image: a Schematic diagram of photogenerated carrier transport routes and photocurrent waveforms under long wavelength and short wavelength irradiation. The optical field distributions in b 3D MAPbI3 and c 2D (PEA)2PbI4 under different wavelengths analyzed by FDTD simulation.
Credit: by Liangliang Min, Yicheng Zhou, Haoxuan Sun, Linqi Guo, Meng Wang, Fengren Cao, Wei Tian and Liang Li
Deciphering the composite information within a light field through a single photodetector, without optical and mechanical structures, is challenging. The difficulty lies in extracting multi-dimensional optical information from a single dimension of photocurrent. Emerging photodetectors based on information reconstruction has potential, yet it only extracts information contained in the photoresponse current amplitude (responsivity matrix), neglecting the hidden information in response edges driven by carrier dynamics.
In a new paper published in Light: Science & Applications, a team of scientists, led by Professor Liang Li from School of Physical Science and Technology, Jiangsu Key Laboratory of Frontier Material Physics and Devices, Center for Energy Conversion Materials & Physics (CECMP), Soochow University, Suzhou 215006, China, and co-workers have demonstrated a wavelength sensor capable of distinguishing the wavelength and intensity of monochromatic light using only the photocurrent waveform at a single detection point, without the need for additional supporting systems. By adjusting the thickness of 2D perovskite films, they have achieved varying penetration depths for perovskite absorption with different bandgaps. Additionally, by regulating the charge transport layer against the built-in electric field of the 2D perovskite, they obtained diverse photocurrent curve waveforms over time under different light wavelengths from 350 to 750 nm. These waveforms, analyzed using a machine learning model, enabled precise wavelength recognition with an error rate in light intensity detection below 0.1%. This approach will offer valuable insights for future spectrum optoelectronic devices.
These scientists summarize the operational principle of their wavelength sensor:
“We have introduced a prototype of a wavelength sensor capable of distinguishing the wavelength and intensity of monochromatic light using only the photocurrent waveform at a single detection point, without the need for additional supporting systems. By adjusting the thickness of 2D perovskite films, we were able to achieve different penetration depths for perovskite absorption with different bandgaps. Furthermore, through the regulation of the charge transport layer against the built-in electric field direction of the 2D perovskite, various photocurrent curve waveforms over time under different wavelengths of light ranging from 350 to 750 nm was obtained.”
“These current waveforms, serving as a database, underwent comprehensive analysis and learning through machine learning model, ultimately achieving precise wavelength recognition with an error rate in light intensity recognition not exceeding 0.1%” they added.
“Our approach not only provides unique insights into monochromatic light recognition but also offers valuable perspectives and potential applications for the development of future spectrum optoelectronic devices.” the scientists forecast.
Article Title
Carrier Dynamic Identification Enables Wavelength and Intensity Sensitivity in Perovskite Photodetectors