Improvement of the perovskite photodiodes performance via advanced interface engineering with polymer dielectric

TL;DR

This study enhances perovskite photodiode performance by interface engineering with P(VDF-TrFE), leading to improved detectivity, dynamic range, and response times without altering the film morphology.

Contribution

It introduces a novel interface modification using P(VDF-TrFE) that significantly improves charge transport and device performance in perovskite photodiodes.

Findings

Increased specific detectivity from 10^11 to 10^12 Jones

Expanded linear dynamic range up to 100 dB

Reduced rise/fall times and increased cut-off frequency

Abstract

Halide perovskite-based photodiodes are promising for efficient detection across a broad spectral range. Perovskite absorber thin-films have a microcrystalline morphology, characterized by a high density of surface states and defects at inter-grain interfaces. In this work, we used dielectric-ferroelectric poly(vinylidene-fluoride-trifluoroethylene-P(VDF-TrFE) to modify the bulk interfaces and electron transport junction in p-i-n perovskite photodiodes. Our complex work demonstrates that interface engineering with P(VDF-TrFE) induces significant Fermi level pinning, reducing from 4.85 eV for intrinsic perovskite to 4.28 eV for the configuration with dielectric interlayers. The integration of P(VDF-TrFE) into the perovskite film did not affect the morphology and crystal structure, but significantly changed the charge transport and device performance. IV curve analysis and 2-diode model calculations showed enhanced shunt properties, a decreased non-ideality factor, and reduced saturation dark current. We have shown that the complex introduction of P(VDF-TrFE) into the absorbers bulk and on its surface is essential to reduce the impact of the trapping processes. For P(VDF-TrFE) containing devices, we increased the specific detectivity from 10^11 to 10^12 Jones, expanded the linear dynamic range up to 100 dB, and reduced the equivalent noise power to 10^-13 W*Hz^-0.5. Reducing non-radiative recombination contributions significantly enhanced device performance, improving rise/fall times from 6.3/10.9 us to 4.6/6.5 us. The cut-off frequency (3dB) increased from 64.8 kHz to 74.8 kHz following the introduction of the dielectric. These results provide new insights into the use of organic dielectrics and an improved understanding of trap-states and ion defect compensation for detectors based on perovskite heterostructures.