Highly efficient rubrene-graphene charge transfer interfaces as phototransistors in the visible regime

TL;DR

This paper demonstrates highly efficient rubrene-graphene phototransistors with exceptional responsivity and detectivity, leveraging long-range order in organic crystals for ultra-broadband, low-cost imaging applications.

Contribution

It introduces a novel organic semiconductor-graphene interface using rubrene single crystals that significantly improves phototransistor performance over previous organic devices.

Findings

Achieved responsivity up to 10^7 A/W

Demonstrated detectivity of 1.5×10^9 Jones at room temperature

Surpassed previous photo-gating efficiencies by an order of magnitude

Abstract

Atomically thin materials such as graphene are uniquely responsive to charge transfer from adjacent materials, making them ideal charge transport layers in phototransistor devices. Effective implementation of organic semiconductors as a photoactive layer would open up a multitude of applications in biomimetic circuitry and ultra-broadband imaging but polycrystalline and amorphous thin films have shown inferior performance compared to inorganic semiconductors. Here, we utilize the long-range order in rubrene single crystals to engineer organic semiconductor-graphene phototransistors surpassing previously reported photo-gating efficiencies by one order of magnitude. Phototransistors based upon these interfaces are spectrally selective to visible wavelengths and, through photoconductive gain mechanisms, achieve responsivity as large as 10^7 A/W and a detectivity of 1.5 10^9 Jones at room temperature. These findings point towards implementing low-cost, flexible materials for amplified imaging at ultra-low light levels.