Flexible series-integrated a-Si thin film cell modules on polymer substrate are studied and fabricated.The importance of metal finger grids on ITO in flexible monolithic a-Si modules is discussed and calculated.Laser scribing of a-Si thin film solar cell on polyimide is discussed and optimized.On polyimide substrate,the back reflector Ag/ZnO is sputtered by roll-to-roll sputtering technique,the n-i-p a-Si is deposited by roll-to-roll plasma enhanced chemical vapor deposition(PECVD) technique,and the ITO layer is sputtered by roll-to-roll sputtering technique with a mask.At last,monolithic series integration is obtained by laser scribing and screen printing,and the monolithically series-connected single-junction modules reach the initial aperture area solar energy conversion efficiencies of 4.572% at AM0 spectrum,with open-circuit voltage of Voc=5.065 V and filling factor fo FF=0.552.