Highly Sensitive Weak-Light Positioning Detection Enabled by a P(VDF-TrFE)-Doped Perovskite Heterojunction

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Self-powered position-sensitive photodetectors (PSDs) are crucial for optical communication and intelligent sensing.
• Current organic-inorganic hybrid perovskite PSDs suffer from low position sensitivity and limited weak-light detection.

Purpose of the Study:

• To enhance the performance of perovskite-based self-powered PSDs.
• To improve position sensitivity and weak-light detection capabilities.
• To investigate the pyro-phototronic effect in ferroelectric polymer-doped perovskite heterojunctions.

Main Methods:

• Fabrication of a Spiro-OMeTAD/MAPbI₃:P(VDF-TrFE) heterojunction by integrating ferroelectric P(VDF-TrFE) into a CH₃NH₃(MA)PbI₃ matrix.
• Optimization of P(VDF-TrFE) doping concentration (0.42 wt %) to enhance the built-in electric field.
• Characterization of device performance, including position sensitivity, linearity, responsivity, detectivity, and response times across varying electrode spacings.

Main Results:

• Optimized PSD achieved zero-bias broadband position detection (405-780 nm) with <15% nonlinearity.
• Exceptional position sensitivity of 629.28 mV/mm under weak light (10 μW), boosted to 1305.76 mV/mm via the pyro-phototronic effect.
• High responsivity (up to 3.33 × 10⁴ V/W) and detectivity (up to 8.93 × 10¹³ Jones) were observed, improving with larger electrode spacing.

Conclusions:

• Integrating P(VDF-TrFE) into perovskite significantly enhances self-powered PSD performance through improved built-in electric fields and the pyro-phototronic effect.
• The developed heterojunction offers a promising strategy for high-performance, self-powered position sensors with excellent sensitivity and weak-light detection.
• The study elucidates the pyro-photovoltaic coupling mechanism in ferroelectric polymer-doped perovskite composites.