Research

Organic Solar Cells

  • Global warming

 The burning of fossil fuels produces huge amounts of carbon dioxide per year (around 21.3 billion tonnes). Carbon dioxide is one of the greenhouse gases that enhances radiative

forcing and contributes to global warming, causing the average surface temperature of the Earth to rise in response. The production and use of fossil fuels raise environmental concerns. A global movement toward the generation of renewable energy such as solar cells is therefore under way to help meet increased energy needs.

  • Organic Solar Cells

Due to the needs to develop flexible and low-cost photovoltaic devices, the organic photovoltaics (OPV) have introduced. We performs systematic researches on efficient charge extraction from photo-active layer to achieve the highly efficient and reliable organic photovoltaics.
 

We developed new flexible polymeric anodes, which has high work function to control energy level barriers at the interface of a photo-active layer. Our high work function polymeric anodes are composed of a conducting polymer, PEDOT:PSS, a perfluorinated ionomer for work function tunning, and a polar organic additive to increase conductivity. With the high work function polymeric anodes, the organic photovoltaic cells can be simplified even with good performance.

The OPV fabricated on our high work function polymeric anode exhibited PCE = 5.5 %, which is comparable to that on a conventional ITO/PEDOT:PSS anode OPV (PCE = 5.5 %).

We also developed flexible organic solar cells incorporating graphene electrodes which is synthesized by CVD method. We could demonstrate flexible organic solar cells with flexible graphene anodes

We were able to fabricate organic soalr cells on the graphene electrode with uniformly coated hole extraction layer.

[References]

1. ChemSusChem (2015), 8, 3062

2. ChemSusChem (2014), 7, 4, 1125

3. J. Mater. Chem.(2012),  22, 23148

4. Angew. Chem. Int. Ed. (2011), 50, 6274