Bifunctionally Driven Organic Photonic Conversion Devices Facilitated by Minimalistic Synthesis-Based Interfacial...

Area of Science:

• Materials Science
• Organic Electronics
• Optoelectronics

Background:

• Integrating indoor organic photovoltaics (OPVs) and photodetectors (OPDs) is challenging due to conflicting requirements for charge extraction and noise suppression.
• Conventional hole transport layers (HTLs) struggle to meet these demands while ensuring commercial viability, including large-area uniformity, photostability, and cost-effectiveness.

Purpose of the Study:

• To develop a novel hole transport layer (HTL) that addresses the limitations of existing materials for bifunctional OPV/OPD integration.
• To introduce benzene-phosphonic acid (BPA) as a minimalist self-assembled monolayer (SAM) based HTL for enhanced performance and commercial practicality.

Main Methods:

• Utilized benzene-phosphonic acid (BPA) as a self-assembled monolayer (SAM) for the hole transport layer.
• Investigated BPA's interfacial properties, including energy alignment, monolayer uniformity, and stability on ITO substrates.
• Evaluated the performance of the integrated devices in terms of power conversion efficiency (PCE) for OPVs and key metrics for OPDs, such as noise equivalent power and 3 dB frequency.

Main Results:

• Achieved a high power conversion efficiency (PCE) of 28.6% for indoor OPVs under 1000 lx LED light.
• Demonstrated excellent scalability with 93% PCE retention over a ≈220× area increase.
• Obtained competitive self-powered photodetector performance with a noise equivalent power of 584 fW and a 3 dB frequency of 103 kHz.
• Reduced production costs by 720% compared to counterpart SAMs, achieving a 9× higher power-per-cost ratio.

Conclusions:

• The minimalist BPA-based HTL effectively resolves the thermodynamic and practical challenges in bifunctional OPV/OPD integration.
• BPA offers a cost-effective, stable, and scalable solution for high-performance indoor optoelectronics.
• This advancement positions BPA-HTL as a key enabler for self-powered Internet of Things (IoT) devices and wearable optoelectronics.