ACT/SGER: "ON-THE-FLY" Materials Modification During Laser Direct-Write Deposition of Micro Power Sources

Princeton University, Princeton NJ

Investigators

Abstract

This project entitled "ON-THE-FLY" MATERIALS MODIFICATION DURING LASER DIRECT-WRITE DEPOSITION OF MICROPOWER SOURCES addresses innovative approachs to the rapid processing and optimization of materials for micropower sources. A recognized need for miniaturized power sources exists in national security applications to provide integrated energy for low observable and small autonomous devices that cannot be powered by commercially available batteries or fuel cells. However, the techniques currently available to produce such small power sources require secondary processing such as high temperatures or pressures that can be detrimental to the sensitive materials used in many microdevices. In this project, a laser interacts with the microbattery material as it flies toward the substrate thus modifying its properties and reducing the need for secondary processing. The fundamental material response is studied in order to understand and control the structural and electrochemical properties. This study not only enhances the basic understanding of laser-material interactions, but also may revolutionize the use of laser processing for small electrochemical devices. Students with diverse interests and backgrounds in chemistry, physics, engineering and materials science will all be involved and educated through this truly interdisciplinary laser-based technique. The results obtained will be disseminated to provide researchers in a variety of disciplines with important new opportunities and techniques for microdevice development. %%% Innovative approaches to the processing and optimization of materials for micropower sources is of high interest for device fabrication for applications such as remote weather sensing, implantable microdevices, or bio-analytical microdevices. Laser direct-write methods are being developed and used to deposit patterns of microbattery and micro-ultracapacitor materials on various substrates under ambient conditions. The influence of the incident laser as well as secondary laser irradiation is studied and exploited in order to modify the material "on the fly" (OTF) during deposition. For example, in this project, hydrous ruthenium oxide ink will be transferred with varying incident laser energy and duration as well as secondary laser irradiation. The fundamental issues of laser interactions with the moving droplets of multiphase material are probed through structural and electrochemical characterization on the deposited films. By removing the need for pre- and post- processing, the substrates remain at ambient temperatures thereby enabling the use of novel low-temperature substrates such as flexible plastics or biological platforms for device development. OTF processing has the potential to rapidly prototype unique structures and chemistries that can transform the field of micropower and micro-sensor development. The interdisciplinary nature of this study involves chemistry, physics, engineering, and materials science and educates students with diverse interests and backgrounds in this new laser-based technique. The results obtained will be disseminated to provide researchers in a variety of disciplines with important new opportunities and techniques for microdevice development. This project is supported jointly by the Office of Multidisciplinary Activities and the Division of Materials Research, Directorate for Mathematical and Physical Sciences.