Photodetectors are optoelectronic devices that serve the purpose of converting light signals into electronic signals. Therefore, their function allows the interfacing of light with solid-state electronics, which is an essential element of the Information and Communications Technology (ICT). Indeed, this function underlies innumerable applications, ranging from those that we have daily experience of (e.g., digital photography and video recording through cameras and smartphones) to applications in industry, agriculture, security, research, as well as in emerging areas such as the Internet of Things (IoT), computer vision, and Artificial Intelligence (AI).
The Pecunia Research Group researches on next-generation photodetectors based on emerging solution-processible semiconductors. In contrast to conventional technologies, the photodetector technologies we investigate (based on organic and perovskite/perovskite-inspired semiconductors) can be processed through facile and low-cost methods (e.g., printing and coating), at low temperatures, and on flexible plastic substrates. By enabling low-cost optical sensors with unique form factors, these emerging technologies have formidable potential to address application areas that require compact optical sensors embedded in the objects and environments of our daily lives—e.g., smart homes, health monitoring, lab-on-chip devices, optical communications. Additionally, the optoelectronic properties of these semiconductors can be easily tailored by compositional engineering, in turn allowing the facile tunability of the photodetector characteristics, and opening up new application and performance opportunities.
Organic narrowband photodetectors
Narrowband photodetection involves the detection of light within a narrow wavelength range—for instance, for color detection in the visible range, but also for spectrally-selective light sensing in the ultraviolet (UV) and near-infrared (NIR) ranges. Due to the considerable diversity of their spectral characteristics, organic semiconductors provide the most versatile platform for narrowband photodetection, and also have arguably the greatest potential to deliver sustainable, low-cost, high-performance solutions. By exploring new families of compounds with enhanced spectral characteristics as well as new device concepts, our research aims to harness these solution-processible semiconductors into high-performance narrowband photodetectors. For instance, we have recently demonstrated solution-processed far-red organic narrowband photodetectors with cutting-edge performance (10.1002/adom.201902056
). Our ultimate goal is to develop organic narrowband photodetectors into a technology for next-generation colour imagers, as needed for wearable optoelectronics, computer vision, and IoT devices.
In recent years, halide perovskites have emerged as a class of semiconductors with outstanding potential for photodetection. However, the commercialisation of halide perovskite photodetectors to date has been hampered by instability and toxicity issues. With the aim of realising the full technological potential of perovskite photodetectors, we are exploring solutions that can enhance photodetector stability and/or that rely on low-toxicity perovskite/perovskite-inspired photoactive materials. For instance, we have recently demonstrated perovskite photodetectors with cutting-edge stability (10.1002/adom.202000845
), thus paving the way for their use in real-world applications. Additionally, we have revealed the capability of lead-free perovskite-inspired Ag2
for low-toxicity, NIR-blind, visible light photodetectors (10.1007/s40820-020-0371-0
a) High-performance narrowband-absorption-type organic photodetector selective to the far-red range based on a fullerene-free bulk heterojunction (10.1002/adom.201902056). b) Responsivity of NIR-blind visible-light photodetectors based on solution-processed, lead-free, perovskite-inspired Ag2BiI5 (10.1007/s40820-020-0371-0). c) Cover of our recent book on narrowband organic photodetectors published by Institute of Physics Publishing (10.1088/978-0-7503-2663-6).
V. Pecunia†*, “Organic Narrowband Photodetectors: Materials, Devices and Applications”, Institute of Physics (IOP) Publishing
, Bristol, UK, 2019. ISBN: 9780750326629, DOI: 10.1088/978-0-7503-2663-6
S.V.N. Pammi, V.D. Tran, R. Maddaka, J.H. Eom, J. S. Jung, H.M. Jeong, M.D. Kim, V. Pecunia†, S. G. Yoon†, “Bromine Doping of MAPbI3
Films Deposited via Chemical Vapor Deposition Enables Efficient and Photo-Stable Self-Powered Photodetectors”, Advanced Optical Materials
, 2000845, 2020. DOI: 10.1002/adom.202000845
S.V.N. Pammi*, M. Reddeppa*, V.D. Tran, J.H. Eom, V. Pecunia, S. Majumder, M.D. Kim, S. G. Yoon†, “CVD-Deposited Hybrid Lead Halide Perovskite Films for High-Responsivity, Self-Powered Photodetectors with Enhanced Photo Stability Under Ambient Conditions”, Nano Energy,
74, 104872, 2020. DOI: 10.1016/j.nanoen.2020.104872
K. Xia*, Y. Li, Y. Wang, L. Portilla, V. Pecunia†*, “Narrowband-Absorption-Type Organic Photodetectors for the Far-Red Range Based on Fullerene-Free Bulk Heterojunctions”, Advanced Optical Materials
, 1902056, 2020. DOI: 10.1002/adom.201902056
V. Pecunia†*, Y. Yuan*, J. Zhao, K. Xia, Y. Wang, S. Duhm, L. Portilla, F. Li, “Perovskite-Inspired Lead-Free Ag2
for Self-Powered NIR-Blind Visible Light Photodetection”, Nano-Micro Letters
, 12:27, 2020. DOI: 10.1007/s40820-020-0371-0
V. Pecunia†*, “Efficiency and Spectral Performance of Narrowband Organic and Perovskite Photodetectors: a Cross-Sectional Review”, Journal of Physics: Materials
, 2, 042001, 2019. DOI: 10.1088/2515-7639/ab336a