Flexible solar cells in milliseconds: Pulse Thermal Processing of CdTe devices

Materials for a CdTe solar cell (ITO/CdS/CdTe/Cu/Pt) were sputtered at room temperature onto kapton, then transformed from resistive layers into a working solar cell by Pulse Thermal Processing (PTP), a novel radiant heat treatment developed at Oak Ridge National Laboratory (ORNL). Unlike conventional device fabrication approaches, the solar cell was a complete device, front-to-back contact, prior to heat treatment. In this proof-of-concept approach, the I-V curves for the as-deposited sputtered materials demonstrate little measurable photovoltaic (PV) activity, but achieved a V_oc of 634 mV after PTP. Based on process simulations, it´s estimated that the material/device transformation occurred in under 30 ms, while maintaining the kapton substate at temperatures below 250 °C.