Multilevel view of charge transport in oCVD polymers

Vella, Jarrett H.; Nikodemski, Stefan; Benasco, Anthony R.; Prusnick, Timothy A.; Vasiliyev, Vladimir

doi:10.1016/j.synthmet.2022.117277

Cited by 3 publications

(4 citation statements)

References 74 publications

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“…Beyond 3 μm, the photocurrent is affected by readout noise of the 𝜂G detection system, producing artificial local maxima that are not present for samples with a higher efficiency measured using the same setup. [39] The noise equivalent power (NEP) defines the minimum optical power that a detector can distinguish from noise and is a key metric that quantifies the performance and sensitivity of a photodetector. Because a photodetectors performance varies with its area (A d ) and the noise equivalent bandwidth (Δf), specific detectivity (D*) is used to compare performance between different detector technologies, with D* = (A d Δf) 1/2 /NEP, given in units of Jones (cm Hz 1/2 W −1 ).…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Ultrasensitive Room Temperature Infrared Photodetection Using a Narrow Bandgap Conjugated Polymer

Liu,

Vella,

Eedugurala

et al. 2023

Advanced Science

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Photodetectors operating across the short‐, mid‐, and long‐wave infrared (SWIR–LWIR, λ = 1–14 µm) underpin modern science, technology, and society in profound ways. Narrow bandgap semiconductors that form the basis for these devices require complex manufacturing, high costs, cooling, and lack compatibility with silicon electronics, attributes that remain prohibitive for their widespread usage and the development of emerging technologies. Here, a photoconductive detector, fabricated using a solution‐processed narrow bandgap conjugated polymer is demonstrated that enables charge carrier generation in the infrared and ultrasensitive SWIR–LWIR photodetection at room temperature. Devices demonstrate an ultralow electronic noise that enables outstanding performance from a simple, monolithic device enabling a high detectivity (D*, the figure of merit for detector sensitivity) >2.44 × 109 Jones (cm Hz1/2 W−1) using the ultralow flux of a blackbody that mirrors the background emission of objects. These attributes, ease of fabrication, low dark current characteristics, and highly sensitive operation overcome major limitations inherent within modern narrow–bandgap semiconductors, demonstrate practical utility, and suggest that uncooled detectivities superior to many inorganic devices can be achieved at high operating temperatures.

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Section: Resultsmentioning

confidence: 99%

“…Beyond 3 µm, the photocurrent is affected by readout noise of the ηG detection system, producing artificial local maxima that are not present for samples with a higher efficiency measured using the same setup. [ 39 ]…”

Section: Resultsmentioning

confidence: 99%

Ultrasensitive Room Temperature Infrared Photodetection Using a Narrow Bandgap Conjugated Polymer

Liu,

Vella,

Eedugurala

et al. 2023

Advanced Science

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“…An extensive investigation into the optical, morphological, and electrical properties of this oCVD-deposited polymer was recently reported by this group. [27] Notably absent from the as-deposited (doped) PT transmission spectrum is the PT 𝜋-𝜋* transition, a hallmark of heavily doped, bipolaronic conjugated polymers. [28] The dominant absorption feature in a neutral (or lightly doped in this case) PT film is a 𝜋−-𝜋* electronic transition at 𝜆 ≈ 0.500 μm, which corresponds to highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) bandgap absorption.…”

Section: Origin Of Ir Photon Absorptionmentioning

confidence: 99%

Shortwave Infrared Photodetection with oCVD Polythiophene

Vella

Benasco

Nikodemski

et al. 2023

Macromol. Rapid Commun.

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Shortwave infrared (SWIR, λ = 1–3 µm) photodetectors typically use compound semiconductors that are fabricated using high‐temperature epitaxial growth and require active cooling. New technologies that overcome these constraints are the focus of intensive current research. Herein, oxidative chemical vapor deposition (oCVD) is used for the first time to create a room temperature, vapor‐phase deposited SWIR photoconductive detector with a unique tangled wire film morphology that detects nW‐level photons emitted from a 500 °C cavity blackbody radiator—a rarity for polymer systems. A new, window‐based process that greatly simplifies device fabrication is used to construct doped polythiophene‐based SWIR sensors. The detectors feature an 8.97 kΩ dark resistance and are limited by 1/f noise. They feature an external quantum efficiency (gain‐external quantum efficiency) product of 395% and have a measured specific detectivity (D*) of 106 Jones, with the potential to reach D* = 1010 Jones after 1/f noise is minimized. Still, the measured D* is only a factor of 102 lower than a typical microbolometer and after optimization, the newly described oCVD polymer‐based IR detectors will be in a category competitive with commercially available, room temperature lead salt photoconductors and within reach of room temperature photodiodes.

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“…This results in a unique characteristic of conjugated polymers: they can transport charges in one, two, or three dimensions. 3 Resonance delocalization and charge hopping also applies to n-type conjugated polymers, both intrinsic and doped.…”

Section: A B Cmentioning

confidence: 99%

Uncooled SWIR detection using conjugated polymers

Vella

Benasco

Nikodemski

2023

Infrared Technology and Applications XLIX

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III-V and II-VI compound semiconductors have long dominated high sensitivity IR detection applications. In recent years, technologies such as strained layer superlattices have emerged, but they still require cooling. We have recently demonstrated uncooled detection in predominantly the SWIR with residual detection in the MWIR and LWIR. The devices operate at uncooled, ambient temperatures and exhibit mA/W responsivities when measured against a cavity blackbody radiator, have low-kHz -3 dB electronic bandwidths, but with specific detectivities comparable to III-V and II-VI semiconductors. In one example, a polymer with an undoped SWIR bandgap well beyond 1 μm—a first for any polymer system—demonstrated broadband responsivity of 6.5 mA/W against a cavity blackbody radiator. An introduction to conjugated polymers is included that provides a bridge between the polymer and semiconductor communities.

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Multilevel view of charge transport in oCVD polymers

Cited by 3 publications

References 74 publications

Ultrasensitive Room Temperature Infrared Photodetection Using a Narrow Bandgap Conjugated Polymer

Ultrasensitive Room Temperature Infrared Photodetection Using a Narrow Bandgap Conjugated Polymer

Shortwave Infrared Photodetection with oCVD Polythiophene

Uncooled SWIR detection using conjugated polymers

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