Quasi-omnidirectional Silicon Solar Cells-沈文忠

Wenzhong Shen (沈文忠 ) Institute of Solar Energy Shanghai Jiao Tong University E-mail: wzshen@sjtu.edu.cn, Tel: +86-21-54747552 Quasi-omnidirectional Silicon Solar Cells ① Diamond wire sawn p-type mc-Si solar cells ② p-type PERC (passivated emitter and rear contact) solar cells ③ n-type PERT (passivated emitter, rear totally-diffused) bifacial c-Si solar cells ④ n-type BJBC (back-junction back-contact) solar cells ⑤ a-Si/(n-type)c-Si heterojunction solar cells ⑥ Ultrathin c-Si solar cells ⑦ Perovskite/c-Si tandem solar cells 19.0-20.5% 21.0-22.5% 20.5-22.5% (f) 18.5-20.5% (r) 22.5-24.5% 22.5-24.5% 20.0% 30.0% Industrial Eff. ① Background ② All-solution-processed nanopyramids for c-Si ③ Application for DWS mc-Si and PERC solar cells ④ Application for a-Si/(n-type)c-Si heterojunction solar cells ⑤ Summary and perspective Outline Large-scale PV Plants Low-cost + High-efficient Modules Top Runner Program Bifacial Modules + Tracking System I. Background Distributed PV Plants High-efficient (2) etched in alkaline solution. Si nanopyramids (SiNPs) Si micropyramids (SiMPs) Superior Recombination Suppression of SiNPs Lower surface area indicates lower surface dangling bonds and thus lower surface recombination, which is responsible for the higher τeff and lower J0e. J0e 9 fA/cm2 J0e 22 fA/cm2 Advanced Science 4, 1700200-(1-9) (2017) Heterojunction and Homojunction Solar Cells on 156mmx156mm Wafers Quasi-omnidirectional Solar Cell Characteristics Incident light is efficiently coupled into the substrate by optical resonance and light scattering provided by the SiNPs, whose sizes are comparable to the wavelength of incident light. Higher Electric Energy Production Noble metal high molecular high molecular Silicon wafer HF+H2O2 silver particle Compound structure Surface SEM photo Single nanometer noble metal micro- particle micro-particle liquid applied to silicon surface and dried Anti-reflection structure is formed by soaking liquid only silver particle Metal-assisted chemical etching for DWS mc-Si wafers： +0.5% +1.3% (PERC) III. Application for DWS mc-Si and PERC Solar Cells mass production in 2016 Solar Energy Materials & Solar Cells 179, 372-379 (2018) Post acid modification of DWS mc-Si solar cell with improved performance and appearance Post acid modification of DWS mc-Si solar cell with quasi- omnidirectional performance Nanotechnology 29, 015403 (2018) Inverted Pyramid Quasi-omnidirectional Silicon Solar Cells Silicon Inverted Pyramid Quasi-omnidirectional PERC Solar Cells Source: https://panasonic.net/ecosolutions/solar/index.html a-Si/(n-type)c-Si Heterojunction Solar Cells Direct copper metallization Progress in Photovoltaics: Research and Applications 26, 385-396 (2018) IV. Application for a-Si/(n-type)c-Si Heterojunction Solar Cells 金属化发展 铜金属化 ： Bifacial n-SHJ Solar Cells with Bifaciality 95%+ CIE 160MWp Mass Production (2017- )  Average eff. 22.6% in March and 22.8% in May  Eff. improves 0.2%/month  Produce in a full capacity Quasi-omnidirectional Silicon Heterojunction Solar Cells 300 450 600 750 900 1050 0 10 20 30 40 50 R e f le c t a n c e ( % ) Wave length (nm ) M i c r o-p yr am i d s N an o- p yr am i d s Quasi-omnidirectional Silicon Heterojunction Solar Cells 300 400 500 600 700 800 900 1000 1100 0 20 40 60 80 100 Micro -py ra m i ds A OI (Degree ) 0 15 30 45 60 70 80 E Q E ( % ) Wave length (nm ) 300 400 500 600 700 800 900 1000 1100 0 20 40 60 80 100 N a no -py ra m i ds A OI (Degree ) 0 15 30 45 60 70 80 E Q E ( % ) Wave length (nm )500 1000 1500 2000 2500 3000 0. 0 0. 5 1. 0 1. 5 2. 0 6 ： 52 7 ： 32 8 ： 12 9 ： 12 10 ： 12 11 ： 12 12 ： 12 S p e c tr a l ir r a d ia n c e ( W /m 2 /n m ) Wave length (nm ) 6 8 10 12 14 16 18 0 20 40 60 80 100 A O I ( D e g r e e ) Ti m e ( o cloc k ) -6 -4 -2 0 2 4 R e la tiv e e n h a n c e m e n t (% ) 0. 0 0. 1 0. 2 0. 3 0. 4 0. 5 0. 6 0. 7 0. 8 0 2 4 6 8 10 C u r r e n t (A ) Voltag e (V ) Micr o Na n o VOC (mV) : 724 723 ISC (A) ： 9.13 9.12 FF (%) ： 79.67 78.55 η (%) ： 21.58 21.19 P (W) : 5.18 5.11 (a) (b) (c) (d) (e) Mar. 21st Jun. 22nd Sept . 23rd D ec. 23rd 0. 0 0. 5 1. 0 1. 5 2. 0 R e la ti v e e n h a n c e m e n t (% ) Ha in a n S h a n g h a i Inn e r M o n g o li a (f) V. Summary and Perspective  Easy realization of the nano-textures  Same processes for the manufacture of silicon solar cells  Applicable to all kind of silicon solar cells  ~1.5% increase of solar cell performance  Suitable for rooftop PV power stations  Application for ultrathin c-Si solar cells (50μm) Source: MEYER BURGER Thin c-Si Solar Cells Applying the all-solution-processed nanopyramids to ultrathin c-Si (30μm), near-Lambertian light trapping effect is achieved, the calculated Jsc is far higher than that of the planar c-Si. Advanced Functional Materials 26, 4768-4777 (2016) Ultrathin SHJ Solar Cells  The influence of surface recombination increases with reducing cell thickness.  SHJ solar cell structure has demonstrated to have excellent surface passivation effect and have a potential to realize high open circuit voltage.  Fabricate nanopyramid textured ultrathin SHJ solar cells. Simultaneously realize excellent optical and electrical properties, ultrathin SHJ (50μm) solar cells with efficiencies of higher than 22% can be achieved. 37th IEEE PVSC, 2011, 57-61