上海交通大学：《材料与文明》课程教学资源（学生作业）更高效的使用太阳能 宋嘉诚

e@e®e 大 更高效的使用太阳能 机械与动力工程学院宋嘉诚 2017.12.17 上海充通大 SHANGHAI JIAO TONG UNIVERSITY

更高效的使用太阳能 机械与动力工程学院 宋嘉诚 2017.12.17

上海文通大学 SHANGHAI JIAO TONG UNIVERSITY 2017 Summer Exchange Program-Solar Cells Prof.Hawwaz School of Engineering and Applied Science,Harvard

2017 Summer Exchange Program-Solar Cells Prof. Hawwaz School of Engineering and Applied Science,Harvard

上海文通大学 SHANGHAI JIAO TONG UNIVERSITY Solar Cells Background Photovoltaic effect Proper band gap size Silicon as a semi-conductor conduction electron Abundance,cost,efficiency band ·Needs doping and band gap electron or solar energy forbidden photon metal contacts energy gap textured surface front contact AR coat ME emitter n si front contact valence band hole base PSi heat Irear contact

▪ Photovoltaic effect ▪ Proper band gap size ▪ Silicon as a semi-conductor ▪ Abundance, cost, efficiency ▪ Needs doping and metal contacts Solar Cells Background

上海疚通大￥ SHANGHAI JIAO TONG UNIVERSITY Solar Cells Background Efficiency in chemical compound solar cells.. ·CdTe-22.16 CulnGaSe2 -22.6% ·GaAs-38.8% versus monocrystalline silicon ·24.1%world record

▪ Efficiency in chemical compound solar cells… ▪ CdTe - 22.1% ▪ CuInGaSe2 - 22.6% ▪ GaAs - 38.8% ▪ …versus monocrystalline silicon ▪ 24.1% world record Solar Cells Background

上海疚通大鼻 SHANGHAI JIAO TONG UNIVERSITY Design Design

Design Design

上海文通大学 SHANGHAI JIAO TONG UNIVERSITY Specifications p-Si monocrystalline wafer ·Resistivity:1-10cm Doping:3-5 x 1020 cm-3 Boron Three 1 cm x 1 cm cells Dopants: ·Boron and Phosphorus Contacts: ·Al,Au,Ag,Pd,Cr,Ti

▪ p-Si monocrystalline wafer ▪ Resistivity: 1-10 Ω∙cm ▪ Doping: 3-5 x 1020 cm-3 Boron ▪ Three 1 cm x 1 cm cells ▪ Dopants: ▪ Boron and Phosphorus ▪ Contacts: ▪ Al, Au, Ag, Pd, Cr, Ti Specifications

上海文通大学 SHANGHAI JIAO TONG UNIVERSITY Design (not to scale) Dopant:Phosphorus >1020cm-3 0.19μm 0.01μm n+-Si Gradient 0.3μm n+-Si p-Si (Given) 500μm 0.35μm p+-Si p+-Si Gradient 0.2μm- Al Dopant:Boron >1020-cm3

Dopant: Phosphorus > 1020 cm-3 Design (not to scale) Gradient Gradient Dopant: Boron > 1020 cm-3 p-Si (Given) n+-Si p+-Si 500μm 0.3μm 0.35μm 0.2μm Al 0.19μm 0.01μm n+-Si p+-Si

上海文通大学 SHANGHAI JIAO TONG UNIVERSITY Design(not to scale) Good interface with Si 0.19μm Good conductivity,but 0.01μm Ag poor interface with Si 0.3μm n+-Si Cr p-Si (Given) 500μm 0.35μm p+-Si (Recommended) Al Stable interface with 0.2μm- Al Si,good conductivity

Good interface with Si Design (not to scale) Good conductivity, but poor interface with Si (Recommended) Stable interface with Si, good conductivity p-Si (Given) n+-Si p+-Si 500μm 0.3μm 0.35μm 0.2μm Al 0.19μm 0.01μm Cr Ag Al

上海疚通大鼻 SHANGHAI JIAO TONG UNIVERSITY Fabrication Fabrication

Fabrication Fabrication

国上通大学 SHANGHAI JIAO TONG UNIVERSITY Cleaning Hydrofluoric acid(-10%)dip 1 minute rinse with DI water Piranhat dip(at80°C) 5 minutes tmixture of concentrated H2SO and 30%H2O2,2:1 rinse with DI water Ultrasonication in acetone 3 minutes Ultrasonication in isopropyl alcohol(IPA) 3 minutes rinse with DI water Blow dry with a N2 gun

Hydrofluoric acid (~10%) dip 1 minute rinse with DI water Piranha † dip (at 80°C) † mixture of concentrated H2SO4 and 30% H2O2 , 2:1 5 minutes rinse with DI water Ultrasonication in acetone 3 minutes Ultrasonication in isopropyl alcohol (IPA) 3 minutes rinse with DI water Blow dry with a N2 gun Cleaning