Luminescent Down Shifting

What is Luminescent Down Shifting?

Luminescent Down Shifting involves the conversion of one photon of high energy light, which is inefficiently absorbed by the photovoltaic material, to one photon of with an energy that can be efficiently absorbed by the photovoltaic material. The luminescent down shifting layer is placed on top of the photovoltaic material. Therefore no change to the optimised electrical properties of the photovoltaic material is required. A common trend across current photovoltaic technologies is that the response of the photoactive material reduces for lower wavelengths (blue and UV). Therefore luminescent down shifting layers can be used to enhance a range of photovoltaic materials. 

Ideal luminescent down shifting material should exhibit; a wide absorption band in the range of enhancement, high absorption coefficient, narrow emission band in the peak conversion efficiency region of the photoactive material, good separation between absorption and emission bands, and low cost. Luminescent materials under research include quantum dots, organic dyes and rare-earth ions/complexes. The most frequently used host materials for the luminescent species are polymers such as PMMA and inorganic crystalline materials such as Al2O3. 

 

What are the challenges for Luminescent Down Shifting?

The addition of an extra layer in front of the photovoltaic material introduces additional loss mechanisms for the light. Therefore any potential gain made by shifting the spectrum will have to compensate for these losses before showing an additional improvement. These loss mechanisms include parasitic absorption from the host material, low conversion efficiency of the luminescent material, re-absorption from the luminescent species, increased reflection due to the additional surfaces and losses from the top surface of the luminescent layer. 

The cost of both the materials used and fabrication procedures should be minimised and the layer should be stable for the lifetime of the photoactive material for luminescent down shifting layers to become economically viable. 

 

How are these challenges being addressed by SISER researchers?

Heriot Watt University is carrying out research into the use of organic luminescent down conversion layers for both microcrystalline silicon (mc-Si) and cadmium telluride (CdTe) solar cells. Their work includes the encapsulation of organic dyes into the encapsulating layer that is present in all mc-Si solar cells: thereby removing the need for an extra layer of material. They are also investigating the use of the luminescent down shifting species to remove the need for UV stabilisers in the encapsulant material. 

 

SISER researchers with interest in this area are: Prof. Neil Robertson.

Full details of all SISER researchers are found on the SISER People Page

 

Publications

  1. Diego Alonso-Alvarez, David Ross, Keith R McIntosh, Bryce S Richards and Ieee. Performance of luminescence down shifting for CdTe solar cells as a function of the incident solar spectrum. 2012 38th Ieee Photovoltaic Specialists Conference series, 2012.
    BibTeX

    @book{Performance of luminescence down shifting for CdTe solar cells as a function of the incident solar spectrum,
    	author = "Alonso-Alvarez, Diego and Ross, David and McIntosh, Keith R. and Richards, Bryce S. and Ieee",
    	title = "Performance of luminescence down shifting for CdTe solar cells as a function of the incident solar spectrum",
    	series = "2012 38th Ieee Photovoltaic Specialists Conference",
    	note = "Times Cited: 0 Alonso Alvarez, Diego/B-8863-2013 Alonso Alvarez, Diego/0000-0002-0060-9495 Pvsc 38th IEEE Photovoltaic Specialists Conference (PVSC) Jun 03-08, 2012 Austin, TX IEEE; IEEE Electron Devides Soc (EDS); IEEE Photon Soc; IEEE Power & Energy Soc (PES); HelioVolt Corp; SunShot, US Dept Energy",
    	pages = "2504-2508",
    	year = 2012
    }
    
  2. Diego Alonso-Alvarez, David Ross, Bryce S Richards and Ieee. Luminescent down-shifting for CdTe solar cells: A review of dyes and simulation of performance. 2012 38th Ieee Photovoltaic Specialists Conference series, 2012.
    BibTeX

    @book{Luminescent down-shifting for CdTe solar cells: A review of dyes and simulation of performance,
    	author = "Alonso-Alvarez, Diego and Ross, David and Richards, Bryce S. and Ieee",
    	title = "Luminescent down-shifting for CdTe solar cells: A review of dyes and simulation of performance",
    	series = "2012 38th Ieee Photovoltaic Specialists Conference",
    	note = "Times Cited: 0 Alonso Alvarez, Diego/B-8863-2013 Alonso Alvarez, Diego/0000-0002-0060-9495 Pvsc 38th IEEE Photovoltaic Specialists Conference (PVSC) Jun 03-08, 2012 Austin, TX IEEE; IEEE Electron Devides Soc (EDS); IEEE Photon Soc; IEEE Power & Energy Soc (PES); HelioVolt Corp; SunShot, US Dept Energy",
    	year = 2012
    }
    
