Highly Sensitive Narrowband Photomultiplication-Type Organic Photodetectors Prepared by Transfer-Printed Technology

Challenges and recent advances in photodiodes-based organic photodetectors

Spectroscopic photodetection plays a key role in many emerging applications such as context-aware optical sensing, wearable biometric monitoring, and biomedical imaging. Photodetectors based on organic semiconductors open many new possibilities in this field. However, ease of processing, tailorable optoelectronic properties, and sensitivity for faint light are still significant challenges. Here, the authors report a novel concept for a tunable spectral detector by combining an innovative transmission cavity structure with organic absorbers to yield narrowband organic photodetection in the wavelength range of 400-1100 nm, fabricated in a full-vacuum process. Benefiting from this strategy, one of the best performed narrowband organic photodetectors is achieved with a finely wavelength-selective photoresponse (full-width-at-half-maximum of ≈40 nm), ultrahigh specific detectivity above 1014 Jones, the maximum response speed of 555 kHz, and a large dynamic range up to 168 dB. Particularly, an array of transmission cavity organic photodetectors is monolithically integrated on a small substrate to showcase a miniaturized spectrometer application, and a true proof-of-concept transmission spectrum measurement is successfully demonstrated. The excellent performance, the simple device fabrication as well as the possibility of high integration of this new concept challenge state-of-the-art low-noise silicon photodetectors and will mature the spectroscopic photodetection into technological realities.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/adma.202102967

Miniaturized VIS-NIR Spectrometers Based on Narrowband and Tunable Transmission Cavity Organic Photodetectors with Ultrahigh Specific Detectivity above 1014 Jones

Strong dark current suppression in flexible organic photodetectors by carbon nanotube transparent electrodes

Continuously enhanced photoresponsivity and suppressed dark/noise current combinatorially lead to the recent development of high-detectivity organic photodetectors with broadband sensing competence. Despite the achievements, reliable photosensing enabled by organic photodetectors (OPDs) still faces challenges. Herein, we call for heed over a universal phenomenon of detrimental sensitivity of dark current to illumination history in high-performance inverted OPDs. The phenomenon, unfavorable to the attainment of high sensitivity and consistent figures-of-merit, is shown to arise from exposure of the commonly used electron transport layer in OPDs to high-energy photons and its consequent loss of charge selectivity via systematic studies. To solve this universal problem, "double" layer tin oxide as an alternative electron transport layer is demonstrated, which not only eliminates the inconsistency between the initial and after-illumination dark current characteristics but also preserves the low magnitude of dark current, good external quantum efficiency, and rapid transient response.

Understanding and Countering Illumination-Sensitive Dark Current: Toward Organic Photodetectors with Reliable High Detectivity.

Superior Noise Suppression, Response Time, and Device Stability of Non‐Fullerene System over Fullerene Counterpart in Organic Photodiode

https://onlinelibrary.wiley.com/doi/pdf/10.1002/adfm.202070293

Non-Fullerene Acceptors: Superior Noise Suppression, Response Time, and Device Stability of Non-Fullerene System over Fullerene Counterpart in Organic Photodiode (Adv. Funct. Mater. 45/2020)

Shafket Rasool

Papers

Superior Noise Suppression, Response Time, and Device Stability of Non‐Fullerene System over Fullerene Counterpart in Organic Photodiode

Non-Fullerene Acceptors: Superior Noise Suppression, Response Time, and Device Stability of Non-Fullerene System over Fullerene Counterpart in Organic Photodiode (Adv. Funct. Mater. 45/2020)