In-Operando Characterization of P-I-N Perovskite Solar Cells Under Reverse Bias
Institute of Electrical and Electronics Engineers (IEEE) 00 (2021) 1365-1367
Temperature Coefficients of Perovskite Photovoltaics for Energy Yield Calculations.
ACS energy letters 6:5 (2021) 2038-2047
Abstract:
Temperature coefficients for maximum power (T PCE), open circuit voltage (V OC), and short circuit current (J SC) are standard specifications included in data sheets for any commercially available photovoltaic module. To date, there has been little work on determining the T PCE for perovskite photovoltaics (PV). We fabricate perovskite solar cells with a T PCE of -0.08 rel %/°C and then disentangle the temperature-dependent effects of the perovskite absorber, contact layers, and interfaces by comparing different device architectures and using drift-diffusion modeling. A main factor contributing to the small T PCE of perovskites is their low intrinsic carrier concentrations with respect to Si and GaAs, which can be explained by its wider band gap. We demonstrate that the unique increase in E g with increasing temperatures seen for perovskites results in a reduction in J SC but positively influences V OC. The current limiting factors for the T PCE in perovskite PV are identified to originate from interfacial effects.Limits to electrical mobility in lead-halide perovskite semiconductors
Journal of Physical Chemistry Letters American Chemical Society 12:14 (2021) 3607-3617
Abstract:
Semiconducting polycrystalline thin films are cheap to produce and can be deposited on flexible substrates, yet high-performance electronic devices usually utilize single-crystal semiconductors, owing to their superior charge-carrier mobilities and longer diffusion lengths. Here we show that the electrical performance of polycrystalline films of metal-halide perovskites (MHPs) approaches that of single crystals at room temperature. Combining temperature-dependent terahertz conductivity measurements and ab initio calculations we uncover a complete picture of the origins of charge-carrier scattering in single crystals and polycrystalline films of CH3NH3PbI3. We show that Fröhlich scattering of charge carriers with multiple phonon modes is the dominant mechanism limiting mobility, with grain-boundary scattering further reducing mobility in polycrystalline films. We reconcile the large discrepancy in charge-carrier diffusion lengths between single crystals and films by considering photon reabsorption. Thus, polycrystalline films of MHPs offer great promise for devices beyond solar cells, including light-emitting diodes and modulators.Incorporating Electrochemical Halide Oxidation into Drift‐Diffusion Models to Explain Performance Losses in Perovskite Solar Cells under Prolonged Reverse Bias
Advanced Energy Materials Wiley 11:10 (2021)
Halide segregation in mixed-halide perovskites: influence of a-site cations
ACS Energy Letters American Chemical Society 6:2 (2021) 799-808