Fast nonlinear ion transport via field-induced hydrodynamic slip in sub-20-nm hydrophilic nanofluidic transistors

Electrolyte transport through an array of 20 nm wide, 20 μm long SiO_2 nanofluidic transistors is described. At sufficiently low ionic strength, the Debye screening length exceeds the channel width, and ion transport is limited by the negatively charged channel surfaces. At source−drain biases >5 V, the current exhibits a sharp, nonlinear increase, with a 20−50-fold conductance enhancement. This behavior is attributed to a breakdown of the zero-slip condition. Implications for energy conversion devices are discussed

Controlled growth of CH3_3NH3_3PbI3_3 nanowires in arrays of open nanofluidic channels

Spatial positioning of nanocrystal building blocks on a solid surface is a prerequisite for assembling individual nanoparticles into functional devices. Here, we report on the graphoepitaxial liquid-solid growth of nanowires of the photovoltaic compound CH$_3$NH$_3$PbI$_3$ in open nanofluidic channels. The guided growth, visualized in real-time with a simple optical microscope, undergoes through a metastable solvatomorph formation in polar aprotic solvents. The presently discovered crystallization leads to the fabrication of mm2-sized surfaces composed of perovskite nanowires having controlled sizes, cross-sectional shapes, aspect ratios and orientation which have not been achieved thus far by other deposition methods. The automation of this general strategy paves the way towards fabrication of wafer-scale perovskite nanowire thin films well-suited for various optoelectronic devices, e.g. solar cells, lasers, light-emitting diodes and photodetectors

Low-cost technology for the integration of micro- and nanochips into fluidic systems on printed circuit board: fabrication challenges

Nowadays, micro- and nanochips are usually\ud fabricated with Silicon and/or glass. A simple, low-cost and\ud reliable integration packaging method that provides flexibility\ud to the incorporation of electronic and fluidic devices into a\ud system has not been fully developed yet. The use of Printed\ud Circuit Board material as substrate to create dry film resist\ud microfluidic channels is the core technology to provide such an\ud integration method. The feasibility and potential of the\ud proposed packaging method is demonstrated in this wor

Nanofluidic tuning of photonic crystal circuits

By integrating soft-lithography-based nanofluidics with silicon nanophotonics, we demonstrate dynamic, liquid-based addressing and high Delta n/n(~0.1) refractive index modulation of individual features within photonic structures at subwavelength length scales. We show ultracompact tunable spectral filtering through nanofluidic targeting of a single row of holes within a planar photonic crystal. We accomplished this with an optofluidic integration architecture comprising a nanophotonic layer, a nanofluidic delivery structure, and a microfluidic control engine. Variants of this technique could enable dynamic reconfiguration of photonic circuits, selective introduction of optical nonlinearities, or delivery of single molecules into resonant cavities for biodetection

Controlling ion transport through nanopores: modeling transistor behavior

We present a modeling study of a nanopore-based transistor computed by a mean-field continuum theory (Poisson-Nernst-Planck, PNP) and a hybrid method including particle simulation (Local Equilibrium Monte Carlo, LEMC) that is able to take ionic correlations into account including finite size of ions. The model is composed of three regions along the pore axis with the left and right regions determining the ionic species that is the main charge carrier, and the central region tuning the concentration of that species and, thus, the current flowing through the nanopore. We consider a model of small dimensions with the pore radius comparable to the Debye-screening length ($R_{\mathrm{pore}}/\lambda_{\mathrm{D}}\approx 1$), which, together with large surface charges provides a mechanism for creating depletion zones and, thus, controlling ionic current through the device. We report scaling behavior of the device as a function the $R_{\mathrm{pore}}/\lambda_{\mathrm{D}}$ parameter. Qualitative agreement between PNP and LEMC results indicates that mean-field electrostatic effects determine device behavior to the first order

Transport in nanofluidic systems: a review of theory and applications

In this paper transport through nanochannels is assessed, both of liquids and of dissolved molecules or ions. First, we review principles of transport at the nanoscale, which will involve the identification of important length scales where transitions in behavior occur. We also present several important consequences that a high surface-to-volume ratio has for transport. We review liquid slip, chemical equilibria between solution and wall molecules, molecular adsorption to the channel walls and wall surface roughness. We also identify recent developments and trends in the field of nanofluidics, mention key differences with microfluidic transport and review applications. Novel opportunities are emphasized, made possible by the unique behavior of liquids at the nanoscale