The cover is a fantastic illustration that represents the ternary diagram of organic solar cells formed by ternary active layers (composition of two acceptors and one donor) to find the optimum conditions for the best performance. This ternary diagram is represented as a pirate treasure map: the treasure is found where the optimum conditions are. The cover also features the three organic molecules, and some typical elements of this kind of treasure maps.
The design of the illustration is by the talented graphic illustrator Gustavo Regalado, after an original idea of the authors.
Organic solar cells based on ternary active layers can lead to higher power conversion efficiencies than corresponding binaries, and improved stability. The parameter space for optimization of multicomponent systems is considerably more complex than that of binaries, due to both, a larger number of parameters (e.g., two relative compositions rather than one) and intricate morphology–property correlations. Most experimental reports to date reasonably limit themselves to a relatively narrow subset of compositions (e.g., the 1:1 donor/s:acceptor/s trajectory). This work advances a methodology that allows exploration of a large fraction of the ternary phase space employing only a few (<10) samples.
Each sample is produced by a designed sequential deposition of the constituent inks, and results in compositions gradients with ≈5000 points/sample that cover about 15%–25% of the phase space. These effective ternary libraries are then colocally imaged by a combination of photovoltaic techniques (laser and white light photocurrent maps) and spectroscopic techniques (Raman, photoluminescence, absorption). The generality of the methodology is demonstrated by investigating three ternary systems, namely PBDB‐T:ITIC:PC70BM, PTB7‐Th:ITIC:PC70BM, and P3HT:O‐IDFBR:O‐IDTBR. Complex performance‐structure landscapes through the ternary diagram as well as the emergence of several performance maxima are discovered.
The article is Open Access for everyone to read.
Efficient Exploration of the Composition Space in Ternary Organic Solar Cells by Combining High‐Throughput Material Libraries and Hyperspectral Imaging
Albert Harillo‐Baños, Xabier Rodríguez‐Martínez, Mariano Campoy‐Quiles
Advanced Energy Materials, Volume 10, Issue 1, January 7, 2020, Article number: 1902417