71BM loading and it's impact on nanostructuring for blend of PBDTTT-EFT:PC71BM bulk heterojunction solar cell

The data included in this article is based on additional supporting information presented in our recent publication Komilian et al. [1]. The role of acceptor material (PC71BM) in restructuring copolymer PBDTTT-EFT from its relaxed pristine structure to interfaces suitable for exciton dissociation is discussed. The analysis of data indicates that the impact of acceptor material on nanostructuring initiates concurrent processes some of which supports and some impedes charge extractions. Therefore, this manuscript is designed to identify these processes and give and account of their impact on power conversion efficiency.


Value of the Data
IV data presented in this article is based on several samples tested to identify the reproducibility of the results and providing further evidence to the conclusions made.
Raman spectroscopy presented here identifies the impact of 685 nm laser used on collected data.
The 785-nm laser used in the original manuscript can only provide evidence for PBDTTT-EFT vibrational mode impacted by PC 71 BM content.
The analysis of surface morphology using AFM further supports our interpretation of donor acceptor Nano structuring based on device surface roughness.

Data
In order to improve power conversion efficiency of blend of PBDTTT-EFT:PC 71 BM solar cell, it is better to have insight into how donor acceptor material interface will form within the thin film structure. To this end, purposely various percentage loading of PC 71 BM was introduced in the blend, to observe its impact on parameters such as power conversion efficiency, fill factor, Short circuit current density, open circuit voltage, device shunt and series resistance. The data presented here are based on additional experimental observation reported in our recent paper [1]. Electrical characterisation of these devices are shown in Fig. 1 and after analysis, summarized and presented in Table 1. To elaborate on the mechanisms for exciton creation, dissociations and finally charge extractions it is necessary to understand the role of PC 71 BM within the blend and how it may impact the polymer  Electrical parameters extracted from J-V curves in Fig. 1.

Ratio
Device phase. To assist us with this, it was found necessary to have experimental evidences associated with these impacts. Also, experimental results associated with Raman and AFM are also included here to support readers to have clear picture to the approaches we have taken (Figs. 2 and 3).

Experimental design, materials, and methods
Pre-fabricated ITO/glass substrates were first cleaned using ultra sonic bath with three step process; deionised water, acetone, isopropanol and left to dry in nitrogen environment [2]. PEDOT: PSS purchased from Ossila was filtered and then spin coated onto the substrate at a speed of 5,000 rpm for 30 s and then baked on a hotplate at 120°C for 10 min. A DektakXT thickness profiler accurately  measured the film to be 30-40 nm. The substrate was then transferred to a nitrogen glove box maintained at 0.1 ppm for O2 and H2O level left for 30 min before fabricating the active layer. PBDTTT-EFT: PC 71 BM (1-Material, used as received) with concentration of 25 mg mL −1 in 1,2dichlorobenzene but with blend ratios of 1:0.5, 1:1, 1:1.15, 1:2 and 1:3 were produced. The pre-tested PBDTTT-EFT: PC 71 BM spin-casted at 600 rpm for 18 s resulted in a film thickness of~100 nm. After fabrication of the active layer, substrates then vacuum dried for 5 min at −100 kPa ready for surface washing with 60 µL of Ethanol purchased from Sigma Aldrich and drop cast at 4000 rpm for 30 s. For fabrication of top electrodes, substrate was transferred to a metallisation rig (Auto 500) via an interconnecting chamber. First 10 nm of Calcium (sigma Aldrich) was fabricated at a rate of 0.1 nm s −1 using mask aligner. After a delay time of 5 minutes 100 nm of Aluminium was then deposited through the mask aligner at a rate of 0.1 nm s −1 for the first 20 nm and then at a rate of 0.5 nm s −1 for the remaining 80 nm. A microbalance quartz crystal monitor (Intellmetrics IL 150) was used to measure the deposition rate as well as the Aluminium thickness. During the deposition, the chamber vacuum was maintained below 10 −6 Torr. For Raman and AFM studies, no metallisation were used.
The active area for each device was 0.13 cm 2 , illuminated through a shadow mask under 1 SUN condition using 1.5 AMG filter (LOT-LSZ389) and xenon arc lamp solar simulator (LOT-LS0306). I-V characteristics were collected using Keithley 2400 source meter. To test the accuracy of solar simulator, silicon reference solar cell (LOT-LS0041) which its accuracy is certified by National renewable energy laboratory was used to adjust the input power. The full experimental detail and the method of analysis and device characteristic parameters are presented in our previous communication [3].
Raman measurements were collected using (Renishaw inVia) with 685 nm excitation laser. The experimental set up and methodology is previously presented [4]. The device morphology was performed using Agilent AFM 5400 series. The analysis of data is based on film surface roughness previously reported [5].