Bio

Siddharth is a PhD student in Materials Science at Stanford University, where he is a Meta PhD Fellow working with Mark Brongersma and Nicholas Melosh. His research is focused on developing electrically tunable active optical metasurfaces using soft polymers, enabling applications ranging from on-the-fly reconfigurable optical computing devices to wearable photonics. Previously, he received his Bachelor's degree in Engineering from the University of New South Wales (Sydney, Australia) and spent time in industry designing award-winning consumer products.

Contact

  • Academic
    sdos@stanford.edu
    University - Student Department: Materials Science and Engineering Position: Graduate

Additional Info

  • Mail Code: 4034

All Publications

  • Direct electron beam patterning of electro-optically active PEDOT:PSS. Nanophotonics Doshi, S., Ludescher, D., Karst, J., Floess, M., Carlström, J., Li, B., Mintz Hemed, N., Duh, Y. S., Melosh, N. A., Hentschel, M., Brongersma, M., Giessen, H. 2024; 13 (12): 2271-2280

    Abstract

    The optical and electronic tunability of the conductive polymer poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) has enabled emerging applications as diverse as bioelectronics, flexible electronics, and micro- and nano-photonics. High-resolution spatial patterning of PEDOT:PSS opens up opportunities for novel active devices in a range of fields. However, typical lithographic processes require tedious indirect patterning and dry etch processes, while solution-processing methods such as ink-jet printing have limited spatial resolution. Here, we report a method for direct write nano-patterning of commercially available PEDOT:PSS through electron-beam induced solubility modulation. The written structures are water stable and maintain the conductivity as well as electrochemical and optical properties of PEDOT:PSS, highlighting the broad utility of our method. We demonstrate the potential of our strategy by preparing prototypical nano-wire structures with feature sizes down to 250 nm, an order of magnitude finer than previously reported direct write methods, opening the possibility of writing chip-scale microelectronic and optical devices. We finally use the high-resolution writing capabilities to fabricate electrically-switchable optical diffraction gratings. We show active switching in this archetypal system with >95 % contrast at CMOS-compatible voltages of +2 V and -3 V, offering a route towards highly-miniaturized dynamic optoelectronic devices.

    View details for DOI 10.1515/nanoph-2023-0640

    View details for PubMedID 38774765

    View details for PubMedCentralID PMC11104293

  • Applying heat and humidity using stove boiled water for decontamination of N95 respirators in low resource settings. PloS one Doshi, S., Banavar, S. P., Flaum, E., Kulkarni, S., Vaidya, U., Kumar, S., Chen, T., Bhattacharya, A., Prakash, M. 2021; 16 (9): e0255338

    Abstract

    Global shortages of N95 respirators have led to an urgent need of N95 decontamination and reuse methods that are scientifically validated and available world-wide. Although several large scale decontamination methods have been proposed (hydrogen peroxide vapor, UV-C); many of them are not applicable in remote and low-resource settings. Heat with humidity has been demonstrated as a promising decontamination approach, but care must be taken when implementing this method at a grassroots level. Here we present a simple, scalable method to provide controlled humidity and temperature for individual N95 respirators which is easily applicable in low-resource settings. N95 respirators were subjected to moist heat (>50% relative humidity, 65-80°C temperature) for over 30 minutes by placing them in a sealed container immersed in water that had been brought to a rolling boil and removed from heat, and then allowing the containers to sit for over 45 minutes. Filtration efficiency of 0.3-4.99 μm incense particles remained above 97% after 5 treatment cycles across all particle size sub-ranges. This method was then repeated at a higher ambient temperature and humidity in Mumbai, using standard utensils commonly found in South Asia. Similar temperature and humidity profiles were achieved with no degradation in filtration efficiencies after 6 cycles. Higher temperatures (>70°C) and longer treatment times (>40 minutes) were obtained by insulating the outer vessel. We also showed that the same method can be applied for the decontamination of surgical masks. This simple yet reliable method can be performed even without electricity access using any heat source to boil water, from open-flame stoves to solar heating, and provides a low-cost route for N95 decontamination globally applicable in resource-constrained settings.

    View details for DOI 10.1371/journal.pone.0255338

    View details for PubMedID 34591858