Case 11996

Zinc-Oxide Nanowire Photosynthetic Solar Cell


Self-assembled, low-tech, low-skill methods for photosynthetic solar power, zinc-oxide, nanowires, bio-photovoltaic, bio-sensitized solar cell (BSSC), practical, open source hardware, local production, off-grid, ambient conditions.


Ultra low cost, ultra low technology solar cells, biophotovoltaics, chemical sensors, biosensors, nanocircuitry


Drastically reducing complexity and cost of making solar power off-grid by unskilled personnel, requiring mostly locally available resources and readily available tools and raw materials (open air kitchen equipment sufficient)


This invention mimics natural photosynthesis to generate electricity using plant or other photosynthetic matter extracts dried on a high surface area electrode. The circuit is completed by non-toxic, inexpensive liquid electrolyte and a layer of transparent conducting plastic. A layer of self-assembled photosynthetic complexes is dried on high surface area ZnO nanowires that are grown solvothermally at ambient temperatures and pressures. This required minimal equipment, low technical skill and only cheap, easily transportable, resilient and non-perishable Zn sheets, stabilizing powders, pH adjusting pellets and transparent conducting plastic sheets. Not even an open flame is required to build these solar panels and there is no need for electricity, vaccum or clean conditions to assemble these cells. This invention shows how it is possible to integrate photosynthetic proteins found virtually everywhere on earth with solvothermally (i.e. at ambient temperature, dirty conditions), grown high-surface area photoanodes produced from inexpensive raw materials using minimal energy and requiring no infrastructure to assemble functional biophotovoltaics that produce useable electricity from incident sunlight.

  • When exposed to AM1.5 calibrated illumination (standard Sunlight) the proof-of-principle un-optimized photosystem-I (PS-I) devices give circuit photovoltage of 0.5V, fill factor of 71%, electrical power density of 81µW/cm2 and photocurrent density of 362µA/cm2 on TiO2 nanocrystals of roughness factor ρΤιΟ2 ~200 and proportionally for ZnO nanowires of any ρ. This is 10,000 times higher than any PS-I biophotovoltaic to date. Optimization is expected to yield 1-2 orders of magnitude further improvement.
  • Making a high-surface area photoanode out of ZnO nanowires of high aspect ratio is simply achieved by exposing a sheet of Zinc to mildly high pH solution of Zinc Sulfate requiring no sophisticated technology. Process can be completed using dirty vats in open air and requires no special handling or skill, not even an open flame. There are no expensive or hazardous materials involved.
  • Photosynthetic raw material can be collected locally, almost anything “green” will do, and a simple tube filtration scheme instead of centrifugation is expected to produce pure enough PS-I extract at minimal cost and maximum ease of preparation.

  • Andreas Mershin (Center for Biomedical Engineering, MIT)
  • Brian L. Cook (Center for Biomedical Engineering, MIT)
  • Shuguang Zhang (Center for Biomedical Engineering, MIT)

Intellectual Property:

US Patent application 11/639372 filed on December 14, 2006


Self-assembled photosystem-I biophotovoltaics on nanostructured TiO2 and ZnO ANDREAS MERSHIN*, KAZUYA MATSUMOTO, LISELOTTE KAISER, DAOYONG YU, MICHAEL VAUGHN, MD. K. NAZEERUDDIN, BARRY D. BRUCE, MICHAEL GRAETZEL AND SHUGUANG ZHANG,In review Nature Scientific Reports –Aug 2011


Last revised:January 18, 2012

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