Architectures for high-efficiency. crystalline silicon solar cells

Transcription

1 Architectures for high-efficiency 27 april 2011 crystalline silicon solar cells Miro Zeman, G. Yang, P. P. Moya, G. Limodio, A. Weeber, O. Isabella Department of Electrical Sustainable Energy Photovoltaic Materials and Devices group

2 Outline Introduction Photovoltaic Materials and Devices group c-si wafer-based PV technology c-si solar Structures for minimizing recombination Performance optimization using modelling Poly-c-Si(O x ) carrier-selective contacts Summary

3 Photovoltaic Materials and Devices group

4 PVMD leading strategy Photovoltaics everywhere

5 PVMD group: People 3 Full professors (Miro Zeman, Arno Smets, Arthur Weeber) 2 Associate professors (Rene van Swaaij, Olindo Isabella) 2 Technical staff (Martijn Tijssen, Stefaan Heirman) 1 Secretary (Ilona van der Wenden) 4 PostDoc 14 PhD students MSc diploma students 1 visitor/trainee Total: ~ members Miro Zeman Arno Smets Arthur Weeber Rene van Swaaij Olindo Isabella Martijn Tijssen Stefaan Heirman Ilona vd Wenden

6 PVMD group: Research areas c-si solar cells PV systems Large-scale cost-effective electricity generation New applications for increased penetration of PV TF solar cells (TF-Si, CIGS, Hybrid) Testbed for innovation & new applications Ag Back ZnO Solar fuels Storage for abundant solar electricity Solar water cleaning

7 c-si wafer-based PV technology

8 Commercial PV technologies ~ 75 GW p PV module production in Fraunhofer ISE: Photovoltaics Report, updated: 12 July 2017

9 c-si wafer-based PV technology

10 c-si wafer-based solar cells Contacts HOMO-junction HETERO-junction / carrier-selective contacts Si Heterojunction Poly c-si(o x ) Doping free Front and Back Contacted Fully or partially metal covered back-side Full-area M/S Partial-area M/S MoO x, WO x, VO x TiO 2, MgF 2, ZnO Interdigitated Back Contacted c-si surface field c-si emitter Doping free hole collector Passivation layer a-si:h surface field a-si:h emitter Doping free electron collector TCO poly-si(o x ) surface field poly-si(o x ) emitter Tunneling oxide i-asi:h Metal

11 Trend in c-si PV technology BSF Full area metal PRC Partial area metal SHJ Si Heterojunction IBC Back contacted International Technology Roadmap for Photovoltaics, Eight Edition (2016)

12 c-si solar Minimizing recombination

13 c-si c-si wafer-based solar cells c-si n a-si:h TCO c-si SiO 2 n + poly-c-si c-si TiO 2 Metal Metal Metal Metal i a-si:h a-si:h J 0,contact ρ contact High low V oc Low High FF Low High V oc Low High FF Low High V oc Low High FF Low High V oc Low High FF Parasitic absorption High free Carrier Absorption Low absorption Low/no absorption Thermal stability High Low High Low

14 c-si wafer-based solar Supporting films Thermal budget low high Category Metal oxides / Organics Si:H alloys Poly c-si alloys Electron selective TiO 2, LiF x Cs 2 CO 3, PCBM n + a/μc-si(o x ) :H n + a/μc-si(c x ) :H n + poly-c-si, n + poly-c-sio x n + poly-c-sic x Hole selective MoO x, WO x, VO x P3HT, PEDOT:PSS p + a/μc-si(o x ) :H p + a/μc-si(c x ) :H p + poly-c-si, p + poly-c-sio x p + poly-c-sic x Interface layer a-si:h, a-sic:h, a-sio:h; high band-gap dielectrics (SiO 2, HfO x, AlO x, ) PVMD.TUDelft.nl MoO x, TiO 2 HTJ doped poly-c-si doped poly-c-sio x

15 c-si wafer-based solar Si heterojuncton Doping free collector Hybrid HJ/poly-c-SiO x PERFECT Homo/poly-c-Si(O x ) Poly-c-Si(O x ) FBC i/p a-si:h i/n a-si:h MoO x, WO x, VO x TiO 2, MgF 2, ZnO i/n a-si:h p + poly-c-si n + c-si n + poly-c-si(o x ) n + poly-c-si p + poly-c-si p + poly-c-si(o x ) η = 20.8% η = 21.0% η = 20.1% η = 19.5% Si heterojuncton Doping free collector Homo-junction Poly-c-Si(O) x i/p a-si:h FSF i/n a-si:h FSF Hole collector Electron collector n + c-si FSF p + c-si FSF n + poly-c-si(o x ) p + poly-c-si(o x ) η = 15.5% η = 20.2% η = 23.0% (2cm 2 )

