Thin‐film solar cells: device measurements and analysis

TLDR

Thin‑film solar cells based on amorphous Si, CdTe, and Cu(InGa)Se₂ deviate from ideal models due to high defect densities, parasitic losses, and voltage‑dependent photocurrent collection. The study presents methods to characterize parasitic effects and voltage‑light bias dependencies in thin‑film solar cells to diagnose specific loss mechanisms and reveal fundamental device properties. The authors review QE, J–V, and admittance measurements and describe techniques to identify loss mechanisms in these devices. Voltage and light bias dependencies in QE, J–V, and admittance measurements expose specific losses, with illustrative examples provided for each cell type. © 2004 John Wiley & Sons, Ltd.

Abstract

Abstract Characterization of amorphous Si, CdTe, and Cu(InGa)Se 2 ‐based thin‐film solar cells is described with focus on the deviations in device behavior from standard device models. Quantum efficiency (QE), current–voltage ( J – V ), and admittance measurements are reviewed with regard to aspects of interpretation unique to the thin‐film solar cells. In each case, methods are presented for characterizing parasitic effects common in these solar cells in order to identify loss mechanisms and reveal fundamental device properties. Differences between these thin‐film solar cells and idealized devices are largely due to a high density of defect states in the absorbing layers and to parasitic losses due to the device structure and contacts. There is also commonly a voltage‐dependent photocurrent collection which affects J – V and QE measurements. The voltage and light bias dependence of these measurements can be used to diagnose specific losses. Examples of how these losses impact the QE, J – V , and admittance characterization are shown for each type of solar cell. Copyright © 2004 John Wiley & Sons, Ltd.