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Universal Framework for Charge Transport
in Quantum Dot Systems

Final Report Summary - UNIQDS (Universal Framework for Charge Transport in Quantum Dot Systems)

From UniQDs project, we made an important technology platform of QD based optoelectronic, and electrochemical devices and system by combining the comprehensive understanding of charge transport dynamics in various QD systems, such as energy harvester (solar cell), lighting/display, photo detectors, thin film transistor, and energy storage. Our most important outcomes is expanding the basic understanding of i)QDs materials synthesis, surface functionalization, together with atomistic level of modelling, ii) design and assembly of the QD structure for the desired devices, using macro computational modelling such as kinetic Monte Carlo, iii) monolayer level of film process for the system, iv) towards the optimized system integration for the QD based complex system, i.e. “platform technology”.
For example, we have performed QD heterogenous synthesis, interface dipole design/control, stoichiometric alternation, and lattice structure engineering, together with computational simulation upon material level with atomistic level of DFT modelling. We apply this material level approach to the design and process the structure, using the structure level modelling with kinetic Monte Carlo for various model of QD-QD chain with 1D/2D/3D, and device and system level with Finite Element Method for QD charge transport model. These achievements could provide enormous knowledges and scientific findings to the scientific community who are working on low-dimensional solid-state physics, microelectronic engineering and material chemists.
We have integrated new QD materials with flexible/large-area substrates by monolayer-level control which enables charge transport based QD devices with high efficiency and longer lifetime. We demonstrate 73% quantum yield CuInZnS3 QDs with full width at half-maximum as small as 69 nm; we propose a large scale QD synthesis protocol with wavelength coverage from 400 nm to 1476 nm (Covering from visible to NIR); we show the concept proof with 16,000 cd/m2 brightness quantum dot LED (QLED) lighting application with EQE of 7.8%; we also fabricate QD solar cell with 10.24% PCE; QD photodetector with Detectivity of 1.1 × 1011 Jones; thin film transistor (TFT) with mobility of 31.6 ± 4.78 cm2/Vs based on the final device integration through computational simulation and system optimization. Using 1D QD chain, this project has provided new opportunity of QDs for energy storage system. This will offer enormous opportunities to enable scientific community not only to broaden and deepen their knowledge/experience in fundamental QD material chemistry, but also to make rational predictions and open new device/system concepts for emerging QD optoelectronics and energy conversion and storage technologies.