Tailoring Perovskite Properties
Perovskite-based tandem photovoltaics usually consist of a wide- and low-bandgap perovskite subcell and Silicon or CIGS subcell. The wide-bandgap perovskite typically requires a bandgap higher than 1.6 eV, such as 1.68 eV for perovskite/Si or CIGS and >1.75 eV for all-perovskite tandem photovoltaics. All-perovskite tandem photovoltaics require a Sn-Pb perovskite with a bandgap below 1.3 eV for efficient utilization of solar photon. Thus, the properties of perovskite absorbers must be adjusted to the specific purpose. In conjunction with bandgap tuning, the long-term stability of different perovskite layers must be engineered to mitigate halide segregation (wide bandgap perovskite), humidity sensitivity (inorganic perovskite) or the oxidation of elementary Sn (Sn-Pb perovskite).
Perovskite solar cells are typically made from solutions (yellow) containing lead iodide (yellow powder) and methylammonium iodide (white powder). Picture: S. Albrecht / HZB
- With superior tailoring function of SAMs hole transport materials, we investigate a novel wide bandgap perovskite composition with high optoelectronic quality and improved operational stability for all-perovskite monolithic tandem photovoltaics.
- To improve photovoltaic performance of Sn-Pb perovskite for all-perovskite tandem photovoltaics, we use additive engineering strategies to reduce radiative recombination losses and enhanced device performance.
- Inorganic halide perovskites show outstanding photophysical properties with high potential long-term operational stability against thermal stress. The lead-based inorganic perovskite CsPbX3 (X = Br or I) has a tunable band gap from 1.72 eV to 1.92 eV. In our group, we are dedicated to quantifying the efficiency potential of inorganic perovskite solar cells by applying a method using intensity-dependent photoluminescence measurements . In addition, we investigate phase-stable inorganic perovskite solar cells with mild annealing temperatures by using additive-assisted intermediate phase engineering with superior photovoltaic performance.
- Stolterfoht, M.; Grischek, M.; Caprioglio, P.; Wolff, C.M.; Gutierrez-Partida, E.; Peña-Camargo, F.; Rothhardt, D.; Zhang, S.; Raoufi, M.; Wolansky, J.; Abdi-Jalebi, M.; Stranks, S.D.; Albrecht, S.; Kirchartz, T.; Neher, D.: How To Quantify the Efficiency Potential of Neat Perovskite Films Perovskite Semiconductors with an Implied Efficiency Exceeding 28%. Advanced Materials 32 (2020), p. 2000080/1-10
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