  3. Efthymios Klampaftis, Martina Congiu, Neil Robertson and Bryce S Richards. Luminescent Ethylene Vinyl Acetate Encapsulation Layers for Enhancing the Short Wavelength Spectral Response and Efficiency of Silicon Photovoltaic Modules. Ieee Journal of Photovoltaics 1(1):29-36, 2011.
    BibTeX

    @article{Luminescent Ethylene Vinyl Acetate Encapsulation Layers for Enhancing the Short Wavelength Spectral Response and Efficiency of Silicon Photovoltaic Modules,
    	author = "Klampaftis, Efthymios and Congiu, Martina and Robertson, Neil and Richards, Bryce S.",
    	title = "Luminescent Ethylene Vinyl Acetate Encapsulation Layers for Enhancing the Short Wavelength Spectral Response and Efficiency of Silicon Photovoltaic Modules",
    	journal = "Ieee Journal of Photovoltaics",
    	volume = 1,
    	number = 1,
    	pages = "29-36",
    	note = "Times Cited: 4 4",
    	year = 2011
    }
    
  4. Efthymios Klampaftis, David Ross, Keith R McIntosh and Bryce S Richards. Enhancing the performance of solar cells via luminescent down-shifting of the incident spectrum: A review. Solar Energy Materials and Solar Cells 93(8):1182-1194, 2009.
    BibTeX

    @article{Enhancing the performance of solar cells via luminescent down-shifting of the incident spectrum: A review,
    	author = "Klampaftis, Efthymios and Ross, David and McIntosh, Keith R. and Richards, Bryce S.",
    	title = "Enhancing the performance of solar cells via luminescent down-shifting of the incident spectrum: A review",
    	journal = "Solar Energy Materials and Solar Cells",
    	volume = 93,
    	number = 8,
    	pages = "1182-1194",
    	note = "Times Cited: 78 79",
    	year = 2009
    }
    
  5. Efthymios Klampaftis, David Ross, Sieghard Seyrling, Ayodhya N Tiwari and Bryce S Richards. Increase in short-wavelength response of encapsulated CIGS devices by doping the encapsulation layer with luminescent material. Solar Energy Materials and Solar Cells 101:62-67, 2012.
    BibTeX

    @article{Increase in short-wavelength response of encapsulated CIGS devices by doping the encapsulation layer with luminescent material,
    	author = "Klampaftis, Efthymios and Ross, David and Seyrling, Sieghard and Tiwari, Ayodhya N. and Richards, Bryce S.",
    	title = "Increase in short-wavelength response of encapsulated CIGS devices by doping the encapsulation layer with luminescent material",
    	journal = "Solar Energy Materials and Solar Cells",
    	volume = 101,
    	pages = "62-67",
    	note = "Times Cited: 2 2",
    	year = 2012
    }
    
  6. Keith R McIntosh, Gay Lau, James N Cotsell, Katherine Hanton, Derk L Baetzner, Fabian Bettiol and Bryce S Richards. Increase in External Quantum Efficiency of Encapsulated Silicon Solar Cells from a Luminescent Down-Shifting layer. Progress in Photovoltaics 17(3):191-197, 2009.
    BibTeX

    @article{Increase in External Quantum Efficiency of Encapsulated Silicon Solar Cells from a Luminescent Down-Shifting layer,
    	author = "McIntosh, Keith R. and Lau, Gay and Cotsell, James N. and Hanton, Katherine and Baetzner, Derk L. and Bettiol, Fabian and Richards, Bryce S.",
    	title = "Increase in External Quantum Efficiency of Encapsulated Silicon Solar Cells from a Luminescent Down-Shifting layer",
    	journal = "Progress in Photovoltaics",
    	volume = 17,
    	number = 3,
    	pages = "191-197",
    	note = "Times Cited: 26 27",
    	year = 2009
    }
    
  7. Keith R McIntosh, Bryce S Richards and Ieee. Increased mc-Si module efficiency using fluorescent organic dyes: A ray-tracing study. Conference Record of the 2006 IEEE 4th World Conference on Photovoltaic Energy Conversion, Vols 1 and 2 series, 2006.
    BibTeX

