sources at 1000 lux had an irradiance of 340 and 320 µW cm −2 , respectively. The accuracy of the light meter and power meter is the primary determinant of the uncertainty in the measured PCE values, which amounts to approximately ±6-7%, as can be determined from a straightforward uncertainty analysis based on the device testing conditions and the specifications of the power and light meters. Consequently, the PCE values are reported herein with 1 decimal place.

The ongoing Internet of Things revolution has led to strong demand for lowcost, ubiquitous light sensing based on easy-to-fabricate, self-powered photodetectors. While solution-processable lead-halide perovskites have raised significant hopes in this regard, toxicity concerns have prompted the search for safer, lead-free perovskite-inspired materials (PIMs) with similar optoelectronic potential. Antimony-and bismuth-based PIMs are found particularly promising; however, their self-powered photodetector performance to date has lagged behind the lead-based counterparts. Aiming to realize the full potential of antimony-based PIMs, this study examines, for the first time, the impact of their structural dimensionality on their self-powered photodetection capabilities, with a focus on 2D Cs 3 Sb 2 I 9−x Cl x and Rb 3 Sb 2 I 9 and 0D Cs 3 Sb 2 I 9 . The 2D absorbers deliver cutting-edge self-powered photodetector performance, with a more-thantenfold increase in external quantum efficiency (up to 55%), speed of response (>5 kHz), and linear dynamic range (>four orders of magnitude) compared to prior self-powered A 3 M 2 X 9 implementations (A + : monovalent cation; M 3+ : Sb 3+ / Bi 3+ ; X − : halide anion). Detailed characterization reveals that such a performance boost originates from the superior carrier lifetimes and reduced exciton self-trapping enabled by the 2D structure. By delivering cutting-edge performance and mechanistic insight, this study represents an important step in lead-free perovskite-inspired optoelectronics toward self-powered, ubiquitous light sensing.

The formidable rise of lead‐halide perovskite photovoltaics has energized the search for lead‐free perovskite‐inspired materials (PIMs) with related optoelectronic properties but free from toxicity limitations. The photovoltaic performance of PIMs closely depends on their defect tolerance. However, a comprehensive experimental characterization of their defect‐level parameters—concentration, energy depth, and capture cross‐section—has not been pursued to date, hindering the rational development of defect‐tolerant PIMs. While mainstream, capacitance‐based techniques for defect‐level characterization have sparked controversy in lead‐halide perovskite research, their use on PIMs is also problematic due to their typical near‐intrinsic character. This study demonstrates on four representative PIMs (Cs3Sb2I9, Rb3Sb2I9, BiOI, and AgBiI4) for which Photoinduced Current Transient Spectroscopy (PICTS) offers a facile, widely applicable route to the defect‐level characterization of PIMs embedded within solar cells. Going beyond the ambiguities of the current discussion of defect tolerance, a methodology is also presented to quantitatively assess the defect tolerance of PIMs in photovoltaics based on their experimental defect‐level parameters. Finally, PICTS applied to PIM photovoltaics is revealed to be ultimately sensitive to defect‐level concentrations <1 ppb. Therefore, this study provides a versatile platform for the defect‐level characterization of PIMs and related absorbers, which can catalyze the development of green, high‐performance photovoltaics.

In article number 2002761, Robert L. Z. Hoye, Vincenzo Pecunia, and co‐workers demonstrate that lead‐free perovskite‐inspired materials are particularly attractive for low‐toxicity indoor photovoltaics. This finding is expected to encourage future efforts for their exploration in the context of sustainably powering the Internet of Things ecosystem–as found in smart homes, where people can seamlessly interact with all types of smart devices for greater comfort and safety.

Perovskite‐Inspired Materials In article number 2106295, Vincenzo Pecunia and co‐workers investigate self‐powered photodetectors comprising antimony‐based perovskite derivatives. 2D embodiments—consisting of sheets of corner‐sharing metal‐halide octahedra—more readily convert light into mobile charges. This enables self‐powered photodetectors with considerably higher performance compared to lower‐dimensional perovskite derivatives. Tuning the structural dimensionality is thus key to advancing perovskite‐inspired optoelectronics toward self‐powered, ubiquitous light sensing.