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

Abstract

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.

Strain Regulation and Photophysical Properties in Halide Perovskite

“…[130] Similar to other mechanical stress, the DAC pressure also modulates the lattice strain via a change in the overlap of atomic orbitals, which can achieve a prolonged carrier lifetime, [131] suppressed carrier traps, [132] structural stability, [133] and photoresponse enhancement. [134]…”

Photoelectric Properties of Functional Materials under High Pressure

“…[16,[46][47][48] Thus far, a series of strategies have been applied to further optimize the properties of perovskites, particularly their structural stability and optoelectronic properties. [35,[49][50][51][52] Effective pressure-enhanced stability has been achieved for many perovskite materials. CH 3 NH 3 SnI 3 began amorphization at ≈3 GPa and subsequent recrystallization upon pressure release.…”

Unlocking the potential of metal halide perovskite thermoelectrics through electrical doping: A critical review

“…Exploiting the thermogalvanic effect in MHPs could open new routes as a low‐cost material for solid‐state thermogalvanic energy conversion. In addition, their superior optoelectronic properties, including high absorption coefficient, slow hot‐carrier cooling, 116 and long carrier lifetime 117 can offer a unique physical basis for the unexplored area of photo‐thermoelectric effects, 118,119 and designing photovoltaic‐thermoelectric hybrid devices where the waste heat from solar power conversion can be harnessed as a useful form of electrical energy, increasing the overall solar energy conversion efficiency.…”