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The mixed‐metal quaternary chalcohalides of group IV and V elements are a promising class of low‐toxicity perovskite‐inspired materials with tunable bandgaps and desirable defect tolerance. Sn2SbS2I3 is known for its broadband absorption, low exciton binding energy, ambient stability, and solution processability in thin films. However, its use in optoelectronic devices has so far been only limited to solar cells. In this work, the first self‐powered photodetectors based on Sn2SbS2I3 thin films, sandwiched in an n–i–p device configuration are reported. The insertion of an interlayer at the hole‐transport layer/gold top‐electrode interface reduces the dark current and improves the device performance. The high external quantum efficiency of the devices in the range of 350−900 nm hints to a broadband spectral photoresponsivity. The devices indeed exhibit promising photodetection properties, namely a photoresponsivity of 0.33 A W−1, a specific detectivity of 1.55 × 1012 Jones, and photoresponse/decay times of 0.52 and 0.45 s at zero bias voltage. These results, combined with the excellent operational stability of the photodetectors, encourage the exploration of a wide range of practical light‐sensing applications for quaternary chalcohalides and stimulate device and material engineering to further enhance photodetection across the UV‐Visible‐NIR spectrum. [ABSTRACT FROM AUTHOR]

Ag3BiI6 (ABI) is one of the most widely explored lead‐free perovskite‐inspired materials for eco‐friendly solar cell applications. However, despite the intense research efforts, the photovoltaic performance of ABI‐based devices remains very modest, primarily due to poor film morphology and ineffective charge extraction. This work aims at investigating the potential benefits of a thermally evaporated cesium iodide (CsI) interlayer on the performance of ABI‐based solar cells. Upon the addition of CsI atop the ABI layer in the device stack, the solar cells deliver a power conversion efficiency (PCE) of 2.27%. This is the highest efficiency reported for ABI solar cells employing a similar device architecture. It is found that the enhancement in PCE is largely due to improvement in the ABI|hole transport layer interface upon the introduction of CsI interlayer. The improvement is largely ascribed to enhanced surface coverage upon introduction of CsI interlayer, as evidenced by our comprehensive microscopy studies. Furthermore, impedance spectroscopy analysis is employed to provide further insights into the changes in charge transfer dynamics interlayer that dictate the enhancement of fill factor and short‐circuit current density in the devices. The findings indicate that the addition of CsI promotes charge transfer and minimizes recombination losses. [ABSTRACT FROM AUTHOR]

Growing oriented and monocrystalline layers of lead halide perovskites over device substrates helps to harness their outstanding optoelectronic properties. Epitaxial growth of lead halide perovskites for device fabrication is limited by the lack of lattice-matched substrates and the requirement of compact pinhole-free films. Most optoelectronic devices use amorphous substrates, hindering oriented epitaxial growth. Herein, highly crystalline methylammonium lead iodide (MAPbI3) thin films over amorphous substrates are demonstrated by meticulously optimizing the nucleation and growth kinetics in spin-coating. The "epitaxial-like" films enable large-area crystalline layer fabrication, with larger than 100 μm spherulitic grains oriented along [200] and [224] planes. The compact, highly crystalline, and oriented films of MAPbI3 formed over indium tin oxide/SnO2 are used to fabricate perovskite solar cells (PSCs) with an area of 1 cm². Despite the perovskite films being highly oriented and crystalline, the PSCs' performances highlight the critical role the interfaces play in photovoltaic cells. [ABSTRACT FROM AUTHOR]

Perovskite-inspired materials (PIMs) provide low-toxicity and air-stable photo-absorbers for several possible optoelectronic devices. In this context, the pnictogen-based halides Cu 2 AgBiI 6 (CABI) are receiving increasing attention in photovoltaics. Despite extensive studies on power conversion efficiency and shelf-life stability, nearly no attention has been given to the physicochemical properties of the interface between CABI and the hole transport layer (HTL), which can strongly impact overall cell operations. Here, we address this specific interface with three polymeric HTLs: poly( N , N '-bis(4-butylphenyl)- N , N '-bis(phenyl)benzidine) (poly-TPD), thiophene-(poly(3-hexylthiophene)) (P3HT), and poly(bis(4-phenyl)(2,4,6-trimethylphenyl)amine) (PTAA). Our findings reveal that devices fabricated with poly-TPD and P3HT outperform the commonly used Spiro-OMeTAD in terms of device operational stability, while PTAA exhibits worse performances. Density functional theory calculations unveil the electronic and chemical interactions at the CABI-HTL interfaces, providing new insights into observed experimental behaviors. Our study highlights the importance of addressing the buried interfaces in PIM-based devices to enhance their overall performance and stability., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Cu 2 AgBiI 6 (CABI) is a promising perovskite-inspired absorber for solar cells due to its direct band gap and high absorption coefficient. However, the nonradiative recombination caused by the high extrinsic trap density limits the performance of CABI-based solar cells. In this work, we employ halide engineering by doping bromide anions (Br - ) in CABI thin films, in turn significantly improving the power conversion efficiency (PCE). By introducing Br - in the synthetic route of CABI thin films, we identify the optimum composition as CABI-10Br (with 10% Br at the halide site). The tailored composition appears to reduce the deep trap density as shown by time-resolved photoluminescence and transient absorption spectroscopy characterizations. This leads to a dramatic increase in the lifetime of charge carriers, which therefore improves both the external quantum efficiency and the integrated short-circuit current. The photovoltaic performance shows a significant boost since the PCE under standard 1 sun illumination increases from 1.32 to 1.69% (∼30% relative enhancement). Systematic theoretical and experimental characterizations were employed to investigate the effect of Br - incorporation on the optoelectronic properties of CABI. Our results highlight the importance of mitigating trap states in lead-free perovskite-inspired materials and that Br - incorporation at the halide site is an effective strategy for improving the device performance.