High Efficiency BHJ Solar Cells with IQE Approaching 100% fabricated - PowerPoint PPT Presentation

High Efficiency BHJ Solar Cells with IQE Approaching 100% fabricated with th P l ( the Poly (2,7 ‐ Carbazole) Copolymer, PCDTBT C b l ) C l PCDTBT Sung Heum Park Heeger Center for Advanced Materials, Gwangju Institute of Science and Technology, Korea Gwangju Institute of Science and Technology, Korea

i) Large area ii) Easy fabrication ii) Easy fabrication iii) Room temp. processibility iv)Thin film form v) Flexibility vi) Mass production (Spin cast, Ink ‐ jet printing method, etc.) Ink jet printing method, etc.) vii) Low cost

Efficiency = I sc x V oc x FF / Power • I sc : – Better harvest of solar spectrum p – Increase absorption in active layer – Improve Internal Quantum Efficiency • V oc : – Higher HOMO – Lower LUMO – Increase internal Field • FF : • FF : – Higher Carrier Mobility – Decrease Internal resistance Decrease Internal resistance

1.0 PCDTBT 0.8 PC BM PC 70 BM Coefficient 0.6 0 4 0.4 Extinction TiO x TiO 0.2 0 0 0.0 300 400 500 600 700 800 900 1000 Wavelength (nm)

6% 6% under AM 1.5 condition under AM 1.5 condition 17% 17% under green light condition under green light condition

5 m 2 ) ty (mA/cm 0 -5 Light curent - dark current nt Densit Light current Dark current -10 Curren -15 -20 -4 -3 -2 -1 0 1 Voltage (V) Every photon absorbed leads to a separated pair of charge carriers!!! Every photogenerated mobile carrier is collected at the electrode!!!

• High efficiency BHJ solar cell has been demonstrated. PCE ~ 6% under AM 1.5G PCE~ 17% with monochromatic radiation (532 nm) • IQE of device approaches 100% Every photon absorbed leads to a separated pair of charge carriers and that every photogenerated mobile carrier is collected at the electrode that every photogenerated mobile carrier is collected at the electrode “There is fundamentally no problem that cannot be overcome There is fundamentally no problem that cannot be overcome with regard to collecting charge from polymer solar cells”.