Novel Polymer Can Improve the Performance of Organic and Perovskite Solar Cells.
Skoltech scientists and their colleagues have synthesized a brand-new conjugated polymer for organic electronic devices through two different chemical reactions and shown the influence of both methods on its efficiency in organic and perovskite solar batteries. The paper was published in the journal Macromolecular Chemistry and Physics.
As the world attempts to shift to clean and renewable energy, such as solar power, scientists are working to make solar cells more effective at generating electrical power. Amongst the promising approaches are two rapidly expanding photovoltaic or PV modern technologies with the potential for cost-effective, sustainable solar energy generation: natural solar batteries and lead-halide perovskite solar cells. Their primary benefit over the mass-produced solar cells based on crystalline silicon is the lower cost of depositing the photoactive layer from the solution, resulting in cheaper energy productions, simplifying scaling up with printing techniques and roll-to-roll manufacture, and allowing device fabrication on adaptable and elastic surfaces.
However, there are several challenges to the proliferating usage of these innovations. For something, the efficiency of natural solar batteries still has a long way to go. This will undoubtedly require tweaking photoactive layer composition. In organic solar batteries, the light-to-energy conversion happens in the photoactive layer consisting of a blend of donor and also acceptor materials– the contributor is usually a conjugated polymer.
As for perovskite, solar batteries have reached a stunning 25.5% certified document efficiency; however, long-lasting security stays a concern. A recent study has shown that device stability can be improved by covering the photoactive perovskite product with a charge-extraction layer that supplies effective encapsulation. Along with a few materials, this protective ability might be fulfilled by conjugated polymers, making it crucial to maximize their top quality by bettering their synthesis.
” Conjugated polymers have a variety of essential applications, motivating us to investigate ways to optimize their synthesis to boost their top quality, which would certainly lead to a far better performance of photovoltaic devices. Our research focuses on a specific kind of conjugated polymers containing the isoindigo unit in the polymer chain. The discovery demonstrates that both synthetic pathways worked for the synthesis of isoindigo based materials. The Stille reaction ought to be provided choice over the Suzuki reaction as the last step in the synthesis,” Skoltech Ph.D. student Marina Tepliakova clarified.
Along with Skoltech Provost Keith Stevenson and their colleagues at the RAS Institute for Problems of Chemical Physics, Marina Tepliakova synthesized a conjugated polymer based on an indigo dye popular isomer, isoindigo. The group used two synthesis pathways to generate isoindigo based polymers: the Stille and the Suzuki polycondensation reaction.
Conjugated polymers are organic products usually with alternating donor and acceptor units in their structure, which is why they are additionally described as D-A-D-A-D materials. The D and A units, referred to as monomers are connected into polymeric chains using numerous polymerization reactions, each of which counts on the monomers birthing specific additional functional groups to start. For polymers assuming the isoindigo system as the acceptor element, two synthetic routes are readily available. The research study by the Skoltech-IPCP RAS team analyzed them both.
Besides the functional group distinction stated above, the two synthesis paths are different in terms of required reaction conditions. As an example, the Suzuki polycondensation process calls for an inorganic base and monomers in the mixture of immiscible fluids: water and organic solvent. Monomer shift between phases is made possible by unique particles referred to as transfer catalysts. The Stille reaction usually takes place in one phase and also at raised temperature levels. Additionally, both reactions call for palladium-based catalysts.
” Our very first observation was that the common conditions of the Suzuki reaction were inappropriate for isoindigo-based monomer synthesis,” Marina Tepliakova commented. “Using high-performance liquid chromatography, we noticed monomer signal decomposition into three unique signals of some by-products with various retention times under the standard Suzuki problems. This indicated permanent destruction of the isoindigo-based monomer was happening. So we changed the reaction problems up until they were not dangerous to the material.”
After altering the Suzuki reaction, the group synthesized the polymer, making use of both paths. The resulting materials were discovered to have similar molecular weights and also optoelectronic properties. Next off, the researchers tested the examples in photovoltaic or PV tools: organic and perovskite solar cells. The polymer obtained using the Stille response showed exceptional performance with 15.1% and 4.1% efficiencies in perovskite and organic solar batteries, respectively, with the Suzuki-derived material delivering 12.6% and 2.7% effectiveness.
The team connected the difference in performance to the presence of “charge traps” in the material acquired utilizing the Suzuki reaction. This assumption was verified using a technique called electron-spin resonance, which showed the material produced using the Stille pathway had five times fewer problems.
By adjusting the approach to isoindigo based monomer synthesis, the researchers have discovered a way to make premium material that performs well in photovoltaic cells. In a follow-up experiment, the group synthesizes several materials to be tested in perovskite solar cells. That upcoming research study will clear up just how material structure correlates with device performance.
Originally published on Scitechdaily.com. Read the original article.
Reference: Marina M. Tepliakova et al, Impact of Synthetic Route on Photovoltaic Properties of Isoindigo‐Containing Conjugated Polymers, Macromolecular Chemistry and Physics (2021). DOI: 10.1002/macp.202100136
