TY  - JOUR
A1  - Zeiske, Stefan
A1  - Sandberg, Oskar J.
A1  - Zarrabi, Nasim
A1  - Wolff, Christian Michael
A1  - Raoufi, Meysam
A1  - Peña-Camargo, Francisco
A1  - Gutierrez-Partida, Emilio
A1  - Meredith, Paul
A1  - Stolterfoht, Martin
A1  - Armin, Ardalan
T1  - Static disorder in lead halide perovskites
JF  - The journal of physical chemistry letters
N2  - In crystalline and amorphous semiconductors, the temperature-dependent Urbach energy can be determined from the inverse slope of the logarithm of the absorption spectrum and reflects the static and dynamic energetic disorder. Using recent advances in the sensitivity of photocurrent spectroscopy methods, we elucidate the temperature-dependent Urbach energy in lead halide perovskites containing different numbers of cation components. We find Urbach energies at room temperature to be 13.0 +/- 1.0, 13.2 +/- 1.0, and 13.5 +/- 1.0 meV for single, double, and triple cation perovskite. Static, temperature-independent contributions to the Urbach energy are found to be as low as 5.1 ?+/- 0.5, 4.7 +/- 0.3, and 3.3 +/- 0.9 meV for the same systems. Our results suggest that, at a low temperature, the dominant static disorder in perovskites is derived from zero-point phonon energy rather than structural disorder. This is unusual for solution-processed semiconductors but broadens the potential application of perovskites further to quantum electronics and devices.
KW  - Cations
KW  - External quantum efficiency
KW  - Perovskites
KW  - Solar cells
KW  - Solar energy
Y1  - 2022
U6  - https://doi.org/10.1021/acs.jpclett.2c01652
SN  - 1948-7185
VL  - 13
IS  - 31
SP  - 7280
EP  - 7285
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Le Corre, Vincent M.
A1  - Diekmann, Jonas
A1  - Peña-Camargo, Francisco
A1  - Thiesbrummel, Jarla
A1  - Tokmoldin, Nurlan
A1  - Gutierrez-Partida, Emilio
A1  - Peters, Karol Pawel
A1  - Perdigón-Toro, Lorena
A1  - Futscher, Moritz H.
A1  - Lang, Felix
A1  - Warby, Jonathan
A1  - Snaith, Henry J.
A1  - Neher, Dieter
A1  - Stolterfoht, Martin
T1  - Quantification of efficiency losses due to mobile ions in Perovskite solar cells via fast hysteresis measurements
JF  - Solar RRL
N2  - Perovskite semiconductors differ from most inorganic and organic semiconductors due to the presence of mobile ions in the material. Although the phenomenon is intensively investigated, important questions such as the exact impact of the mobile ions on the steady-state power conversion efficiency (PCE) and stability remain. Herein, a simple method is proposed to estimate the efficiency loss due to mobile ions via "fast-hysteresis" measurements by preventing the perturbation of mobile ions out of their equilibrium position at fast scan speeds (approximate to 1000 V s(-1)). The "ion-free" PCE is between 1% and 3% higher than the steady-state PCE, demonstrating the importance of ion-induced losses, even in cells with low levels of hysteresis at typical scan speeds (approximate to 100mv s(-1)). The hysteresis over many orders of magnitude in scan speed provides important information on the effective ion diffusion constant from the peak hysteresis position. The fast-hysteresis measurements are corroborated by transient charge extraction and capacitance measurements and numerical simulations, which confirm the experimental findings and provide important insights into the charge carrier dynamics. The proposed method to quantify PCE losses due to field screening induced by mobile ions clarifies several important experimental observations and opens up a large range of future experiments.
KW  - hysteresis
KW  - mobile ions
KW  - perovskite solar cells
Y1  - 2021
U6  - https://doi.org/10.1002/solr.202100772
SN  - 2367-198X
VL  - 6
IS  - 4
PB  - Wiley-VCH
CY  - Weinheim
ER  -