“Unleaded” Perovskites: Status Quo and Future Prospects of Tin‐Based Perovskite Solar Cells

Abstract

The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adma.201803230.The tremendous interest focused on organic-inorganic halide perovskites since 2012 derives from their unique optical and electrical properties, which make them excellent photovoltaic materials. Pb-based halide perovskite solar cells, in particular, currently stand at a record efficiency of ≈23%, fulfilling their potential toward commercialization. However, because of the toxicity concerns of Pb-based perovskite solar cells, their market prospects are hindered. In principle, Pb can be replaced with other less-toxic, environmentally benign metals. Sn-based perovskites are thus the far most promising alternative due to their very similar and perhaps even superior semiconductor characteristics. After years of effort invested in Sn-based halide perovskites, sufficient breakthroughs have finally been achieved that make them the next runners up to the Pb halide perovskites. To help the reader better understand the nature of Sn-based halide perovskites, their optical and electrical properties are systematically discussed. Recent progress in Sn-based perovskite solar cells, focusing mainly on film fabrication methods and different device architectures, and highlighting roadblocks to progress and opportunities for future work are reviewed. Finally, a brief overview of mixed Sn/Pb-based systems with their anomalous yet beneficial optical trends are discussed. The current challenges and a future outlook for Sn-based perovskites are discussed.

Stabilization of Inorganic CsPb0.5Sn0.5I2Br Perovskite Compounds by Antioxidant Tea Polyphenol

“…The hysteresis index (HI) can be calculated according to the equation of , where J RS (0.8 V OC ) and J FS (0.8 V OC ) represent the photocurrent density at 80% of V OC for the RS and FS, respectively . With the aid of TP, the HI is decreased from 12.85% to 0.84%, and the V OC is increased from 0.48 to 0.62 V, indicating that the corresponding PSCs have higher‐quality perovskite films and less trap states . Figure c shows the corresponding external quantum efficiency (EQE) of control device and the other device with TP addition.…”

“…[51] With the aid of TP, the HI is decreased from 12.85% to 0.84%, and the V OC is increased from 0.48 to 0.62 V, indicating that the corresponding PSCs have higher-quality perovskite films and less trap states. [52] Figure 4c shows the corresponding external quantum efficiency (EQE) of control device and the other device with TP addition. The two devices both exhibited wide optical response in a wide spectral range from the near-infrared region to ultraviolet wavelength region.…”

Metal Cations in Efficient Perovskite Solar Cells: Progress and Perspective

“…Long‐term exposure to Pb causes severe nerve and brain damage . This toxicity issue boosts the development of Pb‐less or Pb‐free perovskites. From computational studies, the conduction band of perovskite is predominantly derived from the unoccupied p orbitals of Pb while the valence band is constituted mainly by halogen p orbitals mixed with a small amount of s orbitals of Pb .…”

“…The isoelectronic s 2 p 2 group IV elements such as Sn and Ge are thus the most apparent candidates to replace Pb. However, the efficiency of PVSCs incorporating Sn and/or Ge is still lagging behind that of Pb‐based analogs since only the heavy Pb 2+ with an s 2 electron pair in group IV is stable due to the relativistic contraction, while the upper group elements Sn and Ge are more stable in the +4 oxidation state, which leads to lattice vacancies and critical stability issues for the perovskite layers . Therefore, it is crucial to search for alternative candidates for low toxic development as well as enhancing performance.…”

Ag/In lead‐free double perovskites

“…A massive effort was headed toward the simultaneous substitution of Pb, A-site cation and/or anion; however, combinations including a single B-site replacement capable to preserve the abovementioned virtues of lead perovskites remained elusive so far (promising exceptions are Sn-based perovskites [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] for solar cells and Ge-based layered perovskites [45][46][47][48][49][50] for LEDs).…”