Advanced light management techniques for building integrated PV (BIPV) A. Ingenito, J. C. O. Lizcano, O. Isabella, M. Zeman Delft University of Technology
Advanced light management Roadmap for decreasing costs of c-si PV Decrease wafer cell costs [1] Wafer accounts for more than 50% of the cell costs [2] Customized PV products [1] Building integrated PV (BIPV) combining building elements and PV functionality Oskomera Solar 2015 2020 [1,3] Roadmap [1] International Technology Roadmap for Photovoltaic (ITRPV), (2013) [2] A. Goodrich et al. SOLMAT 114,110 135 (2013) [3] Predictions for the Solar Industry in 2014, IHS Whitepaper (2013) 2
Advanced light management in c-si Experimental demonstration of upper limit 4n 2 absorption enhancement [1] Front nano-texture (RIE) 2 µm 1.0 0.8 DBR Ag (ref.) Bulk c-si 20 μm Thermal SiO 2 DBR A Si [-] 0.6 0.4 1.28 μm Textured BS 2 µm 0.2 0.0 400 600 800 1000 1200 Wavelength [nm] [1] A. Ingenito, O. Isabella, M. Zeman, ACS Photonics, 1, 3 (2014) 3
Advanced light management in c-si IBC c-si solar cells IBC structure 1.0 1.0 0.8 0.8 EQE [-] 0.6 0.4 V OC (mv) 635 J SC (ma/cm 2 ) 40.5 FF (%) 77.0 0.6 0.4 R [-] 280 μm 0.2 η (%) 19.8 0.2 Front side 0.0 0.0 300 450 600 750 900 1050 1200 Wavelength [nm] A. Ingenito, O. Isabella, M. Zeman. Progress in Photovoltaics, DOI: 10.1002/pip.2606 (2015) 4
Advanced light management in c-si Black IBC c-si solar cells for high yield and BIPV applications [1] Black modules are highly requested for residential PV [2] [1] H. Savin, P. Repo, G. von Gastrow, P. Ortega, E. Calle, M. Garín, Nature Nanotechnology, DOI: 0.1038/nnano.2015.89 (2015) [2] Paul de Jong, Exasun, BJ-BC workshop, Freiburg, (2015) 5
Advanced light management Roadmap for decreasing costs of c-si PV Decrease wafer cell costs [1] Wafer accounts for more than 50% of the cell costs [2] Customized PV products [1] Building integrated PV (BIPV) combining building elements and PV functionality Oskomera Solar 2015 2020 [1,3] Roadmap [1] International Technology Roadmap for Photovoltaic (ITRPV), (2013) [2] A. Goodrich et al. SOLMAT 114,110 135 (2013) [3] Predictions for the Solar Industry in 2014, IHS Whitepaper (2013) 6
Optical filters (OF) as coloured coatings OF for front and/or back side coloured PV Glass EVA x 10 Glass EVA 10 x ARC ARC Emitter c-si Emitter c-si c-si BSF 10 x BSF Rear coating EVA Al Al Glass 7
OF s requirements and materials Exploits interference effect Based on pairs of dielectric thin-films Stronger effect with high/low refractive refractive index mismatch Several materials can be used, among the others: MgF 2 SiO 2 TiO 2 Si x N y a-si:h SiO 2 Si x N y x pairs Features Non absorbing materials in spectral range of interest o [300-1200] nm for Front side o [900-1200] nm for Back side Reflectance above 80% at desired wavelength Substrate (Glass or wafer) Protected by glass/encapsulant 8
OF s optical modelling 1,00 0,90 0,80 0,70 0,60 0,50 0,40 0,30 0,20 0,10 1. 2-D Ray tracing* 0,00 390 440 490 540 590 640 690 740 790 2. Reflectance profile 3. Color Coordinates SunRay software by dr. R. Santbergen 9
Selected colours for validation SiO 2 = 100 nm Si x N y = 100 nm SiO 2 = 90 nm Si x N y = 100 nm SiO 2 = 40 nm Si x N y = 110 nm PE-CVD 10
Optical filters (OF) as coloured coatings OF for front and/or back side coloured PV Glass EVA x 10 Glass EVA 10 x ARC ARC Emitter c-si Emitter c-si c-si BSF 10 x BSF Rear coating EVA Al Al Glass 11
