Lightweight, High-Efficiency Solar Cells. Aarohi Vijh. Company

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Miles Ward
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1 Lightweight, High-Efficiency Solar Cells arohi Vijh

2 History lta Devices Founded World renowned founders CalTech Professor Harry twater Berkeley Professor Eli Yablonovitch lta sets records Single Junction 28.8% Pilot line completed Dual Junction 31.6% cquired by Technology Development Process Development Market Development Manufacturing Ramp Mission is to bring highest efficiency solar to broad markets 2

3 Single and Dual Junction Records World record for non-concentrator 1-J and 2-J cells 3

4 High Performance Ultra-High Efficiency Single Junction Dual Junction 29 % Today 33 % Next Gen Super-thin solar cell material employing photon recycling enables world record efficiency 4

Weight Reduction Ultra-Light Weight Baseline Q4 2016 240 Today 170 Next Gen *Weights shown in g/m 2 We

5 Weight Reduction Ultra-Light Weight Baseline Q Today 170 Next Gen *Weights shown in g/m 2 We are targeting low weight designs to increase our power-toweight performance, by using advanced materials. 5

6 Mass and rea Ratios 300 Watts per square meter CIGS Traditional Gas c-si dvanced c-si * Data is for fully encapsulated modules or submodules and includes bypass diodes and interconnect ribbons Watts per kilogram >1000 W/kg unencapsulated >750 W/kg with encapsulation on one side 6

7 Ranked in World s 50 Disruptive Companies Listed 3 consecutive years World s most influential technology awards: MIT Technology Review 7

8 Mobile Power pplications Unmanned Systems Wearable Devices Mobile Devices Internet of Things utomotive Remote Power lta Devices provides power where it simply doesn t exist today: anything that moves, can be carried, or worn 8

9 UV Example 9

10 Technology Overview

11 Key Enablers Mission is to bring highest efficiency solar to broad markets 1. Single crystal Gas 2. Thin film/epitaxial growth and lift off 3. Photon recycling 11

12 Optimal Bandgap Cells Gas is close to the ideal bandgap for single junction cells (1.4 ev) Lower bandgap wastes energy of blue photons Higher bandgap cannot absorb red photons 12

13 Comparing Gas vs. Silicon Over 100 microns (0.004 ) of silicon are needed to absorb 90% of photons For Gas, this number is about 1 micron ( ) of material. Silicon layer will need to be a hundred times thicker than Gas for same absorption Because Gas is a direct bandgap material 13

Design of Thin-Film, Single-Crystal Cell Strong external fluorescence Thinned cell Radiative recombination Photon recycling Light trapping

14 Design of Thin-Film, Single-Crystal Cell Strong external fluorescence Thinned cell Radiative recombination Photon recycling Light trapping Single-crystal thin films provide new solar cell design opportunities Minimizing optical, as well as electrical, losses key to high performance 14

15 lta Devices World-Record Cell 15 B. M. Kayes et al., 37 th IEEE Photovoltaic Specialists Conference, 2011

16 Dual Junction Solar Cells Top Cell (1.86 ev) Gas (1.42 ev) Tunnel junction Load Voltage adds in series Both junctions designed to have the same current Efficiency increases because top cell better utilizes high-energy photons

17 NREL-Certified 31.6% Cell Efficiency 17

18 Process Overview

19 Summary of lta s Process Flow 19

20 pplication

21 Performance of Production Cells ~214 mw (M1.5) ~1 volt per cell Temperature coefficient -0.1%/C over a wide temperature range 21

22 Series/Parallel Connections 22

23 Example ~3U Layout 6 watts 10 grams of added weight including diodes, adhesives and encapsulation Cells are thin (~0.1mm) and can be overlapped for high packing factors

24 Example ~2U folding subarray 29W Weight 60 grams (plus deployment) including encapsulation 310x700mm Thickness per fold <0.5mm Can also be rolled 24

25 Is weight important? Initial launch costs per kg are coming down Weight is still important For higher orbits, moon missions Station keeping and reorientation maneuvers Raising and lowering orbits >>> Particularly interesting for electric propulsion 25

26 Summary Thin Gas solar provides high W/kg, W/m 2 and W/m 3 lta Devices (Sunnyvale, C) is a world leader in this technology Open to working with cubesat teams Contact: aarohiv@altadevices.com 26

27 Thank You

Your Origin SLIVER system will be supplied with one of the following sets of panels:

SLIVER3000 Solar System Panel Specifications Your Origin SLIVER system will be supplied with one of the following sets of panels: Manufacturer Mono Or Poly Size (Watts) Panels Required To Achieve Minimum