《Nature · Communication》Continuously Reports Breakthroughs in the Regulation of Excited States of Fluorescent Materials

With the spread of human footprint in space and based on the needs of certain national defense applications, some semi-permanent energy systems are needed to provide energy for equipment under harsh circumstance. Nuclear battery is so far the most ideal power supply system, which can support equipment continually for years or even decades in the absence of the sun or away from the sun and is relatively simple and safe. This power system has been equipped by the farthest manned spacecraft in the universe. However, previous systems mainly use thermoelectric modules, despite it can provide high power, the equipment is too bulky to be used for some miniature or latent equipment.

Fluorescent type nuclear battery (NB) composed of scintillator and photovoltaic device (PVD) has the advantages of relatively high conversion efficiency, small size and high reliability, which has received extensive attention. From the perspective of device structure, the radiation conversion efficiency and stability of scintillator determine the performance of the final device. In spite of the progress of device structure design, the development of scintillators with high light yield (LY) and longer emission wavelength catering to PVDs is far behind. The new metal halide scintillators reported at present still have problems such as low light yield, low stability, differential emission wavelength and inconsistent response with PVDs. Recently, Professor Zeng's team has made a breakthrough in the research of new zero-dimensional metal halide scintillators. Related work entitled by “Mn2+ Induced Significant Improvement and Robust Stability of Radioluminescence in Cs3Cu2I5 for High Performance Nuclear Battery” is published in Nature Communication. Professor Xiaoming Li and Professor Haibo Zeng are the first author and the corresponding author of this paper, respectively.

It is generally believed that materials with self-trapped excitons (STEs) can achieve high radioluminescence efficiency due to the large Stokes shift. After further study of the mechanism of radioluminescence, they found that STE is not an ideal radioluminescence mode due to the large difference between the radioluminescence process and the photoluminescence process. Hence, they truncated the STE process by constructing a new ultrafast radiative recombination center in the original scintillator, which exhibits an ultrahigh LY of ~67000 ph/MeV at an emission wavelength of 564 nm, and this is the highest value of non-rare earth materials at present. Besides, doping and intrinsic features endow Cs3Cu2I5: Mn with robust thermal stability and irradiation hardness that 71% and >95% of the initial RL intensity can be maintained in an ultra-large temperature range of 77 K-433 K or after a total dose of 2590 Gy at 333 K, respectively. Finally, a highly efficient and stable NB based on Cs3Cu2I5 :Mn and GaAs PVD was fabricated, which showed an output improvement of 237% compared to the NB without scintillator and the efficiency almost did not decay after a long time of operation.

The visual system is essential for both survival and competition of organisms. It is an efficient process in which the retina detects light stimuli and pre-processes image information in parallel before the brain conducts more complex actions. The challenges of developing neuromorphic vision systems inspired by the human eye come not only from how to recreate the flexibility, sophistication, and adaptability of animal systems, but also how to do so with computational efficiency and elegance. In recent years, digital vision systems, based on conventional complementary metal-oxide-semiconductor (CMOS) imagers or charge-coupled device (CCD) cameras, have been rapidly developed to achieve the computer vision through extended interfaced digital processing units on serial or coarsely parallel structures. However, these conventional digital artificial vision systems tend to consume too much power, and have a large size and high cost for practical applications. In contrast, the human visual system has many optic neurons with synapses, which can not only detect image information, but also store information and process data, thus processing large amounts of information in parallel, with only 1-100 fJ of energy per synaptic activity. Therefore, it is of great significance to realize neuromorphic vision system to integrate functions of image sensing, memory and processing into single space of these neuromorphic circuits, and process continuous analog brightness signal in real-time. Photoelectric sensors with neuromorphic can achieve special visual processing function inspired by biological systems through imitating analog electronic circuits, which are particularly suitable for trying to imitate the construction of biological visual systems.

Based on the previous research foundation in perovskite quantum dot defect types and concentration control, Professor Xiaoming Li cooperate with Hui-Ming Cheng Dongming Sun (Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences) and Song Qiu. They use a combination of carbon nanotubes and perovskite quantum dots as active materials for an efficient neuromorphic vision system and integrate functions of image sensing, memory and processing into the device, and data pre-processing. The process of visual image reinforcement learning is successfully realized, which is the first time of a highly integrated physical device array that achieves the response of an ultra-weak light pulse (1μW/cm2) and achieves neuromorphic reinforcement learning. These results have important implications for artificial visual systems that attempt to mimic biological visual processing. Related work entitled by “A flexible ultrasensitive optoelectronic sensor array for neuromorphic vision systems” is published in Nature Communications, Xiaoming Li, Dongming Sun, Huiming Cheng, and Song Qiu are co-corresponding authors.

This work was financially supported by NSFC (61874054, 51902160, and 61725402), the Natural Science Foundation of Jiangsu Province (BK20180489, BK20190475), Young Elite Scientists Sponsorship Program by CAST (2018QNRC001), and Fundamental Research Funds for the Central Universities.


Xiaoming Li, Jiaxin Chen, Haibo Zeng* et al. Mn2+ induced significant improvement and robust stability of radioluminescence in Cs3Cu2I5 for high-performance nuclear battery. Nat. Commun. https://www.nature.com/articles/s41467-021-24185-7

Dongming Sun*, Xiaoming Li*, Song Qiu*, Huiming Chen*, et al. A flexible ultrasensitive optoelectronic sensor array for neuromorphic vision systems. Nat. Commun. https://www.nature.com/articles/s41467-021-22047-w