Solution-processed visible-blind UV-A photodetectors based on CH₃NH₃PbCl₃ perovskite thin films

Abstract

In this work, methylammonium lead trichloride (CH3NH3PbCl3) perovskite thin films were fabricated via a two-step spin coating and solvent-vapor-assisted thermal annealing method under low temperature. The films exhibited cubic crystalline structure and pinhole-free morphologies.The possible charge traps were investigated via the analysis of photoluminescence (PL) spectra of perovskite films prepared with different lead chloride (PbCl2) precursor concentrations while maintaining the same concentration of methylammonium chloride (CH3NH3Cl). Prototypical ultraviolet (UV) photodetectors with the structure of ITO/CH3NH3PbCl3/Poly (triaryl amine) (PTAA)/Al were fabricated and showed low dark current density 1.60 × 10 -5 mA/cm 2 under -1 V reverse bias, strong photoresponse in 300-400 nm region, and a high UV-visible rejection ratio up to 500 under 0 or -0.5 V bias. All the results demonstrated that low-temperature solution-processed CH3NH3PbCl3 perovskite thin films offer a great potential for making flexible, lightweight visible-blind UV-A photodetectors.

Intrinsic Defect Properties in Halide Double Perovskites for Optoelectronic Applications

“…In this paper, we show that, by exploring the phase diagram of a halide double perovskite, one can control the effects of intrinsic defects on carrier trapping and Fermi level pinning. We reveal the ideal growth conditions to grow p-type Cs2AgInCl6 and Cs2AgBiCl6 as well as semi-insulating Cs2AgBiBr6 with low trap density for targeted photovoltaic or visible-light/radiation detection application.Lead (Pb) halide perovskites have been extensively investigated for diverse applications, including photovoltaics [1-10], light-emitting diode [11][12][13], laser [14][15][16], and radiation detection [17][18][19][20], owing to their unique electronic and optical properties. However, the toxicity of Pb and the intrinsic material instability have hindered their development.…”

Highly Efficient and Stable Self‐Powered Ultraviolet and Deep‐Blue Photodetector Based on Cs2AgBiBr6/SnO2 Heterojunction

“…The EQE curve is similar to the absorbance of Cs 2 AgBiBr 6 film, indicating the purity double perovskite phase of Cs 2 AgBiBr 6 . The value of EQE is above 10% between 310 and 480 nm, and with a peak value of 38.5% at 350 nm, which is higher than MAPbCl 3 based UV detectors, indicating the potential for high performance UV‐A photodetectors . The following responsivity curve is shown in Figure c, which is the ratio of photocurrent to incident light intensity, indicating how efficiently the detector responds to an optical signal.…”

“…But many perovskite photodetectors have broadband response, which limits their practical applications. UV photodetectors prepared with lead perovskite also showed relatively low responsivity . Therefore, it is necessary to develop new environment‐friendly materials with excellent properties for UV photodetectors.…”

Solution‐Processed Visible‐Blind Ultraviolet Photodetectors with Nanosecond Response Time and High Detectivity

“…These merits enabled perovskite visible light photodetectors with both high sensitivity and fast response speed . Yet, solution‐processed visible‐blind perovskite UV photodetectors, despite their advances, are still far from the performance offered by high‐temperature‐processed commercial visible‐blind UV photodetectors (see Table S1, Supporting Information). For example, photodetectors based on methylammonium lead chloride (MAPbCl 3 ) perovskite polycrystalline thin film, which is an ideal candidate material for solution‐processed visible‐blind UV photodetectors as its absorption is mainly limited to wavelengths shorter than 400 nm, still suffer from low sensitivity or response speed due to the difficulty of fabricating a uniform and dense thin film with low trap density .…”