Novel Nonconjugated Polymer as Cathode Buffer Layer for Efficient Organic Solar Cells

Abstract

A novel nonconjugated polymer named poly(2-acrylamido-2-methyl-1-propanesulfonic acid sodium salt) (PAMPS-Na) was designed and synthesized. The PAMPS-Na has good solubility in polar solvents, such as water, methanol, and ethanol, which can be used as the cathode buffer layer in organic solar cells (OSCs) through solution processing without damaging the underlying active layer. Moreover, it was found that PAMPS-Na can significantly decrease the Al work function when it was modified with Al. To reveal its universal application in organic photovoltaic devices, a variety of photovoltaic donor materials, including two medium-band gap polymers, a wide-band gap polymer, and a small molecule donor were employed to fabricate OSCs. Compared with OSCs with Ca/Al electrode, the devices based on PAMPS-Na/Al exhibited higher photovoltaic performance, mainly because of the increased short-circuit current. Additionally, OSCs with PAMPS-Na/Al displayed better ambient stability than devices with Ca/Al. It is also interesting to find that the performance of the devices can tolerate a wide change of PAMPS-Na's thickness, enabling the potential for large-scale fabrication of OSCs. The results suggest that PAMPS-Na is a promising candidate as the cathode buffer layer to improve the efficiency and stability of OSCs.

Aminonaphthalimide‐Based Molecular Cathode Interlayers for As‐Cast Organic Solar Cells

“…The calculation formula is J = 9ee 0 mV 2 =8d 3 , where J represents the current density, and e and e 0 are the relative dielectric and vacuum dielectric constant, respectively, and V is the voltage drop, and d is approximately 100 nm. [45] Figure 6d shows the electron mobility curves of the optimal devices with different imide-based interfacial materials. It could be observed that the electron mobility of devices with NAA and NEA interlayers are 8.18 × 10 À 4 and 7.47 × 10 À 4 cm 2 V À 1 s À 1 , respectively.…”

Use of the Phen‐NaDPO:Sn(SCN)2 Blend as Electron Transport Layer Results to Consistent Efficiency Improvements in Organic and Hybrid Perovskite Solar Cells

“…Commonly used hole‐transporting layers include PEDOT:PSS and CuSCN, which are deposited on top of the ITO electrode. For the cathode, a variety of materials have been used for the interfacial layer to transport electrons including alkali metal halides and oxides, organic small molecules, conjugated, and nonconjugated polymers. Organic small molecules are particularly attractive for use as ETLs as they possess well‐defined chemical structures and they are easy to synthesize and process .…”

Engineered Cathode Buffer Layers for Highly Efficient Organic Solar Cells: A Review

“…A diverse variety of organic materials including non-conjugated/conjugated polymers, small-molecules, and fullerene derivatives, have been explored as CBL in OSCs. [96][97][98][99] Out of these materials, small molecule-based CBL offers advantages owing to their well-defined molecular weight and easy purification process. Bathocuproine (BCP) is one the films that has been applied as CBL in various OSCs devices.…”

“…Cai et al [99] designed and synthesized the non-conjugated novel polymer namely PAMPS-Na. It was soluble in polar OSCs, with and without PAMPS-Na layer.…”