Pressure‐Tailored Self‐Driven and Broadband Photoresponse in PbI₂

Abstract

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.

Pressure‐Driven Polymorphic Transition, Emergent Insulator‐To‐Metal Transition, and Photoconductivity Switching in Violet Phosphorus

“…The photoresponse evolutions of materials under pressure are of great significance for the manufacturing of novel pressureresponsive optoelectronic devices. [41][42][43] In view of the extensive application prospects in optoelectronic devices, we revealed the pressure-dependent photoresponse of violet phosphorus by in situ HP photocurrent measurements. As shown in Figure 3, violet phosphorus exhibits an excellent PPC response with an I on /I off ratio of around 10 4 at the initial pressure.…”

Photoelectric Properties of Functional Materials under High Pressure

“…Including significant enhancements in photocurrent, induces inverse photoconductivity (IPC) and extends the spectrum response range to the nearinfrared waveband. [28][29][30][31][32] Some investigations have even demonstrated the feasibility of pressure-regulated photoelectric properties in functional materials for practical applications. [33][34][35][36] Such a 2.8-nm-wide edge-closed graphene nanoribbon was obtained by irreversibly squashing carbon nanotubes via high-pressure and thermal treatment, and superb field-effect properties were obtained.…”

Pressure‐Tuning Photothermal Synergy to Optimize the Photoelectronic Properties in Amorphous Halide Perovskite Cs3Bi2I9

“…[17,[23][24][25] In particular, a remarkably enhanced photocurrent by over three orders of magnitude via a pressurereduced exciton binding energy in the all-inorganic perovskite Cs 2 PbI 2 Cl 2 [23] and even an extended spectral response range from the visible to near-infrared waveband were achieved in bulk iodine, PbI 2 and hypervalent CsI 3 . [26][27][28] These efforts have indicated that pressure application is an efficient strategy to optimize photoelectric properties such as the photocurrent and detection bandwidth dominated by the photoconductive mechanism. Intriguingly, many halide perovskites, such as Cs 3 Bi 2 I 9 , exhibit successive bandgap reduction with increasing pressure, [29][30][31] which hints at the possibility of extending the spectral response range to a longer waveband.…”