# Dilution Effect for High‐Performance Multiple‐Component Near‐Infrared Organic Photodetectors

## TL;DR

This paper introduces a dilution effect in multi-component organic photodetectors that improves performance by reducing dark current and enhancing light detection.

## Contribution

The study identifies and validates the dilution effect as a novel mechanism to enhance performance in multiple-component near-infrared organic photodetectors.

## Key findings

- The dilution effect suppresses non-radiative decay and reduces dark current density to 1.52 × 10−10 A cm−2.
- Electron transfer between acceptors governed by energy level offset maintains efficient charge transport and fast response times.
- The device achieves high detectivity (6.98 × 1013 Jones) and is suitable for wearable health and imaging technologies.

## Abstract

Despite the demonstrated efficacy of multiple‐component (MC) blends in enhancing the performance of near‐infrared organic photodetector (NIR‐OPD), elucidating the fundamental working mechanism and material design criteria is still crucial for further optimizing MC NIR‐OPDs. Here we elucidate a dilution effect as mechanism in MC‐OPDs featuring two highly miscible constituents. Compared with the binary NIR‐OPD, the MC device with dilution effect enables higher luminescence quantum efficiencies for suppressing non‐radiative decay, significant reduction in dark current density (J
d) to 1.52 × 10−10 A cm−2 at −0.2 V, and leading to a high detectivity (D
*) of 6.98 × 1013 Jones at 840 nm. Additionally, we revealed that electrons can transfer between different acceptors, governed by their energy level offset, which contributes to the largely unperturbed charge transport and faster response time of 0.63/3.59 µs. Moreover, we successfully validate the efficacy of dilution effect in high‐fidelity pulse signal detection and low‐light NIR imaging, demonstrating great promise for next‐generation wearable health/imaging‐monitoring technologies.

The dilution effect in multi‐component organic photodetector effectively suppresses non‐radiative decay and minimizes dark current, while energy‐level‐offset‐governed electron transfer between acceptors maintains efficient charge transport. This synergistic mechanism collectively enables remarkable device performance, including high detectivity and accelerated response speed, suitable for advanced near‐infrared sensing applications.