IARPA-RFI-23-04-08142023C.pdf

Request for Information (RFI) on High Specific Power, Durable Solar Photovoltaic Systems

Agency: Office of the Director of National Intelligence Office: Intelligence Advanced Research Projects Activity

RFI Number: IARPA-RFI-23-04

Synopsis:

The Intelligence Advanced Research Projects Activity (IARPA) seeks information regarding innovative system and component level approaches to achieve a generational leap in high specific power, highly-durable photovoltaic (PV) systems for application in terrestrial, aerial, and space environments. Greater design flexibility is desired to deploy higher energy-consuming instrumentation on platforms that best match mission requirements, but often designers face tradeoffs due to limited onboard energy conversion. The envisioned cells and systems would enable new freedom to deploy capabilities for long-term missions not possible with today’s technology.

Background & Scope:

Multijunction (MJ) solar cells (SCs) based upon III-V chemistries1 (e.g., GaAs and GaInP) are a proven technology for use in applications where high specific power (SP, W/kg) and/or areal power density (W/m2) are desired. As such, MJ-SCs have found wide application in space,2 aerial,3 and space-constrained terrestrial applications. While lab-scale efficiencies for some III-V MJ-SCs have exceeded 45% under optical concentration,4 practically manufacturable MJ-SCs typically demonstrate far lower efficiency in the low 30% range5 (under AM0*). The highest-efficiency cells typically require complex architectures to optimally manage light and current, introducing numerous potential points of failure and/or degradation over time, and limiting the application form factor. Cell performance degrades over time, particularly in harsh environments that are prone to large temperature cycles and/or with charged particle irradiation.6 Furthermore, the impacts of continuously varying solar incidence angle and the surrounding environment (terrestrial, aerial, or space) limit the mission life energy yield from a solar power system.

Unexpected high-energy irradiation fluxes from solar or other events may also pose longevity risks in non-terrestrial environments. As such, remote capabilities deployed on platforms employing high-efficiency SCs may ultimately be restricted, either by the limited power available for onboard instrumentation, or in reduced longevity of the mission.

While there are undoubtedly further refinements to make upon established PV designs, isolated optimization by cell researchers alone are likely to lead to incremental improvements in efficiency and durability looking forward. A systems-level approach beyond established III-V MJ-SC paradigms is needed, incorporating a fresh look at the multitude of available materials systems,

* https://en.wikipedia.org/wiki/Air_mass_(solar_energy) cell architectures, optics, and integrated power electronics to enable a transformational leap in lifetime PV system energy yield, system specific power, durability, and application flexibility.

Advanced III-V and perovskite7 materials (among others) deposited with robust methods, innovative light8 and carrier management layers to optimally use the solar spectrum, new (potentially flexible) substrates, and novel cell/micro-cell architectures9 that reduce points of failure (or improve tolerance to failure) while enhancing performance may offer opportunities.

Several approaches have been attempted on the optical coupling side of solar cells to enhance performance and efficiency. While optical concentration is a means to boost solar cell performance per unit of active area through current enhancement,10 strict pointing accuracy requirements and tolerance to environmental stressors usually results in cumbersome and heavy optical assemblies that are not practical in many applications. Recent developments in micro/nano-scale optics11,12 and their manufacturability could enable new paradigms for low-weight optical solar cell concentration to enhance performance while also ensuring long-term reliability of solar cells in harsh environments or resilience towards unexpected sudden events. Other lower-profile photon management methods designed to increase power output, such as luminescent solar concentration,13 photon up/down conversion,14 and nano/micro-patterning15 have been attempted, but thus far have not been implemented in practical, reliable, high-efficiency PV devices.

This RFI seeks innovative systems-level approaches and component technologies that contribute towards improving the lifetime energy yield and SP of high-efficiency photovoltaic systems while simultaneously improving reliability and opening-up greater design freedom for mobile system designers to tailor SCs and SC assemblies regardless of application. These systems, when fully realized, have the opportunity to greatly increase the lifetime harvestable energy compared to conventional cell assemblies (and associated power electronics components) of the same mass, both at beginning of life (BOL) and through mission end of life (EOL) that goes beyond 20 years.

This could enable new applications for space, aerial, and mobile terrestrial platforms that were previously impossible due to limited power or energy collection capacity. Maximum domestic sourcing of materials and domestic manufacturability of these cells and systems will also be key to ensure adequate supply.

Components of Interest

1. PV Materials: III-V, perovskite, and other semiconductor chemistries that can withstand decades of operation in harsh terrestrial and non-terrestrial environments (i.e., diurnal temperature cycling within 150 deg C, charged particle irradiation, etc.) with minimal degradation, deposited with robust reliable methods;

2. Cell architectures: tandem and/or multijunction cells, microcells, or other novel designs potentially with integrated low-weight optical concentration and/or tracking, potentially integrated on flexible substrates, using robust packaging and integrating proper thermal management (if needed);

3. Optical Systems: methods for achieving modest concentration ratios and/or solar illumination tracking (or greater acceptance angles) using low-profile, low-weight, durable optical designs, potentially exhibit mechanical compliance when bent or stressed, optics could also tailor light delivery to appropriately-matched PV cells, and/or offer protection from environmental stressors;

4. Photon up/down conversion: materials and systems capable of converting higher- or lower-energy photons (in AM0 or AM1.5 solar illumination) to better align with the bandgap of PV subcells, or other approaches to make fruitful use of otherwise un-harvested solar energy (Note: mechanical heat engines are specifically out of scope); and

5. Integrated Power Electronics: cell, subcell-level (or more discrete) integrated radiation-hard electronics for MPPT, charge controlling, DC-DC optimization, and other applications that enable reliability and resilience while enhancing overall mission duration energy output and minimizing energy losses.

