Hybrid metal halides are a remarkable class of ionic semiconductors with great promise for device applications. Their optical properties can be chemically controlled and they can form single crystals at low temperatures. Single crystals are a highly ordered form of condensed matter and enable high performance electronics and photonics. The aim of this project is to fabricate low-cost, high performance printed devices based on high-quality single crystals and single crystal microarrays of perovskites. The project will focus on direct printing of semiconductor single crystal pixels with chemically-tuned spectral properties on device-ready wafers. The PI will use a co-design strategy to simultaneously tackle single crystal growth and device integration. Direct writing of single crystal transistor and photodetector arrays on wafers will be a crucial step toward next-generation optoelectronic devices and circuits.
This multidisciplinary project seeks to advance the synthesis, processing, and device integration of hybrid metal halide (HMH) semiconductor materials by enabling the direct ink-based growth of single crystal-based optoelectronic devices and arrays thereof. The salt-like nature of HMH materials makes them a unique class of semiconductors with chemical diversity on par with organic semiconductors, crystalline order on par with conventional inorganic semiconductors, and superior transport and optoelectronic properties thanks in part to large spin-orbit coupling. This project will focus on developing synthetic and processing approaches which enable the formation of microscopic single crystals and arrays thereof at pre-determined locations on device-ready substrates using readily available printing and coating technologies. A co-design strategy will simultaneously tackle material formulation, surface chemistry, spectral properties and device performance to successfully and rapidly integrate semiconductor single crystals into (opto)electronic device components and arrays. A direct writing approaches will be developed to produce spectrally-tunable single crystal devices, including field-effect transistors and phototransistors, as well as conventional and polarization-sensitive photodetectors. This will be expanded to demonstrate wafer-scale integration of single crystal device microarrays. The scientific and engineering knowledge developed in this proposal will enable solution-processing to ultimately deliver materials of single crystal caliber without resorting to conventional ultrahigh vacuum techniques or epitaxial growth. The implementation of single crystal microarray fabrication through existing high throughput coating and printing infrastructure designed for traditional thin film coating is pursued for two main reasons: (I) mature platforms which co-integrate materials synthesis and device integration on the same substrate are suitable for co-design, and (II) broad adoption of manufacturing approaches is more likely given the available infrastructure across the nation. The proposed co-design strategy will provide intensification of experiments and assist in verifying scientific and engineering hypotheses crucial to the intended outcomes of this project. The research will raise a new generation of leaders in electronic materials processing and optoelectronic devices. Future career opportunities in these areas will be given to graduate and undergraduate students including women and underrepresented minorities. Dissemination of the research will take place through high impact publications, published datasets, and presentations for the scientific community, as well as through social media and hands-on activities in local K-12 schools, Citizen Science program at the North Carolina Museum of Natural Science, and established outreach programs at North Carolina State University.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
