Juzer Vasi National Centre for Photovoltaic Research & Education - - PowerPoint PPT Presentation

Juzer Vasi

National Centre for Photovoltaic Research & Education (NCPRE) & Solar Energy Research Institute for India and the US (SERIIUS) IIT Bombay

Indian Institute of Technology Bombay

Overview of NCPRE and SERIIUS Photovoltaics Technologies Research in Silicon Technologies

Conventional mono / multi Si Aluminium Oxide Passivation Silver replacement Sawing Non‐conventional Silicon Thin Film crystalline silicon Si nanocrystal tandem junction Si nanowire

Research in other Materials

Earth‐abundant materials – CZTS Perovskites Flexible Glass Substrates

Conclusions

NCPRE set up at IIT Bombay in October 2010 5 year Project funded by MNRE Multidisciplinary – 50 faculty investigators from 13 Depts Strong Education + Research thrust

NCPRE

Education Research

Si Solar Cells New Materials & Devices Solar PV Systems & Modules Characterization, Modeling & Simulation

www.ncpre.iitb.in

SERIIUS set up October 2012 Leading universities, research laboratories and industries

from India and USA

5 year project funded by DST (India) and DOE (USA)

www.seriius.org

Our Team:

http://www.i-micronews.com/

Silicon (mono/multi) is the most mature technology It has seen steep fall in prices in recent years Can the prices decrease further?

ITRPV 2012

AlOx for p‐Si surface passivation Negative charge repels electrons, good interface By ALD (slow process) or DC sputtering (at IITB)

Anil and Meenakshi, IITB

Meenakshi et al., IEEE E JPV, 2013 Meenakshi et al., IEEE PVSC, 2013

Copper much cheaper than silver Problems

Copper is a lifetime killer; it oxidizes – extra protection layers More complex processing

ITRPV 2012

Silver per cell (g/cell)

Improved wafer slicing techniques can give thinner

wafers, higher throughput, lower kerf loss

Diamond wire sawing, Wire‐EDM

ITRPV 2012

Throughput for diamond wire sawing and slurry based sawing

Wire Electrical Discharge Machining (WEDM) Low kerf loss; 100 micron wafers possible

Dongre & Joshi, IITB

Clamp Silicon ingot (75 mm square) Brass wire (Diameter: 100 µm) Machine table Upper wire guide Lower wire guide

20.1% Thin Film crystalline Si solar cells on flex substrates Solexel’s patented process Reusable silicon wafer

Solexel www.solexel.com

Wires by etching

ITO deposition is done using metal Sputter System N‐poly is deposited on Si Nano Wires Residual PS beads removed using Toluene solution Si etched by using DRIE chemistries of C4F8 and SF6 Size of beads was reduced by O2 plasma Deposition of 500 nm diameter PS beads was done by spin coating

Anil Kottantharayil, IIT Bombay, unpublished

Deep reactive ion etching of nanowires O2 ashing of beads N-polySi deposition Dispersal of beads ITO deposition

Ga0.35In0.65P 1.67 eV Ga0.83In0.17As 1.18 eV Ge 0.66 eV

• W. Guter et al., Applied Physics Letters, vol. 94, no. 22, p. 223504, 2009.

JSC = 16.4 mA/cm2, VOC = 2282 mV, FF = 84.3%, η = 31.6%.

All-Si 3-cell Multijunction Tandem Solar Cell Si Nanocrystals (Quantum Dots) in a SiO2 matrix. Varying the size of the QDs changes their bandgap.

E.C. Cho et al., Advances in Opto Electronics, vol. 2007, pp. 1-11, 2007.

• M. Green, MRS Spring Symposium, San Francisco, 2006

Mavilla Narasimha Rao, IIT Bombay

Schematic of CZTS solar cell (inset) and SEM

• f solution processed CZTS cell (Mitzi et al.,

IBM)

Mitzi et al. Adv. Mater. 2010, 22, E156–E159

J-V Characteristics of solution processed CZTSSe cells of Mitzi et al. (IBM) with varying S and Se composition ratio

“Earth‐abundant” materials 11% cells achieved at IBM

Perovskite sensitized solar cell (it replaces the dye in DSSC) Gratzel (HOPV 2013) 14.1% 5% perovskite sensitized solar cell at IIT Bombay (Sarkar)

0.0 0.2 0.4 0.6 0.8 1.0 2 4 6 8 10 12 14 16 0.0 0.2 0.4 0.6 0.8 1.0 2 4 6 8 10 12 14 16

Current Density (mA/cm

2)

Voltage(V)

Mixed Halide Organometal Perovskites CH3NH3PbI2X perovskites (X = Cl, Br, I)

Planar configuration of Vapour deposited and spin coated p-i-n cell configuration “Efficient planar heterojunction perovskite solar cells by vapour deposition” by

• M. Liu, M. B. Johnston & H. J. Snaith

Nature (2013) doi:10.1038/nature12509 Received:19 June 2013 Accepted: 25 July 2013 Published online 11 September 2013 Current-density/voltage curves of the best-performing solution-processed and vapour-deposited planar heterojunction perovskite solar cell “over 15%” efficiency

100 micron thick flexible glass substrates from Corning Processing temperatures of ~ 500 C possible Roll‐to‐roll processing Ideal for ink‐based processing

Source: NREL

August 2013 gust 2013

New developments in photovoltaic technologies Research continues for silicon as well as new

materials; new processing

Some exciting developments recently

Thin Film Crystalline Si Perovskite based solar cells

Research on many of these going on at IIT

Bombay through NCPRE and SERIIUS