Controlled thermomechanical delamination of thin films
Disclosed herein are CdTe-based solar cells that are successfully removed from their glass superstrate through a combination of lamination to a backsheet followed by thermal shock.
1. A method for making a CdTe device stack film comprising the steps of laminating a CdTe device stack on a CdS layer of a substrate wherein the substrate comprises glass and a transparent conducting oxide (TCO) layer on top of the glass and a CdS layer on top of the TCO layer; and wherein the CdTe device stack laminated on a CdS layer of a substrate is laminated to a stressor layer wherein the stressor layer and the CdTe device stack have a coefficient of thermal expansion (CTE) mismatch between the stressor layer and the CdTe device stack and wherein the CdTe device stack is delaminated from the substrate to make the CdTe device stack film wherein the delamination of the CdTe device stack film from the substrate takes place at temperatures between about −30° C. and −135° C.; and further comprising applying a transparent front contact to the CdTe device stack film after the delamination step; and wherein the CdTe device stack film has a post-delamination efficiency of at least 11.4%.
2. The method of claim 1 wherein the stressor layer comprises a handle layer.
3. The method of claim 1 wherein the CdTe device stack film is crack-free.
4. A method for making a CuIn x Ga 1-x Se 2 (CIGS) device stack film comprising the steps of laminating a CIGS device stack on a molybdenum layer of a substrate wherein the substrate comprises glass and a transparent conducting oxide (TCO) layer on top of the glass and a molybdenum layer on top of the TCO layer; and wherein the CIGS device stack laminated on a molybdenum layer of a substrate is laminated to a stressor layer wherein the stressor layer and the CIGS device stack have a coefficient of thermal expansion (CTE) mismatch between the stressor layer and the CIGS device stack and wherein the CIGS device stack is delaminated from the substrate to make the CIGS device stack film wherein the delamination of the CIGS device stack film from the substrate takes place at temperatures between about −30° C. and −135° C.; and further comprising applying a transparent front contact to the CIGS device stack film after the delamination step.
5. The method of claim 4 wherein the stressor layer comprises a handle layer.
6. The method of claim 4 wherein the CIGS device stack film is crack-free.