SITIS Archives - Topic Details
Program:  SBIR
Topic Num:  N102-174 (Navy)
Title:  Development and scale-up of very low-cost, light-weight, flexible solar cells
Research & Technical Areas:  Ground/Sea Vehicles, Materials/Processes, Electronics, Battlespace

Acquisition Program:  PM Mariine Corps Expeditionary Power Systems
  Objective:  The objective of this effort is to develop and demonstrate on increasing scales novel solar cells designs and manufacturing processes consistent with production of very low cost solar cells (<$0.50 per watt) that are lightweight, flexible, rugged, with greater than 6% power conversion efficiency and greater than 3 year lifetime.
  Description:  Current solar cell technology is impressive, but for the home or business owner, the cost is too high to compete with conventional grid power. Real energy costs can be substantially higher for the military, but high acquisition costs and difficult form factors still limit the adoption of solar technologies. The availability of light-weight, flexible, and low-cost solar cells would significantly increase adoption of solar technologies in the military, particular at the warfighter level for personal power, at the base camp level, and for use in distributed sensing. Organic solar cell technology, on the research level, has improved to the point where simple printed cells can have a power conversion efficiency of 6 percent, close to that of commercial amorphous silicon cells and at a level where there is commercial viability. The organic cells could potentially cost 80 percent less than cells with similar efficiency. To reach this production cost, manufacturing processes and cell designs need to be developed consistent both with large scale manufacturing and with the precision, cleanliness, and control necessary to obtain optimal cell performance. The challenges here push the state-of-the-art not only in demanding high performance from the active materials, but also in light trapping, electrode design, and barrier strategies, all of which must be consistent with low cost manufacturing on flexible substrates.

  PHASE I: Using an ambient atmosphere processing technique, produce active films with at least 100 square cm area and containing at least 10 cells of 5 sq cm. Non-ambient processing can be used for electrodes and packaging. Demonstrate at least 4.0% total area power conversion efficiency under AM1.5 illumination and for 100 hours of continuous illumination at 1 sun or higher. Deliver a film for performance verification. Prepare a report on approach to further develop process to meet full objectives (<$0.50 watt, >6% power conversion efficiency, > 3 year lifetime).
  PHASE II: Meet full program objectives (<$0.50 watt, >6% power conversion efficiency on module level, > 3 year lifetime) on 0.1 sq meter devices manufactured on flexible substrates by processes directly amenable to cost effective scale-up for full production. Present a plan for commercialization of this technology.

  PHASE III: Scale to cost effective production level. Work with acquisition programs or current vendors to insert lower cost solar cell technology into products for military applications. PRIVATE SECTOR COMMERCIAL POTENTIAL/

  DUAL-USE APPLICATIONS: Low cost solar cells will greatly shorten the payback period associated with investing in solar power for the home or business and thus could significantly increase adoption of solar technologies.

  References:   1. C.N. Hoth, S.A. Choulis, P. Schilinsky, C.J. Brabec, Adv. Materials 19 (2007) 3973. 2. C.N. Hoth, R. Steim, P. Schilinsky, S.A. cholis, S.F. Tedde, O. Hayden, C.J. Brabec, Organic Electronics 10 (2009) 587.

Keywords:  organic photovoltaics; OPV; printing; spray coating; low cost manufacturing; flexible

Questions and Answers:
Q: Has this topic been written for an ambient atmosphere process, organic solar cell, or would an inorganic solar cell meeting your cost and performance metrics be acceptable?
A: The topic was written for an ambiently processed potentially very low cost solar cell as described in the solicitation. Organic cells were used as an example, but this does not exclude other approaches.
Q: Could you please clarify your definition of "ambient atmosphere processing technique?" Does this just apply to "atmosphere" as it relates to atomospheric pressure, or does it also apply to atmospheric composition i.e. a 0xygen/Nitrogen composition, temperature range or humidity?
A: Ambient processing literally means an open air process such a printing from an inkjet printer without a controlled atmosphere around the printing process. However, the overall goal for the solicitation is very low cost solar cells with reasonable efficiency and lifetime on flexible substrates. Some level of cleanliness or atmospheric control may be necessary, but it shouldn't have a large impact on the costs for the manufacturing process.
Q: What is the minimum radius of curvature the cells must withstand in order to be classified as "flexibile"?
A: No specific requirement was given in the solicitation. The solar cell film should be flexible enough to be rolled up compactly.

It is likely that the device packaging/encapsulant will determine bend radius and for different applications there will be different lifetime requirements. Thus the bend radius may vary with application.
Q: Is there a power density (W/Kg) requirement or specification on the solar cells - especially for phase I?
A: There is no power density (W/g) requirement in phase I. A long term target for this technology is expeditionary applications and so, amongst many factors, power density is important.
Q: Currently our company is working on a low cost and low energy intensive method to produce an organic polymer P-type layer for use in production of solar cells. We currently utilize Si(000) as the N-type layer. Would you advise the use of an organic or hybrid or silicon N-type layer while proposing our submission?
A: The solicitation does not exclude inorganic materials. The offeror needs to decide whether his approach has the potential to meet and exceed all phase I and phase II cost and performance metrics.

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