Perovskite Solar Absorbers Research Articles

Ultrathin Poly(3-hexylthiophene) Nanowires as Chemically Robust and Versatile Surface Passivators of Perovskite Solar Absorbers

Ultrathin Poly(3-hexylthiophene) Nanowires as Chemically Robust and Versatile Surface Passivators of Perovskite Solar Absorbers

Discovering layered lead-free perovskite solar absorbers via cation transmutation.

For the exploration of stable lead-free perovskites for solar cell applications, we propose a series of Dion-Jacobson (DJ) double perovskites with the formula BDA2MIMIIIX8 (BDA = 1,4-butanediamine) by substituting two Pb2+ in BDAPbI4 with an MI+ (Na+, K+, Rb+, Cu+, Ag+, and Au+) and MIII3+ (Bi3+, In3+, and Sb3+) pair. First-principles calculations demonstrated the thermal stabilities of all the proposed BDA2MIMIIIX8 perovskites. The electronic properties of BDA2MIMIIIX8 depend strongly on the choice of MI+ + MIII3+ and the structural archetype, and three out of 54 candidates with suitable solar band gaps and superior optoelectronic properties were selected for photovoltaic application. A highest theoretical maximal efficiency of over 31.6% is predicted for BDA2AuBiI8. The DJ-structure-induced interlayer interaction of apical I-I atoms is found to play a crucial role in promoting the optoelectronic performance of the selected candidates. This study provides a new concept for designing lead-free perovskites for efficient solar cells.

Atomic Layer Deposition of CsI and CsPbI3

Cesium iodide (CsI) is a well-established scintillator material that also serves as a precursor for all-inorganic halide perovskite solar absorbers, such as CsPbI3. However, the lack of conformal and scalable methods to deposit halide perovskite thin films remains a major challenge on their way to commercialization. In this work, we employ atomic layer deposition (ALD) as the key method due to its inherent scalability to large areas and complex-shaped surfaces. We demonstrate two new ALD processes for the deposition of CsI and CsPbI3 thin films. The CsI process relies on cesium bis(trimethylsilyl) amide (Cs(btsa)) and tin(IV) iodide (SnI4) as precursors and yields high-purity, uniform, and phase-pure thin films. This process works in a wide temperature range (140–350 °C) and exhibits a large growth per cycle value (GPC) of 3.3 Å (85% of a CsI monolayer). Furthermore, we convert CsI into CsPbI3 perovskite by exposing a CsI film to our earlier PbI2 ALD process. We demonstrate the deposition of phase-pure γ- or δ-CsPbI3 perovskite thin films, depending on the applied deposition temperature and number of PbI2 cycles. We believe that the ALD-based approach described in this work will offer a viable alternative for depositing perovskite thin films in applications that involve complex high aspect ratio structures or large substrate areas.

A copper-based 2D hybrid perovskite solar absorber as a potential eco-friendly alternative to lead halide perovskites

Hybrid organic–inorganic perovskites (HOIPs) have attracted considerable attention for their scientific and technological potential in photovoltaics and optoelectronic devices.

Selective Passivation of Grain Boundaries via Incorporation of a Fluidic Small Molecule in Perovskite Solar Absorbers

Selective Passivation of Grain Boundaries via Incorporation of a Fluidic Small Molecule in Perovskite Solar Absorbers

Electronic Properties of {111} Twin Boundaries in a Mixed-Ion Lead Halide Perovskite Solar Absorber

We present first-principles theoretical predictions of the electronic properties of {111} twin boundaries in pure formamidinium lead iodide (FAPI) as well as a mixed-ion lead halide perovskite containing formamidinium, Cs, I, and Br. We find that the {111} twin boundary is extremely stable in pure FAPI but introduces no electron or hole trapping states and presents relatively small barriers (<100 meV) to transport of electrons and holes, suggesting that they are relatively benign for solar cell performance. However, in the mixed-ion perovskite, twin boundaries serve as a nucleation site for formation of an I- and Cs-rich secondary phase. The reduced band gap in this segregated phase leads to hole trapping and is likely to enhance electron–hole recombination and lead to reduced open-circuit voltage in solar cell devices. These results highlight the role of twin defects as nucleation sites for secondary phases, which can be extremely detrimental to solar cell performance.

