SeriesInformation ; 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 3247-3250 ; Abstract ; Tensile tests of commercially available a-Si:H flexible solar cells were carried out under the xenon lamp irradiation and mechanical damage accumulation was evaluated by AE technique. The open circuit voltage (Voc) was also monitored during the test. Specimens were observed during and after the tests by a digital microscope and a scanning electron microscope, respectively. AE signals were classified based on projected wavelet transform (PWT) analysis so that AE signals corresponding to each failure mode could be identified. Onset of the degradation of Voc was observed at the strain of ~0.9% and cumulative AE energy with frequency range of 600-800 kHz began to increase. In addition, it was observed that TCO, a-Si:H and back electrode through-wall cracks perpendicular to loading direction took place. As tensile strain increased to 11%, Voc decreased to ~0% and cumulative AE energy with frequency range of 800-1000 kHz increased. Simultaneously, cracks perpendicular to loading direction in the grid electrode were observed. Mechanical damage accumulation in a-Si:H solar cells under tensile strain was successfully monitored by AE technique and corresponding damages were observed. Consequently, fundamental implications for the characterization of durability of a-Si:H flexible solar cells were obtained in the present work.