Precision Thin-Film
Deposition Platform
Primary application: Nanosolar Tile — transparent perovskite solar film for building-integrated photovoltaics
$20k–$150k commercial systems
full tool exchange cycles
channel count expands with application
A Purpose-Built Deposition System
The Rister platform is a precision multi-channel liquid handling and deposition system engineered for multi-material thin-film fabrication on flexible substrates. Developed in-house at HTS Resources, it delivers capabilities comparable to commercial dispensing systems costing $20,000–$150,000 — at a fraction of the price, and purpose-built for the specific demands of flexible substrate work in controlled atmospheres.
Existing commercial dispensing platforms are designed for rigid substrates, single-material workflows, and controlled manufacturing environments. The Rister platform was designed from the ground up for multi-material, multi-layer deposition on flexible film substrates — the configuration required for next-generation thin-film devices.
What Makes It Different
- Purpose-engineered for flexible substrate deposition — not adapted from a rigid-substrate platform
- Scalable multi-channel architecture — each tool head supports multiple independent dispensing channels (up to 8 demonstrated per tool), with multiple tools loadable per run. Total channel count expands with the application
- Multi-material in a single run — dedicated tool heads per ink chemistry enable sequential or parallel deposition without substrate removal, making larger tile sizes and faster throughput practical
- Near-zero cost to scale — syringe pumps, valves, and tool bodies are fabricated in-house on the same platform. Adding channels means printing more hardware, not purchasing expensive proprietary components
- Heated dispensing at 60°C with PTFE-lined fluid paths — compatible with high-viscosity and temperature-sensitive inks
- Integrated camera inspection with fiducial-based referencing — sub-millimeter accuracy maintained across tool exchanges
- Designed for N₂ and controlled atmosphere environments — required for air-sensitive material systems
- Compact and portable — the complete system can be transported and operated at external facilities
Platform Capabilities
The platform's core capabilities address a broad range of thin-film deposition applications requiring precise, multi-material, multi-layer workflows on flexible substrates.
Adjacent Application Areas
While perovskite BIPV is the current focus, the platform's capabilities apply directly to other thin-film deposition workflows:
Toolchanger Platform
The Rister toolchanger is a purpose-built motion control and dispensing platform running proven open-motion-control firmware. Each tool head is a self-contained dispensing unit with printed syringe pumps and servo-actuated valves — all fabricated in-house. Tool heads support multiple channels (up to 8 demonstrated), and multiple tools can be loaded per run. All mechanical and fluid components are documented in the hardware repository.
Specialized Tool Heads
Liquid Handling Tool
Multi-channel heated pipette tool at 60°C. PTFE tubing (1.5mm ID), removable polypropylene tips, 150 µm nozzles. Syringe pumps and servo-controlled valves are printed in-house — channels scale by printing additional hardware. Pipette load/unload supported for prototyping; dedicated tool heads used for production throughput.
UV Curing Tool
In-situ UV curing for layer stabilization and encapsulant crosslinking at ambient pressure.
Camera Inspection Tool
Raspberry Pi 5 with autofocus camera. Real-time QC, fiducial-based absolute referencing, sub-millimeter positional verification across tool swaps.
Video Demonstrations — Tool Loading & Pipette Handling
Pressure Control System
Stable, repeatable pressure at the pipette tip is the core challenge in precision ink deposition. The system uses multi-stage pressure management to prevent dripping, air entrainment, and meniscus instability across the full deposition cycle.
- Pressure compensation reservoir — liquid level sensor triggers automatic peristaltic refill
- Stepper-driven syringe pump with servo-controlled 3-way valve: Input / Output / Pipette / Bypass positions
- Sub-nanoliter accuracy — 1–10 µL aspiration at 1 µL/s; multiple cycles enable sub-nL delivery
- Automated cleaning loop — IPA flush, exterior wash, and waste evacuation in a closed-loop process
- Dynamic nozzle swapping — 10G–34G (0.26–2.69 mm) for control over line width and flow across different ink viscosities
Fluid Management System Diagrams
Figure 1 — Single syringe pump: pressure compensation reservoir, 3-way valve positions, and automated cleaning.