Perovskite Solar Absorbers: Materials by Design

AbstractSolar‐cell materials with a tetrahedral diamond structure and its derived structures (i.e., zinc blende and chalcopyrite) are the most successful family of materials, with power conversion efficiencies exceeding 20%. Recent breakthroughs based on lead halide perovskites have inspired intensive research on low‐cost photovoltaics beyond diamond‐structured materials. While research has focused on addressing the key challenges faced by lead halide perovskites, that is, the stability and toxicity issues, it is of greater interest to develop perovskites into a new family of solar‐cell materials. Here, the recent efforts toward this goal are reviewed. The focus is on computational materials design, including single, double, 2D, and nonhalide perovskites and perovskite‐like materials. Meanwhile, related experiments are also reviewed with a hope that such this will help identify potential issues as well as enlightening ideas to achieve further computation‐driven materials discovery.

Bismuth and antimony-based oxyhalides and chalcohalides as potential optoelectronic materials

In the last decade the ns2 cations (e.g., Pb2+ and Sn2+)-based halides have emerged as one of the most exciting new classes of optoelectronic materials, as exemplified by for instance hybrid perovskite solar absorbers. These materials not only exhibit unprecedented performance in some cases, but they also appear to break new ground with their unexpected properties, such as extreme tolerance to defects. However, because of the relatively recent emergence of this class of materials, there remain many yet to be fully explored compounds. Here, we assess a series of bismuth/antimony oxyhalides and chalcohalides using consistent first principles methods to ascertain their properties and obtain trends. Based on these calculations, we identify a subset consisting of three types of compounds that may be promising as solar absorbers, transparent conductors, and radiation detectors. Their electronic structure, connection to the crystal geometry, and impact on band-edge dispersion and carrier effective mass are discussed.

Thermal engineering of FAPbI3 perovskite material via radiative thermal annealing and in situ XRD

Lead halide perovskites have emerged as successful optoelectronic materials with high photovoltaic power conversion efficiencies and low material cost. However, substantial challenges remain in the scalability, stability and fundamental understanding of the materials. Here we present the application of radiative thermal annealing, an easily scalable processing method for synthesizing formamidinium lead iodide (FAPbI3) perovskite solar absorbers. Devices fabricated from films formed via radiative thermal annealing have equivalent efficiencies to those annealed using a conventional hotplate. By coupling results from in situ X-ray diffraction using a radiative thermal annealing system with device performances, we mapped the processing phase space of FAPbI3 and corresponding device efficiencies. Our map of processing-structure-performance space suggests the commonly used FAPbI3 annealing time, 10 min at 170 °C, can be significantly reduced to 40 s at 170 °C without affecting the photovoltaic performance. The Johnson-Mehl-Avrami model was used to determine the activation energy for decomposition of FAPbI3 into PbI2.

Photocatalysis: HI-time for perovskites

Organolead halide perovskite solar absorbers demonstrate high photovoltaic efficiencies but they are notorious for their intolerance to water. Now, methylammonium lead iodide perovskites are used to harvest solar energy — in water — via photocatalytic generation of hydrogen from solutions of hydriodic acid.

Antiferroelectric-to-Ferroelectric Switching inCH3NH3PbI3Perovskite and Its Potential Role in Effective Charge Separation in Perovskite Solar Cells

Charge recombination is a bugaboo of solar-cell efficiency, and much effort has been devoted to understanding and preventing it. There has been debate about whether the important hybrid organic-inorganic perovskite solar absorbers are ferroelectric; if so, their polarization could be exploited to boost charge separation, $i.e.$ reduce recombination. The authors show that CH${}_{3}$NH${}_{3}$PbI${}_{3}$ does in fact present both ferroelectric and semiconducting behaviors, adding a new angle to optimizing perovskite solar cells.

ChemInform Abstract: Organic—Inorganic Halide Perovskite Based Solar Cells — Revolutionary Progress in Photovoltaics

AbstractReview: 151 refs.