Colour matrix (OF on glass and c-si solar cell) 10 x Glass EVA ARC 1.0 0.8 EQE [-] 0.6 0.4 0.2-3.5 ma/cm 2 Standard ARC (NO-OF) Coloured 0.0 400 600 800 1000 1200 Wavelength [nm] 12
Colour matrix (OF on glass and c-si solar cell) Angular resilience 10 x Glass EVA ARC 13
Colour matrix (OF on c-si solar cell in glass) 10 x Glass EVA ARC 1.0 0.8 EQE [-] 0.6 0.4-1.8 ma/cm 2 Standard ARC (NO-OF) Coloured 0.2 0.0 400 600 800 1000 1200 Wavelength [nm] 14
Colour matrix (OF on c-si solar cell in glass) Angular resilience 10 x Glass EVA ARC 15
Passive thermal control [1] for BIPV Preliminary study Glass +20 pairs EVA ARC Emitter c-si BSF Al Potential for Passively reducing module temperature Concurrently combining colour and thermal control [1] A. P. Raman, et al., Nature, 515, 540-544 (2014) 16
Optical filters (OF) as coloured coatings OF for front and/or back side coloured PV Glass EVA x 10 Glass EVA 10 x ARC ARC Emitter c-si Emitter c-si c-si BSF 10 x BSF Rear coating EVA Al Al Glass 17
Distributed Bragg Reflector (DBR) DBR can act as both back reflector (BRs) and OF High R at SiO 2 / Si interface in the weak absorption region if Si 1.0 PCB 0.8 R Sim [-] 0.6 0.4 0.2 Region of weak absorption in c-si DBR λ B 0.0 400 600 800 1000 1200 1400 Wavelength [nm] A. Ingenito, O. Isabella, M. Zeman, ACS Photonics, 1, 3 (2014) 18
Fabrication of DBR on textured surfaces 1.0 0.8 DBR R, T [-] 0.6 0.4 R 0.2 T 0.0 400 600 800 1000 1200 Wavelength [nm] Co-depostion of 6 x a-si:h (80 nm) / a-sin x :H (180 nm) 19
Fabrication of DBR on textured surfaces 1.0 0.8 DBR R, T [-] 0.6 0.4 R? 0.2 R T T DBR 0.0 400 600 800 1000 1200 Wavelength [nm] Co-depostion of 6 x a-si:h (80 nm) / a-sin x :H (180 nm) 20
DBR optimization for textured surface =54.7 X= Y*sin (90 - θ) = Y*0.57 A. Ingenito, S.L. Luxembourg, P. Spinelli, J. Liu, J. C. O. Lizcano, A. Weeber, O. Isabella, M. Zeman, IEEE JPV, accepted for publication (2015) 21
DBR optimization for textured surface Influence of scaling factor on A Si 1.0 39.0 ma / cm 2 0.8 A Si [-] 0.6 0.4 0.2 0.8 1.0 1.2 1.5 1.7 DBR 38.1 ma/cm 2 0.0 400 600 800 1000 Wavelength [nm] 1000 1050 1100 1150 Wavelength [nm] A. Ingenito, S.L. Luxembourg, P. Spinelli, J. Liu, J. C. O. Lizcano, A. Weeber, O. Isabella, M. Zeman, IEEE JPV, accepted for publication (2015) 22
DBR optimization for textured surface Influence of scaling factor on λ B at DBR / air interface 0.8 1.0 1.2 1.5 1.7 R DBR air [-] 1.0 0.8 0.6 0.4 0.8 1.0 1.2 1.5 1.7 0.8 1 1.2 1.5 1.7 Light 0.2 DBR 0.0 400 600 800 1000 1200 1400 Wavelength [nm] 23
DBR (OF) as coloured coatings Application in glass/glass modules Coloured cell [1] Coloured module n-pasha cell [2] [1] A. Ingenito, S.L. Luxembourg, P. Spinelli, J. Liu, J. C. O. Lizcano, A. Weeber, O. Isabella, M. Zeman, IEEE JPV, accepted for publication (2015) [2] I. G. Romijn, A. Gutjahr, D. Saynova, J. Anker, E.J Kossen, K. Tool. Photovoltaics International, 2013, vol. 20. pp. 33-40 24
Advanced light management for BIPV Experimental demonstration of advanced light management techniques for absorption enhancement in thin c-si absorbers Application of advanced light management for black IBC c-si solar cells with efficiency of 19.8% EQE [-] 1.0 0.8 0.6 0.4 0.2 1.0 0.8 0.6 0.4 0.2 R [-] Design of OFs as colour-tuning coatings for front and/or rear side coloured PV Model validation Design and optical simulations of DBR on textured surfaces Concurrent colour and thermal control (on-going) 0.0 0.0 300 450 600 750 900 1050 1200 Wavelength [nm] 25