16 c-si solar Modelling

17 Device structure + input parameters Advanced opto-electrical modelling [1] Homo-junction device Doping Concentration (cm -3 ) SIMS BSF SIMS FSF SIMS Emitter BSF model FSF model Emitter model Occurrence Measured Simulated 25µm Depth (µm) Pyramid height (µm) [1] P. Procel, et al., PiP /pip.2874 (2017)

18 Advanced opto-electrical modelling [1] Model validation R,T Simulated R Measured R Simulated T Measured T Wavelength (nm) J (ma/cm 2 ) FSF-simulated FSF-measured NO FSF-simulated NO FSF-measured V (V) EQE, IQE (%) IQE-simulated IQE-measured EQE-simulated EQE-measured (b) FSF Wavelength (nm) [1] P. Procel, et al., PiP /pip.2874 (2017)

19 Performance analysis Advanced opto-electrical modelling [1] 100 J rec =1.21 ma/cm 2 J o =743 fa/cm 2 R,T,Abs,EQE (%) R 2.26 ma*cm -2 T 0.48 ma*cm -2 Abs SiN 0.2 ma*cm -2 Abs emitter 0.46 ma*cm -2 Abs BSF 0.09 ma*cm -2 F.C.A ma*cm -2 Rec ma*cm -2 EQE (40.76 ma*cm -2 ) Implied J ph (41.97 ma*cm -2 ) Wavelength (nm) Bulk srh 66.78% Other conributions 2.13% FSF srh 2.53% BSF cont 6.02% FSF surf 10.75% Emitt. srh 54% Bulk auger 11.78% Other conributions 1.23% FSF surf 1.01% Bulk auger 1.27% Emitt. auger 2.04% Bulk srh 26.3% Emitt. cont 7.41% FSF srh 3.6% BSF cont 3.08% [1] P. Procel, et al., PiP /pip.2874 (2017)

20 Performance optimization Advanced opto-electrical modelling [1] Homo-junction optimized design η=23% Passivated poly-c-si optimized design [2] η=27.1% Silicon Hetero-junction optimized design [3] η=27.1% [1] P. Procel, et al., PiP /pip.2874 (2017) [2] P. Procel, presented at SiliconPV (2017) [3] P. Procel, presented at EUPVSEC (2017)

21 c-si solar High temperature poly-c-si(o x ) carrierselective contacts

22 c-si solar cells: High temperature poly-c-si(o x ) carrier-selective contacts IBC Objectives for IBC poly-c-si cell: 1. Quench back-side recombination losses FSF n + poly-c-si(o x ) FZ n-type c-si, <100>, 1~5 Ωcm p + poly-c-si(o x ) Deploying poly-c-si CSCs 2. Quench front-side recombination losses FSF passivation Metal Metal 3. Quench back-side parasitic absorption poly-sio x alloys

23 c-si solar cells: High temperature poly-c-si(o x ) carrier-selective contacts Development: Semi-insulating poly-c-si (SIPOS) Tunneling Oxide Passivating Contact [2] Ion-implanted poly-c-si thin SiO 2 FSF n + poly-si(o x ) p + poly-si(o x ) V oc = 720 mv [1] 25.1% [3] 25.7% [4] 22.1% [6] 19.2% [5] 25% [8] 23.9% [7] 1. E. Yablonovitch, APL, 47, (1985) [2] F. Feldmann, et al., SOLMAT, 120, (2014) 270. [3] S. W, Glunz, et al. EUPVSEC-31, (2016) Hamburg [4] A. Richter, et al. SOMAT, (2017) [5] G. Yang, et al., APL, 118, (2016) [6] G. Yang, et al. SOMAT, 158 (2016) 84. [7] M. Rienacker, et al., energy procedia, 92 (2016) 412. [8] F. Haase, et al. PVSEC-26, (2016) Singapore.

24 c-si solar cells: High temperature poly-c-si(o x ) carrier-selective contacts Tunneling FBC IBC n + poly-c-si(o x ) p + poly-c-si(o x ) FZ n-type c-si, <100>, 1~5 Ωcm FSF n + poly-c-si(o x ) FZ n-type c-si, <100>, 1~5 Ωcm p + poly-c-si(o x ) c-si surface field poly-c-si(o x ) emitter poly-c-si(o x ) surface field Tunneling oxide Passivation layer Metal

25 c-si solar cells: High temperature poly-c-si carrier-selective contacts Ion-implanted poly-c-si passivated carrier-selective contacts P/B implantation TEM TEM ~1.5 nm Intrinsic n + /p + poly-c-si 1.5nm - SiO 2 5 nm n-fz, <100> 1~5 Ωcm Poly-Si 1.5nm - SiO 2 Intrinsic n + /p + poly-c-si SiO 2 c-si 50 nm Si crystals P/B implantation

