How Polycrystalline Devices Can Outperform Single‐Crystal Ones: Thin Film CdTe/CdS Solar Cells

Grain boundaries (GBs) participate in the photovoltaic energy conversion process in polycrystalline solar cells as efficient photocurrent collectors and transporters, as shown by high‐ resolution characterization of CdTe GBs in CdTe/CdS cells (see Figure). This suggests that structural defects can be advantageous for device performance, if properly designed, even in devices whose operation is based on physics of ideal, perfect solids.