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The bandgap and type of optical transition are key factors in determining the functionalities and applications of photoelectric materials. However, it is extremely difficult to modulate the bandgap and indirect‐direct bandgap transition for most materials. This study reports significant enhancements in photocurrents and an extended detection bandwidth resulting from pressure‐regulated indirect–direct bandgap transition in hypervalent CsI3. Furthermore, this study achieves an increase in the photocurrent by almost five orders of magnitude under visible‐light illumination. Impressively, the detection band‐edge shows a successive redshift from visible light to 1650 nm (optical communication waveband) upon compression. And high pressure is conducive to CsI3 operating at an ultralow bias input. Extensive high‐pressure spectroscopy analyses and theoretical calculations suggest that changes in the photoelectric properties of CsI3 are associated with enhanced I–I interactions along the quasi‐endless linear chain directions under compression. These findings offer an effective band engineering strategy for achieving broadband spectral response and high gains with an ultralow bias in photoelectric detectors.

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Constantly exploring and improving the photoelectric properties of functional materials is of paramount importance for the development of the optoelectronics industry. Herein, a new strategy to extend the spectral response range and enhance the photoelectric properties of functional materials using high pressure is presented. In addition, the successful application of this strategy to the regulation of the photoelectric properties of 2D layered semiconductor iodine is reported. The maximum photocurrent is four orders of magnitude higher than that measured under initial pressure, with visible‐light illumination. Impressively, the light‐response range of iodine is successfully extended to the near‐infrared (1064 nm) with the application of pressure, and the photoresponse properties are also significantly enhanced with compression. These dramatically enhanced photoelectric activities are attributed to charge delocalization as well as an increased charge density in the regions between parallel molecules, which occur as a result of pressure‐induced charge transfer in the iodine molecules. These findings can be extended to guide the modification of the spectral response range and photoelectric properties of other functional materials.

Effective modification of the structure and properties of halide perovskites via the pressure engineering strategy has attracted enormous interest in the past decade. However, sufficient effort and insights regarding the potential properties and applications of the high-pressure amorphous phase are still lacking. Here, the superior and tunable photoelectric properties that occur in the pressure-induced amorphization process of the halide perovskite Cs 3 Bi 2 I 9 are demonstrated. With increasing pressure, the photocurrent with xenon lamp illumination exhibits a rapid increase and achieves an almost five orders of magnitude increment compared to its initial value. Impressively, a broadband photoresponse from 520 to 1650 nm with an optimal responsivity of 6.81 mA W −1 and fast response times of 95/96 ms at 1650 nm is achieved upon successive compression. The high-gain, fast, broadband, and dramatically enhanced photoresponse properties of Cs 3 Bi 2 I 9 are the result of comprehensive photoconductive and photothermoelectric mechanisms, which are associated with enhanced orbital coupling caused by an increase in Bi-I interactions in the [BiI 6 ] 3− cluster, even in the amorphous state. These findings provide new insights for further exploring the potential properties and applications of amorphous perovskites.

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Silicon is a long-standing photosensitive material because of its unique photoelectronic properties and mature manufacturing technology. However, silicon photodetectors are generally limited by weak photoresponse in the near-infrared region. In this work, pressure is used as an effective means of tuning the photoresponse of silicon, specifically in the near-infrared region. Silicon has two different types of photoresponse under pressure. In the pressure range from 1 atm to 10 GPa, huge pressure-enhanced photocurrent is observed under illumination by a xenon lamp and near-infrared light (1064 nm). At 10 GPa, the photocurrent density ( Jph), responsivity ( R), and external quantum efficiency are increased 40-fold from those at 1.2 GPa. Interestingly, above 10 GPa, a unique pressure-induced positive–negative photoresponse switch is found along with the phase transformation from the semiconductive phase (Si I) to the metallic phase ( β-tin). Further experiments show that the photothermal effect is the main factor for negative photoresponse. All these pressure-induced properties give silicon more possibilities in the further design of visible and infrared photodetectors.

Photoelectric devices based on the photothermoelectric (PTE) effect show promising prospects for broadband detection without an external power supply. However, effective strategies are still required to regulate the conversion efficiency of light to heat and electricity. Herein, significantly enhanced photoresponse properties of PbI2 generated from a PTE mechanism via a high‐pressure strategy are reported. PbI2 exhibits a stable, fast, self‐driven, and broadband photoresponse at ≈980 nm. Intriguingly, the synergy of the photoconductivity and PTE mechanism is conducive to enhancing the photoelectric properties, and extending the detection bandwidth to the optical communication waveband (1650 nm) with an external bias. The dramatically enhanced photoresponse characteristics are attributed to narrowing of the band gap and a significantly decreased resistance, which originate from the enhancement of atomic orbital overlap owing to pressure‐induced Pb‐I bond contraction. These findings open up a new avenue toward designing self‐driven and broadband photoelectric devices.