1. The design and fabrication of materials that simultaneously contain more than one type of functional components, so-called multifunctional materials, is highly desirable for a range of technological applications. Among a variety of possible building blocks, inorganic nanocrystals (NCs) have proven to be ideal ones and can be used as "artificial atoms" to generate higher-order architectures, especially in an ordered and controllable manner, which is also called NC superlattices. In Chen's lab, we are generating NC superlattices from the NCs with different sizes or natures (e.g., semiconductor, metallic, or magnetic) or both. By using chemical and physical tools, we are trying to explore and understand the novel and enhanced collective properties from the near-field coupling that occurs between NC neighbors inside the superlattices.
2. Semiconductor nanocrystals, also known as quantum dots (QDs), are emerging as a class of unique materials due to their unparalleled features: a compact size, broad excitation band, large absorption cross section, tunable narrow/symmetric emission profile, superior photostability and solution processability. We are currently developing new synthetic methodologies for producing high-quality novel QDs materials with the desired properties for applications ranging from biological imaging to solar energy harvesting.
3. The near-field coupling of nanocrystals (NCs) can be greatly enhanced by fine-tuning the inter-particle distance inside NC superlattices, which show promise for a range of technology applications, such as photovoltaics, light-emitting diodes and thermoelectrics. Currently, we are employing high pressure processing as a fast and convenient way to precisely tune the inter-NC distance, allowing for a quick optimization of inter-NC distance that represents one ideal confined-but-connected "sweet spot" for NC superlattices to reach the best performance of their desired properties.