High-Performance Ultraviolet Photovoltaic Detectors Based on Two-Dimensional Wide Bandgap PEA₂PbBr₄ Perovskite with...

Area of Science:

• Materials Science
• Optoelectronics
• Solid-State Physics

Background:

• Efficient and economical ultraviolet (UV) photodetectors are crucial for military and civilian applications.
• Existing photodetectors often face limitations in sensitivity, response speed, or durability.
• Two-dimensional (2D) wide bandgap perovskites offer promising properties for optoelectronic devices.

Purpose of the Study:

• To develop a high-performance UV photovoltaic-type detector using a 2D perovskite material.
• To enhance the photodetector's performance through improved charge transport mechanisms.
• To evaluate the detector's capabilities for sensing weak UV signals and its potential for flexible applications.

Main Methods:

• Fabrication of a UV photovoltaic-type detector using PEA2PbBr4 perovskite as the light-absorbing layer.
• Incorporation of a Molybdenum trioxide (MoO3) thin layer to facilitate hole transport and extraction.
• Characterization of photodetector performance, including responsivity, detectivity, response speed, linear dynamic range, and UV/visible rejection ratio.
• Assessment of device performance on both rigid and flexible plastic substrates.
• Evaluation of dark current levels and sensitivity to ultraweak UV light signals.
• Testing of mechanical flexibility and bending durability for the flexible device.

Main Results:

• The MoO3 layer significantly enhanced UV photoresponse by improving photovoltage/photocurrent and reducing dark current.
• The rigid-substrate detector achieved a high photovoltage responsivity (6.58 × 10^5 V/W), photocurrent responsivity (182.3 mA/W), specific detectivity (1.1 × 10^12 Jones), and a 134 dB linear dynamic range.
• The flexible-substrate detector demonstrated comparable performance with responsivities of 2.61 × 10^5 V/W and 90.1 mA/W, detectivity of 1.57 × 10^11 Jones, and a 119 dB dynamic range.
• Both detectors exhibited ultralow dark currents (pA range), enabling detection of UV light as low as 4.1 nW/cm^2.
• The flexible UV detector showed robust mechanical flexibility and durability, and its use as a UV image sensor was demonstrated.

Conclusions:

• The developed PEA2PbBr4 perovskite-based UV photodetectors, enhanced with MoO3, offer superior performance and sensitivity.
• The flexible UV photodetector exhibits excellent mechanical properties, opening possibilities for wearable and conformable UV sensing applications.
• These advanced UV photodetectors hold significant potential for integration into future UV optoelectronic systems and imaging technologies.