The UHV4i is a modular electrospray deposition source capable of producing a molecular beam from an electrosprayed solution at pressures typically in the 10-8 mbar range. The system features a desolvation entrance capillary, two differentially pumped molecular beam skimmers and a final differentially pumped aperture. The source can be mounted in any orientation on an available DN35CF (2.75″ CF) port of your UHV system, such as the preparation chamber of a synchrotron beamline, a UHV STM or AFM, or thin film preparation system. The UHV4i is suitable for the deposition of all molecules and nanoparticles that can be held in an electrospray compatible solution or suspension including carbon nanotubes, fullerenes, single molecule magnets, organometallic dye complexes, proteins, giant porphyrin nanorings, polymers and biomolecules.
New design inspired by our heated inlet UHV4iH system
Inspired by the development of our vacuum-side inlet capillary heater fitted to our UHV4iH systems, the UHV4i features a vacuum-side alignment block on the inlet which ensures that the alignment of the capillary is reproducible every time. The new inlet flange design also means that the UHV4i can be upgraded to the UHV4iH at any point in the future by simply exchanging the inlet flange.
The UHV4i is supplied complete with an electrospray source head (incorporating a 4-axis manipulator for total flexibility in the emitter positioning), the liquid delivery system, 5 reusable stainless steel emitters, and a virtually indestructible case for easy transportation to different labs. The size of the system (see technical specifications below) means that it can be mounted to a UHV chamber just like an evaporator and aligned optically by shining a light down through the ion path to the sample. Since the UHV4i requires independent pumping it should be mounted on a gate valve so that it can be isolated from the system when not in use.
The source has 3 pumping stages. The first two are roughing stages and the third is a high vacuum stage. The pumping requirements are therefore 2 scroll or rotary pumps and a small turbo. The turbo is in most cases able to be backed by the stage 2 pump. The electrospray plume of the deposition solution is generated by applying a high-voltage to the emitter which requires a controllable high-voltage DC power supply (such as our MV5 series) up to around 5kV. The liquid is delivered to the high voltage junction via a gas-tight syringe which can be operated by pressurising the volume of air above the solution by gently pressing down on the plunger. Alternatively, for more controlled and continuous electrospray depositions the syringe can be placed in a syringe pump (not currently supplied by Molecularspray) so that the flow rate can be accurately controlled.
For monitoring the electrospray plume during the deposition to ensure you have good electrospray parameters (flow rate & voltage) you can add the visualizer which includes a 25X optical microscope and light source that can operated manually or with the supplied HD video camera.
For increased desolvation of the electrosprayed plume as it enters the vacuum system of the UHV4i you can exchange the inlet flange for the heated version as fitted to our UHV4iH system, whic maintains the capillary at temperatures up to 110 C. (For earlier UHV4 systems we offer a conversion kit that includes the new heated inlet, power supply, spacer flange and bolts).
Stage 2 can be pumped by the same pump that backs the stage 3 turbo in most cases. Our coupling tee and bellows can be used to connect these two pumping lines to a single backing pump.
Technical specifications of the UHV4i
Dimensions: 33 x 10 x 10 cm
Pressures & pumping:
Stage 1: 1 x 100 mbar (Scroll or rotary >100 lmin-1)
Stage 2: 1 x 10-1 mbar (Scroll or rotary >100 lmin-1*)
Stage 3: 1 x 10-4 mbar (Turbo >70 ls-1)
Stage 4: 5 x 10-8 mbar (up to 5 x 10-7 mbar during spraying depending on solvent and flow rate – base pressure also depends on main system pumping)
*Stage 2 can be pumped by the Stage 3 turbo backing pump using a suitable connection.
Working distance: tested up to 50 cm from final aperture (no minimum working distance) Emitter voltage: 1.5 kV to 3.5 kV typical
Deposition rate: pA range ion current measured at the sample position (typically corresponding to <1 ML min -1)
Mounting: DN35CF (2.75″ CF) any orientation (preferably via gate valve)