Responses are of particular interest that discuss options toward an integrated design (potentially combining several of the approaches above) that can achieve exceptionally high mission life energy yield and SP (at or beyond today’s best PV systems employing III-V MJ cells) AND durability/reliability (i.e., operation for 20+ years with minimal power degradation) simultaneously, while allowing a significant degree of design flexibility for adaptation of cells or cell assemblies to arbitrary form factors (e.g., size, shape, and curvature) and deployment methods when implemented in the final application. (i.e., custom manufacturing of cells or cell assemblies for a specific target application should not be required). A high degree of modularity is anticipated to be needed to facilitate mass-manufacturing unit cell/assembly components of a potential solution. In addition, IARPA is interested in learning of other recent advances in adjacent fields that might contribute to the efficient conversion of optical photons into electrons for use as part of or as an alternative to conventional PV technologies. (e.g. new material science, new processing technologies, new production/manufacturing techniques)

Preparation Instructions to Respondents:

IARPA requests that respondents submit responses to the above prompts for use by the Government in formulating a potential R&D program. IARPA requests that submittals briefly and clearly describe the potential approach or concept, outline critical technical issues/obstacles, describe how the approach may address those issues/obstacles and comment on the expected performance and robustness of the proposed approach. If appropriate, respondents may also choose to provide a non-proprietary rough order of magnitude (ROM) estimate regarding what such approaches might require in terms of funding and other resources for one to four years to execute the respondent’s vision for a high specific power, durable photovoltaic cell and/or optical assembly. This announcement contains all the information required to submit a response. No additional forms, kits, or other materials are needed.

IARPA welcomes responses from all capable and qualified sources from within and outside of the U.S.

Reponses must meet the following formatting requirements:

1. A one-page cover sheet that identifies the title, organization(s), respondent's technical and administrative points of contact - including names, addresses, phone numbers, and email addresses of all co-authors, and clearly indicating its association with IARPA-RFI-23-04;

2. A substantive, focused, one-half page executive summary;

3. A description of the technical challenges and suggested approaches to achieve high-SP, highly durable solar cell technologies, assemblies, and systems. Responses should be limited to 5 pages (excluding cover pages, executive summary, and citations) in minimum 12-point Times New Roman font, appropriate for single-sided, single-spaced 8.5 by 11-inch paper, with 1-inch margins. Please provide diagrams, figures, charts to help illustrate concepts when possible; and

4. A list of citations (any significant claims or reports of success must be accompanied by citations). There is no page limit for citations.

Submission Instructions to Respondents:

Responses to this RFI are due no later than 5:00 p.m., Eastern Time, September 20, 2023. All submissions must be electronically submitted to dni-iarpa-rfi-23-04@iarpa.gov as a PDF document. Inquiries to this RFI must be submitted to dni-iarpa-rfi-23-04@iarpa.gov. Do not send questions with proprietary content. No telephone inquiries will be accepted.

Disclaimers and Important Notes:

This is an RFI issued solely for information and planning purposes and does not constitute a solicitation or authority to enter into negotiations for a contract. Respondents are advised that IARPA is under no obligation to acknowledge receipt of the information or to provide feedback to respondents with respect to any information submitted under this RFI. Responses to this notice are not offers and cannot be accepted by the Government to form a binding contract. Respondents are solely responsible for all expenses associated with responding to this RFI. IARPA will not provide reimbursement for costs incurred in responding to this RFI. It is the respondent's responsibility to ensure that the submitted material has been approved for public release by the information owner.

The Government does not intend to award a contract on the basis of this RFI or to otherwise pay for the information solicited, nor is the Government obligated to issue a solicitation based on responses received. No proprietary and no classified concepts or information shall be included in the submittal. However, should a respondent wish to submit classified concepts or information, prior coordination must be made with the IARPA Chief of Security. Email the Primary Point of Contact with a request for coordination with the IARPA Chief of Security. Input on technical aspects of the responses may be solicited by IARPA from non-Government consultants/experts who are bound by appropriate non-disclosure requirements.

Contracting Office Address:

Office of the Director of National Intelligence, Intelligence Advanced Research Projects Activity Washington, District of Columbia 20511 United States

Primary Point of Contact:

Dr. Brian Borak, Program Manager dni-iarpa-rfi-23-04@iarpa.gov Intelligence Advanced Research Projects Activity

References

(1) Philipps, S. P.; Dimroth, F.; Bett, A. W. High-Efficiency III-V Multijunction Solar Cells. In McEvoy’s

Handbook of Photovoltaics: Fundamentals and Applications; Elsevier Inc., 2018; pp 439–472.

https://doi.org/10.1016/B978-0-12-809921-6.00012-4.

