基于MCCE的晶硅太阳电池倒金字塔制绒技术研究-苏晓东

基于MCCE 的 晶 硅 太 阳 电 池 倒 金 字 塔 制 绒 技 术 研 究 Inverted pyramid texture on silicon wafers with cost- effective MCCE Prof. Xiaodong Su Soochow university (苏州大学） 2018/11/10· 西安 2018 第十 四届中国太阳级硅及光伏发电研讨会1. R&D background 2. Research progress 3. Summary and prospect Outline1. R&D background 年 报告题目 分会场 2012 全液相刻 蚀制备 黑 硅及其太 阳电池 新型电池 、薄膜 电 池 2013 超18% 高效多 晶黑硅 太阳电 池技术 高效晶硅 电池和 组 件制造技 术 2014 下一代高 效多晶 黑 硅：金刚 线切和 纳 米绒面 新 型 电池技 术 2015 具有普适 性纳米 陷 光绒面黑 硅太阳 电 池技术 金刚石线 切多晶 硅 片高效纳 米 制绒量产 技术 2016 MCCE 技 术 ：构造从 纳米到 亚微米 的陷光 绒面 黑硅技术 与应用 2017 单晶快速 制绒技 术 研究 黑硅技术 与应用 2018 基于MCCE 的晶硅 太 阳电池倒 金字塔 制 绒技术研 究 黑硅技术 与应用DWS-wafer Recipe Temperature Period Mono KOH + additive 80-90 o C 5-10 min Poly HNO 3 + HF + additive 10 o C ~200s Poly-MCCE KOH + additive H 2 O 2 + HF + additives HNO 3 + HF 80-90 o C ~25 o C 10-20 o C ~200s 1. R&D background Si+2NaOH+H 2 O=Na 2 SiO 3 +2H 2 ↑ Si+4H 2 O=H 4 SiO 4 +2H 2 ↑ H 4 SiO 4 =H 2 SiO 3 +H 2 O H 2 SiO 3 +2NaOH=Na 2 SiO 3 +2H 2 O Oxidation Dissolution 3Si+4HNO 3 =3SiO 2 +2HO 2 +4NO  SiO 2 + 6HF = H 2 SiF 6 + 2H 2 O Dissolution Oxidation ⚫ Current texturing process for mono- and poly-Si wafers(100) atom density = 2/a 2 1. R&D background (111) atom density ≈ 2.3/a 2 ⚫ Texturing: Back-bond breaking theory1. R&D background Etching in HNO 3 /HF, R~24% Etching in KOH, R~12% Worm shape texture: Saw damage dominated Upright pyramid texture: Anisotropic dominated 1. R&D background ⚫ Submicron texture of MCCE: better appearance & higher V oc Dominated by MCCE⚫ At present, Ag-MCCE DWS mc-Si solar cells have been mass produced (over 20GW capacity) in china. 1. R&D background 2010 -2012 2012 -2014 2016 -Now 2014 -2016 Self-developed MCCE mass production process in lab first reported that the efficiency was higher than baseline. Established Soochow University-CSI photovoltaic research institute, co-developed MCCE black silicon industrialization technology, and ran in pilot line Mass production(1 st line), the 1 st in the world Has produced over GW capacity, with an average production efficiency over 19.25%.1. R&D background ⚫ What’s coming next? Is there an ultimate texturing route for mono and poly? Mono Poly Qsc or Cast-mono ➢ Cost of poly ➢ Quality of mono!1. R&D background ➢ Reducing reflection of externally incident light. ➢ Giving a high reflection of internally incident light reflected from the back surface. ➢ (111) covered surface is better for passivation. ⚫ Inverted pyramid texture Patterned resist layer for etching Appl. Phys. Lett. 66, 3636(1995) Inverted pyramid texturing with cost-effective MCCE?⚫ For regular inverted pyramids, the number of contributing reflection paths is increased from two to three. Incident light 36 ° Reflected A B Reflected Incident light A Reflected Reflected C B Reflected Incident light 2. Research progress75nm 80nm 85nm 90nm 95nm 1.6 1.8 2.0 2.2 2.4 Reflectance (%) Thickness of front film (SiNx) Upright pyramids-1.4um Upright pyramids-2.0um Upright pyramids-2.5um Upright pyramids-3.0um Invert pyramids-1.4um Invert pyramids- 2.0um Invert pyramids- 2.5um Invert pyramids-3.0um Upright pyramids Inverted pyramids ⚫ Light trapping simulation based on the WAFER RAY TRACER tool for micro-pyramids texture. Simulation results show the antireflection of inverted pyramids texture outperforms upright pyramids texture. 2. Research progress⚫ In 2012, we were first reported that the efficiency of Ag-MCCE mc-Si solar cells could be higher than that industry cells. Nano-pyramid R: ~13.8% R: ~6.5% Nano-pore Adv. Funct. Mater. 24, 6708 (2014) Better blue response 2. Research progressInverted pyramids with a size ~300nm 2. Research progress⚫ Light trapping simulation based on quasi-static effective medium theory (EMT), and nano-texture can be treated as a multilayer of silicon-air binary. multilayer of Si-air binary Sudden change of the impedance at Air/Si interface has been smoothed. Consequently, the reflection can be largely reduced. gradient refractive index and impedance 2. Research progress2. Research progress Texture Uoc （mV ） Jsc （A ） FF （% ） Eff （% ） Alkali-upright pyramids 666.2 40.25 80.5 21.59 MCCE-inverted pyramids 666.3 40.28 81.0 21.74 Upright pyramids Inverted pyramids Alkali texturing MCCE texturing ⚫ Inverted pyramid on mono wafer⚫ Inverted pyramids texture has excellent light-trapping ability, not only for those incident light perpendicular to the wafer, but also for those light incoming to the wafer with a certain angles. 2. Research progress vertical shooting 30 o inclined shooting 45 o inclined shooting 60 o inclined shooting inverted pyramids upright pyramids inverted pyramids upright pyramids inverted pyramids upright pyramids inverted pyramids upright pyramids一种晶体硅太阳能电池的 绒面结 构及 其制备方法，ZL 2013 1 0127230.X 金刚石线切割硅片的表面 处理方 法 及制绒方法，ZL 2015 1 0306801.5 2. Research progress ⚫ Above techniques are included in our patents.2. Research progress ⚫ MCCE is suitable for single face texturing on either poly or mono wafers. 晶体硅太阳电池的单面纳 米绒面 制备方 法 ZL 2015 1 0486388.53. Summary and prospect ➢At present, more than 20GW capacity DWS mc-Si solar cells have been produced by using Ag-MCCE process on the industrial production lines in china. ➢MCCE is an universal technique to form nano-/micro-scale inverted pyramids on multi/mono/cast-mono Si wafer. ➢Preliminary results indicated that the performance of mono- Si solar cells with inverted pyramids texture by using Ag- MCCE process outperforms those cells with upright pyramids texture by using standard alkali process. ➢Most important, MCCE may be a low-cost and high- throughput technique for mono/cast-mono Si wafer by using single-face texturing.⚫ The advantages of MCCE inverted pyramids technology The higher conversion efficiency The better weak-light performances The better tilted-light performances Fast texturing process for mono-Si The lower cost by using single-face texturing 3. Summary and prospectContact information: Su Xiaodong: xdsu@suda.edu.cn