(Invited) Atomic Layer Deposition of Core-Shell Nanowires for Solar Energy Conversion Devices
Semiconductor nanowires (NWs) posses several advantages for energy conversion devices owing to their high surface areas, tunable compositions, and efficient charge transport properties . However, precise control of surfaces and interfacial properties is crucial to maximize charge-transfer efficiency across the interfaces between NWs and the surrounding device components, while minimizing undesirable side reactions and recombination losses. One technique that has been increasingly explored for surface and interfacial engineering of nanostructured energy conversion and storage devices is Atomic Layer Deposition (ALD). This gas-phase process allows for highly conformal deposition of a wide variety of materials with sub-nm precision in material thickness and tunable chemical composition. By coating the surfaces of NWs with ALD, core-shell structures can be fabricated with atomic-scale control. This combination of conformality and thickness control facilitates precise tuning of the electronic, optical, thermal, and chemical properties of nanowire surface to optimize their interfaces in energy conversion devices.
This talk will present several examples of using ALD to fabricate highly-controlled core-shell for energy conversion and storage devices, with an emphasis on solar energy applications. Examples include quantum-dot sensitized nanowires , earth abundant core-shell NW photovoltaics at the singe nanowire and array level , and coating of nanowire surfaces with passivation layers and co-catalysts for photoelectrochemical water splitting [4-5]. Additionally, the use of ALD for precise control of heterogeneous interfaces in hierarchical nanomaterial synthesis will be presented. The importance of fully understanding ALD surface chemistry will be discussed from a theoretical and experimental perspective. The talk will conclude with a perspective on future directions and challenges for widespread commercial adaption of these technologies.
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