Pyrene-Imidazole Based Aggregation Modifier Leads to Enhancement in Efficiency and Environmental Stability for Ternary Organic Solar Cells.

Hui Lin,Caijun Zheng,Silu Tao,Xiaoyang Du,Lijuan Li

doi:10.3389/fchem.2018.00578

Hui Lin, Caijun Zheng + Show 3 more

Open Access

https://doi.org/10.3389/fchem.2018.00578

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Abstract

A novel pyrene-imidazole derivative (PyPI), which can form effcient π-π stacking in solid film, has been utilized in organic solar cells (OSCs). The stacking of small a molecule PyPI can facilitate a charge transfer and suppress fullerene aggregation. As a result, PTB7-Th: PyPI: PC71BM based ternary OSC exhibits a high power conversion efficiency (PCE) of 10.36%, which presents a 15.88% increase from the binary device (8.94%). Concurrently, the ternary OSC shows a much better thermal and light illumination stability. Under continuous 60°C annealing for 3 h, in atmosphere, the device still remains at 94.13% efficiency more than the pristine state, while the control device remains at 52.47% PCE. Constant illumination under Air Mass (AM) 1.5G irradiation (100 mW cm−2) in atmosphere, the PCE of OSC remains at 72.50%. The high conversion efficiency and excellent environmental stability of the PyPI based ternary OSC, has narrowed the gap between laboratory investigation and industrial production.

Highlights

Solvent processed organic solar cells (OSCs) have attracted extensive attention for their superiority in achieving high power conversion efficiency (PCE), low fabrication cost and fascinating potential application in flexible electronics (Kaltenbrunner et al, 2012; Chen et al, 2014; Cui et al, 2017; Bergqvist et al, 2018; Cheng et al, 2018; Zhang H. et al, 2018)
The small molecule PyPI can form efficient π-π stacking in a solid film, which is beneficial to accelerate a charge transfer in an active layer
It is well-known that the fullerene aggregates in the interspace between the stacked clearances of polymers, while the small molecule PyPI can form efficient π-π stacking in the clearance in a polymer, which can suppress this inferior phenomenon as indicated in the diagram of Figure 1A (Liu et al, 2017).We tested through cyclic voltammetry, that the LOMO and HOMO levels of the small molecule PyPI was −2.37 and −5.42

Summary

Introduction

Solvent processed organic solar cells (OSCs) have attracted extensive attention for their superiority in achieving high power conversion efficiency (PCE), low fabrication cost and fascinating potential application in flexible electronics (Kaltenbrunner et al, 2012; Chen et al, 2014; Cui et al, 2017; Bergqvist et al, 2018; Cheng et al, 2018; Zhang H. et al, 2018). 10% PyPI doped ternary OSC showed a high PCE of 10.36% with an optimized JSC of 19.26 mA/cm2, which exhibited a 15.88% enhancement from the control device.

Results

Conclusion