High-performance photodetectors with great detection capability have been widely deployed in our daily life, such as driverless technology, intraoperative navigated surgery, face recognition, anti-counterfeiting, etc. However, we still face challenges as new demands are made for additional features like excellent flexibility without losing sensitivity/stability. Therefore, new photosensitive materials or multifunctional composites are needed to meet the rapid development of technology.
In a new article published in Light: science and applicationsa team of scientists, led by Professor Haotong Wei from the State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, China, has developed a method to introduce carbonized polymer dots (CPDs) to promote the performance of quasi-2D perovskite based on flexible photodetectors.
By controlling the morphology of the unique core/shell structure of CPDs with viscoelastic polymer chains, they significantly improved the flexible stability of perovskite photodetectors, showing no loss of photo-response after 10,000 flexes. Moreover, the distributed defects in the grain boundary of the perovskite were passivated by the coordination effect between the unbonded Pb atoms and the carbonyl groups in the polymer chains of the CPDs.
The devices exhibited lower dark current and resolved weak light with detectable light intensity dropping to 1/50, compared to initial performance. The reported method provides an economical and available way to improve the photodetection performance of flexible optoelectronic devices.
CPDs are composed of carbonized crystalline carbon as the core core in the center and capped by amorphous polymer chains as shells. The size of the carbon core can be easily controlled by modulating the carbonization temperature and time, and the polymer chains have abundant functional groups, which provide tunable surface chemical properties.
Therefore, the unique core-shell structure of CPDs ensures excellent viscoelasticity and tunable optoelectronic properties of CPDs. Moreover, the raw materials of CPDs are abundant in nature and the synthetic processes are also easy and inexpensive. Based on these considerations, these scientists proposed that perovskite/CPD composites can exhibit excellent photodetection performance and excellent flexibility:
“We made a series of CPDs with different morphological properties. By changing the temperature, the adjusted carbonization process leads to different polymer chain lengths on the CPDs. And as we regulated the raw materials, these CPDs would carry abundant functional groups and controllable, that respond to our demands,” the researchers write.
“The different lengths of CPDs provide a convenient way to control the flexibility of the devices. The stretchable polymer chains of the CPDs are said to function as an anchor at the grain boundaries, making the perovskite morphology more stable during the deformation process. In addition, the abundant available raw materials of CPDs provide us with more choices to tune the properties of CPDs.The different functional groups that CPDs carry in the polymer chains coordinate with the Pb atoms to passivate the defects at the grain boundaries. functional groups, CPDs provide a pathway to regulate the optoelectronic performance of devices,” they added.
“Our method opens a new way to tune the properties of optoelectronic materials and devices. By introducing these easy-to-prepare CPDs, we combine the properties of CPDs and perovskite materials and obtain high-performance photodetectors with high flexibility and stability. Our work would inspire and promote flexible and bendable optoelectronic devices and foster their development and advancement.”
Optimizing the efficiency of perovskite photovoltaics
Mingrui Tan et al, Carbonized polymer dots improved stability and flexibility of quasi-2D perovskite photodetector, Light: science and applications (2022). DOI: 10.1038/s41377-022-01000-6
Provided by Chinese Academy of Sciences
Quote: Carbonized polymer dots improve stability and flexibility of quasi-2D perovskite photodetector (2022, Oct 25) Retrieved Oct 25, 2022 from https://phys.org/news/2022-10-carbonized-polymer-dots -stability-flexibility.html
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