Bread Crumb Menu
-
You are in:
- Home
- Research
- Materials R&D
Saturday 22 November 2008
Research
Latest News
|NewsletterMaterials R&D
High efficiency silicon solar cell developed at IMEC
by Steve Bush
Thursday 1 November 2007
Belgium research organisation IMEC has reported 17.4 per cent efficiency in thin multi-crystalline silicon solar cells.
The cells were made using the lab’s i-PERC (industrial-passivated emitter and rear cells) process which to save cost shuns high-purity semiconductor-type processing in favour of more industrial techniques.
The record-breaker is a 100cm sq. 180µm thick device with a short circuit current of 35.22mA/cm sq. and an open circuit voltage of 629.8mV.
I-PERC competes with traditional aluminium-alloyed back surface field (Al-BSF) cells where aluminium is deposited directly onto the back of the silicon.
With i-PERC, a comparatively low-quality rear SiO2/SiN dielectric is deposited using plasma-enhanced chemical vapour deposition (PECVD). Compared with thermal oxide growth, PECVD is faster and cooler.
The dielectric is laser perforated, then screen-printed with aluminium which is fired to form local BSF contacts through the perforations.
Isolating a large part of the silicon from the aluminium reduces rear surface recombination, leading to an increase in short circuit current and open circuit voltage.
The i-PERC rear contact also improves light confinement as it is more reflective than Al-BSF at infra-red wavelengths below 1,000nm.
At 1,100nm, rear reflectance, according to IMEC, is 64% with Al BSF, compared with 91% or i-PERC. This represents a net gain of 0.9mA/cm sq. - or four per cent in overall efficiency.
The cells were made using the lab’s i-PERC (industrial-passivated emitter and rear cells) process which to save cost shuns high-purity semiconductor-type processing in favour of more industrial techniques.
The record-breaker is a 100cm sq. 180µm thick device with a short circuit current of 35.22mA/cm sq. and an open circuit voltage of 629.8mV.
I-PERC competes with traditional aluminium-alloyed back surface field (Al-BSF) cells where aluminium is deposited directly onto the back of the silicon.
With i-PERC, a comparatively low-quality rear SiO2/SiN dielectric is deposited using plasma-enhanced chemical vapour deposition (PECVD). Compared with thermal oxide growth, PECVD is faster and cooler.
| A - Z of Solar Cells | |
|---|---|
| A | Abu Dhabi billions |
| B | Braggone captures light |
| C | CIGS cells |
| D | Drag racing |
| E | Electrical energy |
| F | Flexible power |
| G | Generational substrates |
| H | HSBC |
| I | IMEC |
| I | iPod power |
| J | Junctions |
| K | Kyocera high-efficiency |
| L | Lighting uses |
| M | Mobile phone panels |
| N | NETPark, Co. Durham |
| O | OLED research |
| P | Plastics gov funding |
| Q | Qimonda joint venture |
| R | Recycling wafers |
| S | SpectaWatt |
| T | Thin film |
| U | University of Cambridge |
| V | Video solar cell racing |
| W | Wafer deal |
| X | ISC x VOC |
| Z | Zephyr plane |
|
| |
The dielectric is laser perforated, then screen-printed with aluminium which is fired to form local BSF contacts through the perforations.
Isolating a large part of the silicon from the aluminium reduces rear surface recombination, leading to an increase in short circuit current and open circuit voltage.
The i-PERC rear contact also improves light confinement as it is more reflective than Al-BSF at infra-red wavelengths below 1,000nm.
At 1,100nm, rear reflectance, according to IMEC, is 64% with Al BSF, compared with 91% or i-PERC. This represents a net gain of 0.9mA/cm sq. - or four per cent in overall efficiency.
Site Navigation
Blogs on EW
Mannerisms
Chip industry musings from David Manners
UK Tech StartupsNews on funding for electronics startups
Gadget FreakBuild ingenious inventions, win £250
Made by MonkeysAnalysis of bad designs
Parallel LinesNews and analysis on parallel processing
Directive DecoderGary Nevison on industry legislation
Electro-RamblingsEW website blog, flagging new content and features
Chips and BeerOut on the far flung semiconductor trail