Bio-Phototransistors with Immobilized Photosynthetic Proteins

Arash Takshi,Daniel Jun,J Thomas Beatty,Houman Yaghoubi

doi:10.3390/electronics9101709

Arash Takshi, Daniel Jun + Show 2 more

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https://doi.org/10.3390/electronics9101709

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Abstract

The efficient mechanism of light capture by photosynthetic proteins allows for energy transfer and conversion to electrochemical energy at very low light intensities. In this work, reaction center (RC) proteins, or a core complex consisting of the RC encircled by light harvesting (LH1) proteins (RC-LH1) from photosynthetic bacteria, were immobilized on an insulating layer of an ion-sensitive field-effect transistor (ISFET) to build bio-photodetectors. The orientation of the RC proteins was controlled via application of a hybrid linker made of 10-carboxydecylphosphonic acid and cytochrome c that anchored the RCs to their electron donor side. Bio-phototransistors consisting of either the core RC or the RC-LH1 core complex were tested under white and monochromic light. The difference between the dark and light currents at different wavelengths are well-matched with the absorption spectrum of the photosynthetic proteins. The results show potential for the use of photosynthetic proteins in photodetectors.

Highlights

The mechanism of harvesting photons in the cells of photosynthetic organisms enables them to function effectively, even at low light intensities [1,2]
The results presented in this work are a proof of concept for the feasibility of employing reaction center (RC) and RC-LH1s as the photoactive elements in photodetectors
To obtain the output characteristics of the devices, a constant voltage was applied between the gate and the source while the voltage of the drain was scanned from 0.0 V to 1.0 V, and the drain current was measured

Summary

Introduction

The mechanism of harvesting photons in the cells of photosynthetic organisms enables them to function effectively, even at low light intensities [1,2]. The quantum efficiency in generating separated electron–hole pairs due to absorbed photons inside the photosynthetic proteins is almost. Due to these unique characteristics, the application of photosynthetic proteins and cells has attracted growing interest for the fabrication of solar cells [3,4]. While the low overall efficiency and the limited lifetime of biomaterials are serious challenges for efficient energy production, the elegant mechanism of light absorption and charge separation in photosynthetic proteins is inspiring for the fabrication of ultrasensitive photodetectors. It should be noted that the application of photosynthetic proteins in sensing devices is new and challenging. Due to some limitations, such as the limited absorption spectrum in the proteins (~750 nm < λ < ~950 nm), the performance of a bio-photodetector is not comparable to state-of-art technologies using no biomaterials

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