    @book{Increased mc-Si module efficiency using fluorescent organic dyes: A ray-tracing study,
    	author = "McIntosh, Keith R. and Richards, Bryce S. and Ieee",
    	title = "Increased mc-Si module efficiency using fluorescent organic dyes: A ray-tracing study",
    	series = "Conference Record of the 2006 IEEE 4th World Conference on Photovoltaic Energy Conversion, Vols 1 and 2",
    	note = "Times Cited: 0 4th World Conference on Photovoltaic Energy Conversion May 07-12, 2006 Waikoloa, HI IEEE Electron Devices Soc",
    	pages = "2108-2111",
    	year = 2006
    }
    
  8. B S Richards and K R McIntosh. Overcoming the poor short wavelength spectral response of CdS/CdTe photovoltaic modules via luminescence down-shifting: Ray-tracing simulations. Progress in Photovoltaics 15(1):27-34, 2007.
    BibTeX

    @article{Overcoming the poor short wavelength spectral response of CdS/CdTe photovoltaic modules via luminescence down-shifting: Ray-tracing simulations,
    	author = "Richards, B. S. and McIntosh, K. R.",
    	title = "Overcoming the poor short wavelength spectral response of CdS/CdTe photovoltaic modules via luminescence down-shifting: Ray-tracing simulations",
    	journal = "Progress in Photovoltaics",
    	volume = 15,
    	number = 1,
    	pages = "27-34",
    	note = "Times Cited: 22 23",
    	year = 2007
    }
    
  9. Bryce S Richards, Keith R McIntosh and Ieee. Enhancing the efficiency of production CdS/CdTe PV modules by overcoming poor spectral response at short wavelengths via luminescence down-shifting. Conference Record of the 2006 IEEE 4th World Conference on Photovoltaic Energy Conversion, Vols 1 and 2 series, 2006.
    BibTeX

    @book{Enhancing the efficiency of production CdS/CdTe PV modules by overcoming poor spectral response at short wavelengths via luminescence down-shifting,
    	author = "Richards, Bryce S. and McIntosh, Keith R. and Ieee",
    	title = "Enhancing the efficiency of production CdS/CdTe PV modules by overcoming poor spectral response at short wavelengths via luminescence down-shifting",
    	series = "Conference Record of the 2006 IEEE 4th World Conference on Photovoltaic Energy Conversion, Vols 1 and 2",
    	note = "Times Cited: 0 4th World Conference on Photovoltaic Energy Conversion May 07-12, 2006 Waikoloa, HI IEEE Electron Devices Soc",
    	pages = "213-216",
    	year = 2006
    }
    
  10. David Ross, Diego Alonso-Alvarez, Jochen Fritsche, Michael Bauer, Michael G Debije, Robert M Fifield, Bryce S Richards and Ieee. First Ever Full Size CdTe Luminescent Down-Shifting Module. 2012 38th Ieee Photovoltaic Specialists Conference series, 2012.
    BibTeX

    @book{First Ever Full Size CdTe Luminescent Down-Shifting Module,
    	author = "Ross, David and Alonso-Alvarez, Diego and Fritsche, Jochen and Bauer, Michael and Debije, Michael G. and Fifield, Robert M. and Richards, Bryce S. and Ieee",
    	title = "First Ever Full Size CdTe Luminescent Down-Shifting Module",
    	series = "2012 38th Ieee Photovoltaic Specialists Conference",
    	note = "Times Cited: 0 Alonso Alvarez, Diego/B-8863-2013 Alonso Alvarez, Diego/0000-0002-0060-9495 Pvsc 38th IEEE Photovoltaic Specialists Conference (PVSC) Jun 03-08, 2012 Austin, TX IEEE; IEEE Electron Devides Soc (EDS); IEEE Photon Soc; IEEE Power & Energy Soc (PES); HelioVolt Corp; SunShot, US Dept Energy",
    	pages = "1978-1982",
    	year = 2012
    }
    
  11. David Ross, Efthymios Klampaftis, Jochen Fritsche, Michael Bauer and Bryce S Richards. Increased short-circuit current density of production line CdTe mini-module through luminescent down-shifting. Solar Energy Materials and Solar Cells 103:11-16, 2012.
    BibTeX

    @article{Increased short-circuit current density of production line CdTe mini-module through luminescent down-shifting,
    	author = "Ross, David and Klampaftis, Efthymios and Fritsche, Jochen and Bauer, Michael and Richards, Bryce S.",
    	title = "Increased short-circuit current density of production line CdTe mini-module through luminescent down-shifting",
    	journal = "Solar Energy Materials and Solar Cells",
    	volume = 103,
    	pages = "11-16",
    	note = "Times Cited: 2 2",
    	year = 2012
    }