26 c-si solar cells: High temperature poly-c-si carrier-selective contacts n-type poly-c-si NAOS - SiO 2 n-fz, <100> 1~5 Ωcm NAOS - SiO 2 n-type poly-c-si [P] (1/cm -3 ) [P] (1/cm 3 ) Poly c-si c-si Depth (nm) ECV τ (ms) lifetime 1e14 1e15 MCD(cm -3 ) 1e16 p-type poly-c-si NAOS - SiO 2 n-fz, <100> 1~5 Ωcm NAOS - SiO 2 p-type poly-c-si [P] (1/cm -3 ) ECV τ (ms) 10 Poly c-si c-si Depth (nm) lifetime 1e14 1e15 1e16 MCD(cm -3 ) G. Yang, et al., Appl. Phys. Lett. 108, (2016)

27 c-si solar cells: High temperature poly-c-si carrier-selective contacts n-type poly-c-si NAOS - SiO 2 n-fz, <100> 1~5 Ωcm NAOS - SiO 2 n-type poly-c-si p-type poly-c-si + SiN x :H capping Annealing: 950 C, 5 min τ eff [ms] R sh [Ω/ ] J 0 [fa/cm 2 ] iv oc [mv] NAOS - SiO 2 n-fz, <100> 1~5 Ωcm NAOS - SiO 2 p-type poly-c-si + SiN x :H capping τ eff [ms] R sh [Ω/ ] J 0 [fa/cm 2 ] iv oc [mv] G. Yang, et al., Appl. Phys. Lett. 108, (2016)

28 c-si solar cells: High temperature poly-c-si carrier-selective contacts Tunneling oxide/poly-c-si FBC n + poly-c-si p + poly-c-si FZ n-c-si, <100> 1~5 Ωcm n+ poly-si FSF: (35-nm, textured) J 0 = 14 fa/cm 2 iv OC = 708 mv p + poly-si emitter: J 0 = 11 fa/cm 2 iv OC = 716 mv Solar cell: V OC = 703 mv J SC = 38.4 ma/cm 2 FF = 70.0% η = 18.9% 7.8 cm 2 5.0% shading η = 19.5% c-si surface field poly-c-si(o x ) emitter poly-c-si(o x ) surface field Tunneling oxide Passivation layer Metal G. Limodio, G. Yang, H. Ge, O. Isabella, M. Zeman, SiliconPV, (2017), Freiburg.

29 c-si solar cells: High temperature poly-c-si carrier-selective contacts Tunneling oxide/poly-c-si FBC n + poly-c-si p + poly-c-si FZ n-type c-si, <100>, 1~5 Ωcm EQE (~) Front poly-si thickness 35 nm 75 nm 250 nm c-si surface field poly-c-si(o x ) emitter poly-c-si(o x ) surface field Tunneling oxide Passivation layer Metal Wavelength (nm)

30 c-si solar cells: High temperature poly-c-si carrier-selective contacts PeRFeCT (Passivated Rear and Front ConTacts) solar cell FBC n + poly-c-si n + c-si EQE (~) PeRFeCT cell 35 nm 75 nm 250 nm p + poly-c-si 0.2 c-si surface field poly-c-si(o x ) emitter poly-c-si(o x ) surface field Tunneling oxide Passivation layer Metal Wavelength (nm)

31 c-si solar cells: High temperature poly-c-si carrier-selective contacts PeRFeCT (Passivated Rear and Front ConTacts) solar cell n+ poly-c-si contact: (flat, 4% area fraction) J 0 = 4.5 fa/cm 2 iv OC = 735 mv FBC n+ c-si FSF: (textured, 96% area fraction) J 0 = 31 fa/cm 2 iv OC = 680 mv Solar cell: V OC = 656 mv J SC = 40.7 ma/cm 2 FF = 75.2% η = 20.0% n + poly-c-si p + poly-c-si n + c-si n+ c-si FSF: (optimized, textured) J 0 = 6.5 fa/cm 2 iv OC = 708 mv p + poly-si emitter: J 0 = 11 fa/cm 2 iv OC = 716 mv Work in progress Estimated V OC > 710 mv 3x3 cm 2

32 c-si solar cells: High temperature poly-c-si carrier-selective contacts PeRFeCT (Passivated Rear and Front ConTacts) solar cell FBC IBC n + poly-c-si p + poly-c-si n + c-si FSF n + poly-c-si p + poly-c-si

33 Interdigitated Back Contact (IBC) c-si solar cell Passivation Tunnelling Oxide Front surface field Poly-Si emitter Poly-Si BSF c-si bulk n - FZ Area (cm 2 ) 2 V OC (mv) 701 J SC (ma/cm 2 ) 42.2 FF (%) 77.8 η (%) 23.0 Self-aligned process developed at TU Delft Best c-si solar cell fully fabricated in the Netherlands

34 Summary c-si wafer-based solar cells Architectures for minimizing recombination Thermal budget Opto-electrical modeling important tool for optimization High T poly-c-si selective-carrier contact cells Good passivation IBC solar cell 22.5%

35 Acknowldgements FUNDING: NWO, TNO, TKI RVO Agency EU Commission PVMD group PVMD group

36 Thank you for your attention!