Device pre‐conditioning and steady‐state temperature dependence of CH3NH3PbI3 perovskite solar cells. (4th November 2016) - Dunbar, Ricky B.
Abstract: The recent rise in power conversion efficiencies reported for perovskite solar cells has been a remarkable development in photovoltaics research. It is now pressing that the technology transitions from a research phenomenon to a real‐world deployable device: this will require both robust methods for efficiency measurement, and accurate models for performance variation at different conditions. However, the generally slow response of perovskite solar cells to changes in voltage bias and irradiance, and the susceptibility of these cells to degradation, presents significant challenges. In this paper, we investigate current and voltage stabilisation of planar CH3 NH3 PbI3 perovskite solar cells and observe remarkably large variations in stabilisation time depending on exposure history. To address this, we demonstrate a dynamic approach that continues device pre‐conditioning until pre‐determined stability criteria are met. This approach is then employed to obtain measurements of short‐circuit current and open‐circuit voltage temperature coefficients under quasi‐steady‐state conditions for perovskite devices and a control monocrystalline silicon cell. The obtained open‐circuit voltage temperature coefficient for the perovskite is −2700 ppm/°C, which interestingly, is similar to typically reported values for crystalline silicon devices. It is shown that the implemented approach can successfully differentiate between transient responses to the onset of illumination and true temperature related changes. We also find new manifestations of the complex transient processes that occur in perovskite devices. These observations highlight the importance of sophisticated characterisation approaches for correct characterisation of the performance of perovskite solar cells. Copyright © 2016 John Wiley & Sons, Ltd. Abstract : Current stabilisation time in perovskite solar cells can vary by an order of magnitude depending on cell history. Sophisticated pre‐conditioning required to differentiate between transient responses and temperature‐dependent changes. Steady‐state open‐circuit voltage temperature coefficient of planar perovskite cell: −2700 ppm/°C