Figure 2 — Multichannel configuration (4 syringes) with valves, gantry frame, peristaltic pumps, and waste/wash stations.
Control Architecture
Two purpose-built web applications replace static G-code macros with a visual, integrated control environment for the full fabrication workflow.
Printer Designer
Array Management System
| Method | Endpoint | Description |
|---|---|---|
| GET | /api/samples | List all samples |
| POST | /api/samples | Create a new sample |
| GET | /api/samples/:id | Get sample details |
| PATCH | /api/samples/:id/status | Update sample status |
| POST | /api/arrays/create | Create array grid |
Nanosolar Tile
Nanosolar Tile is the platform's primary development application — a thin, flexible transparent perovskite solar film that turns existing windows and building facades into distributed power generation surfaces.
Transparent window-attached perovskite solar film — visible light passes through while sunlight is converted to electricity.
to electricity
passes through
no cleanroom required
cost at scale
Visually indistinguishable from lightly tinted architectural glass. Retrofit-compatible — applies to existing windows without structural modification.
Top-down PV fabrication process flow — substrate preparation through encapsulation on flexible ITO-PET.
Why Perovskite on This Platform
- Line-array architecture — interdigitated patterning achieves both high transparency and usable photovoltaic output simultaneously
- Ambient-pressure processing — full stack deposited at ≤100°C, eliminating vacuum deposition requirements
- Multi-material in sequence — hole transport, absorber, and electron transport layers deposited in a single substrate-loaded run
The BIPV Opportunity
California's commercial buildings consume over 40% of the state's electricity. Current transparent solar film options are either too expensive to manufacture or require cleanroom infrastructure inaccessible to small developers — creating a gap that the Nanosolar Tile addresses directly.
Low-cost printable perovskite film changes the economics of building-integrated solar — making distributed generation viable on existing commercial glazing at under $15/m².
- Reduces peak demand by generating power at the point of consumption
- Lowers transmission losses through distributed generation on existing building envelopes
- Enables daylighting credits while generating clean energy on-site
- Retrofit-compatible — no structural modification required
Validated Milestones
- Aspiration and dispensing of mimic inks validated with 25G pipettes — tunable line width, volume, and flow rate confirmed
- Multi-material toolchanger validated: full load/unload cycles mid-fabrication without coordinate loss
- 3-drop precision array confirmed sub-millimeter placement accuracy through complete tool exchange workflow
- Camera fiducial referencing and tool-offset measurement implemented and tested
- Printer Designer integrated end-to-end: layout → dispenser config → G-code → execution
Mimic Ink Validation Approach
All hardware and process development uses rheology-matched proxy inks before transitioning to actual perovskite precursors. Mimic inks (water + xanthan gum at varying concentrations) match the flow characteristics of perovskite precursor inks and can be dispensed with 34G needles at room temperature — enabling full process validation without hazardous material handling.
Proxy ink formulations matched to target perovskite ink viscosities for hardware and process validation.
Precision Assessment: 3-drop array with reference markers
Three drops placed within pen-marked target zones after full camera toolchange + liquid handler reload + pipette loading sequence.
Syringe Pump Dispense Calibration (32g needle dispenser)
Calibration sweeps across five target volumes (40–190 µL total, 10–47.5 µL per nozzle). Each test uses a three-phase dispense sequence: prime, main dispense, and retract. An acceleration ramp of SA 50 was required at F14000 to prevent stepper skipping — at this feedrate the motor demands approximately 30,500 steps/sec, which exceeds reliable cold-start capability without ramping. SA 50 provides a minimal 50-step ramp sufficient to prevent stalling while keeping ramp length short enough to preserve accuracy at small volumes.
