Periodic Reporting for period 1 - CQDplay (Colloidal Quantum Dot Molecules for Display Applications)
Reporting period: 2022-05-01 to 2023-10-31
Displays are all around us. They are in smartphones, laptops, TVs, and cars and have become entwined in our everyday lives with new features being added, such as the Augmented Reality technology. The market strives for constant improvement in display technology performance, with better colors, thinner formats, and new functionalities. In that respect, utilization of Quantum Dots (QDs) can promote this desired technological leap. QDs are nano-sized structures, composed of tens to thousands of atoms. Their most prominent feature is the ability to tune their properties, including their color emission, based on their size and dimension. The significance of QDs was also recognized by the Royal Swedish Academy of Sciences, awarded the 2023 Nobel Prize in Chemistry for the discovery, synthesis, and development of QDs. Due to quantum confinement effects, QDs emit purer colors, allowing for a more vibrant and colorful viewing experience, when incorporated in QD-based displays. Yet, the current QD displays are inefficient, not bright enough, consume relatively high energy, and have limited pixel resolution. In the recent years, the Banin group has been working on developing a general method of binding and fusing two QDs into a new class of CQDM (Coupled QD Molecules). These new structures, termed ‘artificial molecules’ in analogy to molecules (i.e. CQDMs) that are composed of artificial atoms (i.e. QDs), present a unique system in which the two QDs in the CQDM demonstrate two separate emission centers with coupling effects. The coupled behavior is better explained on a CQDM system composed of two different QDs (i.e. monomers), where each of them can emit light in a different color. Once the CQDM is excited optically, the emission route can be tuned to proceed through either one of the monomers by applying an electric field, thus controlling the emitted color from the CQDM system. This is in contrast to a system containing those similar monomers, yet without a coupling mechanism, in which light will be emitted only by the specific monomer that absorbed the energy. Similarly, by varying the composing monomers of the CQDMs, a rich palette of CQDMs can be achieved, with multi-functional activity.
Herein, we proposed to realize and develop this concept towards the commercialization of CQDMs as unique and novel materials for innovative high quality displays. Such CQDMs, with two different QDs each tuned to a different color, have the ability of dual-color emission, red and green, which can be controlled electrically. A pixel layer of these novel materials can be inserted as the emissive layer in future-day display technologies, providing brighter and more stable and efficient displays alongside a much simpler production process compared to patterned separate red and green QD pixels.
Preliminary discussions with companies and investors have highlighted that the development of this technology can be of significant industrial value. We aimed to pursue this within the ERC-PoC grant by two main work packages focusing on the development of both the technological and business aspects aiming towards spinning-off a company or research and license agreement with a suitable chosen strategic partner.
Herein, we proposed to realize and develop this concept towards the commercialization of CQDMs as unique and novel materials for innovative high quality displays. Such CQDMs, with two different QDs each tuned to a different color, have the ability of dual-color emission, red and green, which can be controlled electrically. A pixel layer of these novel materials can be inserted as the emissive layer in future-day display technologies, providing brighter and more stable and efficient displays alongside a much simpler production process compared to patterned separate red and green QD pixels.
Preliminary discussions with companies and investors have highlighted that the development of this technology can be of significant industrial value. We aimed to pursue this within the ERC-PoC grant by two main work packages focusing on the development of both the technological and business aspects aiming towards spinning-off a company or research and license agreement with a suitable chosen strategic partner.
In agreement with the project’s aims, we demonstrated switchable dual-color emission, from an artificial molecule, composed of two quantum dots. The dots were similar in composition, yet, a difference in their size endowed each dot with a different emission wavelength. Following a structural fusion process between both dots, a continuous lattice structure was formed, enabling quantum coupling effects between them. Spectroscopic characterization on the single particle level revealed that upon illumination, the artificial molecule absorbing the light can emit a different wavelength each time, depending on the voltage applied by an external field. A specific structural correlation, based on electron microscopy characterization, confirmed this effect as uniquely representative of artificial molecules that contained strongly fused dots. In addition, we developed a physical model, based on the parameters of our experiment, predicting an even broader color-switching effect when increasing the structural dissimilarity between the composing dots of the artificial molecule. Our results were published in the Nature Materials journal, earlier this year (https://doi.org/10.1038/s41563-023-01606-0(opens in new window)).
Originally, our goal was to fabricate an artificial molecule-based pixel. This technology will boast the display field in general, and emanating fields, such as augmented reality technology, which requires high-resolution and bright displays, based on cost-effective means. Yet, upon delving deeper into the project, we realized that additional applications might be more within reach, such as single photon sources for quantum computing and quantum cryptography applications. As the operation principle was already demonstrated, we now need to look for additional relevant industries and technologies, which might be interested in incorporating this technology, such as quantum cryptography, or quantum computing.