# Presentation: 085831

## Slide 1

## Process Tolerances in Roll-to-Roll Manufacturing of CIGS-Based Photovoltaics on Flexible Substrates 

**Process Tolerances in Roll-to-Roll Manufacturing of CIGS-Based Photovoltaics on Flexible Substrates **

_**M.E. Beck**_**, I.L. Repins, and J.S. Britt**
**This research was funded by UniSource Corporation and the National Renewable Energy Laboratory through subcontract #ZDJ-2-30630-14.  **

##  Thin Film Coating
Continuous roll-to-roll processing onto 1000 ft. low-cost metal foils 

- ** ****Thin Film Coating**
- **Continuous roll-to-roll processing onto 1000 ft. low-cost metal foils **

- ** ****Challenges**
- **Yield **
- **Efficiency**
- **Cost**

- **Robust sensors**
- **Real-time, *****in-situ***** process control**
- **Design of experiment process optimization**
- **68.8 cm****2**** production cells**

- 

**M.E. Beck, DOE SET Meeting 11/2005**

##  Product Lines

**http://www.scottevest.com/v3_store/access_solar.shtml**

- ** ****Product Lines**
- **P3 Portable Power Pack 15-55W**
**	****12 and 24V, ****** **20-30W/kg**
- **PowerFlex****TM**** – SunLinq Series** **6-25W**
**	****14.4V regulated, ******** 30W/kg**
- **OEM**

##  CIGS
1000 ft. at 12 ipm

- **1000 ft. at 12 ipm**

##  Two-level experiment to simultaneously examine effects of final & max. Cu ratio

- ** ****Two-level experiment to simultaneously examine effects of final & max. Cu ratio**
- **Efficiency decreases with final Cu ratio (<1)**
- **Cu-rich excursion mitigates this decrease**
- 	**More robust process for maximum Cu ratio of 1.1**

##  Two-variable 3-level experiment to study impacts of Ga/(In+Ga) profile through the CIGS film thickness

- ** ****Two-variable 3-level experiment to study impacts of Ga/(In+Ga) profile through the CIGS film thickness**
- **Limitations due to continuous**
**	****RTR process**
- **Hardware modifications**
- 	**Maximum ******** and best uniformity**
**	****(tolerance) for configuration B & E**

##  Four-factor two-level experiment to improve  and yield via enhanced adhesion

- ** ****Four-factor two-level experiment to improve ******** and yield via enhanced adhesion**
- **Sig. sensitivity to Na precursor deposition conditions**

##  Se delivery rate

- ** ****Se delivery rate**
- **Process centered around optimal parameter space**
- 	**Negative impacts due to insufficient or excessive Se delivery**

- ** ****Back contact optimization**
- **Studied diffusion barrier properties of alternate back contact schemes**
- **Additional improvements in absorber adhesion**
- 	**Small, but stat. Sig. reduced device performance**

##  Pros and cons

- ** ****Pros and cons**
- **Reduced costs**
- **Improved availability**
- 	**Negative impacts due to electronically active impurities**

- ** ****Experiment**
- **One-factor, three-level DOE with full replica set**
- **I-V and QE analysis revealed sig. shortfall in J****sc**** (primarily red region) at lower purity levels**
- 	**No stat. sig. gains for highest purity levels**

##  Device Efficiency
68.8 cm2 devices
	12%    13%
	average  = 10%

- **68.8 cm****2**** devices**
**	****12% ******** ******** ******** 13%**
**	****average ******** = 10%**

- ** ****Yield**
- **Substantial increase**
**	******** ****> 5.2%**

- ** ****Module Efficiency**
- **NREL certified**
**	********(aper.)**** = 10.2% (88.9W)**

##  Robust sensors and processes
 Consistent material at 1000 ft. web length
 Design of Experiment approach successful in efficiency and yield improvements
12%    13%; average  = 10%
Yield > 90%
 Champion module power-to-weight ratios  40W/kg
 Improved module reliability
 Reduced manufacturing cost
	This research was funded by Unisource Corporation and the National Renewable Energy Laboratory through subcontracts #ZDJ-2-30630-14
www.globalsolar.com

- ** ****Consistent material at 1000 ft. web length**
- ** ****Design of Experiment approach successful in efficiency and yield improvements**
- **12% ******** ******** ******** 13%; average ******** = 10%**
- **Yield > 90%**
- ** ****Champion module power-to-weight ratios ******** 40W/kg**
- ** ****Improved module reliability**
- ** ****Reduced manufacturing cost**
**	****This research was funded by Unisource Corporation and the National Renewable Energy Laboratory through subcontracts #ZDJ-2-30630-14**
**www.globalsolar.com**