(2) Li, J.; Aierken, A.; Liu, Y.; Zhuang, Y.; Yang, X.; Mo, J. H.; Fan, R. K.; Chen, Q. Y.; Zhang, S. Y.; Huang, Y.

M.; Zhang, Q. A Brief Review of High Efficiency III-V Solar Cells for Space Application. Frontiers in Physics. Frontiers Media S.A. February 2, 2021. https://doi.org/10.3389/fphy.2020.631925.

(3) El-Atab, N.; Mishra, R. B.; Alshanbari, R.; Hussain, M. M. Solar Powered Small Unmanned Aerial Vehicles: A Review. Energy Technology. John Wiley and Sons Inc December 1, 2021.

https://doi.org/10.1002/ente.202100587.

(4) Green, M. A.; Dunlop, E. D.; Levi, D. H.; Hohl-Ebinger, J.; Yoshita, M.; Ho-Baillie, A. W. Y. Solar Cell Efficiency Tables (Version 54). Progress in Photovoltaics: Research and Applications 2019, 27 (7), 565–

575. https://doi.org/10.1002/pip.3171.

(5) For examples, see: spectrolab.com/photovoltaics; rocketlabusa.com/space-systems/solar; cesi.it/space-solar-cells; azurspace.com.

(6) Raya-Armenta, J. M.; Bazmohammadi, N.; Vasquez, J. C.; Guerrero, J. M. A Short Review of Radiation- Induced Degradation of III–V Photovoltaic Cells for Space Applications. Solar Energy Materials and Solar Cells. Elsevier B.V. December 1, 2021. https://doi.org/10.1016/j.solmat.2021.111379.

(7) Hoang, M. T.; Yang, Y.; Tuten, B.; Wang, H. Are Metal Halide Perovskite Solar Cells Ready for Space Applications? Journal of Physical Chemistry Letters. American Chemical Society April 7, 2022, pp 2908– 2920. https://doi.org/10.1021/acs.jpclett.2c00386.

(8) Forghani, K.; Reddy, R.; Rowell, D.; Tatavarti, R. MOVPE Growth of AlInP-InGaP Distributed Bragg Reflectors (DBR) for Monolithic Integration into Multijunction Solar Cells. In 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC); 2019; pp 227–229. https://doi.org/10.1109/PVSC40753.2019.8980776.

(9) Schmieder, K. J.; Mood, T. C.; Meitl, M. A.; Fisher, B.; Carter, J.; Bennett, M. F.; Armour, E. A.; DIaz, M.;

Kotulak, N. A.; Ruppalt, L.; Pulwin, Z.; Burroughs, S.; Lumb, M. P. Micro-Transfer Printer-Assembled Five Junction CPV Microcell Development. In Conference Record of the IEEE Photovoltaic Specialists Conference; 2019. https://doi.org/10.1109/PVSC40753.2019.8981397.

(10) Shanks, K.; Senthilarasu, S.; Mallick, T. K. Optics for Concentrating Photovoltaics: Trends, Limits and Opportunities for Materials and Design. Renewable and Sustainable Energy Reviews. Elsevier Ltd July 1, 2016, pp 394–407. https://doi.org/10.1016/j.rser.2016.01.089.

(11) Ruud, C. J.; Gordon, J. M.; Giebink, N. C. Microcell Concentrating Photovoltaics for Space. Joule 2023, 7 (6), 1093–1098. https://doi.org/10.1016/j.joule.2023.04.004.

(12) Haney, M. W. The ARPA-E MOSAIC Program: Advancing Micro-Scale Concentrated Photovoltaics. In Optics InfoBase Conference Papers; 2017; Vol. Part F69-OSE 2017.

https://doi.org/10.1364/OSE.2017.RW3B.1.

(13) Rafiee, M.; Chandra, S.; Ahmed, H.; McCormack, S. J. An Overview of Various Configurations of Luminescent Solar Concentrators for Photovoltaic Applications. Opt Mater (Amst) 2019, 91, 212–227.

https://doi.org/10.1016/j.optmat.2019.01.007.

(14) Chen, C.; Zheng, S.; Song, H. Photon Management to Reduce Energy Loss in Perovskite Solar Cells. Chemical Society Reviews. 2021. https://doi.org/10.1039/d0cs01488e.

(15) Li, D.; Li, L.; Jared, B.; Keeler, G.; Miller, B.; Wood, M.; Hains, C.; Sweatt, W.; Paap, S.; Saavedra, M.;

Alford, C.; Mudrick, J.; Das, U.; Hegedus, S.; Tauke-Pedretti, A.; Hu, J.; Gu, T. Wafer Integrated Micro- Scale Concentrating Photovoltaics. Progress in Photovoltaics: Research and Applications 2018, 26 (8), 651–658. https://doi.org/10.1002/pip.3034.