| Test | Prime | Main Dispense | Retract | Retract Δ | Total (4×) | Per Nozzle |
|---|---|---|---|---|---|---|
| 1 | D1 E50 F10000 G4 P1000 |
D1 E120 F14000 G4 P500 |
A1 E120 F6000 G4 P100 |
0 µL | ~190 µL | 47.5 µL |
| 2 | D1 E40 F10000 G4 P1000 |
D1 E90 F14000 G4 P500 |
A1 E90 F6000 G4 P100 |
0 µL | ~160 µL | 40.0 µL |
| 3 | D1 E20 F10000 G4 P1000 |
D1 E80 F14000 G4 P500 |
A1 E80 F6000 G4 P100 |
0 µL | ~85 µL | 21.2 µL |
| 4 | D1 E20 F10000 G4 P1000 |
D1 E70 F14000 G4 P500 |
A1 E80 F6000 G4 P100 |
+10 µL | ~50 µL | 12.5 µL |
| 5 | D1 E20 F10000 G4 P1000 |
D1 E50 F14000 G4 P500 |
A1 E60 F6000 G4 P100 |
+10 µL | ~40 µL | 10.0 µL |
Table 1 — Dispense calibration across five volume targets. Retract Δ = retract E − main dispense E. Positive Δ indicates active meniscus pullback.
Observations
At F14000 the stepper demands approximately 30,500 steps/sec. Without ramping the motor stalls on cold start. SA 50 provides a minimal 50-step ramp — sufficient to prevent skipping at this feedrate while keeping ramp length short enough not to affect small volume accuracy. A longer ramp (SA 300+) would enable F16000+ but was not required for this calibration range.
Tests 1 and 2 use a larger prime (E50, E40) versus E20 for tests 3–5. At higher dispense volumes there is greater residual hydraulic pressure in the fluid path after the main dispense. The larger prime pre-pressurizes the system before the main dispense fires, ensuring the first drop delivers full volume rather than being under-filled due to pressure lag.
Tests 1–3 retract exactly the dispensed volume (Δ = 0). Tests 4 and 5 retract 10 µL more than dispensed. At smaller volumes the liquid column at the nozzle orifice has a higher surface-tension-to-volume ratio and tends to hang rather than break cleanly. The additional 10 µL of retract actively pulls the meniscus back into the nozzle, preventing satellite droplet formation and ensuring a clean break. The threshold appears to lie between 21.2 µL and 12.5 µL per nozzle.
A 500 ms dwell (G4 P500) after the main dispense allows residual hydraulic pressure in the fluid path to equilibrate before retract fires. Without this dwell the retract competes with pressure still pushing liquid forward, resulting in inconsistent retract depth — particularly at higher dispense volumes where system pressure is greatest.
7-Step PV Process Flow
Complete transparent PV fabrication on flexible ITO-PET substrates in a controlled N₂ environment — all steps executed on the Rister platform at ≤100°C:
UV-Ozone Cleaning
ITO-PET surface activation. 185 nm + 254 nm, 12–15 min. Target contact angle: <10°.
PEDOT:PSS Deposition
Hole transport layer. Printed onto activated ITO surface. Anneal 120°C / 20 min.
Perovskite Printing
FASnI₃ line-array deposition. N₂ atmosphere, 60°C heated pipette, 150 µm nozzle. Anneal 100°C / 10 min.
Electron Transport Layer
PCBM / SnO₂ deposition for charge extraction.
Electrode Formation
Silver nanowire or carbon-based top contact deposition.
Barrier Coating
UV-crosslinked encapsulant protecting perovskite from moisture and oxygen.
Encapsulation
Final lamination for mechanical and environmental protection.
Two-Horizon Strategy
Development is staged: validate the platform in a technically demanding real-world application first, then expand into adjacent markets from a position of demonstrated capability.
Development Roadmap
UV-ozone activation validated; PEDOT:PSS deposition trials begin on ITO-PET substrates
Lab partnership for perovskite characterization; sunlight conversion efficiency and transmittance measured
First commercial pilot — Southern California BIPV retrofit partner; <$15/m² cost target validated
Platform expansion into adjacent deposition applications — contingent on Horizon 1 performance
Immediate Priorities
Get Involved
Seeking lab partnerships, accelerator programs, and early-stage investors aligned with advanced manufacturing, thin-film materials, and California energy goals. Also open to conversations with research institutions interested in applying the platform to new materials applications.