Polymer photo voltaic cells, identified for his or her gentle weight and adaptability, are perfect for wearable gadgets. But, their broader use is hindered by the poisonous halogenated solvents required of their manufacturing. These solvents pose environmental and well being dangers, limiting the attraction of those photo voltaic cells. Various solvents, that are much less poisonous, sadly, lack the identical solubility, necessitating greater temperatures and extended processing occasions.
This inefficiency additional impedes the adoption of polymer photo voltaic cells. Creating a technique to get rid of the necessity for halogenated solvents may considerably improve the effectivity of natural photo voltaic cells, making them extra appropriate for wearable expertise.
In a lately revealed paper, researchers define how bettering molecular interactions between the polymer donors and the small molecule acceptors utilizing side-chain engineering can scale back the necessity for halogenated processing solvents.
The paper was lately revealed in Nano Analysis Power.
“Mix morphology of polymer donors and small molecule acceptors are extremely affected by their molecular interactions, which will be decided by interfacial energies between the donor and acceptor supplies. When their floor pressure values are related, the interfacial energies and molecular interactions between the donors and the acceptors are anticipated to be extra favorable,” mentioned Yun-Hello Kim, a professor at Gyeongsang Nationwide College in Jinju, Republic of Korea. “To boost the hydrophilicity of the polymer donors and scale back molecular demixing, side-chain engineering could be a believable avenue.”
The Function of Aspect-Chain Engineering
Aspect-chain engineering is when a chemical group, referred to as a aspect chain, is added to the principle chain of a molecule. The chemical teams within the aspect chain have an effect on the properties of the bigger molecule. Researchers theorized that including oligoethylene glycol (OEG)-based aspect chains would enhance the hydrophilicity of the polymer donors due to the oxygen atoms within the aspect chains. A molecule with hydrophilicity is interested in water.
A mix of hydrocarbon and hydrophilic oligoethylene glycol (2EG) carried out higher than the usual solvent when utilized in PSC creation, primarily based on general efficiency and thermal stability. Credit score: Nano Analysis Power, Tsinghua College Press
Variations within the hydrophilicity of the polymer donors and the small molecule acceptors can affect how they work together. With elevated hydrophilicity of the polymer donors and improved interactions between them and the small molecule acceptors, non-halogenated processing solvents can be utilized with out sacrificing the efficiency of the photo voltaic cell. In truth, polymer photo voltaic cells made with OEG-based aspect chains connected to a benzodithiophene-based polymer donor had the next energy conversion effectivity at 17.7% in comparison with 15.6%.
Enhanced Effectivity and Stability
With a purpose to evaluate outcomes, researchers designed benzodithiophene-based polymer donors with both an OEG aspect chain, hydrocarbon aspect chains, or aspect chains that had been 50% hydrocarbon and 50% OEG. “This elucidated the impact of side-chain engineering on mix morphology and efficiency of non-halogenated solvent-processed polymer photo voltaic cells,” mentioned Kim. “Our findings exhibit that polymers with hydrophilic OEG aspect chains can improve the miscibility with small molecule acceptors and enhance energy conversion effectivity and gadget stability of polymer photo voltaic cells throughout non-halogenated processing.”
Along with improved energy conversion effectivity, the polymer photo voltaic cells with the OEG-based aspect chains had enhanced thermal stability. Thermal stability is important for scaling polymer photo voltaic cells, so researchers heated them to 120 levels Celsius after which in contrast the ability conversion effectivity. After 120 hours of heating, the polymers with the hydrocarbon aspect chains had solely 60% of their preliminary energy conversion effectivity and had irregularities on their floor, whereas the mix of hydrocarbon and OEG retained 84% of their preliminary energy conversion effectivity.
“Our outcomes can present a helpful guideline for designing polymer donors that produce environment friendly and secure polymer photo voltaic cells utilizing non-halogenated solvent processing,” mentioned Kim.
Reference: “Polymer donors with hydrophilic side-chains enabling environment friendly and thermally-stable polymer photo voltaic cells by non-halogenated solvent processing” by Soodeok Search engine marketing, Jun-Younger Park, Jin Su Park, Seungjin Lee, Do-Yeong Choi, Yun-Hello Kim and Bumjoon J. Kim, 24 July 2023, Nano Analysis Power.
DOI: 10.26599/NRE.2023.9120088
Different contributors embody Soodeok Search engine marketing, Jin Su Park, and Bumjoon J. Kim of the Korea Superior Institute of Science and Expertise; Jun-Younger Park and Do-Yeong Choi of Gyeongsang Nationwide College; and Seungjin Lee of the Korea Analysis Institute of Chemical Expertise.
The Korea Institute of Power Analysis and Planning and the Korean Nationwide Analysis Basis funded this analysis.