1. Light management in thin-film solar cells Albert Polman Center for Nanophotonics FOM-Institute AMOLF Amsterdam, The Netherlands

2. Vanguard satellite 1958

3. The first practical solar panel (1954) Bell Laboratories (1954)

4. 2010

5. Price per solar Watt vs. installed power P. Maycock

6. Black dots: area of solar panels needed to generate all of the worlds primary energy (all energy consumed: electricity, heat, fossil fuels) Solar irradiance on earth assuming 8% efficient photovoltaics

7. Available renewable energy sources

8. Solar cell basic geometry

9. Solar cell operation

10. Effects of R shunt and R series on I-V curve Ideal IV curve Low R sh High R se R sh = ∞ R se = 0

11. Light is poorly absorbed in a thin-film solar cell Solar spectrum absorbed in 2 m thick Si film

12. “Quantum defect” limits efficiency Photons are quantized energy packets: A 2 eV photon will give create max. 1 Volt over the p-n junction A 0.5 eV photon is not absorbed E g (Si)=1.1 eV

13. Triple-junction tandem solar cell 1.5 V 1.0 V 0.5 V

14. Record efficiency solar cell

15. From: Richard King (Spectrolab) Triple-junction tandem solar cell layer geometry

16. Efficiency limits of different solar cell types (2010) 3-junction tandem crystal Si wafer thin film: CdTe poly-Si amorphous Si organic/polymer dye-sensitized other Too expensive Too low efficiency 2009: CdTe thin film cells costs: < 1 $/W

17. Relative abundance of elements vs. atomic nr. from P.H. Stauffer et al, Rare Earth Elements - Critical Resources for High Technology, USGS (2002) Materials resources are limited Solutions: 1) Earth Abundant Semiconductors (Si,Cu 2 O, Zn 3 P 2, FeS 2 ) 2) Enhance Light Absorption/reduce semiconductor volume Requirements to construct 1 TW of PV with optically thick cells at 15% efficiency

18. Photovoltaic materials production and reserve base

19. Si solar cell efficiencies

20. … © Ron Tandberg