Thank you! Acknowledgments: Martijn Tijssen Martijn van Sebille Stefan Luxembourg Pierpaolo Spinelli Funding: Agentschap NL
Outline Roadmap for decreasing the cost of c-si PV module Advanced light management techniques as possible solution to decrease LCOE Thin c-si solar cells Customized products as Building integrated PV Conclusions 2
DBR optimization for textured surface Ray tracing simulations Parameter space: a-si:h [40:10:140] nm a-sin x :H [70:10:240] nm Si SiO 2 DBR DBR = 6 x (a-si:h /a-sin x :H) [1] a-sin x :H [nm] 230 210 190 170 150 130 110 90 J PH-T = 6.1 10-3 ma/cm 2 [2] Textured 70 40 60 80 100 120 140 a-si:h [nm] J ph T [ma/cm 2 ] 0.005 0.01 0.05 0.1 0.5 1.0 1.5 2.0 [1] A. Ingenito, O. Isabella, M. Zeman, ACS Photonics, 1, 3, (2014) [2] J.C.O. Lizcano, MSC thesis, Optic Filters for BIPV applications (2014) 20
Color resilience against angle of incidence 13
Device level color matrix 14
Performance of a cell under colored glass Parameter Standard Green Yellow J PH [ma/cm 2 ] 39.90 38.04 38.13 V OC [V] 0.684 0.683 0.683 FF [-] 0.784 0.786 0.786 iη[%] 21.41 20.42 20.46 15
Color resilience against angle of incidence 16
Color resilience against angle of incidence 17
DBR optimization for textured surface Losses analysis 6x a-si:h (80 nm) / a-sin x :H (180 nm) Max 6x a-si:h (120 nm) / a-sin x :H (270 nm) Min 38
DBR optimization for textured surface Influence of scaling factor on R and T 1.0 1.0 R [-] 0.8 0.6 0.4 0.8 1.0 1.2 1.5 1.7 DBR 0.8 0.6 0.4 T [-] 0.2 0.2 400 600 800 1000 1200 Wavelength [nm] 0.0 400 600 800 1000 1200 Wavelength [nm] From DBR = 6 x a-si:h (80 nm) / a-sin x :H (180 nm) to scaled thicknesses A. Ingenito, S.L. Luxembourg, P. Spinelli, J. Liu, J. C. O. Lizcano, A. Weeber, O. Isabella, M. Zeman, IEEE JPV, accepted for publication (2015) 34
DBR optimization for textured surface Scaling factor = 1 Scaling factor = 1.5 A. Ingenito, S.L. Luxembourg, P. Spinelli, J. Liu, J. C. O. Lizcano, A. Weeber, O. Isabella, M. Zeman, IEEE JPV, accepted for publication (2015) 36
DBR optimization for textured surface Transmittance of optimized DBR 1.0 0.8 T [-] 0.6 Measured 1.0 Measured 1.5 Sim? 0.4 0.2 0.0 400 600 800 1000 1200 Wavelength [nm] DBR = 6 x a-si:h (80 nm) / a-sin x :H (180 nm) scaled of 1.5 37
Effect of Defect Removal Etching on surface morphology After DRE in TMAH 1% A F /A Proj =4.6 A F /A Proj = 2.7 Initial A F /A Proj =5.2 15 s 1 µm 30 s 1 µm A F /A Proj =2.1 A F /A Proj =1.6 0 s 1 µm Mask less RIE 45 s 1 µm 60 s 1 µm A. Ingenito, O. Isabella, M. Zeman, Progress in Photovoltaics, DOI:10.1002/pip.2606 (2014) 4
Effect of Defect Removal Etching TEM* analysis 0 s 15 s 30 s Damaged region 200 nm 200 nm 200 nm *TEM taken at 12
Effect of Defect Removal Etching QSSPC analysis 10-2 SiO 2 (a) Al 2 O 3 (b) 10-3 eff [s] 10-4 10-5 10 14 10 15 n [cm -3 ] 10 14 10 15 n [cm -3 ]
MST-textured* IBC c-si solar cell SiN Recombination 1.0 0.8 MST-T Std 1.0 0.8 Long wavelength scattering EQE [-] 0.6 0.4 V OC (mv) 634 640 J SC (ma/cm 2 ) 40.5 41.0 FF (%) 77.0 76.9 0.6 0.4 R [-] 0.2 η (%) 19.8 20.2 0.2 0.0 0.0 300 450 600 750 900 1050 1200 Wavelength [nm] 30 s DRE 5 µm 10 µm A. Ingenito, O. Isabella, M. Zeman, Progress in Photovoltaics, DOI:10.1002/pip.2606 (2014) 17
Advanced light management in c-si 4n 2 absorption enhancement [1] Light R Light in-coupling R = 0 Light scattering Absorber (n) R b Ideally diffused light scattering [1] E.Yablonovitch J. Opt. Soc. Am. 72,899 1982 Efficient back reflector R b = 1 4