Metal Clusters Based Multifunctional Materials for Solar Cells.

As a multifunctional material, metal clusters have recently received some attention for their application in solar cells.This review delves into the multifaceted role of metal clusters in advancing solar cell technologies, covering diverse aspects from electron transport and interface modification to serving as molecular precursors for inorganic materials and acting as photosensitizers in metal-cluster sensitized solar cells (MCSSCs). The studies conducted by various researchers illustrate the crucial impact of metal clusters, such as gold nanoclusters (Au NCs), on enhancing solar cell efficiency through size-dependent effects, distinct interface behaviors, and tailored interface engineering. From optimizing charge transfer rates to improving light absorption and reducing carrier recombination, metal clusters prove instrumental in shaping the landscape of solar energy conversion.The promising performance of metal-cluster sensitized solar cells, coupled with their scalability and flexibility, positions them as a exciting avenue for future clean energy applications. The article concludes by emphasizing the need for continued interdisciplinary research and technological innovation to unlock the full potential of metal clusters in contributing to sustainable and high-performance solar cells.

Direction Modulation of Intramolecular Electric Field Boosts Hole Transport in Phthalocyanines for Perovskite Solar Cells.

Tuning the strength of intramolecular electric field (IEF) in conjugated molecules has emerged as an effective approach to boost charge transfer. While direction manipulation of IEF would be a potential way that is still unclear. Here, we leverage the control of peripheral substituents of conjugated phthalocyanines to chemically tune the spatial orientation of IEF. By analyzing the spatial swing of side chains using the Kolmogorov-Arnold representation and least squares algorithm, a comprehensive mathematical-physical model has been established. This model enables rapid evaluation of the IEF and maximum hole transport performance induced by spatial swings. The champion phthalocyanine as dopant-free hole transport material in perovskite solar cell realizes a record performance of 23.41 %. Greatly device stability is also exhibited. This work affords a new way to enhance hole transport capabilities of conjugated molecules by optimizing their IEF vector for photovoltaic devices.

Porphyrin Supramolecule as Surface Carrier Modulator Imparts Hole Transporter with Enhanced Mobility for Perovskite Photovoltaics.

Modulating the surface charge transport behavior of hole transport materials (HTMs) would be as an potential approach to improve their hole mobility, while yet realized for fabricating efficient photovoltaic devices. Here, an oxygen bridged dimer-based monoamine FeIII porphyrin supramolecule is prepared and doped in HTM film. Theoretical analyses reveal that the polaron distributed on dimer can be coupled with the parallel arranged polarons on adjacent dimers. This polaron coupling at the interface of supramolecule and HTM can resonates with hole flux to increase hole transport efficiency. Mobility tests reveal that the hole mobility of doped HTM film is improved by 8-fold. Doped perovskite device exhibits an increased efficiency from 19.8 % to 23.2 %, and greatly improved stability. This work provides a new strategy to improve the mobility of HTMs by surface carrier modulation, therefore fabricating efficient photovoltaic devices.

Directional Defect Management in Perovskites by In Situ Decomposition of Organic Metal Chalcogenides for Efficient Solar Cells.

Directional defects management in polycrystalline perovskite film with inorganic passivator is highly demanded while yet realized for fabricating efficient and stable perovskite solar cells (PSCs). Here, we develop a directional passivation strategy employing a two-dimensional (2D) material, Cu-(4-mercaptophenol) (Cu-HBT), as a passivator precursor. Cu-HBT combines the merits of the targeted modification from organic passivator and excellent stability offered by inorganic passivator. Featuring with dense organic functional motifs on its surfaces, Cu-HBT has the capability to "find" and fasten to the Pb defect sites in perovskites through coordination interactions during a spin-coating process. During subsequent annealing treatment, the organic functional motifs cleave from Cu-HBT and convert in situ into p-type semiconductors, Cu2 S and PbS. The resultant Cu2 S and PbS not only serve as stable inorganic passivators on the perovskite surface, significantly enhancing cell stability, but also facilitate efficient charge extraction and transport, resulting in an impressive efficiency of up to 23.5 %. This work contributes a new defect management strategy by directionally yielding the stable inorganic passivators for highly efficient and stable PSCs.

Directional Transformation of Heterometallic Oxo Clusters: A New Approach to Prepare Wide-Bandgap Cathode Interlayers for Perovskite Solar Cells.

Typical wide-band gap cathode interlayer materials are difficulty in reducing interface recombination without limiting charge transport in perovskite solar cells (PSCs). Here, a lead-doped titanium-oxo cluster protected by S-containing ligands is introduced at the interface of perovskite and SnO2 . By in situ heating, the cluster is transformed into PbSO4 -PbTi3 O7 heterostructure. The oxygen atoms from sulfate ion in heterostructure connect with iodine from perovskite to boost interfacial electron extraction and reduce charge recombination. While the yielded metallic interface between PbSO4 and PbTi3 O7 promotes the electron transport across the interface. Finally, an efficiency as high as 24.2 % for the modified PSC is obtained. The heterostructure well-stabilize the interface of perovskite and SnO2 , to greatly improve the device stability. This work provides a novel strategy to prepare wide-band gap cathode interlayer by directional transformation of heterometallic oxo clusters.